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Volume 47,Issue 11,2020 Table of Contents
2020, 47(11):1-9.
DOI: 10.12177/emca.2020.144
Abstract:
Most traditional position sensorless control algorithms for dual three-phase permanent magnet synchronous motors (PMSMs) rely on extracting the back electromotive force (EMF) to estimate rotational speed and rotor position. These algorithms will fail under low-and zero-speed operating conditions. In order to solve this problem, a sensorless algorithm for a dual three-phase PMSM based on fundamental pulse width modulation (PWM) excitation is proposed. The rotor position, even under low-and zero-speed conditions, can be accurately tracked. This method uses the mathematical model of the dual three-phase PMSM and its saturation saliency effect to extract rotor position information contained in the current variation rate during one PWM period, so as to achieve position sensorless control. The correctness of the algorithm is verified in simulation. Finally, the reliability of the algorithm under various operating conditions is verified on a dual three-phase PMSM experimental platform.
Most traditional position sensorless control algorithms for dual three-phase permanent magnet synchronous motors (PMSMs) rely on extracting the back electromotive force (EMF) to estimate rotational speed and rotor position. These algorithms will fail under low-and zero-speed operating conditions. In order to solve this problem, a sensorless algorithm for a dual three-phase PMSM based on fundamental pulse width modulation (PWM) excitation is proposed. The rotor position, even under low-and zero-speed conditions, can be accurately tracked. This method uses the mathematical model of the dual three-phase PMSM and its saturation saliency effect to extract rotor position information contained in the current variation rate during one PWM period, so as to achieve position sensorless control. The correctness of the algorithm is verified in simulation. Finally, the reliability of the algorithm under various operating conditions is verified on a dual three-phase PMSM experimental platform.
2020, 47(11):10-17，24.
DOI: 10.12177/emca.2020.121
Abstract:
There are problems of low precision, poor stability and algorithm complexity in the sensorless control of permanent magnet linear synchronous motor (PMLSM) at standstill and low speed. In order to solve these problems, an improved sensorless control method based on pulsating high frequency injection is proposed. Based on the preliminary position estimation using saturation saliency of PMLSM, the method of special position correction and magnetic pole judgment is proposed. In this way, more accurate mover position is obtained and the sensorless operation of PMLSM at standstill and low speed is realized. On this basis, the model of PMLSM sensorless control is established by Simulink, and a prototype experimental platform is built for experimental verification. The simulation and experimental results show that the proposed method can accurately and quickly detect the initial position of PMLSM mover and the mover position at low speed, ensure the smooth starting and running of the motor, and have good position estimation accuracy and dynamic performance.
There are problems of low precision, poor stability and algorithm complexity in the sensorless control of permanent magnet linear synchronous motor (PMLSM) at standstill and low speed. In order to solve these problems, an improved sensorless control method based on pulsating high frequency injection is proposed. Based on the preliminary position estimation using saturation saliency of PMLSM, the method of special position correction and magnetic pole judgment is proposed. In this way, more accurate mover position is obtained and the sensorless operation of PMLSM at standstill and low speed is realized. On this basis, the model of PMLSM sensorless control is established by Simulink, and a prototype experimental platform is built for experimental verification. The simulation and experimental results show that the proposed method can accurately and quickly detect the initial position of PMLSM mover and the mover position at low speed, ensure the smooth starting and running of the motor, and have good position estimation accuracy and dynamic performance.
2020, 47(11):18-24.
DOI: 10.12177/emca.2020.133
Abstract:
During the operation of the maglev linear synchronous motor, due to the different height of suspension and the resistance change caused by the armature loop current, the system has the problem of parameter perturbation. A method for H∞ control of parameter uncertainty system of the linear synchronous motor is proposed. First, the structure and operation mechanism of the linear synchronous motor are analyzed, and the mathematical model of the parameter uncertainty feed control system is established. Second, the uncertainty of the control system and the interference suppression of the parameters are reduced to the standard H∞ state feedback design. By acquiring the positive definite solution of Riccati inequality, the H ∞ robust controller of the feed subsystem of the parameter uncertainty control system is obtained. Finally, MATLAB/Simulink simulation results show that the system has better performance than PI control when there are parameter uncertainties and external disturbances, and the requirements for the control system of maglev linear synchronous motor for CNC machine tool can be met.
