AI-based 100kHz 200kW SiC Inverter Evaluation System Eliminates 70% to 95% of Switching Losses

May 07, 2019 by Paul Shepard

Pre-Switch, Inc. today announced its CleanWave 200kW SiC automotive inverter evaluation system that enables power design engineers to investigate the accuracy of the company's artificial-intelligence-based soft switching architecture and platform over varying load, temperature, device tolerance and degradation conditions.

Pre-Switch's platform, including the Pre-Drive™3 controller board, powered by the Pre-Flex™ FPGA, and RPG gate driver board, virtually eliminates switching losses, enabling fast switching at 100kHz, significantly improving low torque motor efficiency. High switching frequency also reduces motor copper and iron losses.

For electric vehicles this results in an increase in range of 5-12%. The soft-switching solution also benefits industrial motors, solar, wind and traction applications or any other power converter requirement greater than 100kW that is looking to reduce costs and improve efficiency.

Pre-Flex technology learns and adapts ‘in-system', on a cycle-by-cycle basis to reliably force resonant soft-switch across changing loads, input voltages, temperatures, and manufacturing tolerances. The technology has proven efficiencies greater than those of five-level topologies at a fraction of the cost and complexity. Pre-Flex also significantly lowers EMI and dramatically decreases dV/dt for any switch type.

Pre-Flex employs Pre-Switches' auxiliary resonant commutated pole (ARCP) technology in which auxiliary switches (left) are activated before the main power output switches are and generate a current in the auxiliary inductor (center) that induces the condition required to soft-switch the main inverter switches. The auxiliary switches are turned on and off at zero current while the main switches are switched at zero voltage.

Pre-Flex enables Silicon carbide-like performance for low-cost IGBTs and allows SiC- and GaN-based topologies to switch up to 20x faster than they do today. Built into the architecture are innovative cycle-by-cycle safety features and communications that were never possible before. Pre-Flex has switched 900V Wolfspeed SiC MOSFETs up to 1MHz, and 650V Infineon IGBTs at over 100kHz with unprecedented efficiencies. The technology presently scales from 1kW to above gigawatts.

A white paper is available for download that describes "The Operation of Auxiliary Resonant Commutated Pole (ARCP) and Its benefits for Electric Motor Drives."

"We have removed the biggest barrier to advancing the power conversion industry," said Bruce Renouard, chief executive officer of Pre-Switch, Inc. "Our technology enables simple, reliable, and cost effective forced resonant soft-switching on any topology."

"With Pre-Switch, critical design challenges hindering EV adoption, have been solved. Previously, the limited switching frequency of inverters resulted in a distortion of the output power sine wave causing excessive motor inefficiencies. Our CleanWave inverter evaluation system - which is available to pre-order now - uses Artificial Intelligence (AI) to constantly-adjust the relative timing of elements within the switching system required to force a resonance to offset the current and voltage wave forms - thereby minimizing switching losses and increasing EV range," concluded Renouard.

Pre-Switch's forced-resonant soft-switching topology replaces the traditional IGBT driver or silicon carbide driver with a common intelligent controller board, Pre-Drive3, and a specific plug-in RPG (Resonant Power Gate) module optimized for the customer's chosen SiC or IGBT package. The Pre-Switch architecture increases efficiency and range, while reducing size and weight.