Mobile website
Volume 48,Issue 11,2021 Table of Contents
2021, 48(11):1-5.
DOI: 10.12177/emca.2021.106
Abstract:
The chattering caused by using symbolic functions exists in the traditional sliding mode observer. In order to solve the problem, a synergetic observer method based on continuous function is proposed to realize the sensorless control of permanent magnet synchronous motor (PMSM). The discrete mathematical model of the PMSM is studied. The functional relationship between the current deviation at time k+1 and that at time k is established. The arctangent function calculates the rotor position and adds angle compensation to improve the observation accuracy. The simulation results show that the designed synergetic observer has no chattering and has higher estimation accuracy and good anti-interference performance. It can better realize the sensorless control of the PMSM than the traditional sliding mode observer.
The chattering caused by using symbolic functions exists in the traditional sliding mode observer. In order to solve the problem, a synergetic observer method based on continuous function is proposed to realize the sensorless control of permanent magnet synchronous motor (PMSM). The discrete mathematical model of the PMSM is studied. The functional relationship between the current deviation at time k+1 and that at time k is established. The arctangent function calculates the rotor position and adds angle compensation to improve the observation accuracy. The simulation results show that the designed synergetic observer has no chattering and has higher estimation accuracy and good anti-interference performance. It can better realize the sensorless control of the PMSM than the traditional sliding mode observer.
2021, 48(11):6-13.
DOI: 10.12177/emca.2021.115
Abstract:
In order to avoid the design and tuning of the weighting factors in conventional cost function, the ranking approach is used to implement the model predictive torque control (MPTC) for surface permanent magnet synchronous motor (SPMSM). The control variables with different dimension are converted to dimensionless ranking scores, therefore, the weighting factors are eliminated. The priority rules are given to solve the problem that the optimal voltage vector is not unique for ranking approach, and the effects of different priorities on control performances are analyzed. Simulation results verify the effectiveness of the ranking approach in the SPMSM MPTC system.
In order to avoid the design and tuning of the weighting factors in conventional cost function, the ranking approach is used to implement the model predictive torque control (MPTC) for surface permanent magnet synchronous motor (SPMSM). The control variables with different dimension are converted to dimensionless ranking scores, therefore, the weighting factors are eliminated. The priority rules are given to solve the problem that the optimal voltage vector is not unique for ranking approach, and the effects of different priorities on control performances are analyzed. Simulation results verify the effectiveness of the ranking approach in the SPMSM MPTC system.
2021, 48(11):14-20，26.
DOI: 10.12177/emca.2021.119
Abstract:
Switched reluctance motor (SRM) has strong nonlinearity, so it is difficult to establish its accurate mathematical model. In the whole speed range of the traditional PID control, the optimal combination of KP, KI and KD is hardly to obtain. The traditional PID regulator with fixed parameters is not suitable for the accuracy and anti-interference of system speed regulation. In order to solve these problems, the control characteristics of three parameters of traditional PID regulator are analyzed. The appropriate and general fuzzy control rules under several states are established, such as starting, speed regulation, load disturbance, etc. Combined with PID control, a fuzzy PID speed regulator of SRM is formed, which realizes the adaptive adjustment of three control parameters KP, KI and KD. So, the better speed regulation characteristics under different loads in the whole speed regulation range are obtained. The simulation results show that the proposed method avoids the speed overshoot and vibration which is caused by the proportional and integral part of the fixed parameter speed regulator under low speed and light load conditions. Meanwhile, it overcomes the speed regulation error caused by simple fuzzy control.
Switched reluctance motor (SRM) has strong nonlinearity, so it is difficult to establish its accurate mathematical model. In the whole speed range of the traditional PID control, the optimal combination of KP, KI and KD is hardly to obtain. The traditional PID regulator with fixed parameters is not suitable for the accuracy and anti-interference of system speed regulation. In order to solve these problems, the control characteristics of three parameters of traditional PID regulator are analyzed. The appropriate and general fuzzy control rules under several states are established, such as starting, speed regulation, load disturbance, etc. Combined with PID control, a fuzzy PID speed regulator of SRM is formed, which realizes the adaptive adjustment of three control parameters KP, KI and KD. So, the better speed regulation characteristics under different loads in the whole speed regulation range are obtained. The simulation results show that the proposed method avoids the speed overshoot and vibration which is caused by the proportional and integral part of the fixed parameter speed regulator under low speed and light load conditions. Meanwhile, it overcomes the speed regulation error caused by simple fuzzy control.