During the operation of the maglev linear synchronous motor, due to the different height of suspension and the resistance change caused by the armature loop current, the system has the problem of parameter perturbation. A method for H∞ control of parameter uncertainty system of the linear synchronous motor is proposed. First, the structure and operation mechanism of the linear synchronous motor are analyzed, and the mathematical model of the parameter uncertainty feed control system is established. Second, the uncertainty of the control system and the interference suppression of the parameters are reduced to the standard H∞ state feedback design. By acquiring the positive definite solution of Riccati inequality, the H ∞ robust controller of the feed subsystem of the parameter uncertainty control system is obtained. Finally, MATLAB/Simulink simulation results show that the system has better performance than PI control when there are parameter uncertainties and external disturbances, and the requirements for the control system of maglev linear synchronous motor for CNC machine tool can be met.
2020, 47(11):25-33.
DOI: 10.12177/emca.2020.130
Abstract:
Permanent magnet synchronous motor (PMSM) direct torque control (DTC) system using fuzzy control to adjust duty ratio of voltage vector is proposed. The applying voltage vector is determined by switching table and the duty ratio of voltage vector is adjusted by fuzzy controller. Simulation results show that, compared with conventional DTC, the proposed fuzzy control system can suppress stator flux and torque ripples. But in the condition of large torque, there will be the torque ripple resulting from the failure of switching table. Aiming at this problem, an improved vector selection control strategy eliminating the switching table is put forward. This control strategy can suppress torque ripple, but its dynamic response is poor. Therefore, an adaptive control strategy is proposed, which uses switching table at the dynamic state and the improved vector selection control at the steady state. Simulation results show that the adaptive control strategy can improve the dynamic response and maintain the steady state performance of the system.
Permanent magnet synchronous motor (PMSM) direct torque control (DTC) system using fuzzy control to adjust duty ratio of voltage vector is proposed. The applying voltage vector is determined by switching table and the duty ratio of voltage vector is adjusted by fuzzy controller. Simulation results show that, compared with conventional DTC, the proposed fuzzy control system can suppress stator flux and torque ripples. But in the condition of large torque, there will be the torque ripple resulting from the failure of switching table. Aiming at this problem, an improved vector selection control strategy eliminating the switching table is put forward. This control strategy can suppress torque ripple, but its dynamic response is poor. Therefore, an adaptive control strategy is proposed, which uses switching table at the dynamic state and the improved vector selection control at the steady state. Simulation results show that the adaptive control strategy can improve the dynamic response and maintain the steady state performance of the system.
2020, 47(11):34-39.
DOI: 10.12177/emca.2020.134
Abstract:
The method based on saddle-shaped magnetic field waveform to calculate the position of linear motor can provide a new choice for cost-effective position calculation. It includes two parts: offline database establishment and real-time calculation. In real-time calculation, interval matching is the key. The relationship between the double-saddle magnetic field values is analyzed, and the real-time algorithm of matching and determining interpolation interval by point distance is put forward, in which the interpolation interval is determined by combining point distance and change trend of special points. In addition, the influence of data fluctuation and the total amount of database information on the calculation is also studied. Compared with the results of the samples, the calculation method using point distance has clear physical meaning, and the calculation accuracy can be regulated and optimized through adjusting the height parameters of data collection and the total amount of database data, so it has a good research value and application prospect.
