A new modulation algorithm for voltage and current source inverters, based on AC-AC matrix converter theory

A pulse width modulation algorithm that is derived from AC-AC matrix converter theory is presented. The algorithm can be used to implement either a voltage-source or a current-source inverter, using only conventional bridge topologies. The resultant modulation strategy produces minimum low-order AC harmonics and is capable of being computed online in a single switching cycle by a low-cost microprocessor at switching frequencies of up to several kilohertz. The algorithm also allows independent control of the output waveform magnitude and frequency and provides for a wide range of operation without changing the switching frequency. The strategy guarantees DC source current continuity for the current source inverter topology while still allowing the AC output current to step change to a new value within one switching cycle. Physical implementation of the strategy is shown to be feasible even with a low-cost 8 bit microprocessor.<>