High-Precision Control for ZVS Inverter to Reduce Nonlinear Distortion of Semiconductor Voltage Drop

Owing to low switching loss and low dead-time effect, the extra-LC auxiliary resonant snubber converter as a zero-voltage-switching inverter is very suitable for high-precision applications. However, the semiconductor voltage drop caused by the on-resistance is one of the main problems in the high-precision application, which has not been researched before. Besides, the conventional forward compensation method leads to obvious error due to the nonlinear characteristic of on-resistance. Thus, this letter proposed a high-precision control through controlling the auxiliary circuit current to reduce the nonlinear distortion caused by the semiconductor voltage drop. Compared with the forward compensation method, the on-resistance of the switches is not required to be estimated. In this letter, the voltage error caused by the on-resistance is analyzed. The proposed high-precision control is introduced. The experimental results demonstrate that the quality of the output current and voltage is improved by utilizing the proposed control method.

I. Introduction

In High-Precision applications, such as the lithography machine, power converters are used to provide the output currents to drive electromechanical actuators, such as voice coil motors and permanent magnet linear motors. Power converters are required with high current precision and high bandwidth to achieve nanometer-position error range of the system [1]. Thus, high switching frequency is the least important requirement. However, as the switching frequency increases to hundreds of kilohertz, large switching loss and severe electromagnetic interference noise occur. In addressing the problems above, the soft-switching technique is one of the best solutions.