The method based on saddle-shaped magnetic field waveform to calculate the position of linear motor can provide a new choice for cost-effective position calculation. It includes two parts: offline database establishment and real-time calculation. In real-time calculation, interval matching is the key. The relationship between the double-saddle magnetic field values is analyzed, and the real-time algorithm of matching and determining interpolation interval by point distance is put forward, in which the interpolation interval is determined by combining point distance and change trend of special points. In addition, the influence of data fluctuation and the total amount of database information on the calculation is also studied. Compared with the results of the samples, the calculation method using point distance has clear physical meaning, and the calculation accuracy can be regulated and optimized through adjusting the height parameters of data collection and the total amount of database data, so it has a good research value and application prospect.
2020, 47(11):40-46.
DOI: 10.12177/emca.2020.145
Abstract:
In order to improve the current decoupling effect of permanent magnet synchronous motor (PMSM), an active disturbance rejection control (ADRC) method with current decoupling based on PI observer (PIO) is proposed. In this method, PIO and extended state observer are combined to estimate the disturbance accurately in real time, and the observed disturbance is fed back to the input as compensation value, so as to realize the current decoupling between d and q axes and suppress the disturbance. The disturbance tracking performance of the improved ADRC and the disturbance rejection performance and stability of the closed-loop control system are analyzed theoretically. The results of simulation and experiment show that the disturbance estimation ability of ADRC is enhanced and the decoupling effect of current loop is improved after introducing PIO, which verifies the feasibility and effectiveness of the proposed method.
In order to improve the current decoupling effect of permanent magnet synchronous motor (PMSM), an active disturbance rejection control (ADRC) method with current decoupling based on PI observer (PIO) is proposed. In this method, PIO and extended state observer are combined to estimate the disturbance accurately in real time, and the observed disturbance is fed back to the input as compensation value, so as to realize the current decoupling between d and q axes and suppress the disturbance. The disturbance tracking performance of the improved ADRC and the disturbance rejection performance and stability of the closed-loop control system are analyzed theoretically. The results of simulation and experiment show that the disturbance estimation ability of ADRC is enhanced and the decoupling effect of current loop is improved after introducing PIO, which verifies the feasibility and effectiveness of the proposed method.
2020, 47(11):47-50.
DOI: 10.12177/emca.2020.149
Abstract:
Ultra-high-speed permanent magnet synchronous motor (PMSM) has the characteristics of high speed and low radial force wave orders, but its stator is easy to resonate and cause loud noise. Taking an ultra-high-speed PMSM as an example, the electromagnetic field model of the motor and the 3D modal model of the stator structure are established based on the actual size of the motor. The radial electromagnetic force of the motor is simulated by finite element method, and the main harmonic frequencies of the electromagnetic force causing the vibration of the motor are analyzed, through which the main source of electromagnetic noise is confirmed. Finally, the electromagnetic noise characteristics of ultra-high-speed PMSM are studied by using the sound pressure level cloud image of ANSYS.
Ultra-high-speed permanent magnet synchronous motor (PMSM) has the characteristics of high speed and low radial force wave orders, but its stator is easy to resonate and cause loud noise. Taking an ultra-high-speed PMSM as an example, the electromagnetic field model of the motor and the 3D modal model of the stator structure are established based on the actual size of the motor. The radial electromagnetic force of the motor is simulated by finite element method, and the main harmonic frequencies of the electromagnetic force causing the vibration of the motor are analyzed, through which the main source of electromagnetic noise is confirmed. Finally, the electromagnetic noise characteristics of ultra-high-speed PMSM are studied by using the sound pressure level cloud image of ANSYS.
2020, 47(11):56-61.
DOI: 10.12177/emca.2020.135
Abstract:
In order to reduce the temperature rise of the traction motor windings and improve the flow efficiency of the external flow field of the motor，a permanent magnet synchronous traction motor for locomotives is taken as the research example. According to the actual size of the motor, models of the motor’s external air flow field, stator core and windings are established. Based on the principle of computational fluid dynamics (CFD), the flow field of the external air path of the motor is numerically simulated, the flow of the external air path of the motor is calculated for different stator vents, and the coupled turbulent flow and temperature fields of the stator core and windings are calculated and analyzed. Through calculation and analysis, the best design scheme of stator vents is obtained, which provides reference for the design of stator vents of this type of motor.
