Both software and hardware are part of all motor control systems such as IGBTs, WBG semiconductors, and MCUs. Industry 4.0 relies heavily on motor control for its development, but power consumption is a major issue as it is increasing at a rapid pace and demand is increasing along with design complexity as there are strict control requirements focusing on many electronic technologies. Wideband gap material (WBG) is an example in this case. From a functional point of view, engine control consists of several levels. For example, motion control requires the implementation of very complex and computationally intensive control algorithms. Motor control covers a wide range of applications, from simple control of fans and pumps to more complex problems of industrial control, including automated and servo mechanisms. Here, we take a look at the main components of an engine control system. Motors and Motors DC motors are the most common, because they are cheaper and consist of a stator (stator) – that is, a permanent magnet – and a moving part (rotor), which houses the coil connected to a commutator that supplies current. The motor speed is controlled by direct current regulation. For this purpose and depending on the nature of the application, full bridge, half bridge or step-down transformers are used to power the DC motor. An AC motor is mainly composed of a transformer with a primary section connected to the AC voltage and a secondary section, which transmits the induced secondary current. Microprocessor-based electronics, inverter and signal conditioning are used to control the speed of this motor. A controller is an electronic device that acts as the “brain” of a control system. The number of controllers used varies based on the amount of individual operations that need to be controlled. For a complex system, there may be several controllers. Each of these controllers can send commands to the actuators and, at the same time, receive instructions from the actuators themselves. Robotic systems used in industrial applications primarily use three-phase alternating voltage (AC) motors. As an example, Figure 1 shows the block diagram of an electronic control circuit where a dedicated microcontroller (MCU) generates a PWM signal. As an alternative to MCU, DSP or FPGA solutions, it is more suitable for implementing complex digital filtering algorithms. Figure 1: Control block diagram of an AC three-phase induction motor (source: Texas Instruments) An example of a controller for DC motors is the Trinamic TMCM-1637 5-A RMS and the TMCM-1638 7-A RMS slot-type modules with two of field oriented controllers/actuators that add Hall coding functionality and ABN for field control (or vector control). These units support single-phase DC motors, bipolar two-phase stepper motors, and three-phase BLDC motors (Fig. 2). Figure 2: TMCM-163x Solutions (Source: Trinamic) IGBTs insulated gate bipolar transistors (IGBTs) embody a true innovation in power control electronics. As switching solutions, innovation comes from high switching frequency. IGBTs represent the primary function of electrical power controllers that are well suited for solving complex motor control problems. The latest solutions have developed an excellent relationship between switching speed and behavior stability in particularly harsh conditions of use, such as in the automotive sector when implementing transformers to drive electric motors. One such example is the 1,200-V IGBT S series from STMicroelectronics. IGBTs are optimized for use at lower frequencies (up to 8 kHz) and feature low Vce (sat) power. The 1,200-V IGBT S series is based on third-generation trench field stopping technology. GaN and SiC However, WBG and gallium nitride and silicon carbide materials are making their way into motor control applications as an alternative to silicon-based devices. In power electronics, the main advantages offered by WBG materials include lower power loss, higher efficiency, higher switching frequencies, more compact size, higher operating temperature (well beyond the 150°C maximum achievable with silicon), and greater reliability under Difficult operating conditions, high voltages. For example, the higher electron mobility in a high electron mobility transistor (HEMT) translates into a faster switching velocity, since the charges that normally accumulate at the joints can be dispersed more quickly. The faster rise times, lower impedance drain (RDS(on)) values, and lower gate and output capacitances that can be achieved with GaN contribute to the lower switching losses and the ability to operate at switching frequencies up to 10× higher than silicon. Reducing power loss brings additional benefits, such as more efficient power distribution, less heat dissipation, and simpler cooling systems. Many motor control applications require a fan to provide forced air cooling to operate within the safe operating limits of the device. With GaN, power dissipation can be reduced and “fanless” operation can be enabled, which is especially important in low-weight