BLDC Motor Control Unit for Dynamic PWM Adjustment
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Solution Overview
Problem
Existing motor driving systems for BLDC motors lack the ability to dynamically adjust the ON and OFF periods of PWM signals based on the lead angle and electrical angle position of the rotor, which limits their efficiency and output performance.
Innovation Solution
A motor driving apparatus that includes a control unit capable of estimating the electrical angle position of the rotor using detected voltage, current, and counter electromotive force, and adjusts the start-up period for supplying driving voltage to maximize output power by generating a PWM signal that optimally controls the inverter's switching elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the PWM signal pattern is fixed without dynamic adjustment, then the control system is simple, but the motor cannot achieve maximum output power and efficiency is reduced
Solution Approach 1:
The patent applies dynamics by making the PWM signal pattern adjustable and adaptable to different operating conditions. The control system dynamically changes the PWM pattern based on detected motor parameters (current, voltage, counter electromotive force) and operational state, allowing the motor to achieve maximum output power across varying loads and speeds rather than being constrained by a fixed pattern
Solution Approach 2:
The patent implements feedback by detecting motor parameters (current, voltage, counter electromotive force) and using this information to adjust the PWM signal pattern. The control system continuously monitors the motor's electrical angle position and lead angle, then modifies the PWM timing accordingly to optimize power delivery and efficiency under different operating conditions
2Productivity
If the PWM signal is adjusted based on electrical angle position and lead angle, then the motor efficiency is improved, but the control complexity increases
Solution Approach 1:
The control unit performs self-service by autonomously estimating the electrical angle position and lead angle using detected motor parameters (current, voltage, counter electromotive force). The system calculates these parameters internally without requiring external sensors or complex additional hardware, thereby improving motor efficiency while keeping the control architecture relatively simple
Solution Approach 2:
The patent applies parameter changes by modifying the PWM signal characteristics (timing, duration, frequency) based on calculated electrical angle position and lead angle parameters. The control unit adjusts these parameters dynamically to optimize motor efficiency and power delivery across different operating conditions
3Power
If the start-up period is optimized per rotor rotation, then maximum power delivery is achieved, but the measurement and control precision requirements increase
Solution Approach 1:
The patent uses counter electromotive force as an intermediary to indirectly determine the electrical angle position. Instead of requiring direct high-precision angular sensors, the system calculates the electrical angle position by measuring the counter electromotive force generated in the motor windings, which provides sufficient precision for optimizing the start-up period and achieving maximum power delivery
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 enhances the motor's efficiency and output performance by optimizing the PWM signal pattern according to the rotor's electrical angle position, ensuring maximum power delivery per rotation and improving overall system efficiency.
Implementation Method 1
an electrical angle position of the rotor estimated based on at least one of a voltage, current and counter electromotive force detected in the stator coil
Implementation Method 2
an inverter configured to supply a driving voltage to a stator coil wound on the stator or to cut off the driving voltage supplied to the stator coil
Data Source
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AI summary
Disclosed herein is a motor driving apparatus including a motor including a stator and a rotor rotating in the stator, an inverter configured to supply a driving voltage to a stator coil wound on the stator or to cut off the driving voltage supplied to the stator coil, and a control unit configured to, when a target command value is received, set a start-up period for supplying the driving voltage per rotation of the rotor, according to an electrical angle position of the rotor estimated based on at least one of a voltage, current and counter electromotive force detected in the stator coil and the target command value, and to control the inverter to supply the driving voltage in the start-up period. (Fig.1)