AC–AC Converter With Controllable Phase and Amplitude

By adopting the concept of virtual quadrature source (VQS), a novel method for power transmission control-ac-ac converter with controllable phase and amplitude (ACCPA) was proposed, which has two control variables and is able to continuously regulate the phase and the amplitude of its output voltage independently. The operation principle was studied in detail, and the relationship with the optimization of control parameters of ACCPA´s two duty ratios was analyzed for regulating the phase and amplitude of its output voltage. The phase is regulated in the front part, and the amplitude is regulated in the back part. For phase regulation, two methods were proposed to select optimal control parameters dynamically. The curves followed by two methods are crossed at the reference phase angle and have the same initial control parameters. It is necessary to adjust two independent control parameters for method 1 and one parameter for method 2. So method 2 is simple, easy to implement and has high control stability in comparison with method 1. The control strategy of ACCPA was presented and a prototype of single-phase ACCPA was manufactured. The experimental results verified the correctness of the theory and the feasibility of the control strategy.