2021, 48(11):21-26.
DOI: 10.12177/emca.2021.124
Abstract:
Aiming at the problems that the sliding mode control permanent magnet linear synchronous motor (PMLSM) cannot achieve finite time control and the global sliding mode control (GSMC) cannot achieve rapid convergence, an improved GSMC algorithm is used to design the linear servo speed controller. The algorithm uses a dynamic sliding mode surface combined with a nonlinear term and a linear term and a constant velocity approaching law. The nonlinear sliding mode surface decay function is composed of three exponential function terms to form a first-order derivable function, and it can decay to zero in a finite time. The simulation results show that the improved GSMC not only makes the system globally robust, but also accelerates the response speed and improve anti-interference ability while ensuring high tracking accuracy.
Aiming at the problems that the sliding mode control permanent magnet linear synchronous motor (PMLSM) cannot achieve finite time control and the global sliding mode control (GSMC) cannot achieve rapid convergence, an improved GSMC algorithm is used to design the linear servo speed controller. The algorithm uses a dynamic sliding mode surface combined with a nonlinear term and a linear term and a constant velocity approaching law. The nonlinear sliding mode surface decay function is composed of three exponential function terms to form a first-order derivable function, and it can decay to zero in a finite time. The simulation results show that the improved GSMC not only makes the system globally robust, but also accelerates the response speed and improve anti-interference ability while ensuring high tracking accuracy.
2021, 48(11):27-32.
DOI: 10.12177/emca.2021.097
Abstract:
Aiming at the common working conditions that have accurate requirements for the running time and distance of the stepping motor in production, a set of S-curve control algorithm for the stepping motor is designed, which can flexibly set the motion process according to different operation requirements, and use fewer parameters to plan the whole motion path, so as to achieve the ideal motion effect. A new cosine S-curve is designed, and the MATLAB/Simulink simulation control model and hardware test system are built for simulation and practical verification. The results show that the actual acceleration and deceleration process of the motor runs smoothly and starts stably, and the vibration is small. It can run accurately under the set parameters. Compared with the direct start and stop, the operation effect is greatly improved. It has been applied in an automatic numbering machine project.
Aiming at the common working conditions that have accurate requirements for the running time and distance of the stepping motor in production, a set of S-curve control algorithm for the stepping motor is designed, which can flexibly set the motion process according to different operation requirements, and use fewer parameters to plan the whole motion path, so as to achieve the ideal motion effect. A new cosine S-curve is designed, and the MATLAB/Simulink simulation control model and hardware test system are built for simulation and practical verification. The results show that the actual acceleration and deceleration process of the motor runs smoothly and starts stably, and the vibration is small. It can run accurately under the set parameters. Compared with the direct start and stop, the operation effect is greatly improved. It has been applied in an automatic numbering machine project.
2021, 48(11):33-38.
DOI: 10.12177/emca.2021.101
Abstract:
In order to improve the electric machinery collaborative design function of the motor Industry Internet Cloud Platform of SEARI, a two-dimensional electromagnetic field simulation software based on finite element method is developed to realize the simulation calculation of motor electromagnetic field. In the mesh generation part of the software preprocessing, triangular meshing is adopted. Through the summary and research of existing mesh algorithms, a two-dimensional mesh design method suitable for motor electromagnetic field simulation is proposed. It has the characteristics of strong meshing adaptability and fast calculation speed. The meshing method of the motor electromagnetic field calculation introduced has been applied to the software development of “EMFTest V1.0”, which verifies its feasibility.
