Embedded Computing Design: Pre-Switch Demo in the Lab

Alix Paultre of Embedded Computing Design visits Pre-Switch and gets the live demo of forced-resonant soft-switching.

This unrehearsed video shows Pre-Switch’s James Hamond (CTO) and Derek Kroes (VP Engineering) demonstrating a 10KW full bridge solar inverter running Pre-Switch’s AI forced-resonant soft-switching technology (Pre-Flex). Pre-Flex uses a learning AI to predict and generate a forced-resonance voltage waveform, timed accurately to enable zero voltage switching. The demonstration shows discrete IGBTs running at 50Khz at 98.5% efficiency, inverting 320Vdc to 240Vac. Able to work for both IGBT’s and wide-bandgap devices, Pre-Flex enables switching losses to be reduced from 80% (IGBT), and 95% (wide-bandgap) enabling up to a 5X to 20X faster Fsw when compared to hard-switched legacy solutions.

Get In Touch

If you are interested in making soft-switching work for you, please reach out here:

  • This field is for validation purposes and should be left unchanged.
ADDRESS

2151 O’Toole Avenue,
Suite 30,
San Jose,
California 95131

EMAIL
FOLLOW
Scroll to Top

Motor Benefits

A Pre-Switch-enabled inverter reduces sine wave output distortion by 10X, enabling motors to run more efficiently. In a conventional hard switching design, the output ripple current of the half-bridge circuit switching back and forth at 10-15 switching events per fundamental frequency causes a significant level of distortion.  The distortion is effectively an induction heater in the motor coils and does no useful work. Pre-Switch technology minimizes this ripple by switching 10x faster.  The lower distortion fundamental sine wave to the motor is what we call a ‘clean wave’ and improves motor efficiency predominantly at lower RPM and lower torques which is where EV’s are driven and increases EV range.

The second benefit of the Pre-Switch soft switching architecture is that inverter dV/dt is configurable with a free lossless dV/dt filter that is part of the architecture.  Reducing dV/dt improves motor reliability and reduces motor winding insulation allowing higher power density motors. Due to the fast edge  speeds of WBG (SiC; GaN) transistors, high dV/dt is traded off for reduced switching losses.  But high dV/dt speeds of above 15-20V/ns can cause insulation damage. Inverter designers in the past accommodate these excessive dV/dt speeds by adding extra insulation in the motor. This approach has the adverse affect of reducing motor power density and increasing motor costs.  In contrast, the Pre-Switch architecture slows edge speeds but allows increased switching frequencies, eliminating the problem of high dV/dt speeds and reducing the insulation required. 

The faster switching speeds enabled with Pre-Switch can be used to spin motors faster.  In some applications a lower cost, lighter and higher RPM motor can be used.

The final benefit for motor design is that because Pre-Switch-enabled systems switch so fast, low inductance motors can be used which have the benefit of being smaller and lighter and lower cost. This is particularly suitable for applications such as electric aircraft, where designers are trying to reduce the amount of iron in the motors to keep weight to a minimum.