Steady-State Analysis of ZVS and NON-ZVS Full-Bridge Inverters with Asymmetrical Control for Induction Heating Applications

Abstract

This paper presents a steady-state operation analysis of full-bridge series-resonant inverters focusing on the distorted load current due to low-quality-factor resonant circuits in induction heating and other applications. The regions of operation based on the zero-voltage switching (ZVS) and non-zero-voltage switching (NON-ZVS) operations of the asymmetrical voltage-cancellation control technique are identified. The effects of a distorted load current under a wide range of output powers are also analyzed for achieving a precise ZVS operating region. An experimental study is performed with a 1kW prototype. Simulation and experimental studies have confirmed the validity of the proposed method. An efficiency comparison between the variable frequency method and the conventional fixed-frequency method is provided.

A comparison of asymmetrical control strategies for domestic induction cooking applications with low-quality factor loads

“…To simplify the analysis, the parasitic inductance and capacitance are neglected. The magnitude of the impedance Ẑ eq of the series resonant circuit and the impedance phase angle of harmonic components are found as [17], Fig. 4.…”

“…For domestic low-cost vessels, the quality factor value is even lower due to a high damping factor value. The output current is unavoidably distorted and may result in hard-switching conditions during a switching transition at the end of the positive cycle, resulting in non-zero-voltage switching (NON-ZVS) [17]. This means that the switching frequency is required to be much higher than the resonant frequency for ZVS operation.…”

Application of Frequency Control Techniques for Hot Tensile Testing in Induction Heating

“…Two types of inverters are installed into high frequency induction heaters: voltage source and current source. In the past, series and parallel resonant inverter circuits were used in conjunction with half-bridge and full-bridge to reduce switching loss and increase circuit efficiency [7][8][9][10][11][12][13][14][15][16][17].…”

Design, Analysis and Experimental Verification of the Self-Resonant Inverter for Induction Heating Crucible Melting Furnace Based on IGBTs Connected in Parallel

“…A converter structure with proven application in induction heating, giving high power density and the ability to operate with soft-switching, is the full-bridge circuit with a parallel or series resonant tank, based on different modulation techniques, such as Phase-Shift Modulation (PSM), Pulse-Frequency Modulation (PFM), Pulse-Density Modulation (PDM) and Asymmetrical Duty-Cycle (ADC) [25][26][27][28][29][30][31]. These types of modulation offer flexible control over the wide range of output powers [25].…”

“…These inverters applied for induction heating can have a good match with a Power Factor Correction (PFC) stage [26]. An additional characteristic of the PSM is the ability of the ZVS to be achieved for the required power range under regulation with variable switching frequency [27]. It has been shown that the use of variable switching has a better efficiency than a fixed switching frequency.…”