In order to improve the electric machinery collaborative design function of the motor Industry Internet Cloud Platform of SEARI, a two-dimensional electromagnetic field simulation software based on finite element method is developed to realize the simulation calculation of motor electromagnetic field. In the mesh generation part of the software preprocessing, triangular meshing is adopted. Through the summary and research of existing mesh algorithms, a two-dimensional mesh design method suitable for motor electromagnetic field simulation is proposed. It has the characteristics of strong meshing adaptability and fast calculation speed. The meshing method of the motor electromagnetic field calculation introduced has been applied to the software development of “EMFTest V1.0”, which verifies its feasibility.
2021, 48(11):39-44.
DOI: 10.12177/emca.2021.109
Abstract:
Switched reluctance motors (SRMs) are used in many fields, but due to the structure, they have greater vibration and noise than other traditional motors. Therefore, suppressing the vibration of SRM is still a hot area of research. In order to suppress the vibration of the motor, a new type of motor structure is designed, for which holes are punched on both sides of the rotor and the stator tooth top is slotted. Taking a 7.5 kW, 1 500 r/min, 12/8 poles SRM as an example, through the finite element analysis and simulation, the new motor structure is parameterized and the optimal structure is obtained. Under the condition that the average torque remains basically unchanged, the torque ripple and radial force are reduced. The torque ripple coefficient is reduced by 16.01% and the peak radial force is reduced by 19.96% compared with the original motor. Therefore, it is proved that this method has a good effect on the vibration suppression of the SRM. It has a certain referential significance to the design and control of the SRM.
Switched reluctance motors (SRMs) are used in many fields, but due to the structure, they have greater vibration and noise than other traditional motors. Therefore, suppressing the vibration of SRM is still a hot area of research. In order to suppress the vibration of the motor, a new type of motor structure is designed, for which holes are punched on both sides of the rotor and the stator tooth top is slotted. Taking a 7.5 kW, 1 500 r/min, 12/8 poles SRM as an example, through the finite element analysis and simulation, the new motor structure is parameterized and the optimal structure is obtained. Under the condition that the average torque remains basically unchanged, the torque ripple and radial force are reduced. The torque ripple coefficient is reduced by 16.01% and the peak radial force is reduced by 19.96% compared with the original motor. Therefore, it is proved that this method has a good effect on the vibration suppression of the SRM. It has a certain referential significance to the design and control of the SRM.
2021, 48(11):45-50.
DOI: 10.12177/emca.2021.104
Abstract:
High-power-density induction traction motors have the characteristics of compact structure, high magnetic flux saturation, high operating frequency and high volume loss density. The high operating frequency leads to the significant increase of skin effect and proximity effect of the stator windings. The high frequency eddy current additional loss is generated in the stator windings, causing additional copper loss to increase greatly. Based on the internal harmonic magnetic field theory of the induction motor, the source, calculation method and influencing factors of the stator windings eddy current additional loss are analyzed. A 4-pole 650 kW induction traction motor is analyzed in detail with the finite element method. The stator slot inner magnetic field distribution, the harmonics of the magnetic field in the slot, and the relationship between harmonic amplitude and depth from slot opening are analyzed, and the eddy current additional loss of conductors in the slot is calculated. The calculation results show that the eddy current additional loss of the conductors near the slot opening is the largest, and as the depth from the slot opening increases, the eddy current additional loss of conductors in the slot shows a significant reduction trend. By reasonable design of the stator slot opening depth, the eddy current additional loss of the conductors near the slot opening can be effectively reduced.
High-power-density induction traction motors have the characteristics of compact structure, high magnetic flux saturation, high operating frequency and high volume loss density. The high operating frequency leads to the significant increase of skin effect and proximity effect of the stator windings. The high frequency eddy current additional loss is generated in the stator windings, causing additional copper loss to increase greatly. Based on the internal harmonic magnetic field theory of the induction motor, the source, calculation method and influencing factors of the stator windings eddy current additional loss are analyzed. A 4-pole 650 kW induction traction motor is analyzed in detail with the finite element method. The stator slot inner magnetic field distribution, the harmonics of the magnetic field in the slot, and the relationship between harmonic amplitude and depth from slot opening are analyzed, and the eddy current additional loss of conductors in the slot is calculated. The calculation results show that the eddy current additional loss of the conductors near the slot opening is the largest, and as the depth from the slot opening increases, the eddy current additional loss of conductors in the slot shows a significant reduction trend. By reasonable design of the stator slot opening depth, the eddy current additional loss of the conductors near the slot opening can be effectively reduced.
