In the dynamic wireless power transfering(WPT) process of electric vehicle, the charging current of the battery is affected by some factors, such as the primary coil current and the relative position of the primary and secondary coils. Moreover, due to the travel of the electric vehicle, it is difficult to establish effective feedback between the primary side and secondary side. In this case, the charging method based on the primary side and secondary side independent control is analyzed. In this paper, it shows that the PID controller is set up after modeling the transmitter and the receiver. The effectiveness of this strategy is also verified by simulation on MATLAB

Wireless Power Transfer(WPT) system for Electric Vehicle(EV) battery charging application popularity is increasing due to the safety, convenience, and eco-friendly issue. Nowadays, Lithium-Ion battery is well known as one of the potential options for EV. However, Constant Current/Constant Voltage(CC/CV) control strategy needs to be adopted for achieving high efficiency charging and maintaining battery lifetime. By analyzing the gain curve, Pulse Frequency Modulation(PFM) can be used to perform CC/CV charging due to the load variation. The operating switching frequency needs to be considered and limited to prevent instability of the system. A typical drawback in the PFM control is the use of serial communication module for feedback data transmission from the secondary to the primary side. Therefore, the rectifier side controlled WPT can be a solution to remove the feedback communication part. In this paper, Pulse Width Modulation(PWM) applied in the secondary side(rectifier) for achieving CC/CV charging is investigated and compared with the traditional PFM control. The comparison study is verified by implementing a 3kW Series-Series(SS) WPT topology in the Power Simulation (PSIM) software. It shows that the secondary side PWM control strategy can achieve 94% efficiency during the 35 Ω load in CC mode, while the primary side PFM control only can achieve 88% efficiency.

The power rating for Electric Vehicles wireless charger keeps increasing as the technology develops. With limited space and volume, the maximum transferring power has reached a bottle neck even with an optimized coupling winding design. It is well known that third harmonic injection can increase the maximum power transfer for line-frequency inverter. However, for high frequency resonant converters, it is a big challenge to utilize third harmonic as the resonant network is a band-pass filter for fundamental frequency only. Also, the switching frequency is closed to resonant frequency and the phase relationship between fundamental and third harmonic mostly relies on impedance match. This paper explores the feasibility of third harmonic injection in resonant converters, and theoretically proves the additional third harmonic can lead to a maximum 40% extra output power. A W-filter which is low impedance for both fundamental and third harmonic is proposed. To adjust the phase relationship, a dither feedback across the nonlinear output diode rectifier is proposed. A minimum system and a wireless power transfer(WPT) system have been constructed by W-filters in simulation. Experimental results based on a 20-W scale-down prototype are presented to illustrate the proposed system.

In the field of electric vehicles driven by induction motor with indirect filed oriented control method, the motor is usually operated in torque mode. In order to achieve precise control of torque, it is crucial to estimate the rotor flux. Low pass filter(LPF) with compensation system is usually applied in the voltage model based stator flux estimator. In this paper, the performance of two realizations of LPF scheme are compared. Moreover, an optimized implementation of the band pass filter(BPF) based voltage model is proposed. With the proposed scheme, not only the DC offset in the estimated flux is eliminated, but also the dynamic performance is improved and the unsatisfied high-frequency noise is reduced. Based on the estimated rotor flux, estimation and closed-loop control of torque is achieved. The simulation and experimental results verify the feasibility of the proposed scheme.

A novel 18/12 poles hybrid excitation doubly salient machine(HEDSM) with wide speed range is proposed in this paper. The detailed structure, mathematical model and electromagnetic characteristics of HEDSM based on finite element analysis model are described in this paper. Then, the control strategy for wide speed range is given and the firing angle, extinguished angle of the switches and dc field current are optimized according to different speed ranges in the motor driving system subsequently. Finally, a field-circuit coupling simulation model of HEDSM driving system with open-loop control is built and the tested torque-speed curves and waveforms show that HEDSM acquires wide speed range under the proposed control algorithm.

To reduce the computational burden of the conventional model predictive current control(MPCC), improve the steady state performance of single vector MPCC for the semi-controlled open winding PMSG(OW-PMSG), and further suppress zero sequence current simultaneously, a double vector MPCC method for semi-controlled OW-PMSG generation system is proposed in this session. In this method, the first voltage vector of controllable convertor is selected according to the sector location of the reference voltage vector. For the second voltage vector, the selection method-based deadbeat voltage vector sector is designed to reduce the range of the candidate voltage vector. Finally, the simulation results validate effectiveness of proposed method.

For sensorless control of the permanent magnet synchronous motor(PMSM), the estimated accuracy of the angular velocity and position angle will directly affect the control performance of PMSM. As state observer has the advantages of simple structure and low noise, this paper proposes a novel sensorless control method on the basis of the current closed-loop state observer. The method is based on mathematic deducing of relationship between the electromagnetic torque and the angular velocity in accordance with the PMSM’s mathematic model and the control theory. A system simulation model and experiment platform are set up, simulation and experiment results verify the effectiveness and validity of the proposed sensorless control method.

To meet the needs of its characteristics, this paper studies the space high voltage power conversion system’s circuit topology and the optimization design of its structure. In the first part, the Common space solar power station power management and distribution methods is analyzed. And based on that, a new hybrid power system structure is presented, in which a power transmission bus-bar structure suited for space solar arrays is constructed and the modular multi-converter with serial-parallel combination control strategy is proposed. By applying this new structure, the high transformation ratio in the solar cell arrays and sub-arrays, the low power loss, the large power conversion with high power density and the high efficiency can all be achieved. In the second part, a new soft-switched isolated full-bridge converter is also proposed. And researches is made based on the new converter, which includes the study on the transformer modular magnetic integration, the space temperature field and the thermal design. finally, the simulation and experiment prove the correctness of the theoretical analysis.

With the development of traction supply system, the topology of the traditional phase-shift two-level converter can not be suitable for power electronic transformer in high-voltage, high-power application due to its weak voltage stress capacity. Therefore, a proposed topology named bi-directional LLC resonant converter with three-level half bridge is introduced. Compared with previous topologies, it has the advantages of allowing higher input voltage with its higher voltage stress capacity and reducing the switching device stress demand. In addition, it can delivery the power with higher efficiency and density. In order to know more about that proposed topology, the paper also discusses the working characteristics by the anaysis method of fundamental frequency and also introduce in detail its working modes under falling resonant and varied modulation frequency, so that the expresses in time domain can be get. Meanwhile, a technique optimizing topology parameters is presented by the circuit principle in dead time. Finally the theoretical anaysis and the designed parameters are verifed by the simulation and experiment results.

In the field of electrified railways, a unified energy storage and transformation control system is proposed based on railway static power conditioner and supercapacitor energy storage system. In order to enhance the regenerative braking energy utilization, while improving power quality. Firstly, the parameters design of the supercapacitor energy storage system are given. Then, the working area of the system is divided into different parts under different working conditions. Meanwhile the power allocation strategies among the two power arms and energy storage system in each of the parts are presented in details. Furthermore the coordination control strategies which includes instruction current or power detecting calculation and the control strategies of convertors for both railway static power conditioner included and super capacitor energy storage system are presented in each of the parts. Finally, the simulation under diverse working conditions have verified that the coordination control strategies. The system can not only realize the storage and utilization of regenerative braking energy including peak load shifting, but also can solve the power quality problems in electrified railways.