Single-phase active electric-power filter using analog cascade connection controller

Abstract

The single-phase active electric power filter of using analog cascaded controller includes control circuit, and connected main circuit. The control circuit includes first and second proportional plus integral controllers, multiplier, subtracter, feedforward controller, and adder. Principle of the invention is as following: using voltage loop composed of these analog parts adjusts DC voltage of bus in two control loops including external current loop as well as generates current of reference power supply; using current loop reduces interference effect, and tracks current of reference filter; finally, generating command signal for main circuit to generate compensating current. Using analog devices in low cost without need of microprocessor, the invention realizes active electric power filter capable of restraining harmonic, and correcting power factor. The invention reduces cost of the filter, and has no mathematic burden for calculating fundamental wave and harmonic of load current. 本发明提出一种使用模拟级联控制器的单相有源电力滤波器，其包括控制电路和与其连接的主电路，控制电路包括第一比例积分控制器、乘法器、减法器、前馈控制器、第二比例积分控制器、加法器。其原理是：由这些模拟器件构成电压环在外电流环在内的两个控制环，通过电压环调节母线直流电压，以及为并联型滤波器产生参考电源电流，并通过电流环减少干扰效应，跟踪参考滤波器电流，最后产生指令信号给主电路来产生补偿电流。利用本发明，可以使用低成本的模拟设备而不需要微处理器就能实现可以很好地抑制谐波和校正功率因素的有源电力滤波器，从而大大降低了有源电力滤波器的生产成本，并且没有计算负载电流的基波和谐波所需要的大的数学负担。