Mobile website
Volume 51,Issue 2,2024 Table of Contents
1 Early Health Status Detection of Energy Storage Battery Pack Based on Voltage Range Characteristics
2024, 51(2):1-9.
DOI: 10.12177/emca.2023.186
Abstract:
In order to evaluate the state of health (SOH) of energy storage battery packs more efficiently, an early health status detection method based on voltage range characteristics is proposed. Firstly, the cyclic aging experiment is carried out based on the large-capacity lithium iron phosphate battery pack , and the voltage range signal of each cycle is measured , and the voltage characteristics of key time points are extracted from it. Secondly, health factors highly related to battery aging are screened based on Pearson correlation coefficient and grey correlation degree analysis (GRA) . Finally, the Sparrow search algorithm (SSA) is used to optimize Bi-bidirectional long short-term memory ( BiLSTM ) hyperparameters, and SSA-BiLSTM health state estimation model is built, and realize SOH evaluation of energy storage battery pack. The effectiveness of the health factor and the superiority of the estimation model are verified by the conventional machine learning algorithm. The results show that the extracted voltage range characteristics of charging and discharging for 30 min can effectively reflect the decline trend of battery pack capacity, and the estimated error of SOH is less than士0.8% under various models. The root mean square error (RMSE) of the SSA-BiLSTM model proposed in this paper is as low as 0. 07% . Therefore, this method can effectively monitor the SOH of large-capacity energy storage battery packs online.
In order to evaluate the state of health (SOH) of energy storage battery packs more efficiently, an early health status detection method based on voltage range characteristics is proposed. Firstly, the cyclic aging experiment is carried out based on the large-capacity lithium iron phosphate battery pack , and the voltage range signal of each cycle is measured , and the voltage characteristics of key time points are extracted from it. Secondly, health factors highly related to battery aging are screened based on Pearson correlation coefficient and grey correlation degree analysis (GRA) . Finally, the Sparrow search algorithm (SSA) is used to optimize Bi-bidirectional long short-term memory ( BiLSTM ) hyperparameters, and SSA-BiLSTM health state estimation model is built, and realize SOH evaluation of energy storage battery pack. The effectiveness of the health factor and the superiority of the estimation model are verified by the conventional machine learning algorithm. The results show that the extracted voltage range characteristics of charging and discharging for 30 min can effectively reflect the decline trend of battery pack capacity, and the estimated error of SOH is less than士0.8% under various models. The root mean square error (RMSE) of the SSA-BiLSTM model proposed in this paper is as low as 0. 07% . Therefore, this method can effectively monitor the SOH of large-capacity energy storage battery packs online.
2024, 51(2):10-21.
DOI: 10.12177/emca.2023.185
Abstract:
During normal operation of DC lines, the smoothing reactor can reduce current ripple. When a DC line fails, the rapid operation of the current limiting reactor can suppress the rising speed of the fault current. Therefore, considering the collaboration between current limiting reactors and smoothing reactors can not only suppress the rising speed of fault current, but also reduce the cutting capacity of DC circuit breakers. However, due to investment costs and system dynamic characteristics, the inductance capacity of smoothing reactors and current limiting reactors needs to be maintained within a reasonable range. Therefore, it is very meaningful to optimize the capacity configuration of smoothing reactors and current limiting reactors in the HVDC transmission system, while ensuring the current limiting capacity and reducing investment. Firstly, a fault equivalent model for the AC/DC hybrid power grid is established and the characteristics of the fault current at both ends when a bipolar short circuit occurs in the DC line are analyzed. Secondly, a mathematical model for optimizing the configuration of smoothing reactors and current limiting reactors is established. Finally, the proposed current limiting strategy is validated through MATLAB simulation experiments.
