“The results of this work show a convincing improvement in the efficiency of the motor + converter. It makes an IGBT-based inverter more competitive compared to a SiC inverter – at no additional cost, ”says Larry Rinehart, Director Advanced Engineering, Cascadia Motion.
SOPHIA ANTIPOLIS, France (PRWEB)
July 01, 2021
Silicon Mobility, a solution provider for the digital control of the electrified drive train of electric vehicles / HEVs, shows an increase in efficiency of 2 to 4.6% of the inverter and electric motor compared to the SVPWM control technology customary in the industry through the use of its more intelligent control.
During the 34th International Electric Vehicle Symposium – EVS34 – Silicon Mobility presented its latest research and development results in cooperation with Cascadia Motion. In a scientific paper presented during one of the EVS34 lecture sessions, Silicon Mobility shows the use of Optimized Pulse Pattern (OPP) modulation to increase the efficiency of the inverter and the permanent magnet synchronous motor (PMSM) by reducing the switching losses in the inverter together with Copper and iron losses in the electric motor.
The OPP algorithm was implemented with the powerful field-programmable control unit OLEA® T222 from Silicon Mobility, which is intended for advanced, safe real-time control of energy conversion in the electric drive train. The resulting system efficiency was measured on a high-voltage bench with a modified PM100 IGBT-based inverter from Cascadia Motion and a BorgWarner HVH250 series electric motor. The system efficiency is compared with the SVPWM modulation according to the industry standard using a comparable field-oriented control (FOC) at 8 operating points that represent real driving loads. This enabled the combined losses of the motor and converter systems with OPP to be reduced by 2% to 4.6%, depending on the motor operating conditions.
An advanced software in an advanced integrated circuit
The range of an electric vehicle is heavily influenced by the efficiency of its powertrain. The energy stored in the battery has to be converted into the vehicle movement and as little energy as possible (with the result of waste heat) is lost in the inverter and motor. While many developments aim to improve the battery as the main energy store and to use more efficient power devices with a large band gap, Silicon Mobility is concentrating on further efficiency optimization through the use of advanced control solutions with innovative integrated circuits and software.
Thanks to advanced control algorithms that use the performance of the OLEA® FPCU chip, Silicon Mobility is now able to significantly reduce energy losses and thus improve the efficiency of the inverter / electric motor in electrical drive trains.
The core of the highly innovative, patented solution is the dedicated architecture of the OLEA® FPCU (Field Programmable Control Unit), which enables superior control performance for the electric drive train. By using programmable hardware acceleration for time-critical control loops, the OLEA® FPCU can apply different types of modulation methods, depending on the operating conditions of the motor, in order to provide the optimal modulation for the desired setpoint. In addition to Space Vector PWM (SVPWM), the FPCU supports the flexible implementation of generic angle-based Pulse Control (APC) modulations. One example is Optimized Pulse Patterns (OPP), a modulation technique based on a set of precisely applied switching patterns (pulse patterns) that are precalculated offline in order to optimize the system behavior of the motor and inverter. Its main purpose is to shape the harmonic signature of the control current to reduce iron and copper losses depending on engine operating conditions.
The published paper explains and illustrates in detail how the APC modulation correctly executes the OPP, how a multi-criteria pattern generator tool was developed with scoring and constraints, the details of the measurement protocol and the results.
Result: Up to 4.6% increase in efficiency
The selected real driving points are in the area with the lower efficiency of the map below 50 Nm.
All measurements were carried out in a closed loop with the same average temperature of the converter and the electric motor.
At these points the system efficiency is increased from 2% to 4.6%.
The reduction in e-motor and converter losses varies from 87 W to 1230 W.
3 types of patterns have given the best results (Ri2, Ripple & THD).
"Any improvement in drive system (motor + inverter) efficiency is good because the improvement in motor and inverter efficiency allows for less cooling system requirements and better vehicle range," said Larry Rinehart, director of advanced engineering, Cascadia Motion. “The results of this work show a convincing improvement in the efficiency of the motor + converter. It makes an IGBT-based inverter more competitive compared to a SiC inverter – at no additional cost. "
"The OPP modulation supports the same goals as neighboring work on new power transistor technologies (GaN, SiC), advanced inverter system architecture (multi-stage, multi-stage) and advanced torque, current and magnetic flux control strategies such as model as predictive control or AI-based control," said Khaled Douzane, VP Products at Silicon Mobility. “They are all aimed at improving the energy efficiency of the EV / HEV powertrain. And since the physical approaches to increasing efficiency are different, their practical advantages will usually add up. "
To date, the OLEA® FPCU is the only system-on-chip qualified for the automotive industry that is powerful enough to execute such a demanding algorithm and at the same time to guarantee the ISO 26262 ASIL D security level.
APC technology with OPP is available in the OLEA® APP INVERTER HE control application for the OLEA® FPCU and is available to selected customers.
About silicon mobility
Silicon Mobility is a technology-leading inventor of the FPCU semiconductor architecture for ultra-fast and critically safe real-time control. Silicon Mobility accelerates all transitions to e-mobility in the cleanest, safest, safest and most intelligent way possible. The company designs, develops and sells flexible, secure and open semiconductor solutions in real time for the automotive industry, which are used to increase energy efficiency and reduce pollutant emissions while at the same time ensuring the safety of passengers.
Silicon Mobility's products control electric motors, batteries and energy management systems in hybrid and electric vehicles. By using the technologies of Silicon Mobility, manufacturers improve the efficiency, reduce the size, weight and costs of electric motors and increase the range and service life of the battery. Its technologies and products accelerate the electrification of the automotive powertrain for OEMs. Silicon Mobility is headquartered in Sophia-Antipolis, France, and is represented worldwide in Germany, Silicon Valley, CA, China and Japan. Further information is available at: http://www.silicon-mobility.com
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