A method of regulating a DC bus voltage with a DC crowbar controller, comprising: determining a value of the DC bus voltage; determining a value of an overvoltage regulation reference voltage; generating a modulation voltage waveform; determining a voltage difference between the determined values of the DC bus voltage and the overvoltage regulation reference voltage to detect a shift in the DC bus voltage away from normal operational values during a voltage irregularity; and processing the determined voltage difference between the values of the DC bus voltage and the overvoltage regulation reference voltage and limiting the processed voltage difference, wherein the processing and limiting are configured to generate an output that represents a voltage across the DC bus that is compared with the modulation voltage waveform for controlling a switching device; and regulating the value of the DC bus voltage by modulating a pulse width of a switching signal applied to the switching device during the voltage irregularity; regulating the value of the DC bus voltage further comprises: comparing a value of the limited output voltage with a value of the modulation voltage waveform; and switching on and off the switching device based on the comparison of the value of the limited output voltage and the value of the modulation voltage waveform. determining a value of the DC bus voltage; determining a value of an overvoltage regulation reference voltage; generating a modulation voltage waveform; determining a voltage difference between the determined values of the DC bus voltage and the overvoltage regulation reference voltage to detect a shift in the DC bus voltage away from normal operational values during a voltage irregularity; and processing the determined voltage difference between the values of the DC bus voltage and the overvoltage regulation reference voltage and limiting the processed voltage difference, wherein the processing and limiting are configured to generate an output that represents a voltage across the DC bus that is compared with the modulation voltage waveform for controlling a switching device; and determining a value of an overvoltage regulation reference voltage; generating a modulation voltage waveform; determining a voltage difference between the determined values of the DC bus voltage and the overvoltage regulation reference voltage to detect a shift in the DC bus voltage away from normal operational values during a voltage irregularity; and processing the determined voltage difference between the values of the DC bus voltage and the overvoltage regulation reference voltage and limiting the processed voltage difference, wherein the processing and limiting are configured to generate an output that represents a voltage across the DC bus that is compared with the modulation voltage waveform for controlling a switching device; and regulating the value of the DC bus voltage by modulating a pulse width of a switching signal applied to the switching device during the voltage irregularity; regulating the value of the DC bus voltage further comprises: comparing a value of the limited output voltage with a value of the modulation voltage waveform; and switching on and off the switching device based on the comparison of the value of the limited output voltage and the value of the modulation voltage waveform. comparing a value of the limited output voltage with a value of the modulation voltage waveform; and switching on and off the switching device based on the comparison of the value of the limited output voltage and the value of the modulation voltage waveform.