In order to reduce the temperature rise of the traction motor windings and improve the flow efficiency of the external flow field of the motor，a permanent magnet synchronous traction motor for locomotives is taken as the research example. According to the actual size of the motor, models of the motor’s external air flow field, stator core and windings are established. Based on the principle of computational fluid dynamics (CFD), the flow field of the external air path of the motor is numerically simulated, the flow of the external air path of the motor is calculated for different stator vents, and the coupled turbulent flow and temperature fields of the stator core and windings are calculated and analyzed. Through calculation and analysis, the best design scheme of stator vents is obtained, which provides reference for the design of stator vents of this type of motor.
2020, 47(11):56-61.
DOI: 10.12177/emca.2020.141
Abstract:
In order to obtain a motor with high efficiency, good starting performance and stable operation, an improved multiobjective particle swarm algorithm is introduced to optimize a threephase fourpole asynchronous starting permanent magnet synchronous motor （PMSM）. Based on the structural characteristics of the PMSM, a mathematical model is established. The length of the core, the number of conductors per slot of the stator, the size of the stator slot and the size of the permanent magnet are selected as optimization variables, and the efficiency, power factor, starting current multiple, starting torque multiple and the outofstep torque multiple are the optimization targets. An electromagnetic calculation program is written with MATLAB.By combining the improved multiobjective particle swarm algorithm with electromagnetic calculation program, the efficiency, power factor and starting performance of the motor are optimized. Through the analysis of the optimization results, it is shown that the optimization has achieved the expected results under the premise of meeting the requirements of other performances. The effectiveness of the algorithm is verified.
In order to obtain a motor with high efficiency, good starting performance and stable operation, an improved multiobjective particle swarm algorithm is introduced to optimize a threephase fourpole asynchronous starting permanent magnet synchronous motor （PMSM）. Based on the structural characteristics of the PMSM, a mathematical model is established. The length of the core, the number of conductors per slot of the stator, the size of the stator slot and the size of the permanent magnet are selected as optimization variables, and the efficiency, power factor, starting current multiple, starting torque multiple and the outofstep torque multiple are the optimization targets. An electromagnetic calculation program is written with MATLAB.By combining the improved multiobjective particle swarm algorithm with electromagnetic calculation program, the efficiency, power factor and starting performance of the motor are optimized. Through the analysis of the optimization results, it is shown that the optimization has achieved the expected results under the premise of meeting the requirements of other performances. The effectiveness of the algorithm is verified.
2020, 47(11):62-67.
DOI: 10.12177/emca.2020.138
Abstract:
Interference fit is mostly used between the stator and housing of vehicle driving motor, and the appropriate interference amount needs to meet various requirements. Through theoretical calculation and finite element method (FEM), considering the high and low temperature conditions in practical application, the connection strength and transmission torque under the design interference are checked. Then, through the simulation analysis, the deformation of housing rabbet is obtained. In combination with the measured data, the reliability of the FEM is further verified. The finite element checking method for interference can guide the design of the interference fit of stator assembly and the tolerance of housing rabbet of driving motors.
Interference fit is mostly used between the stator and housing of vehicle driving motor, and the appropriate interference amount needs to meet various requirements. Through theoretical calculation and finite element method (FEM), considering the high and low temperature conditions in practical application, the connection strength and transmission torque under the design interference are checked. Then, through the simulation analysis, the deformation of housing rabbet is obtained. In combination with the measured data, the reliability of the FEM is further verified. The finite element checking method for interference can guide the design of the interference fit of stator assembly and the tolerance of housing rabbet of driving motors.
2020, 47(11):68-74，116.
