Abstract:
The triangular wave carrier signal via the resistance capacitance coupling will affect the transmission characteristics of the PWM controller. In order to study the change of coupling signal after resistance capacitance coupling and its influence on the transmission characteristics of PWM controller, In this paper, by analyzing the model circuit and using Laplace transform method, the time-domain response of the capacitance-resistance coupling circuit under the excitation of the triangular wave signal is solved, Then the influence of coupling parameters on the coupling effect and the transmission characteristics of the PWM controller is obtained by the simulation of the specific data, and the reasons for these effects are analyzed. Through the simulation experiment, it is found that the coupling capacitance value is too small, will cause the coupling effect is poor, which makes serious waveform distortion coupling, PWM controller output and the expected deviation, cannot meet the requirements, at the same time, the time constant of the coupling circuit is small, also can make the coupling effect is poor, affecting the transmission characteristics of PWM. Finally, the reference values of coupling capacitance and time constant in engineering applications are also given.