Mobile QR Code QR CODE : The Korean Institute of Power Electronics
Title Harmonic Suppression of the Input Current in Microwave Oven Using LLC Resonant Inverter
Authors Kyelyong Kang ; Heung-Geun Kim ; Honnyong Cha
Page pp.225-230
ISSN 1229-2214
Keywords HFT(High Frequency Transformer) ; Magnetron ; LLC resonant inverter ; Variable current controller
Abstract This paper proposes a parametric design of an LLC resonant inverter used for a microwave oven. To improve the harmonic performance of the microwave oven, a current controller with a variable PI gain is proposed. Due to the recent strengthening of harmonics regulations, inverter control technology for microwave ovens is now required to satisfy harmonic performance. In an LLC resonant inverter, the voltage gain varies remarkably depending on the magnetron voltage, output power, and input voltage. To satisfy harmonic performance, a controller that can maintain operation in the zero-voltage switching (ZVS) region and control changes in voltage gain is required. The modified design of the LLC resonant inverter ensures ZVS operation even when the magnetron is heated. Application of the variable current controller improves harmonic control according to the instantaneous gain curve change. The validity of the proposed power control with a variable current controller is verified by experiments with a 1200 W microwave oven.