Automotive Motor Control Solution

Application

Description

High-performance motor control solution using AutoChips motor drivers and MCUs for automotive fan, pump, and actuator applications.

Core Advantages

Sensorless Control Integrated sensorless commutation eliminates Hall sensors reducing cost and improving reliability

FOC Support Hardware support for Field Oriented Control enables high-performance motor control

Safety Features ASIL-B capable motor drivers with diagnostic capabilities for safety systems

Wide Voltage Range 6V to 60V operation covers all automotive battery conditions

Local Support LiTong provides motor control expertise and algorithm tuning support

Recommended Bill of Materials (BOM)

Item	Part Number	Description	Quantity	Datasheet
1	AC7801-MOTOR	BLDC motor driver with sensorless commutation	1	📄 Download
2	AC78013	MCU for motor control algorithm execution	1	📄 Download
3	AC7801-LDO	LDO for driver and MCU power supply	1	📄 Download

Applications

Engine Cooling Fans

HVAC Blower Motors

Electric Power Steering

Water and Oil Pumps

HVAC Actuator Motors

Technical Specifications

Supply Voltage

6V to 60V

Output Current

3A continuous, 5A peak

P W M Frequency

Up to 50kHz

Control Method

Sensorless BEMF or FOC

Efficiency

Up to 95%

Customer Success Stories

Automotive HVAC Supplier (Anonymous)

Automotive HVAC |

Challenge

HVAC blower motor controller required quiet operation, high efficiency, and low cost. Previous solution using discrete drivers had audible noise and efficiency below 85%. Required AEC-Q100 qualification and operation from -40°C to +85°C.

Solution

Implemented AC7801-MOTOR driver with sensorless commutation and AC78013 MCU for speed control. Optimized PWM frequency for quiet operation. Designed thermal management for continuous 3A operation. Implemented LIN interface for vehicle integration.

Results

Electric Power Steering Manufacturer (Anonymous)

Automotive Safety |

Challenge

Electric power steering system required ASIL-D capable motor control with precise torque control. System needed to handle 10A continuous current with safety diagnostics. Previous solution had supply constraints and high cost.

Solution

Designed EPS controller using AC7840-MOTOR driver with FOC support and AC78406 ASIL-D MCU. Implemented redundant current sensing for safety. Used AC7840-PMIC for safety power supply. Developed ISO 26262 compliant software with comprehensive diagnostics.

Results

FAE Expert Insights

Senior FAE

Applications Engineer

10+ years

Professional Insights

Through numerous automotive motor control design engagements, I've developed key insights for successful implementations. First, motor parameter characterization is essential - every motor has unique parameters that affect control performance. I always recommend measuring motor resistance, inductance, and BEMF constant before implementing control algorithms. Second, thermal management is critical for reliability. Motor drivers dissipate significant power and require adequate PCB copper or heatsinks. Calculate worst-case power dissipation and ensure junction temperature stays below 125°C. Third, EMC considerations are important for automotive applications. The switching edges of motor drivers generate EMI that can affect other vehicle systems. Use proper filtering and shielding as needed. Fourth, sensorless commutation works well for most applications but has limitations at very low speeds. For applications requiring torque control at stall, consider using Hall sensors or encoders. Overall, AutoChips motor drivers provide excellent foundation for automotive motor control with good performance and value.

Key Takeaways

Characterize motor parameters before implementing control algorithms
Design adequate thermal management based on worst-case power dissipation
Implement EMC filtering for switching noise mitigation
Consider sensor limitations for low-speed torque control applications
Use LiTong FAE support for motor control algorithm tuning

Decision Framework

Motor Control Solution Selection Framework

Steps:

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Ready to Implement This Solution?

Contact our FAE team for design support and quotes

Frequently Asked Questions

What motor control algorithms are supported?

AutoChips motor control solutions support various control algorithms including trapezoidal commutation for simple BLDC control, sinusoidal commutation for smooth operation, and Field Oriented Control (FOC) for high-performance torque control. The AC7801-MOTOR supports trapezoidal and sinusoidal commutation with integrated sensorless BEMF detection. The AC7840-MOTOR provides hardware support for FOC algorithms with current sensing and position feedback. LiTong provides reference software for all control algorithms.

Select trapezoidal for simple fans, sinusoidal for quiet operation, FOC for high-performance torque control.

How do I tune motor control parameters?

Motor control parameter tuning requires understanding motor characteristics and control requirements. Key parameters include PWM frequency (typically 10-20kHz for quiet operation), current loop PI gains (tune for fast response without oscillation), and speed loop gains (balance response and stability). Start with conservative values and incrementally optimize. LiTong provides motor control tuning guidelines and can assist with parameter optimization for specific motors.

Start with reference values and tune incrementally. Contact LiTong for tuning support.

What thermal management is required?

Motor driver thermal management depends on motor current and duty cycle. Calculate power dissipation as P = I² × Rds_on × duty_cycle. For AC7801-MOTOR at 3A with 100mΩ Rds_on, dissipation is approximately 0.9W. Provide adequate PCB copper area (50mm² minimum per watt) or add heatsinks for high-current applications. The drivers include thermal shutdown protection, but continuous operation near thermal limits reduces reliability.

Calculate power dissipation and provide adequate thermal management for reliable operation.

Can sensorless control work at all speeds?

Sensorless BEMF control works well at medium to high speeds where BEMF voltage is sufficient for detection. At very low speeds (below 10% of rated speed), BEMF voltage may be too low for reliable detection. For applications requiring torque control at low speeds or stall, Hall sensors or encoders are recommended. Some applications use open-loop startup transitioning to sensorless control at higher speeds.

Use sensorless for fans and pumps. Consider Hall sensors for applications requiring low-speed torque control.

What safety features are included for ASIL applications?

AutoChips motor drivers include safety features for ASIL-compliant systems including redundant current sensing, hardware over-current protection with fast shutdown, diagnostic SPI interface for fault reporting, and independent safety monitoring outputs. The AC7840-MOTOR includes ASIL-B support with comprehensive diagnostic capabilities. For ASIL-D applications, external safety monitoring and redundant drivers may be required.

AC7840-MOTOR provides ASIL-B support. Contact LiTong for ASIL-D motor control architecture guidance.

How do I reduce audible noise from motor switching?

Audible noise from motor switching can be reduced by increasing PWM frequency above 20kHz (above human hearing range), using sinusoidal commutation instead of trapezoidal, implementing random PWM to spread switching noise spectrum, and optimizing current loop tuning to reduce torque ripple. The AC7801-MOTOR supports up to 50kHz PWM for quiet operation. LiTong can provide noise optimization recommendations for specific applications.

Use >20kHz PWM with sinusoidal commutation for quietest operation.