During normal operation of DC lines, the smoothing reactor can reduce current ripple. When a DC line fails, the rapid operation of the current limiting reactor can suppress the rising speed of the fault current. Therefore, considering the collaboration between current limiting reactors and smoothing reactors can not only suppress the rising speed of fault current, but also reduce the cutting capacity of DC circuit breakers. However, due to investment costs and system dynamic characteristics, the inductance capacity of smoothing reactors and current limiting reactors needs to be maintained within a reasonable range. Therefore, it is very meaningful to optimize the capacity configuration of smoothing reactors and current limiting reactors in the HVDC transmission system, while ensuring the current limiting capacity and reducing investment. Firstly, a fault equivalent model for the AC/DC hybrid power grid is established and the characteristics of the fault current at both ends when a bipolar short circuit occurs in the DC line are analyzed. Secondly, a mathematical model for optimizing the configuration of smoothing reactors and current limiting reactors is established. Finally, the proposed current limiting strategy is validated through MATLAB simulation experiments.
2024, 51(2):22-33.
DOI: 10.12177/emca.2023.182
Abstract:
Aiming at the chattering caused by the traditional sliding mode control using the discontinuous sign function as the switching function, a sensorless vector control method based on an improved sliding mode control with variable structure for the permanent magnet synchronous motors is proposed, so as to improve the static and dynamic performance of the system. Firstly, a control system with variable structure based on an improved sliding mode controller (ISMC) and an improved sliding mode observer (ISMO) is designed. Secondly, a continuous switching function, hyperbolic tangent function, is used as the sliding mode switching function, and its shape coefficient is adjusted by fuzzy logic control to reduce the chattering caused by the fixed boundary layer thickness. Then, the stability of the control system is proved by utilizing Lyaplov's second theorem. Finally, compared with other methods, the simulation results verify the feasibility and effectiveness of the proposed scheme.
Aiming at the chattering caused by the traditional sliding mode control using the discontinuous sign function as the switching function, a sensorless vector control method based on an improved sliding mode control with variable structure for the permanent magnet synchronous motors is proposed, so as to improve the static and dynamic performance of the system. Firstly, a control system with variable structure based on an improved sliding mode controller (ISMC) and an improved sliding mode observer (ISMO) is designed. Secondly, a continuous switching function, hyperbolic tangent function, is used as the sliding mode switching function, and its shape coefficient is adjusted by fuzzy logic control to reduce the chattering caused by the fixed boundary layer thickness. Then, the stability of the control system is proved by utilizing Lyaplov's second theorem. Finally, compared with other methods, the simulation results verify the feasibility and effectiveness of the proposed scheme.
2024, 51(2):34-43.
DOI: 10.12177/emca.2023.179
Abstract:
Abnormal discharge is a dangerous power transformer fault, which can lead to serious safety hazards if not detected in time. A method for identifying abnormal discharge in transformer is proposed by collecting the voiceprint signal in the transformer box through the contact voice pickup. And a feature extraction method and a deep neural network structure are proposed to achieve efficient identification of abnormal transformer discharge. Firstly, a two-dimensional voiceprint feature extraction method combining Mel frequency and key frequency is designed. Then, a hybrid two-dimensional feature recognition model based on convolutional neural network and Transformer network is used to accurately identify the abnormal discharge voiceprint signal while ensuring the speed. Finally, according to the experimental analysis of the discharge data collected from the 110 kV three-phase three-winding transformer in the no-load voltage regulation process, the recognition speed of the proposed method increases by 0.19 seconds per sample, and the accuracy increases by 4.5% compared with ResNet50.
Abnormal discharge is a dangerous power transformer fault, which can lead to serious safety hazards if not detected in time. A method for identifying abnormal discharge in transformer is proposed by collecting the voiceprint signal in the transformer box through the contact voice pickup. And a feature extraction method and a deep neural network structure are proposed to achieve efficient identification of abnormal transformer discharge. Firstly, a two-dimensional voiceprint feature extraction method combining Mel frequency and key frequency is designed. Then, a hybrid two-dimensional feature recognition model based on convolutional neural network and Transformer network is used to accurately identify the abnormal discharge voiceprint signal while ensuring the speed. Finally, according to the experimental analysis of the discharge data collected from the 110 kV three-phase three-winding transformer in the no-load voltage regulation process, the recognition speed of the proposed method increases by 0.19 seconds per sample, and the accuracy increases by 4.5% compared with ResNet50.
