Inverter Configurations with Shoot-Through Immunity
Inventors: Shihong Park, Thomas Jahns
The Wisconsin Alumni Research Foundation (WARF) is seeking commercial partners interested in developing a novel phase leg configuration that is inherently immune to shoot-through conditions.
The two-switch phase leg – a basic building block topology for electrical power inverters – consists of a high- and a low-side semiconductor switch spanning a DC voltage source. Dead time delay intervals are typically added to the software controlling these two switches in order to avoid shoot-through conditions. Shoot-through conditions occur when both switches are on at the same time and cause a short in the VDC voltage source. Although these dead times are brief, they produce harmonic distortion and non-linearity when two-switch phase legs are used in inverters to generate sinusoidal voltages for motors and other types of AC loads.
UW-Madison researchers have developed a novel phase leg configuration that is inherently immune to shoot-through conditions. In the basic embodiment of this invention, the low-side switch acts like a master switch to control switching of the high-side switch. That is, whenever the low-side switch is on, the high-side switch is automatically forced off, and the high-side switch only begins to turn on when the low-side switch turns off. Thus, a short-circuit through both of the main switches is topologically inhibited and a single control signal for the low-side switch is enough to control the entire phase leg.
- Electrical power inverters
- Inherently immune to phase leg shoot-through, eliminating a major failure mechanism
- Provides highly reliable immunity to shoot-through at relatively low-cost and complexity
- Eliminates need for complicated dead time (i.e., blanking time) detection and compensation strategies
- Compatible with simple boot-strap voltage supply for the high-side circuit
- Offers overall simplicity and compatibility with integrated circuit implementation of the gate drive control circuitry