2021, 48(11):51-57.
DOI: 10.12177/emca.2021.110
Abstract:
Because the new drive device for the crane has an outer rotor structure and is more integrated than the traditional hoisting mechanism, it is easy to cause difficulty in dissipating heat from the stator winding. It is different from the intermittent working system of traditional electrical equipment, which puts forward a new problem for the calculation of temperature rise. According to the characteristics of the equipment, the air cooling structure of hollow shaft is designed. Based on the basic principles of fluid mechanics and heat transfer, a mathematical model of fluidstructure coupling is established. Taking a 90 kW rated power drive device as an example, using the computational fluid dynamics (CFD) software and its embedded userdefined function, according to the mechanism working level and limit operation conditions required by the traditional crane design, programming and simulation are carried out. The temperature rise calculation results are compared with the experimental data under the same conditions to verify the scientificity of the calculation method, and the rationality of the cooling structure is analyzed. The final conclusion provides a reference for the followup research on the heat dissipation of crane drive devices.
Because the new drive device for the crane has an outer rotor structure and is more integrated than the traditional hoisting mechanism, it is easy to cause difficulty in dissipating heat from the stator winding. It is different from the intermittent working system of traditional electrical equipment, which puts forward a new problem for the calculation of temperature rise. According to the characteristics of the equipment, the air cooling structure of hollow shaft is designed. Based on the basic principles of fluid mechanics and heat transfer, a mathematical model of fluidstructure coupling is established. Taking a 90 kW rated power drive device as an example, using the computational fluid dynamics (CFD) software and its embedded userdefined function, according to the mechanism working level and limit operation conditions required by the traditional crane design, programming and simulation are carried out. The temperature rise calculation results are compared with the experimental data under the same conditions to verify the scientificity of the calculation method, and the rationality of the cooling structure is analyzed. The final conclusion provides a reference for the followup research on the heat dissipation of crane drive devices.
2021, 48(11):58-64,79.
DOI: 10.12177/emca.2021.108
Abstract:
In order to study the steady-state temperature field of a fully enclosed high-power permanent magnet traction motor under rated condition, a three-dimensional conjugate heat transfer model of temperature field of a permanent magnet synchronous traction motor with rated power of 815 kW is established based on the heat conduction model of the formed winding in slot. Considering the influences of rotating magnetization, stamping process and high-order harmonics of flux density on stator iron loss, and the influence of contact thermal impedance between water jacket and stator core on motor temperature rise, the Fluent software is used to solve the steady-state flow field and temperature field of the motor under rated condition. The average temperature rise of the winding and the local temperature rises at the measuring points at the stator core and the end of the winding are measured by the resistance method and the embedded temperature detector (ETD) method under the rated condition, and the absolute errors are -3.7 K, -0.3 K and 7.6 K, respectively. Furthermore, the flow field distribution characteristics of water and internal air path of the motor, the influence of the contact gap between water jacket and stator core on the average temperature rise of the winding, and the temperature rise distribution near the winding in the slot are analyzed. Finally, the design optimization direction of the motor cooling system is proposed.
In order to study the steady-state temperature field of a fully enclosed high-power permanent magnet traction motor under rated condition, a three-dimensional conjugate heat transfer model of temperature field of a permanent magnet synchronous traction motor with rated power of 815 kW is established based on the heat conduction model of the formed winding in slot. Considering the influences of rotating magnetization, stamping process and high-order harmonics of flux density on stator iron loss, and the influence of contact thermal impedance between water jacket and stator core on motor temperature rise, the Fluent software is used to solve the steady-state flow field and temperature field of the motor under rated condition. The average temperature rise of the winding and the local temperature rises at the measuring points at the stator core and the end of the winding are measured by the resistance method and the embedded temperature detector (ETD) method under the rated condition, and the absolute errors are -3.7 K, -0.3 K and 7.6 K, respectively. Furthermore, the flow field distribution characteristics of water and internal air path of the motor, the influence of the contact gap between water jacket and stator core on the average temperature rise of the winding, and the temperature rise distribution near the winding in the slot are analyzed. Finally, the design optimization direction of the motor cooling system is proposed.
