Mathematic model of ambipolar selected harmonic elimination PWM was explained briefly. The nonlinear surmounting equations of eliminating the specified harmonic were provided. and the new resolving methods for these equations were discussed. and the key parameter of switch angle was deduced. https://safeersappliancers.shop/product-category/neff-b1gcc0an0b-n-30-built-in-circotherm-single-oven-stainless-steel-60cm/