DOI: 10.12177/emca.2020.143
Abstract:
A single-tube parallel motor controller for low cost battery electric vehicle is developed. The overall design scheme of single-tube parallel motor controller is described, and the hardware and software design schemes of the controller are introduced. A design scheme of the motor controller based on the single-tube IGBT parallel connection is proposed. The thermal simulation analysis of the vertical water-cooled radiator is carried out, and the heat dissipation effect of the single-tube parallel motor controller is studied. Finally, the bench test of the single-tube parallel motor controller prototype is carried out. The test results show that the designed controller has a good control performance.
A single-tube parallel motor controller for low cost battery electric vehicle is developed. The overall design scheme of single-tube parallel motor controller is described, and the hardware and software design schemes of the controller are introduced. A design scheme of the motor controller based on the single-tube IGBT parallel connection is proposed. The thermal simulation analysis of the vertical water-cooled radiator is carried out, and the heat dissipation effect of the single-tube parallel motor controller is studied. Finally, the bench test of the single-tube parallel motor controller prototype is carried out. The test results show that the designed controller has a good control performance.
2020, 47(11):75-81.
DOI: 10.12177/emca.2020.136
Abstract:
In-wheel motors are widely used in light electric vehicles due to its simple structure and flexible driving. The cogging effect, nonlinear problem of the inverter and harmonic current cause the ripple of electromagnetic torque, which affects the ride comfort of vehicles. It is found that electromagnetic torque harmonics are mainly low-order harmonics. In order to effectively minimize the torque ripple，an in-wheel motor structure with three-phase independent stator windings is designed，and a compensation current injection method based on current amplitude iteration tuning is proposed. By use of dynamic step dichotomy, the fast convergence of expected compensation current amplitude is realized. The research results show that the proposed method reduces the total harmonic distortion by 2.80%~ 5.84%, and has better harmonic torque suppression effects.
In-wheel motors are widely used in light electric vehicles due to its simple structure and flexible driving. The cogging effect, nonlinear problem of the inverter and harmonic current cause the ripple of electromagnetic torque, which affects the ride comfort of vehicles. It is found that electromagnetic torque harmonics are mainly low-order harmonics. In order to effectively minimize the torque ripple，an in-wheel motor structure with three-phase independent stator windings is designed，and a compensation current injection method based on current amplitude iteration tuning is proposed. By use of dynamic step dichotomy, the fast convergence of expected compensation current amplitude is realized. The research results show that the proposed method reduces the total harmonic distortion by 2.80%~ 5.84%, and has better harmonic torque suppression effects.
2020, 47(11):82-90，103.
DOI: 10.12177/emca.2020.124
Abstract:
Based on the virtual synchronous generator (VSG) technology, the off/on grid smooth switching control strategy of microgrid inverter is studied. Firstly, the mathematical model of VSG is established, and the control parts of VSG including power frequency regulator, excitation regulator and electromagnetic equation are designed. Secondly, the traditional off/on grid switching principle is analyzed. Due to the existence of phase-locked loop (PLL), the pre-synchronization speed and accuracy are greatly affected. Aiming at this problem, an improved pre-synchronization control method is proposed, which can replace the PLL section with only two PI regulators. Thus the number of control parameters is reduced, the switching instantaneous impulse current is small, and the active and reactive power impact is suppressed, resulting in the off/on grid smooth switching of microgrid inverter. Finally, the simulation results of MATLAB/Simulink verify the correctness and superiority of the proposed control strategy.
Based on the virtual synchronous generator (VSG) technology, the off/on grid smooth switching control strategy of microgrid inverter is studied. Firstly, the mathematical model of VSG is established, and the control parts of VSG including power frequency regulator, excitation regulator and electromagnetic equation are designed. Secondly, the traditional off/on grid switching principle is analyzed. Due to the existence of phase-locked loop (PLL), the pre-synchronization speed and accuracy are greatly affected. Aiming at this problem, an improved pre-synchronization control method is proposed, which can replace the PLL section with only two PI regulators. Thus the number of control parameters is reduced, the switching instantaneous impulse current is small, and the active and reactive power impact is suppressed, resulting in the off/on grid smooth switching of microgrid inverter. Finally, the simulation results of MATLAB/Simulink verify the correctness and superiority of the proposed control strategy.
