Seiki Igarashi

A new di/dt control gate drive circuit for IGBTs to reduce EMI noise and switching losses

In this paper, a new di/dt control gate drive circuit for IGBT devices is proposed. By this circuit, the switching performances of IGBT such as dv/dt, di/dt, surge voltage and also switching losses are reduced. This scheme can also eliminate a snubber circuit from the inverter system. From experimental tests, the EMI noise level is reduced by more than 15 dBuV/m as compared with conventional systems.

An active control gate drive circuit for IGBTs to realize low-noise and snubberless system

This paper describes a novel gate drive circuit for IGBTs to realize low-noise and snubberless system. This gate drive circuit controls the gate voltage to suppress the collector current variation ratio di/dt, which causes the reduction of surge voltage and voltage variation ratio dv/dt at the switching operation. The turn on di/dt and turn off di/dt are detected by the secondary winding of a saturation type reactor inserted into the counter-arm and the wiring inductance voltage at the emitter terminal, respectively. The experimental results and simulation results indicate that the surge voltage and dv/dt can be reduced without increasing the switching loss, allowing snubberless, low noise operation of IGBTs.

Analysis and reduction methods of EMI radiational noise from converter system

This paper describes a mechanism and reduction methods of EMI radiational noise on IGBTs. The radiational. Noise is generated by oscillating current flowing through the IGBTs output capacity and the snubber circuit. The oscillating current is forced to flow by the high dv/dt rates of the IGBT switching operation. The radiational noise can be analyzed by frequency evolution of the oscillating current. In addition, it is indicated that using a di/dt control gate drive circuit is effective as a means for reducing the radiational noise. The effect of this method has been verified by experimental and simulational results.

Analysis and reduction of radiated EMI noise from converter systems

It is well known that high dv/dt rates on switching devices are the source of EMI noise. This paper describes a mechanism and reduction methods of radiated EMI noise on IGBTs. The radiated EMI noise is generated by oscillating current flowing through the IGBTs output capacity and the snubber circuit, which we call equivalent circuit of radiated EMI noise. The oscillating current of the equivalent circuit is forced to flow by high dv/dt rates of IGBT switching operation. Radiated EMI noise can be analyzed by frequency evolution of oscillating current. The results of this analysis show the relationship of high-frequency impedance of the equivalent circuit to radiated EMI noise, as well as the behavior of the IGBTs switching voltage waveform. In addition, it is indicated that using a di/dt control gate drive circuit is effective as a means for reducing radiated EMI noise. It is clarified that the standard for industrial equipment of CISPR can be satisfied by using the proposed gate drive circuit. The effects of the method have been verified by experimental and simulational results.

Soft-switching type multiple-chip power device

A soft-switching type multiple-chip power device (M-Power) has been presented. The power supply that applies M-Power satisfies energy saving, low-EMI noise and low-input current distortion requirements while being compact. In this paper, the features of this power supply are introduced. High efficiency and low-EMI noise are achieved by applying a novel soft-switching circuit, and low-input current distortion is achieved by using a novel one converter-type power factor correction circuit. Low-dissipation losses while in standby mode are achieved using a standby mode control that operates at a lower switching frequency than that of normal mode.

Control methods of current balancing for parallel connected IGBTs

This paper describes control methods of current balancing for parallel connected IGBTs. These methods control a gate voltage to realize the current equally during switching and static periods. The effect of the methods has been verified by experimental and simulation results.

A novel gate drive circuit for low-loss system using IGBT saturation voltage characteristics

This paper proposes the new gate drive circuit for IGBTs to reduce the turn-off loss. The feature of the circuit is to drive an IGBT with plural gate resistors which were settled by the turn-off current levels. From the experiment and simulation results, the turn-off loss was cut to more than 50% in comparison with the conventional drive system.