Cheng-Kai Lin

Model-Free Predictive Current Control for Interior Permanent-Magnet Synchronous Motor Drives Based on Current Difference Detection Technique

A model-free predictive current control (PCC) of interior permanent-magnet synchronous motor (IPMSM) drive systems based on a current difference detection technique is proposed. The model-based PCC (MBPCC) of IPMSM requires knowledge of parameters such as resistance, q-axis inductance, and extended back EMF. This paper develops a new model-free approach that alleviates the need for excessive prior knowledge about the system and only utilizes the stator currents as well as the current differences corresponding to different switching states of the inverter. Despite the salient difference of the proposed approach, it adopts a measure similar to that in the MBPCC approach to obtain the next switching state of the inverter by minimizing a cost function. It is noteworthy that the proposed method is easy to implement due to its simplicity and free of any multiplication operation. For comparison purposes, a digital signal processor, TMS320LF2407, is used to execute the two aforementioned current control techniques. Several experimental results show that the proposed method can significantly improve the current-tracking performance.

Adaptive backstepping PI sliding-mode control for interior permanent magnet synchronous motor drive systems

An adaptive backstepping PI sliding-mode control is proposed for speed control of the drive of an interior permanent magnet synchronous motor (IPMSM) subjected to load disturbances. First, a nonlinear model with uncertainties is derived for the IPMSM, and then an adaptive backstepping sliding-mode controller incorporating a linear load torque estimator is designed. Next, the parametric uncertainties of the model are handled with adaptive laws in the design of the controller. To attenuate the chattering problem without sacrificing the feature of the sliding-mode control, an adaptive Pi-saturation function is used to approximate the signum function within the boundary layer. Asymptotic stability of the proposed control method is proven by Lyapunov stability theory and Barbalats lemma. A digital signal processor, TMS320LF2407, is adopted to implement the proposed control scheme. The experimental results show that the proposed system can effectively reduce the chattering phenomenon and has fast transient response, good load disturbance rejection response, and good tracking response.

A sensorless position control for four-switch three-phase inverter-fed interior permanent magnet synchronous motor drive systems

In this paper, a sensorless position control for four-switch three-phase (FSTP) inverter-fed interior permanent magnet synchronous motor (IPMSM) drive systems is proposed and studied. Unlike traditional sensorless position controls that are based on zero-voltage switching mode generated by a six-switch three-phase (SSTP) inverter, the proposed method utilizes the nature of the FSTP inverter; that is, only four active-voltage switching modes are generated. Using basic circuit theory, the relationship between the rotor position and the current-slope differences can be derived and expressed as 24 transformation matrices. The current-slope differences are calculated by two stator current slopes corresponding to the two different active-voltage switching modes. By reducing the number of power switches and using the proposed method to eliminate the encoder, a cost-effective FSTP inverter-fed sensorless IPMSM drive system is developed. Moreover, no additional hardware circuits and no switching strategy change are required for existing drive systems. Simulation results are shown to demonstrate the feasibility and effectiveness of the proposed method.

Model-free predictive current controller for four-switch three-phase inverter-fed interior permanent magnet synchronous motor drive systems

In this study, a model-free predictive current controller (MFPCC) for four-switch three-phase (FSTP) inverter-fed interior permanent magnet synchronous motor (IPMSM) drive systems is proposed. A new method, using the stator current and its difference is proposed to predict the next stator current. The advantages of the proposed MFPCC are low computation, simple to realize, and insensitive to parameter variations. The switching state that minimizes a defined cost function, which is used to evaluate the current error at the next switching state, is obtained to control the drive signals of the FSTP. Due to its simplicity and powerfulness, the proposed method provides an alternative current controller for the FSTP inverter-fed IPMSM drive system. For comparison purpose, the MFPCC and a traditional hysteresis current controller (HCC) for a FSTP inverter-fed IPMSM drive system have been implemented using a digital signal processor, TMS320LF2407. The experimental results show that the proposed MFPCC outperforms the traditional HCC in both steady-state and transient current tracking responses.