2020, 47(11):91-97.
DOI: 10.12177/emca.2020.142
Abstract:
A connection topology and the corresponding current control strategy of photovoltaic (PV) generation for the traction power supply of electric railway are proposed. In this topology, a V/V transformer is used to convert two-phase traction voltage to three-phase voltage, which has the same amplitude and phase angle as the grid voltage. This can provide three-phase balanced voltage for the connection of PV generation. Then, an individual phase current (IPC) control strategy is designed in the three-phase stationary reference frame. In the proposed strategy, the phase current values are used as the controlled variables instead of the positive and negative sequence current components. Without any sequence extraction, it can flexibly inject both symmetrical and asymmetrical current by closed loop control of the phase current. In this way, the PV generation system can operate in two modes: one is the self-generation and self-consumption operation for supplying the locomotive, and the other is the grid-connection operation for feeding back to the grid. Finally, simulation results validate the effectiveness of the connection topology and the IPC control.
A connection topology and the corresponding current control strategy of photovoltaic (PV) generation for the traction power supply of electric railway are proposed. In this topology, a V/V transformer is used to convert two-phase traction voltage to three-phase voltage, which has the same amplitude and phase angle as the grid voltage. This can provide three-phase balanced voltage for the connection of PV generation. Then, an individual phase current (IPC) control strategy is designed in the three-phase stationary reference frame. In the proposed strategy, the phase current values are used as the controlled variables instead of the positive and negative sequence current components. Without any sequence extraction, it can flexibly inject both symmetrical and asymmetrical current by closed loop control of the phase current. In this way, the PV generation system can operate in two modes: one is the self-generation and self-consumption operation for supplying the locomotive, and the other is the grid-connection operation for feeding back to the grid. Finally, simulation results validate the effectiveness of the connection topology and the IPC control.
2020, 47(11):98-103.
DOI: 10.12177/emca.2020.128
Abstract:
Virtual space vector pulse width modulation (VSVPWM) of three-level inverter is widely used. But due to the three-level inverter control, narrow pulses are generated in certain region, which results in unnecessary switching loss and heat accumulation. The narrow pulse distribution of VSVPWM is analyzed, and the narrow pulses are suppressed by the injection of the differential mode voltage and the common mode voltage with the neutral-point voltage controlled within a small range. Simulation and experiment prove that the proposed method can suppress most of the narrow pulses without causing distortion of the output waveform and increase of harmonics.
Virtual space vector pulse width modulation (VSVPWM) of three-level inverter is widely used. But due to the three-level inverter control, narrow pulses are generated in certain region, which results in unnecessary switching loss and heat accumulation. The narrow pulse distribution of VSVPWM is analyzed, and the narrow pulses are suppressed by the injection of the differential mode voltage and the common mode voltage with the neutral-point voltage controlled within a small range. Simulation and experiment prove that the proposed method can suppress most of the narrow pulses without causing distortion of the output waveform and increase of harmonics.
2020, 47(11):104-108，116.
DOI: 10.12177/emca.2020.140
Abstract:
In order to solve the problems of digital control and wide-range input of communication secondary power supply, and realize high power density DC-DC conversion, an implementation scheme of two-stage conversion topology with ADP1046A as the core controller is proposed. The voltage regulation and isolation are implemented in different stages, that is, to achieve the adjustment of the input to the target voltage through the Buck circuit, and the isolation between the input and output through the full bridge circuit. This solution uses the standard I2C interface of ADP1046A to realize the communication between the power control and the host computer. The twostage conversion can not only solve the problem of large transformer size and difficulty in optimization in singlestage conversion, but also greatly reduce the size of the output filter. Using the built experimental prototype to verify the related functions and performance, the experimental results show that the proposed DCDC converter scheme meets the needs of the corresponding products and has practical guiding significance for engineering design.