applications such as electronic drones. In industrial power applications, electronic designers can realize benefits by using SiC MOSFETs as well, which offer significant efficiency improvements, smaller heat sink size, and lower cost than conventional Si-based solutions such as IGBTs. SiC RDS (on) achieves very low per unit area, high switching frequencies and minimal power losses during the reverse recovery phase that occurs after the body diode is turned off. The use of SiC devices in motor control and electrical power control applications is a real advance with features such as energy savings, size reduction, high integration and reliability. These features make it well suited for highly reliable sectors such as automotive control and industrial automation. In industrial engines, special attention must be paid to turning on and off switching speeds. As a matter of fact, SiC MOSFET dV/dt can reach much higher levels than IGBTs. If not handled properly, high dvd/dt switching increases voltage spikes on long motor cables and may generate co- and differential parasitic currents that, over time, cause failures of the insulation winding and motor bearings. Although faster on/off improves efficiency, the typical dV/dt in industrial drives is often set at 5 to 10 V/ns for reliability reasons. The comparison by STMicroelectronics on two similar 1.2 kV power transistors – SiC MOSFET and Si-based IGBT – demonstrated that the SiC MOSFET can guarantee much lower power loss for both on and off, compared to Si IGBT, even under the imposed conditions. 5 V/ns (Fig. 3). Figure 3: Inverter-Based Two-Phase and Three-Phase Motor (Source: STMicroelectronics) The use of SiC devices in motor control and electric power control applications in general is a real advance thanks to features such as energy savings, size reduction, integration opportunities, and reliability. Among other options, it is now possible to use the optimum switching frequency in the inverter circuit of the connected motor, which leads to important advantages in the design of the motor. For example, the CoolSiC MOSFETs based on SiC from Infineon Technologies with interconnect technology .XT in the 1200 package allows D²PAK-7 SMD optimized V -V passive cooling in energy-dense critical drive sectors such as servo motors, thus supporting the robotics and automation industry in implementing maintenance-free and fanless motor inverters (Fig. 4). In automation, fanless solutions offer new design opportunities, driven by the fact that they save costs and effort on maintenance and materials. Infineon’s CoolSiC MOSFET trench chip solution with .XT interconnection technology offers attractive thermal capabilities in a compact form factor, making it well suited for drive integration into a robotic arm, for example. CoolSiC MOSFET SMD devices have a short circuit endurance time of 3 s and are rated from 30 m³ to 350 m³. This meets the requirements of servo motors. Figure 4: Reduced connection loss in all operating modes (Source: Infineon Technologies) Microcontrollers Motor control solutions consist of hardware and software components. The hardware component is electronic control devices such as IGBTs, SiC, GaN MOSFETs, power diodes, etc., while the software component handles the hardware control, which is getting more and more complex and complex. The availability of computing architectures optimized to control and manage power devices allows developers to obtain performance that would not otherwise be possible in the control domain. A couple of examples come from NXP Semiconductors and Renesas Electronics. The NXP MPC57xx family of 32-bit processors is based on Power Architecture for automotive and industrial powertrain applications as well as other automotive control and functional management capabilities. The processors provide AEC-Q100 quality, on-chip security encryption protection to prevent tampering, and support for ASIL-D and SIL-1 functional integrity (ISO 26262 / IEC 61508). They provide Ethernet (FEC), dual-channel FlexRay, and up to 6 SCI/8 DSPI/2 I2C for various communication protocols. Renesas offers RA6T1 32-bit MCUs based on 120MHz Arm Cortex-M4 cores with a suite of peripherals optimized for high performance and precise engine control. One RA6T1 MCU can control up to two BLDC motors simultaneously. In addition, the Google TensorFlow Lite Micro Framework for TinyML Applications adds improved fault detection to the RA6T1 MCU, providing customers with an intelligent, easy-to-use, and cost-effective drive system for predictive maintenance. Engine requirements vary depending on the application, which may need optimization and fine-tuning for a particular use case. The market offers many solutions in terms of IGBTs, WBG semiconductors, and MCUs to meet those requirements. However, new hardware must be developed to unload mission-critical real-time tasks from the processor, enabling more diagnostics, predictive maintenance, artificial intelligence, and functional safety systems. .
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