Soft switching AC/DC/AC converter with current freewheeling circuit

The modified DC-link (MDCL) converter generating sinusoidal output voltage solved the drawbacks of soft switching converters, such as high voltage stresses of devices and/or many device counts. However, it also has problems such as the high peak device current and a wide variation of switching cycle interval. An improved soft-switching AC/DC/AC converter based on a high-frequency link is proposed to solve these problems. By introducing a current freewheeling circuit, it separates the main power flow from the resonating circuit during the commutation interval. As a result, the peak current is limited to around the link current and the switching cycle interval is controllable. Furthermore, the VA ratings of the devices are considerably reduced. Therefore, this converter combines the desired features of the MDCL converter with its improvements.<
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