Yoshihiro Hatanaka

Novel load adaptive frequency tracking control scheme for high frequency inverter without PLL scheme

A Load adaptive frequency tracking control scheme that is named conduction time balanced loop (CTBL) for the high frequency inverter is presented without PLL scheme. Using this control method for the gate circuit of the high frequency inverter that operates in resonant frequency, it is realized to have both the power regulation function and the load adaptive tracking control function by one inverter, though the conventional PLL high frequency inverter cannot do. This paper describes the principle of the proposed control scheme with high frequency inverter operation and the relation between the CTBL and the power regulation by the phase shift modulation.

A method of power regulation applied to the high frequency inverter for the IH home appliances

This paper describes a power regulation concept; CFPDM (Commercial Frequency Pulse Density Modulation) of the high frequency inverter for induction heating home appliances. CFPDM is a new type of PDM and it is easy to put CFPDM into practical use for any circuit topologies without any additional switches and passive components. Conventional PDM (Pulse Density Modulation) enables the high frequency inverter to control the output power over a broad range and to realize high power conversion efficiency at the same time. However, the resonant frequency of non-smoothing filter is close to the duty frequency of PDM, which may cause other harmonic current problems. In CFPDM, the duty frequency is set to lower than the line frequency unlike PLL. Therefore CFPDM surpass the advantages of PDM and also avoids generating harmonic current. This paper shows the sample of CFPDM controller and the operation principle by using simulated results. A prototype soft switching SEPP high frequency inverter controlled by CFPDM has been tested. Some experimental results of it are shown finally.

Cost effective soft-switching PWM high frequency inverter with minimum circuit components for consumer induction heater

This paper presents a novel prototype soft-switching PWM high frequency inverter with minimum circuit components, which can achieve the wider and more stable soft commutation, simpler circuit configuration, smaller size, lower cost and higher-efficiency as compared with active voltage clamped ZVS-PWM and single-ended ZVS-PFM high frequency inverters developed previously. This quasiresonant soft-switching PWM high frequency inverter operating under ZVS and ZCS arms-related soft commutation is including the voltage-clamped ZVS-PWM inverter in the constant frequency variable power scheme as well as a single-ended ZVS-PFM inverter. The operation principle of soft switching PWM high frequency inverter treated here is described on the basis of the simulation and experimental results, together with its comparative operating performances in steady state. The practical effectiveness of a novel type high frequency soft-switching PWM inverter using state-of-the-art IGBT power modules is actuary proved for consumer induction heated appliances as cooker, super heated steamer and hot water producer.