Adaptive controller for d-statcom in the stationary reference frame to compensate for reactive and harmonic distortion under unbalanced conditions

A controller providing a control vector to a three-phase voltage source inverter, each phase of the voltage source inverter having an output capacitor and an output resistor coupled across the voltage source inverter, the voltage source inverter coupled to a corresponding phase of a three-phase power distribution system via a corresponding inductor, the three phase power distribution system providing a source voltage and a source current for each phase to a corresponding three phase load:

• a source current module operative to provide a signal indicative of the value of the source current in each phase;
• a source voltage module operative to provide a signal indicative of the value the source voltage in each phase;
• a three-phase to stationary coordinate converter operative to convert the three-phase source current value into a source current value and to convert the three-phase source voltage value into source voltage value in stationary coordinates;
• an output voltage module operative to provide a signal indicative of the output voltage across the output capacitor;
• a reference voltage;
• a control vector processor including;
• an outer loop controller receiving the reference voltage, the output voltage, and the source voltage value, the outer loop controller configured and arranged to provide an source current reference value as a function of the difference of the square of the reference voltage and the square of the output voltage;
• an adaptation processor coupled to the three phase to stationary coordinate converter module and receiving the source current therefrom, the adaptation processor operative to provide an estimate of a plurality of predetermined harmonic components of the periodic disturbance which is a function of the unknown system parameters, the source current, the source voltage, and their time derivatives in stationary coordinates;
• an inner control loop controller coupled to the three phase to stationary coordinate converter module receiving the source voltage value, the source current value, and the source current reference therefrom, the inner control loop further coupled to the adaptation processor and receiving the estimate of a plurality of predetermined harmonic components of the periodic disturbance, the inner loop further coupled to the outer loop controller and receiving the source reference current therefrom, the inner loop configured and arranged to provide a first control vector that is a function of the source current, the estimate of the harmonic components of the periodic disturbance, and the source voltage;
• the control vector processor further configured and arranged to provide an output control vector as a function of the first control vector and the output voltage.