Square D Company

S&c Electric Company

James W Sember

David G Porter

Stephen E Williams

Donald S Berkowitz

Thomas Walker

Luis J Garces

Terrence Bellei

This patent describes embodiments of systems, apparatus and methods to provide improved control and coordination of a multiplicity of electric distribution grid-connected, energy storage units deployed over a geographically-dispersed area.

Distributed energy storage system and method of distributing energy

A closed loop pulse width modulator (PWM) inverter corrects for variations and distortion in the output AC voltage waveform caused by non-linearities of the switching devices or changes in the DC link voltage. A signal is generated that is a volt-seconds representation of the voltage error between a voltage command and the actual AC output voltage of the PWM inverter. The volt-seconds error signal becomes a controlling means in the closed loop of the PWM inverter to regulate the output AC voltage of the PWM inverter. Another signal that represents changes in the DC link voltage also modifies the voltage command signal. The system will compensate for the non-linear behavior of the PWM inverter due to deadtime, minimum on-times and off-times, and DC link voltage variations and voltage drops across the switching devices, and will also allow the operation of the inverter in a linear fashion for the region of operation when one or more of its phases are saturated, i.e., either full on or full off.

Closed loop pulse width modulator inverter with volt-seconds feedback

Growing community of inventors

Burlington, WI, United States of America

James W Sember