On-board Control Circuit for High-Power BLDC Motor Phase Current
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Solution Overview
Problem
Existing mechatronic assemblies for high-power brushless direct current (BLDC) motors face challenges with power losses due to Joule effect and reliability issues, as well as high material costs, particularly when using control units (ECUs) not designed for high power management, and the control methods for single-phase motors are not easily transposable to polyphase motors.
Innovation Solution
A mechatronic assembly with an on-board electronic control circuit that receives direction and torque information from an ECU and directly modulates the current of the DC power source applied to each motor phase, separating the control and power signals, and using a simplified electronic circuit to control an N-phase polyphase brushless electric motor, reducing the need for complex electronics and microcontrollers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a standard ECU is used to directly control high-power BLDC motors, then the motor can be controlled, but power losses occur due to Joule effect and reliability decreases
Solution Approach 1:
The control system is segmented into two independent parts: a low-power ECU that generates control signals (direction and torque information) and a separate power bridge circuit that handles high-power motor control. This segmentation allows the ECU to remain low-power while the power bridge efficiently manages high-current switching, eliminating Joule losses in the ECU.
Solution Approach 2:
The patent introduces an intermediary power bridge circuit between the ECU and the motor. This intermediary receives low-power control signals from the ECU and translates them into high-power switching operations, acting as a mediator that protects the ECU from direct exposure to high currents while maintaining control functionality.
2Power
If a standard ECU is used for high-power motor control, then the motor can be driven, but material costs increase and reliability decreases
Solution Approach 1:
By segmenting the control architecture into signal-generation (ECU) and power-execution (power bridge) functions, the system uses appropriately-rated components for each task. The ECU remains low-cost and reliable for signal processing, while the power bridge handles high-power switching with dedicated high-current switches, improving overall system reliability.
Solution Approach 2:
The patent employs cost-effective discrete power switches and simple logic circuitry in the power bridge rather than expensive high-power ECU components. This approach uses simpler, cheaper components optimized for their specific functions, reducing material costs while maintaining reliability through proper component selection.
3Adaptability or versatility
If single-phase motor control methods are used, then single-phase motors can be controlled, but they cannot be directly applied to polyphase motors
Solution Approach 1:
The patent applies local quality by implementing phase-specific control logic within the power bridge for each phase of the polyphase motor. Each phase has dedicated switching elements and control logic tailored to its specific requirements, allowing the system to handle polyphase complexity locally while keeping the overall ECU design simple and universal.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows for efficient control of high-power BLDC motors with reduced ECU complexity and cost, minimizing connection points between the mechatronic system and the ECU, while maintaining simplicity and reliability, and is applicable in automotive applications such as camshaft phase shifters and other high-power systems.
Implementation Method 1
control a high power BLDC motor, be compatible with a low or medium power ECU or even without power output, simplify and reduce the costs of the ECU, propose a control solution for a brushless direct current (BLDC) motor free from complex electronics and/or requiring the use of a microcontroller
Implementation Method 2
binary detection probes for the position of the rotor of said motor
Implementation Method 3
The rotor consists of permanent magnets comprising 2 to 8 poles with alternating North and South poles
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention concerns a mechatronic assembly (2) for driving a member intended to be linked to a DC electrical power source (4) and to an ECU control unit (1) comprising a computer for executing a feedback control algorithm delivering an item of direction and torque information (6), said assembly (2) comprising an actuator formed by a brushless polyphase electric motor (8) having N phases, binary detection probes (11) for detecting the position of the rotor of said motor (8), an electronic circuit comprising a power bridge (13) for powering the N phases of the motor (8). It further comprises an onboard electronic control circuit (10) without a microcontroller, computer and memory of which the input receives said item of direction and torque information (6) from the ECU and of which the output controls said power bridge (13) directly modulating the current of the DC electrical power source (4) applied to each of said phases of the motor (8), and the torque and direction information (6) provided by the ECU (1) is separate from the power signal delivered only by the power source (4).