基于脉冲阻塞原理的三相AC/AC系统等脉宽斩波控制

Equal pulse width chopping control based on plugged pulse principle in three-phase AC/AC system

针对传统的三相AC/AC变频电路特点,提出了一种新的电路拓扑,仅用6个功率器件即可实现三相AC/AC变频功能。提出基于脉冲阻塞原理的等脉宽斩波控制策略,取代传统的移相控制策略施加于该电路拓扑,实现了三相输出电压幅值、频率分别可调或同时可调。对等脉宽斩波控制策略进行了详细的理论分析,根据期望输出电压的不同频率和幅值,利用面积等效原则,推导出相应占空比的数学表达式。在PSPICE环境下根据脉冲阻塞原理,对三相AC/AC系统进行等脉宽斩波控制仿真,并设计了三相AC/AC系统主电路和基于FPGA的控制电路,完成了相关实验。仿真和实验结果一致,与文中的理论分析结果也完全一致,验证了该AC/AC变频控制策略的正确性及可行性。

A circuit topology of three-phase AC / AC system is presented,which needs only six power devices to realize the three-phase AC / AC frequency conversion.The traditional phase-shifted control strategy is replaced by the equal pulse width chopping control strategy based on plugged pulse principle to regulate the amplitude and frequency of output voltage separately or simultaneously.The equal pulse width chopping control strategy is analyzed in detail and the mathematic expression of duty cycle is deduced based on the area equivalent rule according to different frequency and amplitude of anticipant output voltage.Under the environment of PSPICE,the three-phase AC / AC system with the equal pulse width chopping control strategy is simulated.Its main circuit and FPGA-based control circuit are designed and tested.The experimental results are consistent with the simulative results,completely same as the theoretical analysis,which verifies the correctness and feasibility of the introduced control strategy.