Medium-Voltage Drives (MVD) - Pulse Width Modulation (PWM) Techniques

Abstract

In order to keep up with rising customer demand, more and more MVDs are being used to fuel MV motors. Power delivery to a load may be modulated by changing the pulse width. A digital signal might be transformed into an analog one using the pulse width modulation (PWM) technique. A pulse-width modulated (PWM) signal, which takes the form of a rectangular wave, alternates between ON and OFF states. The characteristics of a pulse-width modulation (PWM) signal are determined by its frequency and duty cycle. The inverter's switching and harmonic losses may be minimized by using PWM technology. In order to cut down on switching loss, hybrid PWM inverters operate half of their switches at low frequencies while operating the other half at high frequencies. Because switching loss and heat dissipation from switches are unpredictable, system reliability is reduced. It's possible that switching will lead to poor heat dissipation and power losses. However, problems like these may be lessened with the use of a PWM technique. By alternating between low-frequency and high-frequency signals, the output voltage and frequency may be adjusted, which in turn reduces the power supply's harmonic content. Methods such as Multiple Space Vector Modulation, Selective Harmonic Elimination, Multilevel Carrier Phase Shifted, and Multilevel Carrier Level Shifted Pulse Width Modulation has been considered. However, although these methods effectively reduce higher-order harmonics, it is more complex to increase inverter efficiency in a way that does not introduce additional losses. To eliminate these harmonics, a filter is made. Comparisons are made between sinusoidal PWM, PWM with a phase angle of sixty degrees, and trapezoidal PWM in terms of performance. The study tracked the effects of modulation index and carrier frequency adjustments on inverter output.