Brushless Motor Actuator Edge Detection Control
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Solution Overview
Problem
Existing solutions for replacing brushed motors with brushless motors in automotive applications face issues with inconsistent current and torque due to simple control architectures lacking microcontrollers, and are sensitive to voltage variations and electromagnetic interferences, limiting performance and diagnostic capabilities.
Innovation Solution
An actuator with a polyphased brushless motor using a microcontroller and power stage with a rectifier and filtering to decode modulated signals for continuous power supply, determining rising and falling edges to set motor direction, position, and speed, and controlling power to each phase, with optional position encoder simulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple control architecture without a microcontroller is used to replace a brushed motor with a brushless motor, then the device complexity is reduced and ease of manufacture is improved, but the motor operation consistency and torque stability deteriorate due to inability to compensate for voltage variations and electromagnetic interferences
Solution Approach 1:
The patent introduces a microcontroller as an intermediary component between the PWM signal source and the brushless motor. This microcontroller acts as a mediator that receives the PWM signal, processes it through temporal determination of rising and falling edges to generate accurate commutation signals, and compensates for voltage variations and electromagnetic interferences. This resolves the contradiction by adding a moderate level of complexity (the microcontroller) that significantly improves motor operation consistency and torque stability without requiring a fully complex control system.
Solution Approach 2:
The patent implements feedback mechanisms where the microcontroller monitors the actual motor operation and adjusts the commutation signals accordingly. By detecting rising and falling edges of the PWM signal and using this information to synchronize motor commutation, the system creates a feedback loop that ensures consistent motor operation despite voltage variations. This feedback approach maintains reliability while keeping the overall device complexity manageable.
2Measurement precision
If digital processing is used to reconstruct the rectangular signal to mitigate voltage variations and electromagnetic interferences, then the motor control accuracy is improved, but the power consumption increases and calculational resources are consumed
Solution Approach 1:
The patent extracts only the essential information from the PWM signal by detecting rising and falling edges, rather than performing full digital reconstruction of the rectangular signal. This selective extraction approach achieves sufficient measurement precision for motor control while minimizing computational resources and power consumption. The microcontroller focuses on capturing the critical timing information needed for commutation without the overhead of complete signal reconstruction.
Solution Approach 2:
The patent applies partial action by implementing only the necessary level of signal processing required for accurate motor control. Instead of performing excessive digital processing to fully reconstruct and analyze the entire PWM signal, the system performs just enough processing (edge detection and temporal determination) to achieve the required control accuracy. This balanced approach optimizes the trade-off between measurement precision and power consumption.
3Ease of operation
If the motor is controlled by the amplitude of the PWM signal, then the control is simplified, but the control accuracy deteriorates due to signal impairments from voltage variations and electromagnetic interferences
Solution Approach 1:
The patent inverts the conventional approach by not using the PWM signal amplitude directly for control decisions. Instead, it uses the temporal characteristics (rising and falling edge timing) of the PWM signal, which are less susceptible to amplitude variations caused by voltage fluctuations and electromagnetic interferences. This inversion of the control parameter from amplitude-based to time-based measurement maintains control simplicity while significantly improving measurement precision and reliability.
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 provides optimized motor operation insensitive to voltage variations, improves torque consistency, and enables advanced diagnostic and control features like temperature management and reduced power consumption.
Implementation Method 1
a power stage comprising a rectifier and/or a filtering of said modulated signal to deliver a continuous supply signal of the electronic circuit
Implementation Method 2
a power stage comprising a rectifier and/or a filtering of said modulated signal to deliver a continuous supply signal of the electronic circuit
Implementation Method 3
polyphased brushless motor having a two-wire connection for receiving a modulated power supply signal
Data Source
AI summary
An actuator includes a polyphased brushless motor having a two-wire connection for receiving a modulated power supply signal with a cyclic ratio or a modulated frequency, supplied by a motor control unit. The actuator also includes an electronic circuit having a microcontroller and a power stage delivering the power supply signals of the coils of the brushless motor, and a power supply stage including a rectifier and/or a filtering of the modulated signal for delivering a continuous power supply signal of the electronic circuit. The electronic circuit includes: a stage which is external or integral to the decoding microcontroller by temporal determination of the rising and falling edges of the modulated signal for providing: a direction of rotation set point value by analysis of the signal on the two wires; and/or a set point value of the target position of the rotor; and/or a set point value of a pre-recorded movement sequence; and/or a speed set point value, the microcontroller controlling the power supply signal of each of the phases according to the set point values and the power supply signal, the outputs of the power stage feeding the coils of the brushless motor.