This article presents a new zero-current switching technique for a single-phase full-bridge sinusoidal pulse width modulation inverter. Two auxiliary switches and a resonant branch are attached to a conventional single-phase full-bridge inverter. The resonant branch can be controlled independently from the main power switches. This technique decreases turn-on and turn-off switching losses and does not require any snubber capacitor. The technique can be applied to DC/DC converters and DC/AC inverters with suitable switching algorithms. Both theoretical analysis and application of the proposed technique have been realized. It was seen that the proposed technique has 45% less switching losses and better performance than the hard-switching technique for the same load and switching frequency. The experimental results also approve the effectiveness of the zero-switching technique.

A Novel Control Technique for Soft-switching Sinusoidal Pulse Width Modulation Inverter

A new family of three-phase resonant inverters with a high-frequency (HF) ac-link and zero-voltage switching is introduced. In these inverters, the maximum output voltage is not limited to the dc-bus voltage, and the converters can conveniently operate in the step-up and step-down modes in both the forward and the reverse directions. The HF ac-link of the converters is composed of an ac inductor and a small ac capacitor. The link inductor is the main component for transferring power, and the link capacitor provides partial resonances for the zero voltage switching of all the power switches. The link inductor can be replaced by a small HF transformer to achieve galvanic isolation. This transformer is substantially smaller and more efficient than the conventional line-frequency three-phase isolation transformers. The total number of switches of the proposed unidirectional dc–ac converter is as low as seven, suitable for the low power applications. By adding three more switches, the converter can transfer power in both directions. The basic operation of the new converters includes six modes and is described in detail. A detailed analysis of the introduced topology is also given to reveal its behaviour at various operating points. Several simulation and experimental results are given to demonstrate the effectiveness of the proposed power converters.

Step-up/down three-phase resonant high-frequency ac-link inverters

In this paper, a new control strategy for zero-current transition technique is suggested to constant voltage constant frequency sinusoidal PWM inverter. This strategy consists of a resonant arm and auxiliary switches, which are connected to a standard single-phase full-bridge voltage source inverter and also to a proportional integral voltage controller. The main and auxiliary switches can be separately controlled. The suggested strategy is able to reduce switching losses successfully, and also it does not need any snubber circuit. By using appropriate switching algorithms, the strategy can be applied to uninterruptible power supplies, photovoltaic systems and DC/AC inverters as well. In this study, not only the theoretical analysis but the simulations of the suggested strategy have been carried out effectively. From the simulation results, it has been shown that the suggested strategy yields 30% less switching losses and has better performance when compared with the hard switching strategy for the same operating condition, including the conditions of the load and the switching frequency. Eventually, the suggested control scheme verified by the simulation results proves that it can achieve low THD values in addition to less switching losses.

Zero-current switching technique for constant voltage constant frequency sinusoidal PWM inverter

Dynamic performance of a dead-band controlled capacitor charging type inverter

A Novel Control Scheme for Buck-Boost DC to AC Converter for Variable Frequency Applications

A novel zero-voltage-switching (ZVS) DC/AC inverter is proposed. The proposed inverter can not only provide output voltage that is higher or lower than DC input voltage but can also use the pulse-width modulation (PWM) control technique. Furthermore, in the proposed inverter, besides operating at constant frequency, all semiconductor devices operate at soft-switching without additional voltage stress and current stress. A design example of 1000 W ZVS-PWM buck-boost inverter is examined to assess the inverter performance

C.-m. Wang

Papers

Zero-voltage-switching DC/AC inverter