2021, 48(11):65-71,113.
DOI: 10.12177/emca.2021.112
Abstract:
For the wireless charging of electric vehicles, considering the radial offset of transmitting coil and receiving coil, based on the series topology of two coil structures, the anti-offset performances of circular, rectangular and DD coils are compared by 3D electromagnetic simulation software Maxwell. The selected coil is optimized by adding magnetic core and aluminum plate. Joint simulation is realized with the help of Maxwell and Simplorer to verify the feasibility of the design of the wireless power transmission system. In the case of offset between the two coils, to achieve the transmission efficiency of the wireless power transmission system of 95% and above, a design process of magnetic coupling mechanism based on coil comparison and selection is given, and a practical wireless power transmission system is designed according to the process. Finally, its feasibility is verified through experiments
For the wireless charging of electric vehicles, considering the radial offset of transmitting coil and receiving coil, based on the series topology of two coil structures, the anti-offset performances of circular, rectangular and DD coils are compared by 3D electromagnetic simulation software Maxwell. The selected coil is optimized by adding magnetic core and aluminum plate. Joint simulation is realized with the help of Maxwell and Simplorer to verify the feasibility of the design of the wireless power transmission system. In the case of offset between the two coils, to achieve the transmission efficiency of the wireless power transmission system of 95% and above, a design process of magnetic coupling mechanism based on coil comparison and selection is given, and a practical wireless power transmission system is designed according to the process. Finally, its feasibility is verified through experiments
2021, 48(11):72-79.
DOI: 10.12177/emca.2021.116
Abstract:
The linear synchronous motor is analyzed through the winding function theory, and a fault diagnosis method of linear synchronous motor based on convolutional neural network (CNN) is proposed. Starting from the mathematical model of the linear synchronous motor, the normal state and turn-to-turn fault state of the motor are analyzed based on the winding function theory. The short-circuit fault state is simulated, and the fast Fourier transform (FFT) of the current waveform is performed to obtain data sets of different states. This method uses the GoogLeNet network structure in CNN to achieve the characteristics of not increasing the amount of calculation while maintaining the dimension of the network space. The data sets are then input into the network model for fault diagnosis. Simulation results show that the GoogLeNet network structure reaches over 96.5% recognition rate for the short-circuit fault of the armature winding of linear synchronous motor.
The linear synchronous motor is analyzed through the winding function theory, and a fault diagnosis method of linear synchronous motor based on convolutional neural network (CNN) is proposed. Starting from the mathematical model of the linear synchronous motor, the normal state and turn-to-turn fault state of the motor are analyzed based on the winding function theory. The short-circuit fault state is simulated, and the fast Fourier transform (FFT) of the current waveform is performed to obtain data sets of different states. This method uses the GoogLeNet network structure in CNN to achieve the characteristics of not increasing the amount of calculation while maintaining the dimension of the network space. The data sets are then input into the network model for fault diagnosis. Simulation results show that the GoogLeNet network structure reaches over 96.5% recognition rate for the short-circuit fault of the armature winding of linear synchronous motor.
2021, 48(11):80-85.
DOI: 10.12177/emca.2021.120
Abstract:
As a common electrical fault, single-phase grounding fault will distort the DC voltage ripple of ship medium voltage DC power system and affect the normal operation of the system. Taking the single-phase grounding fault in medium voltage DC power system as the research background, we study the influence of neutral grounding mode of rectifier generator on ripple. Firstly, using the symmetrical component method and the switching function method, the normal ripple order of DC voltage and the ripple order under fault are calculated respectively, and the analytical expression of AC component in DC voltage under fault is derived. Then, by analyzing the zero sequence circuit between windings, the correlation between the zero sequence voltage of fault winding and grounding mode is obtained, which can be used to further study the influence of grounding mode on DC ripple. Finally, the model is built by PSCAD and MATLAB/Simulink simulation software for verification. This research can provide a reference basis for the selection of grounding mode of rectifier generator in ship medium voltage DC system.
