Motor Control System Transient State Detection
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Solution Overview
Problem
Existing motor control systems face inefficiencies and complexity when controlling motor rotation speed, particularly when transitioning from high to low speeds, leading to increased power consumption and potential reverse currents due to complex circuit requirements and time delays.
Innovation Solution
A motor control system with a control module, PWM signal detecting module, transient state detecting module, and driving module that converts PWM signals into digital control signals to predict and manage motor speed transitions, using a timer and comparison units to determine when to turn off low side switches and prevent reverse currents, thereby simplifying the circuit and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a complementary switch in the PWM control system is not turned on during high to low speed transition, then the motor speed control is achieved, but the control circuit consumes more power and has lower efficiency
Solution Approach 1:
The patent applies preliminary action by detecting the transient state of the motor before the actual speed transition occurs. The transient state detecting module identifies when the motor is in a transient state (transitioning from high to low speed) and proactively generates a control signal to turn off the complementary switch in advance. This prevents the control circuit from consuming excessive power during the transition period, thereby resolving the contradiction between achieving speed control and minimizing power consumption.
2Measurement precision
If a current comparator is configured as a zero current detector, then the motor control precision is improved, but the circuit complexity increases
Solution Approach 1:
The patent extracts the current detection function from the complex zero current detector configuration and integrates it into the transient state detecting module. Instead of using a separate current comparator configured as a zero current detector, the invention uses the PWM signal detecting module and transient state detecting module to infer motor state information. This extraction approach maintains the necessary detection precision while significantly reducing circuit complexity.
3Measurement precision
If a zero current detector is used with a current comparator, then the current detection accuracy is improved, but the system introduces time delay that causes reverse current
Solution Approach 1:
The patent applies preliminary action by detecting the transient state of the motor before the actual speed transition occurs. The transient state detecting module identifies when the motor is in a transient state (transitioning from high to low speed) and proactively generates a control signal to turn off the complementary switch in advance. This prevents the control circuit from consuming excessive power during the transition period, thereby resolving the contradiction between achieving speed control and minimizing power consumption.
4Manufacturing precision
If the motor control system uses a complex circuit configuration, then the control precision is improved, but the manufacturing cost and system complexity increase
Solution Approach 1:
The patent merges multiple functions into integrated modules to reduce circuit complexity while maintaining control precision. The PWM signal detecting module and transient state detecting module are combined in a way that allows the transient state detection to leverage the existing PWM signal processing infrastructure. This merging approach maintains precise motor speed control through transient state detection while simplifying the overall circuit configuration and reducing manufacturing complexity.
Data Source
AI summary
A motor control system includes a motor driving circuit and a motor. The motor driving circuit includes a control module, a PWM signal detecting module, a transient state detecting module and a driving module. The PWM signal detecting module is electrically connected to the control module to receive a PWM signal and to convert the PWM signal into a first digital PWM control signal. The transient state detecting module provides a second digital PWM control signal to the control module according to the first digital PWM control signal at a first time point and the first digital PWM control signal at a second time point. The driving module receives at least one driving signal from the control module. The control module determines whether to turn off a low side switch of the driving module according to the second digital PWM control signal.