Time delay of the finite control set model predictive current control caused by a large amount of calculations will degrade the control performance of the permanent magnet synchronous machine system. This letter first demonstrates the delay issue at length. Then, a new direct compensation method, by predicting the current variation within the delay time, is proposed. In comparison with the traditional two-step prediction strategy, the novel method is also easy to implement and can single out the best switching state in each period for optimal control. Simulation and experimental results are presented to verify the effectiveness of the proposed method.

Three-phase interior permanent magnet synchronous motor (IPMSM) drive systems have gotten widely used in various applications due to their speed regulation characteristics and high power density. Compared with classical field-oriented control (FOC)and flux-weakening control, model predictive control (MPC) technique is more efficient in achieving excellent performance without complicated controller tuning but with explicit constraints. Yet, the optimum application of MPC algorithm in machine control system is in the exploratory stage.In order to lower the current and torque ripples, this paper retains a modulator, but replaces all PI-control loops which are contained in the conventional FOC systems with a single MPC controller. Moreover, we adopt a brand-new linearization approach to tackle the strong coupled nonlinear IPMSM mathematical model, obtaining an improved linear plant model (ILPM) which is suitable for the motor with constant load torque. When it comes to flux-weakening control,the required d-axis current is calculated, after which it is used as the input of the proposed MPC controller, abandoning the previous natural field weakening method. Finally, for the purpose of lowering the dynamic speed and current overshoot, a further constraint in the change rate of manipulated variables is discussed. The improved control algorithm has been verified in simulation and experiment.

For many servo systems in electric vehicles, high performance controls of permanent magnet synchronous motordrives are widely used due to their high efficiency, low vibration and noise. In order to ensure the high efficiency of the servo systems, some online and offline maximum torque per ampere (MTPA) control strategies are proposed, meanwhile, the vibration and noise of IPMSMs in these servo systems must be smooth and soft. In this paper, the vibration and noise of the IPMSM based on MTPA algorithms are compared. Firstly, the influence of the voltage inventor on the noise of IPMSM is presented in detail and the relationship between the harmonic frequencies of the air gap magnetic force and the vibration frequencies of the IPMSM is investigated. Then, the effect principle of the control strategies on the magnetic vibration of the IPMSMs is defined. Based on this definition, the operation process and noise of different control methods are discussed. Finally, performance of the vibration and noise under classical field-oriented control, offline and online MTPA control are concluded. With the comprehensive analysis and overview provided in this paper, it is significant to guide the selection of a high performance control method for servo systems in EVs.

In order to enhance the dynamic performance of the surface-mounted permanent magnet synchronous machines (PMSM), this paper proposes a novel finite control set (FCS) model predictive direct speed control (MPDSC) strategy that only contains one speed control loop. In comparison with the traditional two-step prediction method, the new controller is achieved by estimating the current at first and then the speed with only one prediction horizon. The practical problem that the optimal switching state cannot be selected by the common implementation procedures of the FCS model predictive control algorithms can be solved by applying the proposed strategy that conforms more to the real situations. Moreover, in order to solve the other critical problem that the load torque (LT) in the predicting plant is unknown, a novel sliding mode LT observer is developed. The simulation and experimental results prove that the proposed algorithms are effective.

This paper proposes a sensorless control strategy using sine-wave high-frequency (HF) voltage injection for three-phase four-switch (TPFS) inverter fed interior permanent magnet synchronous motors (IPMSMs) with a single current sensor. Three-phase currents are reconstructed by a single current sensor with modification of the inverter topology. The principle of the phase current reconstruction strategy in TPFS inverter is analyzed and the topology of the proposed drive system is illustrated. Then, the normal areas and dead zones for current reconstruction are investigated in detail, and the vector synthesis method is also explained. Furthermore, the zero vector synthesis strategy and PWM generation method are also presented, where two current sampling points are applied in each PWM cycle for phase current reconstruction. Finally, HF voltage injection-based sensorless control strategy in the proposed drive system is realized by voltage projection on the proposed k-l axis coordinate system. The reconstructed phase currents track the actual ones accurately, and the estimation error of the rotor position by using the reconstructed phase currents is within μ0.1 rad. The effectiveness of the proposed scheme is verified by simulation and experimental results on a 5 kW IPMSM prototype.

This paper proposes a mutual calibration strategy for multiple current sensors in an electric vehicle motor drive. The motor drive usually consists of three current sensors, i.e., a DC-bus current sensor and two phase current sensors. Due to the aging effect and harsh operating environment, the accuracy uncertainty issue is inevitable in these crucial sensors, which results in poor driving performance. In this paper, the detection voltage injection (DV-Injection) method is proposed for mutual calibration of the aforementioned current sensors. Two opposite basic vectors are set together to detect and eliminate the offset error of the DC-bus current sensor. Then, both the directly measured phase-current values by the phase-current sensors and the indirectly measured values by the DC-bus current sensor are sampled. These values are utilized for mutual calibration of the phase-current sensor offset errors and scaling error differences among all the current sensors. Meanwhile, the DV-Injection process is only applied in the period of calibration process, whereas in the remaining intervals the space vector pulse width modulation (SVPWM) technology is utilized. Finally, the effectiveness of the proposed scheme is verified by simulation study in Matlab/Simulink and experimental results on a 5kW IPMSM motor prototype.