High Voltage Gain Half-Bridge Z-Source Inverter with Low Voltage Stress on Capacitors
Abstract
In this paper, a new topology for half-bridge Z-source inverter (HB-ZSI) is proposed. The proposed topology has only one impedance network. Unlike to the conventional half-bridge inverter, the proposed topology can provide zero voltage level at the output. It also increases output voltage level and stabilizes it in the desired value. Capacitor voltage stress in the proposed topology is low and therefore nominal voltage of capacitor and cost decreases. In this paper, the steady state analysis of the proposed inverter in two new operations which are named synchronous operation of diodes (SOD) and asynchronous operation of diodes (AOD) is conducted based on mathematics calculations. A method to obtain high voltage gains by cascading the Z-network and combining middle inductors is presented that leads to cost, size and weight reduction. Comparison a the proposed converter with conventional ones shows its excellent performance. The experimental results have good agreement with analytical analysis for the proposed topology.
EXISTING SYSTEM:
In, for industrial applications such as electroplating and electrochemical, the Zsource half-bridge converter has been presented, in which, instead of putting two impedance networks, only one impedance network is required. In half-bridge Z-source inverter (HB-ZSI) with one impedance network, capacitors’ voltage stress is high and the output voltage waveform has one positive level and one negative level that limit the applications. In, a quasi-Z-source half-bridge galvanically isolated dc/dc converter has been presented. The topology could be envisioned as an alternative to the boost half-bridge dc-dc converter but the benefit of its symmetric structure reduces the threat of transformer saturation due to the dc flux. In, the half-bridge impedance source converter has been simplified by the implementation of the asymmetrical halfbridge concept. However, the asymmetrical half-bridge topology has only on ST state per switching period; so, its passive elements have large values. Based on provided cascading method in the full-bridge step-up dc/dc converter with cascaded quasi-Z-source networks has been presented. The presented cascaded QZSI has voltage boost and buck functions in a single stage, continuous input current, and improved reliability. The developed topology for switched-Z-source inverter based on cascaded switched inductors cells has been presented. Although developed topology has high voltage gain but voltage stress on capacitor is high. In , a topology for half-bridge switched boost inverter based on has been presented. This inverter uses more active elements rather than capacitors and inductors. By using more active elements, switching losses can reduce efficiency.
PROPOSED SYSTEM:
In this paper, a new topology for half-bridge Z-source inverter is proposed. In upcoming sections, first the proposed topology is introduced then different operating modes are analyzed and the critical inductances between SOD and AOD are calculated. Also extension of the proposed topology is discussed to obtain higher voltage gains. Comparison of proposed converter with conventional topologies is also provided. In the last section, the correctness operation of the proposed topology is validated by experimental results the power circuit of the proposed inverter with one impedance network. According to this figure, the proposed half-bridge converter consists of inductors an L , capacitors 2 C and 1 C , diodes 2 D and a D , switches b S and S , output load and two dc voltage sources with amplitude of 2 V . The proposed topology can be used in electroplating.
CONCLUSION
In this paper, a new topology for Z-source half-bridge inverter is proposed and its various operating modes were studied. Also, critical inductances between SOD and AOD were calculated. The equations of voltage and current of all elements and also voltage gain of the proposed inverter were calculated. Approach to reach high voltage gain through the series Z-networks and merging middle inductors which lead to less cost and weight were presented. Comparison results of the proposed inverter with various conventional inverters in terms of voltage gain and stress across capacitors prove its advantages. The proposed inverter against conventional half bridge topology can produce zero voltage level at output, too. Compatibility of results from experimental with the results extracted from theoretical calculation confirms the accuracy of content provided.
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