An improved predictive current control for interior permanent magnet synchronous motor drives based on current difference detection

An improved predictive current control for interior permanent magnet synchronous motor (IPMSM) drive systems using current difference detection technique is proposed in this paper. First, a conventional model-based predictive current control for IPMSM is introduced, which needs the information of the resistance, q-axis inductance, and extended back-EMF of IPMSM to predict the future current. To remove the usage of all these parameters in the conventional predictive current control algorithms, a new method that only uses the stator current and the current difference is proposed to predict the future stator current at the end of the next switching interval for all possible switching states. Then, the voltage vector that minimizes a defined cost function, which is used to evaluate the current error at the next switching state, is obtained to control the drive signals of the inverter. Also, the proposed method is very simple and can be effectively implemented due to its low computation without using any multiplication operation. A digital signal processor, TMS320LF2407, is used to execute the predictive current control algorithm. Several experimental results show that the proposed method can effectively improve the system performance in terms of current tracking compared to conventional methods.

Passivity-based adaptive complementary PI sliding-mode speed controller for synchronous reluctance motor using predictive current control

In this study we propose a predictive current control (PCC) and a passivity-based adaptive complementary PI sliding-mode (PBACPISM) controller to control the current and speed of the synchronous reluctance motor (SynRM) drive system. In PCC the future stator currents can be predicted using the proposed extended back-EMF estimation method for seven possible voltage vectors generated by the inverter. According to a cost function, the voltage vector that minimizes the cost function can be obtained at the present sampling time to directly control the drive signals of the inverter at the next sampling time. In addition, to improve the speed tracking performance of the SynRM drive system, the PBACPISM controller is proposed. The stability of the whole system is proved by passivity theory and Barbalats lemma. Simulation results show satisfactory performance in both current control and speed control and validate the proposed method.

Model-based predictive current control for four-switch three-phase inverter-fed IPMSM with an adaptive backstepping complementary PI sliding-mode position controller

In this paper, we propose a model-based predictive current control (MBPCC) scheme for four-switch three-phase (FSTP) inverter-fed interior permanent magnet synchronous motor (IPMSM) drive systems based on a three-phase extended back-EMF estimation method. First, we estimate the three-phase extended back-EMFs of IPMSM using the information of the stator currents, the q-axis inductance, and the stator voltages. After that, the future stator currents are predicted for four possible switching states generated by the FSTP inverter. By defining a cost function which is related to current errors, one can select a switching state that minimizes the cost function. Then, the future switching state of the FSTP inverter at the next sampling time can be determined to directly control the drive signals of FSTP. In addition, to improve the performance of the closed-loop system, an adaptive backstepping complementary PI sliding-mode (ABCPISM) position controller is proposed. The stability of the closed loop system is proven by Barbalats lemma. Simulation results are provided to validate the proposed method.

Passivity-based adaptive sliding-mode speed control for IPMSM drive systems

A passivity-based adaptive sliding-mode control is proposed for speed tracking of interior permanent magnet synchronous motor drive systems. Firstly, a nonlinear model of the IPMSM is given with uncertainties embeded. Through adaptive feedback passivation design, the closed-loop system is shown to be feedback equivalent to a strictly passive system with a designated input. The unknown system parameters are dealt with by designed adaptation laws in parallel with the design of the controller. Maximum torque per ampere condition is met through the design of d- and q-axis currents, which serve as the inputs to the motor. Asymptotic stability of closed loop system is proven by passivity theorem and Barbalats lemma. Simulation results show good speed tracking response and good performance.

Chattering-free robust nonlinear controller for an interior permanent magnet synchronous motor speed drive system

A chattering-free robust nonlinear controller is proposed for the speed control of an IPMSM drive system to compensate for the parameter uncertainties and load disturbances. First, the input-output feedback linearization technique is used with a load torque estimator. Next, the upper bounds of the uncertainties are defined in design of the chattering-free robust controller. After that, in order to derive the chattering-free nonlinear robust control laws without reducing the benefits of the sliding mode control, a new method using the sliding manifold information is proposed. Asymptotic stability of the proposed control method is proven by Lyapunov stability theory and Barbalats lemma. A digital signal processor, TMS320LF2407, is used to implement the proposed control scheme. The experimental results show that the proposed system can effectively reduce the chattering phenomenon and has fast transient responses, good load disturbance rejection responses, and good tracking responses.