Inverter cutting power source with double close loop control

Through analyzing the shortcomings of the control system on the traditional cutting inverter, this paper presents the double close loop control system based on pole assignment for cutting inverter, which based on phase shift full bridge zero voltage switched (PS-FB-ZVS). This paper builds the small signal mode of PS-FB-ZVS PWM converter, and assigns the double close loop PI parameters by pole assignment. Though simulating and experiments, it can be seen that: (1) the stability and dynamic performance of the current internal loop are good; (2) voltage external loop can obtain invariable no-load voltage, reduce the no-load wastage, decrease the saturated probability of the transformer, and lessen the voltage stress of the output diodes; (3) the double close loop control system not only can overcome the shortcomings of the parallel loop about continually switching between two loop to realize seamless switching, but also can obtain quick dynamic response, small overshoot, little stability error, and strong robustness.