Motor control circuit technology for automotive MCUs boost energy efficiency

Renesas Electronics has announced the development of a circuit technology dedicated for motor control that realizes green vehicles satisfying stricter automotive CO2 emissions requirements. The newly developed technology is an Intelligent Motor Timer System (IMTS), a dedicated circuit block that can be integrated into automotive MCUs for next-generation EVs and HEVs. It performs field-oriented-control operations, which are essential to EV motor control, in a mere 0.8 microseconds (µs), the world’s fastest rate (Note 2), which is less than 1/10 the operation processing time of software implementation on a CPU running at the same operating frequency. This contributes to the realization of next-generation high-speed EV motors with excellent energy efficiency and inverter systems with high-speed switching performance to drive them. Furthermore, the unique circuit also enables functional safety support required for the automotive powertrain field. With the increasingly stricter fuel efficiency requirements in the recent years, EVs, HEVs, and plug-in hybrid electric vehicles (PHEVs) have come to account for an increasing share of the total number of vehicles produced. To increase the range of such motor-driven vehicles, it is necessary to boost the energy efficiency of motor control. To achieve this, it is important not only to make mechanical improvements to the motors themselves, but also to enhance the functions and performance of the electronic control units (ECUs) that control the motors. ECUs capable of supporting next-generation EVs, HEVs, and PHEVs require advanced functionality and complex control software, and this results in a substantial increase in the operation processing load placed on the MCUs used in these ECUs. At the same time, automotive MCUs required to restrict the amount of heat they generate in order to maintain a high level of reliability in high-temperature environments. It is therefore necessary to keep the operating frequency of the MCUs’ internal circuits, including the CPU core or cores, relatively low, making them difficult to boost performance. In response to these needs, among the various motor control processes performed by the MCU, the company implemented the IMTS as a dedicated circuit block for static processes requiring a high level of responsiveness such as acquisition of sensor data, calculation of control values based on it, and outputting of these values. The IMTS is independent of the CPU and capable of running autonomously, thereby substantially reduces the CPU load of the motor control MCU. The resulting surplus CPU capacity can then be allocated to advanced motor control algorithms designed to boost the energy efficiency of next-generation EVs, HEVs, and PHEVs.