2024, 51(2):44-60.
DOI: 10.12177/emca.2023.173
Abstract:
Energy storage is a promising large-scale technology that effectively addresses the mismatch between energy supply and demand, while also optimizing the energy structure. A comprehensive review of recent advancements in material systems, preparation technologies, and performance characteristics of thermal storage technologies is provided, specifically focusing on chemical thermal storage, sensible thermal storage, and latent thermal storage. The composition, structure, preparation processes, performance characteristics, challenges, application prospects, and future development trends of varions thermal storage meterials are analyzed and discussed. Among these materials, in the process of phase change, the absorption or release of latent heat of phase change for energy storage and release of phase change heat storage stands out due to its significant advantages, including high energy density, ease of reaction control, and exceptional safety and reliability. Moreover, the paper explores further research progress in the realm of phase change energy storage, enhanced heat transfer technology for heat storage systems, and potential applications in different fields.
Energy storage is a promising large-scale technology that effectively addresses the mismatch between energy supply and demand, while also optimizing the energy structure. A comprehensive review of recent advancements in material systems, preparation technologies, and performance characteristics of thermal storage technologies is provided, specifically focusing on chemical thermal storage, sensible thermal storage, and latent thermal storage. The composition, structure, preparation processes, performance characteristics, challenges, application prospects, and future development trends of varions thermal storage meterials are analyzed and discussed. Among these materials, in the process of phase change, the absorption or release of latent heat of phase change for energy storage and release of phase change heat storage stands out due to its significant advantages, including high energy density, ease of reaction control, and exceptional safety and reliability. Moreover, the paper explores further research progress in the realm of phase change energy storage, enhanced heat transfer technology for heat storage systems, and potential applications in different fields.
2024, 51(2):61-70.
DOI: 10.12177/emca.2023.178
Abstract:
In response to the growing demand for aviation power systems in multi-electric aircraft, a high-speed solid-core permanent magnet synchronous motor with a rated power of 75 kW and a rated speed of 65 000 r/min is designed in this paper. The type of high-speed motor operates at high speeds and has a high loss density, and its design is constrained by multiple physical fields. The motor performance, rotor strength, and cooling system are designed from three perspectives: electromagnetic field, mechanical field, and temperature field, through finite element simulation. And the accuracy and rationality of the design is verified by experimental results. The analysis results provide a reference for the motor products of the multi-electric aircraft power generation system.
In response to the growing demand for aviation power systems in multi-electric aircraft, a high-speed solid-core permanent magnet synchronous motor with a rated power of 75 kW and a rated speed of 65 000 r/min is designed in this paper. The type of high-speed motor operates at high speeds and has a high loss density, and its design is constrained by multiple physical fields. The motor performance, rotor strength, and cooling system are designed from three perspectives: electromagnetic field, mechanical field, and temperature field, through finite element simulation. And the accuracy and rationality of the design is verified by experimental results. The analysis results provide a reference for the motor products of the multi-electric aircraft power generation system.
2024, 51(2):71-79.
DOI: 10.12177/emca.2023.174
Abstract:
Aiming at the problem of how to extract more effective characteristic parameters from the capacity increment (IC) curve for state of health (SOH) estimation of lithium batteries, a modified Lorentz voltage-capacity (RL-VC) based model is proposed. The capacity increment analysis (ICA) of lithium batteries is first performed using the traditional filtering method. Then the RL-VC model is used for comparison to obtain the corresponding feature parameters and calculate the capacity modeling error. The experimental data obtained based on the self-constructed experimental platform and the dynamic dataset NCM from the open-source dataset NASA are carried out separately. The errors of VC capacity modeling are within 0.23% and 0.16%, respectively. The feature parameters extracted from the IC curves fitted by the RL-VC model are highly linearly correlated with the capacity of Li-ion batteries, which lays the foundation for the subsequent SOH work. The IC analysis method based on the RL-VC model proposed in this paper not only has higher robustness in battery aging compared with the traditional filtering method, but also avoids subjectivity and uncertainty in feature parameter extraction.
