基于强耦合双支路的永磁同步电机PWM高频效应抑制研究

High-power permanent magnet synchronous motors (PMSM) are increasingly needed in industry and national defense field, such as ship and submarine propeller and heavy vehicle traction system. However, due to finite PWM switching frequency (usually lower than 10 kilohertz) and relatively small phase inductance in high-power PMSM, significant high frequency PWM harmonics are frequently produced, which aggravate eddy current loss in rotor, iron loss in stator, as well as electromagnetic vibration and acoustic noise. Suppression of performance deterioration caused by high frequency PWM harmonics has become a research focus. Aiming at comprehensive suppression of the high frequency effect in high-power PMSM system, strong coupling dual branch PMSM is proposed in this study. By adjusting the PWM harmonic currents in two branches to be equal in magnitude and opposite in phase, harmonics can be eliminated from the total magnetomotive force, then the effect of high frequency PWM harmonics is effectively suppressed. The internal physical phenomena and characteristic of the strong coupling dual branch PMSM is studied at first to establish a cross-coupling PMSM model. Then the design approach of the two branches PMSM is proposed based on impedance balance principle. Suitable drive strategy for the proposed PMSM is also proposed considering the suppression of rotor eddy current losses, electromagnetic vibration and noise, as well as stator iron loss. In addition, torque decoupling control is presented based on the cross-coupling PMSM model. Once the aforementioned aims are achieved, an integrated theory and technology system of the proposed strong coupling dual branch PMSM can be established, which will greatly promote the development of high-power PMSM in both theory and technology.

大功率永磁同步电机在国防与国民经济中有越来越广泛的需求，如船舶与潜艇推进、重型车辆驱动等。大功率永磁同步电机驱动系统的开关频率通常只有几千赫，而且电机电感较小，PWM高频谐波电流引起转子涡流损耗、电磁振动与噪音、定子高频铁损等高频效应非常严重。针对大功率永磁同步电机系统中高频效应综合抑制的难题，提出强耦合双支路永磁同步电机的解决方案，即通过两条支路中PWM谐波电流相位差来抑制合成谐波磁动势，从而达到抑制PWM高频效应的目的。通过研究强耦合双支路永磁同步电机内部物理现象与特性，建立强耦合双支路永磁同步电机交叉耦合模型，提出强耦合双支路永磁同步电机阻抗均衡性设计方法，在此基础上提出综合抑制转子涡流损耗、电磁振动与噪音、定子高频铁损的驱动策略，并提出强耦合双支路永磁同步电机的转矩解耦控制方法，形成强耦合双支路永磁同步的理论与技术体系，促进大功率永磁同步电机理论和技术的发展。

本课题的总体目标是针对大功率永磁同步电机转子涡流损耗、电磁振动与噪音、定子高频铁损抑制的难题，提出了基于强耦合双支路永磁同步电机高频效应抑制的策略。.研究了强耦合双支路永磁同步电机交叉耦合特性，分析绕组空间位置对线圈的交叉耦合特性的影响，研究支路间和相间的交叉耦合特性，建立强耦合双支路永磁同步电机交叉耦合模型。建立dq坐标系下强耦合双支路永磁同步电机模型，采用磁场定向矢量控制策略，对永磁同步电机进行调速控制。.对传统SVPWM(space vector PWM)技术的合成矢量时序进行优化，提出了改进的双边采样SVPWM技术和改进的单边SVPWM技术。对比、分析传统SVPWM技术电压中的PWM谐波，通过调整双边规则采样SVPWM技术载波周期内有效矢量的合成时序提出了双边采样SVPWM技术，利用二维傅利叶积分计算了该技术对应的PWM谐波表达式验证此技术能够抑制大部分载波频率奇数倍次的PWM谐波。针对双边采样SVPWM技术不能彻底消除载波频率PWM谐波的问题，通过改变单边规则采样SVPWM技术载波周期内零矢量V0和V7的时序提出了改进的单边采样SVPWM技术，给出其PWM谐波表达式和实现方法，实验验证此技术可以有效地降低开关频率。.针对无耦合电感的交错并联拓扑载波移相后谐波电流过大的问题提出了用于驱动强耦合双支路电机的隔离型交错并联拓扑。相比于非隔离型交错并联拓扑，隔离型交错并联拓扑具有更好的容错能力；通过载波移相半个PWM周期，开关频率的奇数倍高频谐波在气隙中产生的高频谐波磁动势相互抵消，这样实现了整个强耦合双支路永磁同步电机的高频噪声消除。.将隔离型交错并联拓扑与改进的双边采样SVPWM技术相结合提出了一种综合性PWM谐波抑制技术。改进的双边采样SVPWM能够抑制载波频率奇数倍次的PWM谐波，通过调整逆变器载波相位使交错并联拓扑可以抑制载波频率偶数倍次的PWM谐波，如此这类硬件拓扑和软件PWM技术相融合的综合性PWM谐波抑制技术能够在不增加逆变器数目和开关频率的前提下，提高剩余PWM谐波的频率。.在载波移相的基础上为了进一步削弱偶数倍开关频率谐波，提出了同步随机与周期变化的交错并联技术，通过调整两个逆变器载波同步变化，既可以实现奇数倍开关频率的谐波在气隙中相互抵消，又可以通过开关频率的周期性与随机性变化抑制偶数倍开关频率谐波。