In order to solve the problems of digital control and wide-range input of communication secondary power supply, and realize high power density DC-DC conversion, an implementation scheme of two-stage conversion topology with ADP1046A as the core controller is proposed. The voltage regulation and isolation are implemented in different stages, that is, to achieve the adjustment of the input to the target voltage through the Buck circuit, and the isolation between the input and output through the full bridge circuit. This solution uses the standard I2C interface of ADP1046A to realize the communication between the power control and the host computer. The twostage conversion can not only solve the problem of large transformer size and difficulty in optimization in singlestage conversion, but also greatly reduce the size of the output filter. Using the built experimental prototype to verify the related functions and performance, the experimental results show that the proposed DCDC converter scheme meets the needs of the corresponding products and has practical guiding significance for engineering design.
2020, 47(11):109-116.
DOI: 10.12177/emca.2020.125
Abstract:
The process of energy transfer between electric vehicle and power grid end is widely studied. Based on CLLC bi-directional DC-DC converter used in electric vehicle, a super capacitor staggered parallel current-doubling energy storage and discharge circuit is added to the electric vehicle end. A novel efficient bi-directional DC-DC converter is proposed. The forward and reverse operation processes of the novel DC-DC converter are analyzed, and the gain characteristics are studied. The conditions for realizing zero voltage switching (ZVS) of switch tube are put forward, and the electrical stress of switch tube is analyzed. An 800 W experimental prototype is made. Test results of the prototype prove that ZVS can be realized in the novel bi-directional DC-DC converter. The peak current of the switch tube is small, and the efficiency of the DC-DC converter is improved.
The process of energy transfer between electric vehicle and power grid end is widely studied. Based on CLLC bi-directional DC-DC converter used in electric vehicle, a super capacitor staggered parallel current-doubling energy storage and discharge circuit is added to the electric vehicle end. A novel efficient bi-directional DC-DC converter is proposed. The forward and reverse operation processes of the novel DC-DC converter are analyzed, and the gain characteristics are studied. The conditions for realizing zero voltage switching (ZVS) of switch tube are put forward, and the electrical stress of switch tube is analyzed. An 800 W experimental prototype is made. Test results of the prototype prove that ZVS can be realized in the novel bi-directional DC-DC converter. The peak current of the switch tube is small, and the efficiency of the DC-DC converter is improved.
2020, 47(11):117-121.
DOI: 10.12177/emca.2020.123
Abstract:
In order to solve the problem that the signal in the online detection of high-voltage motor partial discharge (PD) is submerged by Gaussian white noise and narrow-band periodic interference, an algorithm based on improved variational mode decomposition (VMD) is used to filter out the noise. The common VMD algorithm may cause signal under-decomposition or over-decomposition. In order to overcome this shortcoming, the energy loss coefficient is used as the criterion to optimize the decomposition mode number. After the optimal decomposition, the kurtosis value is used to eliminate invalid modes and reconstruct the PD signal. The improved algorithm is compared with the existing methods in simulation. The results show that the improved VMD algorithm can filter out PD signal noise more effectively.
In order to solve the problem that the signal in the online detection of high-voltage motor partial discharge (PD) is submerged by Gaussian white noise and narrow-band periodic interference, an algorithm based on improved variational mode decomposition (VMD) is used to filter out the noise. The common VMD algorithm may cause signal under-decomposition or over-decomposition. In order to overcome this shortcoming, the energy loss coefficient is used as the criterion to optimize the decomposition mode number. After the optimal decomposition, the kurtosis value is used to eliminate invalid modes and reconstruct the PD signal. The improved algorithm is compared with the existing methods in simulation. The results show that the improved VMD algorithm can filter out PD signal noise more effectively.
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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.
