Reduced-Order Models of Series Resonant Inverters in Induction Heating Applications

Abstract

Abstract--From the controller design framework, a simple analytical model that captures the dominant behavior in the range of interest is the optimal. When modeling resonant circuits, complex mathematical models are obtained. These high-order models are not the most suitable for controller design. Although some assumptions can be made for simplifying these models, variable frequency operation or load uncertainty can make these premises no longer valid. In this work, a systematic modeling order reduction technique, Slowly Varying Amplitude and Phase (SVAP), is considered for obtaining simpler analytical models of resonant inverters. SVAP gives identical results as the classical model-order residualization technique from automatic control theory. A slight modification of SVAP, Slowly Varying Amplitude Derivative and Phase (SVADP) is applied in this paper to obtain a better validity range. SVADP is validated for a half-bridge series resonant inverter (HBSRI) and for a highorder plant, a dual-half bridge series resonant inverter (DHBSRI) giving analytical second-order transfer functions for both topologies. Simulation and experimental results are provided to show the validity range of the reduced-order models.

Investigating the steady state mode of power inverters for induction heating

“…It should be underlined that when calculating a and K for discontinuous inverter current mode for Fig. 2 02   must be equal to  in the already given expressions (8) and (10).…”

“…The mathematical relationships between the parameters of the mentioned inverters are rather complicated [5], [8]- [10]. It has been proved that all the quantities in these second order topologies depend on two variables -the ratio between the controlling angular frequency and the generalized angular frequency (frequency coefficient) I n n /      on one hand, and the ratio between the damping coefficient and the generalized angular frequency I n n /      of the power circuit, on the other.…”

A comprehensive overview of power converter topologies for induction heating applications

“…Based on the power conversion stages, the IH converter topologies are classified into two types, namely dual-stage power conversion (AC-DC-AC) and single-stage power conversion (AC-AC). The most commonly used two-stage topologies are single-switch (SS) resonant inverters [13][14][15][16] half-bridge (HB) inverter [17][18][19][20][21] and full-bridge (FB) inverter. [22][23][24][25][26] These topologies are used to feed power, either to single or multi-loads, with additional modifications.…”

Steady-state analysis and design of phase-controlled class-D ZVS inverter

“…The resonant inverters [1][2][3][4][5][6][7][8][9][10][11][12][13] have broad applications ranging from wireless power transfer [3][4][5], RF power supply [6][7][8], induction heating [9][10][11], and power amplifiers for communication [12,13]. Frequency modulation control, which includes an LLC converter, is an effective means to control the output power in resonant inverters and converters.…”