In a single phase inverter, a PWM bipolar voltage-switching scheme is used with the following parameters: m=35, ma=0.5, Vd=300 V and the output frequency, fo=45 Hz. (a) Calculate the rms values of the fundamental voltage and its harmonics at these frequencies: 1575 Hz, 1665 Hz and 3285 Hz. (see a table in the formula sheet and state your approximation method) (15 marks) (b) Can you suggest a method to reduce the output voltage harmonics without changing the switching frequency? Sketch the output voltage waveform of the proposed method (for only one switching cycle) and explain the method. (10 marks) S₁ Load S3