Aiming at the problem of how to extract more effective characteristic parameters from the capacity increment (IC) curve for state of health (SOH) estimation of lithium batteries, a modified Lorentz voltage-capacity (RL-VC) based model is proposed. The capacity increment analysis (ICA) of lithium batteries is first performed using the traditional filtering method. Then the RL-VC model is used for comparison to obtain the corresponding feature parameters and calculate the capacity modeling error. The experimental data obtained based on the self-constructed experimental platform and the dynamic dataset NCM from the open-source dataset NASA are carried out separately. The errors of VC capacity modeling are within 0.23% and 0.16%, respectively. The feature parameters extracted from the IC curves fitted by the RL-VC model are highly linearly correlated with the capacity of Li-ion batteries, which lays the foundation for the subsequent SOH work. The IC analysis method based on the RL-VC model proposed in this paper not only has higher robustness in battery aging compared with the traditional filtering method, but also avoids subjectivity and uncertainty in feature parameter extraction.
2024, 51(2):80-89.
DOI: 10.12177/emca.2023.183
Abstract:
Due to factors such as wind variability and randomness, the power output of wind turbines remains unstable. When the wind speed exceeds the rated wind speed, the stability of the wind power generator’s output power is guaranteed by precisely regulating the pitch angle of the blades. In relation to this issue, a wind turbine pitch control model is built by Matlab/Simulink, and a whale algorithm-optimized fuzzy PID controller is introduced. However, there are many parameters of fuzzy controller, and it is difficult to set up by expert experience alone. Therefore, using the whale algorithm, and achieving optimal tuning of fuzzy parameters, effectively addressing the wind turbine’s significant hysteresis and nonlinearity. Comparing the performance metrics of the PID controller and the fuzzy PID controller, and the simulations results show that the latter ensures rapid power convergence to rated values, enhances system dynamic response, and offers precise pitch angle adjustments. Moreover, the fuzzy PID controller precision minimizes pitch mechanism fatigue, and extends the wind turbine’s lifespan.
Due to factors such as wind variability and randomness, the power output of wind turbines remains unstable. When the wind speed exceeds the rated wind speed, the stability of the wind power generator’s output power is guaranteed by precisely regulating the pitch angle of the blades. In relation to this issue, a wind turbine pitch control model is built by Matlab/Simulink, and a whale algorithm-optimized fuzzy PID controller is introduced. However, there are many parameters of fuzzy controller, and it is difficult to set up by expert experience alone. Therefore, using the whale algorithm, and achieving optimal tuning of fuzzy parameters, effectively addressing the wind turbine’s significant hysteresis and nonlinearity. Comparing the performance metrics of the PID controller and the fuzzy PID controller, and the simulations results show that the latter ensures rapid power convergence to rated values, enhances system dynamic response, and offers precise pitch angle adjustments. Moreover, the fuzzy PID controller precision minimizes pitch mechanism fatigue, and extends the wind turbine’s lifespan.
2024, 51(2):90-102.
DOI: 10.12177/emca.2023.187
Abstract:
The existing mathematical models based on the assumption of magnetic unsaturation for bearingless switched reluctance motors have limitations, as they are only suitable for non-magnetically saturated conditions. A comprehensive radial force mathematical model is developed for a wide rotor single-winding bearingless switched reluctance motor, taking into account the effects of magnetic saturation. Firstly, based on the finite element analysis of the motor’s magnetic field, the expression for the radial force in terms of the air gap magnetic density is derived using the Maxwell stress method. Next, the nonlinear magnetization characteristics of the iron core material are fitted, and the air gap magnetic density, accounting for the effects of magnetic saturation, is calculated using the motor’s equivalent magnetic circuit. Subsequently, the radial force model of the motor is established. After comparing and analyzing the influence of edge air gap magnetic density and main air gap flux density on the radial force, the developed radial force model is simplified to reduce computational complexity. Finally, the model is validated through finite element analysis. The results indicate that the established radial mathematic model is applicable to the motor under conditions of magnetic unsaturation, partial magnetic saturation, and complete magnetic saturation. The development of a full-period radial force model considering magnetic saturation provides a more accurate theoretical reference for the analysis of motor operating characteristics, structural optimization design, and control strategy research.