As a common electrical fault, single-phase grounding fault will distort the DC voltage ripple of ship medium voltage DC power system and affect the normal operation of the system. Taking the single-phase grounding fault in medium voltage DC power system as the research background, we study the influence of neutral grounding mode of rectifier generator on ripple. Firstly, using the symmetrical component method and the switching function method, the normal ripple order of DC voltage and the ripple order under fault are calculated respectively, and the analytical expression of AC component in DC voltage under fault is derived. Then, by analyzing the zero sequence circuit between windings, the correlation between the zero sequence voltage of fault winding and grounding mode is obtained, which can be used to further study the influence of grounding mode on DC ripple. Finally, the model is built by PSCAD and MATLAB/Simulink simulation software for verification. This research can provide a reference basis for the selection of grounding mode of rectifier generator in ship medium voltage DC system.
2021, 48(11):86-91.
DOI: 10.12177/emca.2021.111
Abstract:
Hybrid DC transmission system often has different types of faults, and the traditional control method takes too long to deal with such faults, so the optimization control method of hybrid DC transmission system based on line-commutated converter (LCC) and modular multilevel converter (MMC) is studied. The topological diagram is drawn according to the system structure characteristics, and the LCC and MMC mathematical models are established. The rectifier side DC voltage is controlled by the triangle and star connection to realize the optimal control. The inverter side MMC is optimized by the voltage-sourced converter (VSC) double-closed-loop controller. By directly charging from the system DC side, the intermediate current transfer process is reduced, and the voltage modulation wave is calculated by the MMC mathematical model to achieve balanced voltage and stable operation of the control system. Simulation results show that the proposed method can control the AC fault of the rectifier station within 5 s. For the DC line unipole fault, the proposed method can quickly respond within 5 s, and the currents of LCC and MMC can be controlled in a stable range. All three currents are effectively controlled, proving that the optimal control of the hybrid DC transmission system is realized and the transmission system faults can be handled quickly.
Hybrid DC transmission system often has different types of faults, and the traditional control method takes too long to deal with such faults, so the optimization control method of hybrid DC transmission system based on line-commutated converter (LCC) and modular multilevel converter (MMC) is studied. The topological diagram is drawn according to the system structure characteristics, and the LCC and MMC mathematical models are established. The rectifier side DC voltage is controlled by the triangle and star connection to realize the optimal control. The inverter side MMC is optimized by the voltage-sourced converter (VSC) double-closed-loop controller. By directly charging from the system DC side, the intermediate current transfer process is reduced, and the voltage modulation wave is calculated by the MMC mathematical model to achieve balanced voltage and stable operation of the control system. Simulation results show that the proposed method can control the AC fault of the rectifier station within 5 s. For the DC line unipole fault, the proposed method can quickly respond within 5 s, and the currents of LCC and MMC can be controlled in a stable range. All three currents are effectively controlled, proving that the optimal control of the hybrid DC transmission system is realized and the transmission system faults can be handled quickly.
2021, 48(11):92-97.
DOI: 10.12177/emca.2021.126
Abstract:
In the design and application of the high power converter products, the root mean square (RMS) ripple current of the support capacitor of the converter module is too large, resulting from the mismatch of stray inductance of the busbar, and the capacitor works in excess state for a long time, resulting in damage. In view of the above problems, the corresponding mathematical model according to the different busbar structures of the converter module is established, and the root cause of the large support capacitor current is analyzed. The stray inductors of different busbar structures are measured and extracted by experiments to guide the design of subsequent busbar. According to the theoretical analysis, it is proposed to reduce the ripple current of bus support capacitor by optimizing the bus bar design and improving the control algorithm. Finally, based on a converter platform, the capacitive current ripple under different experimental conditions is measured, and the experimental data are compared and analyzed to verify the effectiveness of the proposed improved measures.
