Motor Controller Switching 120 to 150 Degree Energization
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Solution Overview
Problem
Existing motor controllers for brushless motors are complicated in control and configuration, especially when switching between 120-degree and 180-degree energization methods, requiring accurate rotor speed and position measurement and a more complex configuration for the 180-degree method.
Innovation Solution
A motor controller that switches between 120-degree and 150-degree energization methods based on measured rotation speed, using a sensorless approach with PWM control and frequency adjustment, eliminating the need for precise rotor position measurement and reducing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the 180-degree energization method is used to improve quietness and vibration characteristics, then the motor operates more quietly with reduced vibration, but the control system becomes more complicated and requires additional amplifiers for accurate rotor position measurement
Solution Approach 1:
The patent changes the energization angle parameter from the conventional 120-degree or 180-degree methods to a 150-degree energization method. This parameter change allows the motor to achieve reduced vibration and noise characteristics similar to the 180-degree method, while maintaining the simpler control architecture of the 120-degree method by not requiring continuous sine wave generation based on precise rotor position feedback
Solution Approach 2:
Instead of using the 180-degree energization method which requires complex position-based sine wave generation to achieve quiet operation, the patent inverts the approach by using a 150-degree energization method that achieves similar vibration reduction without requiring the complex feedback control system. This reverses the conventional wisdom that only 180-degree energization can provide quiet operation
2Speed
If the 180-degree energization method is used to increase rotation speed capability, then the motor can operate at higher speeds, but the configuration becomes more complicated requiring accurate rotor speed and position measurement
Solution Approach 1:
The patent changes the energization angle parameter to 150 degrees, which provides a balance between the speed capability of the 180-degree method and the simplicity of the 120-degree method. This parameter change allows the motor to achieve higher rotation speeds without requiring the complex rotor position and speed measurement systems needed for 180-degree energization
3Device complexity
If the 120-degree energization method is used to simplify control, then the control system remains simple without requiring complex position measurement, but the motor produces more vibration and noise
Solution Approach 1:
The patent modifies the energization angle parameter from 120 degrees to 150 degrees. This change maintains the simplicity of the control system characteristic of the 120-degree method while achieving the vibration and noise reduction characteristics associated with wider energization angles like 180 degrees, thus resolving the contradiction between control simplicity and vibration reduction
Data Source
AI summary
A motor controller includes: a rotation speed measurement portion that measures a rotation speed of a motor; and an energization method switching portion that switches an energization method so that the motor is driven by a 120-degree energization method when a rotation speed of the motor measured by the rotation speed measurement portion is less than or equal to a predetermined threshold value, and the motor is driven by a 150-degree energization method when a rotation speed of the motor measured by the rotation speed measurement portion exceeds the predetermined threshold value.