The existing mathematical models based on the assumption of magnetic unsaturation for bearingless switched reluctance motors have limitations, as they are only suitable for non-magnetically saturated conditions. A comprehensive radial force mathematical model is developed for a wide rotor single-winding bearingless switched reluctance motor, taking into account the effects of magnetic saturation. Firstly, based on the finite element analysis of the motor’s magnetic field, the expression for the radial force in terms of the air gap magnetic density is derived using the Maxwell stress method. Next, the nonlinear magnetization characteristics of the iron core material are fitted, and the air gap magnetic density, accounting for the effects of magnetic saturation, is calculated using the motor’s equivalent magnetic circuit. Subsequently, the radial force model of the motor is established. After comparing and analyzing the influence of edge air gap magnetic density and main air gap flux density on the radial force, the developed radial force model is simplified to reduce computational complexity. Finally, the model is validated through finite element analysis. The results indicate that the established radial mathematic model is applicable to the motor under conditions of magnetic unsaturation, partial magnetic saturation, and complete magnetic saturation. The development of a full-period radial force model considering magnetic saturation provides a more accurate theoretical reference for the analysis of motor operating characteristics, structural optimization design, and control strategy research.
2024, 51(2):103-112.
DOI: 10.12177/emca.2023.177
Abstract:
In order to investigate the effects of different rotor topologies on the electromagnetic and noise performance of 8-pole 48-slot interior permanent magnet synchronous motor (IPMSM), finite element models of interior permanent magnet synchronous motors with single-layer non magnetic bridge, singlelayer magnetic bridge, double-layer non magnetic bridge, and double-layer magnetic bridge rotor topologies are established. Except for the rotor topology, the stator topology, permanent magnet usage, and other conditions of the four types of motors are completely the same. Firstly, the electromagnetic performance and noise performance of the motor are analyzed theoretically. Secondly, the finite element models of four kinds of motors are established, and the electromagnetic performances of the four kinds of motors, such as salient pole rate, output torque, torque ripple and no-load back EMF harmonic distortion rate are compared and analyzed, and the modal analysis of the four kinds of motors is carried out. Finally, the vibration response and noise characteristics of the four kinds of motors are compared. The results show that the interior permanent magnet synchronous motor with a double-layer rotor structure with a magnetic isolation bridge has the best electromagnetic performance, and its noise reduction effect is also the best.
In order to investigate the effects of different rotor topologies on the electromagnetic and noise performance of 8-pole 48-slot interior permanent magnet synchronous motor (IPMSM), finite element models of interior permanent magnet synchronous motors with single-layer non magnetic bridge, singlelayer magnetic bridge, double-layer non magnetic bridge, and double-layer magnetic bridge rotor topologies are established. Except for the rotor topology, the stator topology, permanent magnet usage, and other conditions of the four types of motors are completely the same. Firstly, the electromagnetic performance and noise performance of the motor are analyzed theoretically. Secondly, the finite element models of four kinds of motors are established, and the electromagnetic performances of the four kinds of motors, such as salient pole rate, output torque, torque ripple and no-load back EMF harmonic distortion rate are compared and analyzed, and the modal analysis of the four kinds of motors is carried out. Finally, the vibration response and noise characteristics of the four kinds of motors are compared. The results show that the interior permanent magnet synchronous motor with a double-layer rotor structure with a magnetic isolation bridge has the best electromagnetic performance, and its noise reduction effect is also the best.