In the design and application of the high power converter products, the root mean square (RMS) ripple current of the support capacitor of the converter module is too large, resulting from the mismatch of stray inductance of the busbar, and the capacitor works in excess state for a long time, resulting in damage. In view of the above problems, the corresponding mathematical model according to the different busbar structures of the converter module is established, and the root cause of the large support capacitor current is analyzed. The stray inductors of different busbar structures are measured and extracted by experiments to guide the design of subsequent busbar. According to the theoretical analysis, it is proposed to reduce the ripple current of bus support capacitor by optimizing the bus bar design and improving the control algorithm. Finally, based on a converter platform, the capacitive current ripple under different experimental conditions is measured, and the experimental data are compared and analyzed to verify the effectiveness of the proposed improved measures.
2021, 48(11):98-103.
DOI: 10.12177/emca.2021.117
Abstract:
In order to evaluate the rationality of power system operation mode and the operation status of electric power enterprises with high accuracy, the prediction model of line loss rate of low-voltage distribution network based on dual-mode frequency modulation (FM) decomposition is studied, and the high-precision prediction result of line loss rate is used to improve the operation and management performance of power network. The power transmission signals of low-voltage distribution network are collected, and the dual-mode FM basis function is used to decompose the signals and remove useless signals by dual-mode FM decomposition method. The hierarchical node identification strategy is used to divide the load nodes of the low-voltage distribution network from the decomposed distribution signals, and the injection current of each load node is obtained. Support vector machine (SVM) method is used to establish a prediction model of line loss rate in the same period. The injection current obtained is input into the model, and the optimization result of line loss rate prediction is output. Experimental results show that the prediction results of the model are in good agreement with the actual results, and the mean absolute error and root mean square error are both lower than 0.09%, which proves that the model can effectively predict the line loss rate of low-voltage distribution network in the same period with high prediction accuracy, and can provide an effective basis for the operation and management of intelligent distribution network.
In order to evaluate the rationality of power system operation mode and the operation status of electric power enterprises with high accuracy, the prediction model of line loss rate of low-voltage distribution network based on dual-mode frequency modulation (FM) decomposition is studied, and the high-precision prediction result of line loss rate is used to improve the operation and management performance of power network. The power transmission signals of low-voltage distribution network are collected, and the dual-mode FM basis function is used to decompose the signals and remove useless signals by dual-mode FM decomposition method. The hierarchical node identification strategy is used to divide the load nodes of the low-voltage distribution network from the decomposed distribution signals, and the injection current of each load node is obtained. Support vector machine (SVM) method is used to establish a prediction model of line loss rate in the same period. The injection current obtained is input into the model, and the optimization result of line loss rate prediction is output. Experimental results show that the prediction results of the model are in good agreement with the actual results, and the mean absolute error and root mean square error are both lower than 0.09%, which proves that the model can effectively predict the line loss rate of low-voltage distribution network in the same period with high prediction accuracy, and can provide an effective basis for the operation and management of intelligent distribution network.
2021, 48(11):104-113.
DOI: 10.12177/emca.2021.114
Abstract:
In order to eliminate line overload quickly and avoid chain failures, an emergency control strategy for line overload based on power flow tracing and power sensitivity is proposed. Firstly, the power flow tracing method is used to determine the control node group, and the adjustment amount of the control node group is calculated based on the adjustment rate of the generator. Then, the power sensitivity method is used to judge the power adjustment direction of the control node group. Finally, the corresponding control of the control node group is carried out by the reverse equal adjustment method. The superiority and effectiveness of the combined method of power flow tracing and power sensitivity are verified by IEEE39 and IEEE118 node systems.
In order to eliminate line overload quickly and avoid chain failures, an emergency control strategy for line overload based on power flow tracing and power sensitivity is proposed. Firstly, the power flow tracing method is used to determine the control node group, and the adjustment amount of the control node group is calculated based on the adjustment rate of the generator. Then, the power sensitivity method is used to judge the power adjustment direction of the control node group. Finally, the corresponding control of the control node group is carried out by the reverse equal adjustment method. The superiority and effectiveness of the combined method of power flow tracing and power sensitivity are verified by IEEE39 and IEEE118 node systems.
You are thevisitor
沪ICP备16038578号-3
Electric Machines & Control Application ® 2025
Supported by:Beijing E-Tiller Technology Development Co., Ltd.
沪ICP备16038578号-3
Electric Machines & Control Application ® 2025
Supported by:Beijing E-Tiller Technology Development Co., Ltd.
