一种新型无刷直流电机谐振极软开关逆变器

永磁无刷直流电机具有高功率密度、高转矩/电流比和控制简单等优势,得到了广泛应用。然而,无刷直流电机通常采用硬开关逆变器驱动,硬开关逆变器的系统效率较低,散热器的体积和重量较大,限制了大功率无刷直流电机驱动系统功率密度和性能的进一步提升。针对硬开关逆变器问题,提出了一种无刷直流电机专用的谐振极软开关电压源逆变器。通过在传统硬开关逆变器的三相输出端添加辅助谐振网络,实现了逆变桥主开关器件的零电压(ZVS)开关动作,辅助双向开关在零电流开关(ZCS)条件开通和关断。针对新型软开关逆变器,提出了一种新的脉宽调制(PWM)控制策略——TPWM TON,逆变桥上下侧开关器件轮流进行PWM调制,保持了直流母线中点电位的平衡,且使主开关和辅助开关的开关频率降到PWM调制频率的一半。对提出的软开关逆变器进行了实验研究,实验结果验证了电路结构、理论分析和控制策略的正确性与可行性。

A Novel Resonant Pole Inverter for Brushless DC Motor

The brushless DC motor (BLDCM) has high torque, compact size, and high efficiency. Therefore, BLDCM is widely used in computers, household and industrial products, and automobiles. It is usually driven by a hard-switching pulse width modulation (PWM) inverter, which has low switching frequency, high switching loss, high electro-magnetic interference (EMI) and acoustic noise, et al. A novel resonant pole(RP) voltage-source-inverter (VSI) is proposed for brushless DC motor (BLDCM).It can realize zero voltage switching (ZVS) operation of all power devices in inverter by adding auxiliary resonant unit in three phases output. Auxiliary resonant switches are turned on and off under zero current switching (ZCS). A PWM scheme (TPWM TON) is presented for novel resonant pole inverter. It achieves good balance of neutral-point voltage and reduces switching frequency of main and auxiliary switches to half of PWM frequency. Subsequent experimental results confirm validity soft switching inverter and control scheme.