Temperature control of a double-coil drive type IH cooker by means of the PDM control provided with audio noise suppression

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.

Electrónica de potencia para el calentamiento por inducción doméstico: revisión del estado del arte

“…Algunos estudios han regulado la potencia con el PDM logrando variar el intervalo de suministro de corriente a los inductores, encontrando como principal inconveniente el incumplimiento de normas de parpadeo o destello, disminuyendo el calentamiento óptimo del recipiente [46], [54]. Estudios realizados entre el año 2007 y 2008 consideraron: IRS de onda completa en puente con control de potencia PDM, conmutación por ZVS y ZCS para minimizar las pérdidas de conmutación [55]; nuevas topología de IRP para calentar recipientes no magnéticos con un control de temperatura por PDM utilizando el principio de superposición [56]. Fueron también evaluadas nuevas topologías de IRP con conmutación suave por ZVS tipo boost o elevador de una sola etapa con enclavamiento activo, con doble esquema de control ing.cienc., vol.…”

Simple Lossless Inductive Snubbers-Assisted Series Load Resonant Inverter Operating under ZCS-PDM Scheme for High-Frequency Induction Heating Fixed Roller

“…Generally, pulse modulation methodology is employed in the high-frequency inverter to achieve output power regulation for IH application. Mainly, there are three types of modulations, which are as follows: (i) pulse frequency modulation (PFM) [15,16], (ii) pulse width modulation (PWM) [17] and (iii) pulse density modulation (PDM) [18][19][20][21]. The simplest modulation technique is PFM.…”

Analysis of the Acoustic Noise Spectrum of Domestic Induction Heating Systems Controlled by Phase-Accumulator Modulators

“…The noise sources that exist in IH appliances are enumerated in [23]. In [24], a constraint in the PDM frequency is set to suppress audio noise from experimental results.…”