This paper describes the effect of power supply noise on the acoustic noise and pan vibration when making use of the IH (Induction Heating) cooker. Recently, due to the spread of power electronics device, noise superimposed on the AC power supply is a problem. It has been reported that the acoustic noise provides discomfort feeling when using the IH cooker. Other studies have concluded that the vibration of a pan due to the induction heating is the noise source. In this paper, it is elucidated the influence on the pan’s vibration and the acoustic noise when the amplitude of the noise superimposed on the power supply is changed and it is clarified the lowest power supply noise level, which is corresponding to the recognizable audible noise.

No abstract

II. PROPOSED SYSTEMHigh effective induction heating of nonmagnetic metal is very difficult.One achieved method is inducing high frequency eddy current in a metallic load using high frequency coil current. Ho\vever, when the coil frequency is made high, switching loss of IGBT becomes a problem. Moreover, if high frequency current that exceeds 20 kHz is applied to the coil, whose wire has the diameter of a regular IH coil, then skin effect of the coil becolnes a probleln. From these reasons, we here adopted regular switching frequency and heating coil that are used in the regular IH cooker on the market. Fig. 2. shows the model of a newly constructed IH cooker corresponding to the all metals. A double-coil is arranged under a metal load. If two currents with different phase are electrified into each of two coils, magnetic field of twice as high frequency can be generated. Eddy current is induced \vithin a metal whose frequency corresponds to this magnetic field. As shown in Fig. 2., high frequency eddy current can be really obtained without raising the s\vitching frequency of IGBT ; only by shifting the phase of the coil currents as much as 180 degrees. Capacitor Cs connected in parallel with the coil is adopted for the resonance to realize zero volt switching (ZVS). Therefore, nomnagnetic Inetal can be heated without increasing switching-and coil-loss.Abstract-This paper discusses the achievement of the temperature control method of a double-coil drive type induction heating (IH) cooker. Double-coil drive type IH cooker invented by us, is the new induction heating method which can heat nonmagnetic metals. We have already proposed the PDM temperature control method which can be adopted in the proposed system. However, there gives rise to the audio noise trouble when the metal be heated. We investigated the cause of this noise. In this paper, PDM temperature control method that can suppress the audio noise is proposed.The heating characteristic of this new PDM temperature control method is described in this paper. And, active power and temperature characteristic to the PDM-duty-ratio were made clarified. As a conclusion, we report on the successful results on the PDM temperature control system that can be applied for the doublecoil drive type IH cooker, which enables audio noise suppression.

No abstract

This paper discusses high frequency acoustic noise generated by an IH cooker. Mechanism of high frequency acoustic noise generation is clarified by the experimental study. Recently, influence of the electromagnetic wave on the human body is worried. The symptoms; user of home electronics appliances feels; are headache and nausea. There is a report that some users who are using IH cooking heater also feel these symptoms. We have discovered that the high frequency acoustic noise, which is generated from an IH cooker, indicates strong-level sound pressure. High frequency strong acoustic noise must not be ignored, because its danger on our health is reported scientifically and medical standpoints. Then, it becomes necessary to examine the suppressing method of high frequency acoustic noise. In this paper, generating mechanism of the high frequency (20 kHz ~) acoustic noise is made clarify by the experiments. Further, we have experimentally cleared that the lid of a pan has important effect on the suppression of the high frequency acoustic noise.