The switching power supply has been generally used in various fields by the feature
of stability of output voltage，easy performance and simplicity. In AC power supply，
various researches for the application of the digital control is advanced by using the
DSP. Various DSPs for control （including ADC，PWM timer，and Mass memory）have
been specially developed from such a background. We have researched the applications of the next generation of controls such as Neural Network and H infinite control. However，this research hasn't yielded much practical value yet because these controls require expertise and a long time for programming. In this paper I proposed new digital PWM method using a DSP（ADSP-2187）. In this method，the error voltages are entered in to the DSP and the DSP chooses the optimum on-duty regulations from internal memory. Moreover，the DSP consistently monitors the control results and modifies the on-duty data as needed. In addition，the electric power efficiency is improved from 83 to 88% by using unipolar PWM by which dead time is decreased as much as possible.
The analysis of the magnetic field on an induction heating （IH） cooker has not been studied in detail. In the previous paper，we measured distributions of the temperature and the relative magnetic field. From these measurements，we found that the horizontal component of the magnetic field had almost the same form as that of the temperature distribution. In this paper，we analyzed the magnetic field on the IH cooker using the finite element method. The analyzed result well agrees with the measured one. This result will be useful to the designing of the induction coil and the study of the electromagnetic environment in which a human body may be affected.