Novel Digital Voltage Regulation for Inverters with Flux Balance

A novel digital voltage regulation for sinusoidal wave inverter is proposed based on a digital signal processor. Firstly the dynamic flux imbalance of the output transformer caused by the truncation error in ordinary PI arithmetic is analyzed based on fixed-point DSP. And then a new solution of sampling the instantaneous primary current and introducing the on-line calculated dynamic bias current component into the voltage regulation arithmetic is presented. The configuration of the improved digital voltage regulation consists of two parts: an ordinary PI regulation and an additional zero-voltage regulation. Output of the zero-voltage regulation, which is the calculated bias current component, is introduced into the ordinary PI regulation to amend the voltage reference and compensate the DC component in output voltage. Design guidelines and experimental results verify the excellent performance of the method.