Abstract
This paper proposes a feed-forward control in a halfbridgeresonant dc page link inverter. The configuration of feed-forwardcontrol is based on synchronous sigma-delta modulation and the halfbridgeresonant dc page link inverter consists of two inductors, onecapacitor and two power switches. The simulation results show theproposed technique can reject non-ideal dc bus improving the totalharmonic distortion.
Keywords—Feed-forward control, Resonant dc page link inverter,Synchronous sigma-delta modulation.
I. INTRODUCTION
THE dc bus voltage of resonant page link converter techniques isresonated by an LC network and power switches. Theoscillation of this network gives rise to instants of zerovoltage. Therefore, the output power switches are connectedto the network such that switching occurs at such zerocrossing, and then switching losses are significantly reduced[1].However, the resonant dc page link system operates well undercondition of an ideal dc bus (ripple-free) obtained by means ofa passive dc page link filter. To achieve a very low ripple, however,requires large filters. This increases the cost, size, and weightand reduces the overall efficiency of the conversion process.Furthermore, in a practical converter system, it is difficult torealize an ideal dc bus for a number of practical constraints.Most of the dc bus converter systems use a front-end diodebridge for ac–dc rectification. The ripple in the dc bus isundesirable, as it causes low-order harmonics appearing in theinverter output. These harmonics are difficult to filter out andcause deterioration in the quality of the output voltage.This paper therefore proposes a feed forward control usingsynchronous sigma-delta modulation (SSDM) configuration.This control technique is used to control the newconfiguration of half-bridge resonant dc page link (HB-RDCLI).The features of the proposed pattern generator are highlighted.The simulation results show the ripple rejection capability ofthe proposed control technique.
II. RESONANT DC LINK EQUIVALENT CIRCUIT
Fig. 1 shows the resonant dc page link equivalent circuit. Theswitch Ms is turned on by the short pulse to provide initialcondition of inverter operation. When Ms is opened, the dc bus oscillates and returns to zero generating, v (t) d , whereupon Ms is turned again. Then, this process can be repeated.So, it is possible that the power switches of inverter circuit canoperate at high frequency rate without switching losses if theyare turned on and turned off at zero crossing of v (t) d .Therefore, the well-established modulation techniques such aspulse-width modulation (PWM) are not suitable forcontrolling this inverter system. But, the characteristic of zerocrossing switching exists in a suitable set of integral pulsemodulation techniques collectively known as deltamodulation, comprise linear delta modulation, processintegration, and sigma delta modulation [2]. The resonant linkvoltage,


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