双三相电机驱动系统具有容错能力强、易实现低压大功率运行等优点，在电动汽车领域具有广阔的应用前景。本文对双三相电机驱动系统关键技术进行了研究分析，重点针对共模抑制及双三相电机驱动系统实现时的相关技术进行了研究。针对双三相电机驱动系统共模电压抑制问题，本文提出了两种共模抑制方法。论文在矢量分类调制算法的基础上，提出了一种可抑制共模电压的矢量分类调制技术。该方法能将高压区共模电压抑制为原来的1/3，在低压区能抑制共模电压的变化频率和范围，同时也能抑制每套三相绕组的共模电压。论文从双三相电机的空间矢量分解模型出发，提出了一种基于空间矢量分解脉宽调制的共模抑制方法。这种方法利用不产生共模电压的几组开关电压矢量，合成中间矢量，再进行调制。这种方法成功地消除了六相共模电压，并且将每套三相绕组的共模电压抑制为原来的1/3。论文从共模抑制效果和谐波性能两个方面对所涉及的五种脉宽调制方法进行了对比，综合比较发现，本文提出的基于空间矢量分解的共模抑制方法在综合性能上最为优胜。汽车行业对成本极其敏感。为了降低系统成本，论文研究了双三相电机低边电阻电流采样重构技术，通过在逆变器下桥臂串入电流采样电阻，代替电流传感器。这种方法利用零矢量作用时流经下桥臂的电流对相电流进行重构，在硬件上大大简化，降低了成本，适用于低压系统。由于该算法与零矢量的作用密切相关，当零矢量作用时间过短或不作用时，电流重构会受到影响。文中对该算法进行了失效区分析，并通过仿真验证了在算法适用范围内的重构效果。针对电动汽车高可靠性需求，论文对双三相电机驱动系统的容错控制进行了研究。在可靠性要求较高的场合，例如线控转向系统中，常采用硬件冗余设计，针对这类系统，文中通过切断故障绕组来进行容错控制。由于直接切掉一套绕组进行容错控制时，会导致瞬时输出转矩下降，因此需要对输出转矩进行补偿。基于此点考量，文中对容错算法进行了优化，并通过仿真和实验验证了控制效果。
Dual three-phase motor drive system gets more and more attention with many advantages such as strong fault tolerance, easy to achieve high power with low voltage. The paper researches on the key technologies of dual three-phase motor drive system, and focuses on the suppression of common mode voltage and the tolerant control of dual three-phase motor drive system.In order to reduce common mode voltage of dual three-phase motor, two common mode suppression methods are proposed. Based on the space vector classification modulation technology, the paper proposed a new modulation method which can reduce the common-mode voltage. The method can reduce the common mode voltage to 1/3 of the traditional space vector classification modulation technology in the high voltage region. And the frequency and value of common mode voltage are reduced while in the low voltage region. The method reduces not only the common mode voltage of six phases, but also the common mode voltages of two three-phase windings. Another modulation method to reduce common mode voltage is proposed based on the space vector decomposition modulation method. This method uses the space vectors which do not generate common mode voltage to synthesize the new intermediate vectors. Then it uses these vectors to compose the reference voltage vector. This method successfully reduces the six-phase common mode voltage to zero and suppresses the common mode voltage of each three-phase winding to 1/3 of the traditional space vector decomposition modulation method. The paper compares the common mode voltage, fundamental amplitude and THD of the involved five pulse width modulation methods. It shows that the modulation method to reduce common mode voltage based on space vector decomposition modulation method achieves the best performance.The automotive industry is extremely sensitive to costs. In order to reduce the cost, the paper studies the low-side resistance current sampling and reconstruction technology of dual three-phase motor. By the current sampling resistor in the lower arm of the inverter, the phase currents are reconstructed by the currents flowing through the lower arm when adopting the zero vector. This method greatly simplifies the hardware and reduces the cost, and it is suitable for low-voltage system. Because the algorithm is closely related to the role of zero vector, it is not suitable when the zero vector do not act or the time is too short. In this paper, the failure zone of this method is analyzed, and the effect of reconstruction is verified.Aiming at improving the reliability of electric vehicles, the paper studies the fault-tolerant control of dual three-phase motor drive system. In the case of high reliability requirements, such as the wire-steering system, the hardware redundancy design is often adopted. For this kind of hardware circuit, the paper studies the fault-tolerant control by cutting off the fault windings. Since the fault-tolerant control is achieved by directly cut off one set of windings, the instantaneous output torque is reduced, so the output torque needs to be compensated. Based on this consideration, the fault-tolerant algorithm is optimized in the paper, and the control effect is verified by simulation and experiment.
