Haruo Terai

Comparative performance evaluations of IGBTs and MCT in single-ended quasi-resonant zero voltage soft switching inverter

The simple and low-cost operation at zero voltage soft commutation voltage-fed quasi-resonant PFM inverter is widely used, which is more suitable and cost effective for consumer induction heated cooking appliances. This paper presents feasible performance evaluations of each generation IGBT developed and MOS controlled thyristor (MCT) incorporated into the simplest voltage source type quasi-resonant PFM inverter operating in zero voltage soft switching transition mode for induction heated loads. New generation IGBT in addition to MCT have been improved in order to reduce their conduction power losses which are based on their lowered saturation voltage characteristics in addition to high current density. In the first place, each generation IGBT is respectively built and tested on the basis of a single-ended quasi-resonant PFM inverter circuit operating at zero voltage soft switching commutation. In the second place, the power loss-temperature analysis of the latest IGBT with a trench-gate structure is discussed and evaluated from an experimental point of view. In the third place, the further reduced saturation voltage and conduction power loss characteristics of attractive MCT are presented in comparison with the 3rd generation IGBT by using zero voltage high current density soft-switching inverter for consumer high frequency power application.

A novel time ratio controlled high frequency soft switching inverter using 4/sup th/ generation IGBTs

This paper presents a novel prototype of active voltage-clamping capacitor-assisted soft switching PWM inverter operating at a constant frequency variable power (VPCF) regulation scheme, which is suitable for consumer high-power induction-heating cooking appliances. New generation IGBT with a trench gate is particularly improved in order to reduce conduction loss due to its lower saturation voltage characteristics. The soft switching load resonant and quasiresonant inverter using the latest IGBTs designed specially, is evaluated from an experimental point of view.

Utility-interactive solar photovoltaic power conditioner with soft switching sinewave modulated inverter for residential applications

A utility interactive sinewave pulse width modulation soft commutation inverter using trench-gate IGBTs for the solar photovoltaic power conversion conditioning and processing with a high frequency transformer link is presented for residential applications. As compared with the conventional full-bridge hard switching sinewave PWM inverter with a high frequency AC link, the simplest single-ended quasi-resonant soft switching sinewave modulated inverter with a sinewave duty cycle pulse control scheme is implemented, resulting in size and weight reduction, low-cost and efficiency. This paper presents a prototype circuit and system of the single-ended zero voltage soft switching sinewave PWM inverter for solar power conditioner, along with its operating principle and unique features. In addition to these, this paper proposes a control implementation to deliver high quality output current. Major design of each component and the power loss analysis under actual power conditioning and processing is also discussed and evaluated from an experimental point of view. A newly-developed utility-interactive sinewave power conditioning processor which has 92.5% efficiency at 4 kW output is demonstrated herein. It is designed for 540 mm-300 mm-125 mm in size and 20 kg in weight.

Boiling Point Detector for Surface Cooking Unit

The new type of boiling point detector is discussed which detects the boiling point of water in a container irrespective of the volume of water or the type of container. This detector consists of the sensor unit using a thermistor and the signal processor unit using a one-chip 4-b microcomputer. The sensor unit is covered with a stainless casing. It is located at the center of the coil heater and comes In contact with the bottom of the container in place. At the signal processor unit, the temperature signal from the sensor unit is applied to the integral A-D converter, and the digital value is calculated by the microcomputer to detect indirectly the temperature rise of the water in the container. The results are stored in the memory of the computer and are compared to determine the boiling point. As a result of the experiment, the boiling point detection accuracy is higher than 95°C and within 2 min after reaching 100°C when the volume of water is 0.5-2 L and the container is made of aluminum, stainless steel, or iron.

Edge resonant soft switching PWM inverter using trench gate IGBTs for induction heating

This paper presents a novel prototype of active voltage-clamping capacitor-assisted edge resonant soft switching PWM inverter operating at a constant frequency variable power (VPCF) regulation scheme, which is suitable for consumer high-power induction-heating cooking appliances. New generation IGBT with a trench gate is particularly improved in order to reduce conduction loss due to its lowered saturation voltage characteristics. The soft switching load resonant and quasiresonant inverter designed using the latest IGBTs is evaluated from an experimental point of view.

A novel type soft switching PWM DC-DC converter with high voltage transformer link for magnetron drive

A circuit topology of an active voltage clamped quasi-resonant PWM inverter circuit is presented in this paper for a magnetron drive. The resonant voltage of the main active power semiconductor switch is clamped by the subsidiary active power semiconductor switch and capacitor which is connected in series with the main switch. One of the salient features of the circuit is to have ZVS-PWM output power control under a fixed frequency. Its power factor and current harmonics in the utility AC side can be regulated by a variable frequency PWM strategy under a limitation condition of the allowable anode current of its from a viewpoint of the magnetron lifetime.