spacevector

Space vector modulation (SVM) is a method used to control three-phase inverters in AC motor drives and power electronics. It represents instantaneous line-to-line voltages as a single rotating vector in the two-dimensional alpha-beta (α–β) plane, derived from the three-phase quantities by a Clarke transform. The inverter’s DC-link voltage sets the vector’s magnitude, while switching states produce the desired output. SVM uses the six active switching states and two zero states within each switching period to synthesize the reference voltage.

The reference vector, which corresponds to the desired output, lies in one of six sectors formed by the hexagonal space of possible vectors. The modulator computes the on-times (dwell times) for the two adjacent active vectors and a zero vector so that the average output matches the reference vector over the switching period. This approach yields a sinusoidal-like output with improved DC-bus utilization and reduced harmonic distortion compared with conventional sinusoidal PWM, often achieving notably higher fundamental output for the same switching frequency.

Implementation typically relies on digital controllers such as DSPs or microcontrollers and requires careful handling of dead-time and switching transitions to prevent short circuits. SVM is adaptable to two-level and multi-level inverters and is widely used in motor drives for induction motors and permanent-magnet machines, as well as in grid-connected converters and other high-performance power electronics applications.

See also Space Vector Electronics, a company known for motor-control hardware and tutorials that popularized SVM concepts.