As global manufacturing transitions toward stricter energy regulations and decentralized green grids, the demand for highly efficient industrial heat treatment has never been greater. At EMA Indutec, we have spent decades engineering frequency converters that balance massive power output with razor-sharp control. Today, we are proud to introduce a unique inverter control technology:
TIV-SH – Hybrid Modulation for Resonant Power Inverters
Induction heating systems use resonant power inverters for which EMA developed a hybrid modulation method called: TIV-SH. It combines the benefits of the established Phase-Shift-PWM (PSPWM) and the Pulse Density Modulation (PDM). It creates a highly efficient and precise power control method.
PSPWM offers fast and equal power tracking, including high control accuracy. PDM offers low switching losses because the switching takes place in a low current state of the resonant cycle. TIV-SH utilizes both systems in a common control process. It combines short puls blocks with a variable pulse width. Resulting in a high control resolution and fast adjustment of the output power.
Selective pulse skipping with simultaneous higher modulation depth of the remaining pulses results in significantly fewer switching operations with losses. At the same time, controllability stays unchanged. This is key for applications that need a fixed zero transition.
The basic procedure is described in [1, 2, 3].
This method is especially beneficial in full bridge inverters and other resonant circuit-based power electronics where you require a high efficiency, lower switching losses and precise power control.
TIV-SH is developed by EMA and is used in EMAs power electronic systems. The combination of high energy efficiency, good controllability and reduced load of the used parts enables powerful inverter systems for demanding industrial applications.
Sources:
[1] J. Shen; H. Ma; W. Yan; J. Hui; L. Wu: PDM and PSM Hybrid Power Control of a Series-Resonant Inverter for Induction Heating Applications; ICIEA, 2006.
[2] P. Herasymenko: Combined PS-PDM Control Method for Voltage-Source Series-Resonant Inverter; Przeglad Elektrotechniczny; ISSN 0033-2097, No. 5, 2021.
[3] S. Wang; Y. Konishi; O. Koudriatsev; M. Nakaoka; Voltage-Fed Pulse Density and Pulse Width Modulation Resonant Inverter for Silent Discharge Type Ozonizer; IEEJ Transactions on Industry Applications, Vol. 120-D, No. 4, 2000, pp. 587–592.