Recommendations for Key Components in Electric Power Steering System

The electric power steering (EPS) system assists the driver in controlling the steering of the vehicle, improving direction control, steering sense and safety. They also reduce engine load, thereby improving fuel efficiency.Because of these many advantages, EPS system is becoming more and more popular in today's cars. These systems usually use 3-Phase Brushless DC (BLDC) motors instead of hydraulic actuation mechanisms, but on some low-cost systems, brush DC motors can be used.EPS system saves energy and consumes power only when steering force is required to drive the vehicle. For example, in a mid-range vehicle of 2000cc, the use of EPS system can save 0.8L of fuel per 100km.

EPS system diagramThe EPS system uses a motor to generate the required power. The power is transmitted to the steering rack or steering column through the electrified electronic control unit (ECU), which includes a power inverter composed of semiconductor switches. ECU usually uses six switch inverter for BLDC motor and four switch inverter for brushless DC motor.It is becoming more and more common for EPS system to combine motor, power steering gear and ECU into a single component (called "power group").

EPS system block diagramWith the recent popularization of automatic driving technology, EPS system is developing to meet the strict safety requirements of vehicle safety integrity level-D (asil-d), which is the primary safety goal of EPS system. In order to achieve asil-d safety objectives, some customers are using 6-phase BLDC motors or dual 3-phase BLDC motors. These systems require advanced ECUs that can control these motors while maintaining a compact system size.Ansenmey Semiconductor provides most of the key devices for these EPS systems:

For ECU interface I / O:Provide a full range of transceivers or system basic chip (SBC), including FlexRay, Lin and can transceiversFor power management:

Provide power protection IC, voltage regulator, voltage monitor and gate driver IC.For signal conditioning:Provide cost-effective operational amplifier, current detection, thermal management IC and EEPROM.

For flexible power stages and phase break switches (motor lead connections):Provide automotive power MOSFETFor compact power stages:

Provide the latest apm19nxv04v120db1 automotive power module