2024, 51(2):113-122.
DOI: 10.12177/emca.2023.181
Abstract:
The shielded permanent magnet synchronous motor for vacuum pump is seriously heated, so it is of great significance to accurately predict its temperature at the design stage for the safe and stable operation of the vacuum pump system. In view of the fact that the current two-way coupling calculation method of electromagnetic field-temperature field of motor can only consider the influence of temperature on the physical properties of motor materials, a mutual iterative calculation method of electromagnetic field-temperature field of motor is proposed. This method can not only consider the influence of temperature on the loss of motor and the magnetic properties of permanent magnet, but also consider the influence of temperature on the thermal conductivity and heat dissipation capacity of motor components, so that the prediction of electromagnetic field and temperature field of motor is more in line with the actual situation. Taking a 1.5 kW shielded permanent magnet synchronous motor as the research object, the electromagnetic performance and temperature characteristics of the motor are analyzed by using the proposed method, and the analysis results are compared with the electromagnetic thermal two-way coupling calculation results. In addition, the influence of ambient temperature on the temperature rise of the motor is studied by using the proposed mutual iteration method. This study can not only provide a theoretical basis for the optimal design of the shielded permanent magnet synchronous motor, but also provide a reference for its operational safety and reliability.
The shielded permanent magnet synchronous motor for vacuum pump is seriously heated, so it is of great significance to accurately predict its temperature at the design stage for the safe and stable operation of the vacuum pump system. In view of the fact that the current two-way coupling calculation method of electromagnetic field-temperature field of motor can only consider the influence of temperature on the physical properties of motor materials, a mutual iterative calculation method of electromagnetic field-temperature field of motor is proposed. This method can not only consider the influence of temperature on the loss of motor and the magnetic properties of permanent magnet, but also consider the influence of temperature on the thermal conductivity and heat dissipation capacity of motor components, so that the prediction of electromagnetic field and temperature field of motor is more in line with the actual situation. Taking a 1.5 kW shielded permanent magnet synchronous motor as the research object, the electromagnetic performance and temperature characteristics of the motor are analyzed by using the proposed method, and the analysis results are compared with the electromagnetic thermal two-way coupling calculation results. In addition, the influence of ambient temperature on the temperature rise of the motor is studied by using the proposed mutual iteration method. This study can not only provide a theoretical basis for the optimal design of the shielded permanent magnet synchronous motor, but also provide a reference for its operational safety and reliability.
2024, 51(2):123-134.
DOI: 10.12177/emca.2023.175
Abstract:
In order to solve the problem that current control of the permanent magnet synchronous motor (PMSM)is easily affected by factors such as system delay and parameter mismatch, which leads to the decrease of current tracking performance. Thus, an adaptive deadbeat current predictive control algorithm with delay compensation is proposed. Based on the traditional deadbeat predictive current control (DPCC), aiming at the problem of current performance degradation caused by parameter mismatch, the model adaptive compensation method based on affine projection algorithm is improved, and an adaptive current control algorithm with delay compensation is designed. Finally, the simulated experiments are carried out to verify the designed adaptive deadbeat current predictive control with delay compensation has adaptive compensation ability for system parameter mismatch, which can effectively eliminate the influence of system delay and improve the current loop tracking performance.
In order to solve the problem that current control of the permanent magnet synchronous motor (PMSM)is easily affected by factors such as system delay and parameter mismatch, which leads to the decrease of current tracking performance. Thus, an adaptive deadbeat current predictive control algorithm with delay compensation is proposed. Based on the traditional deadbeat predictive current control (DPCC), aiming at the problem of current performance degradation caused by parameter mismatch, the model adaptive compensation method based on affine projection algorithm is improved, and an adaptive current control algorithm with delay compensation is designed. Finally, the simulated experiments are carried out to verify the designed adaptive deadbeat current predictive control with delay compensation has adaptive compensation ability for system parameter mismatch, which can effectively eliminate the influence of system delay and improve the current loop tracking performance.
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.
