Synchronous Motor Control Device Switching PWM Rectangular Wave Drive
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Solution Overview
Problem
Existing control devices for synchronous electric motors struggle to efficiently switch between PWM drive control and rectangular wave drive control based on the motor's rotation speed, leading to potential overcurrent issues and suboptimal voltage utilization.
Innovation Solution
A control device that includes a PWM signal generator, a rectangular wave signal generator, a rotation speed detector, and a signal switching determination part to dynamically select between PWM and rectangular wave drive control based on the motor's rotation speed and voltage command amplitude, ensuring appropriate drive control is applied at optimal times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If rectangular wave drive control is used to improve voltage utilization rate, then voltage utilization rate is improved, but overcurrent may occur at low rotation speeds
Solution Approach 1:
The control device dynamically switches between rectangular wave drive control and PWM drive control based on the detected rotation speed of the synchronous electric motor. At high rotation speeds where induced voltage is high, rectangular wave drive control is applied to maximize voltage utilization. At low rotation speeds where induced voltage is low, PWM drive control is applied to prevent overcurrent. This dynamic adaptation resolves the contradiction by adjusting the control mode according to operating conditions.
2Object-affected harmful factors
If PWM drive control is used to prevent overcurrent at low rotation speeds, then overcurrent is prevented, but voltage utilization rate decreases
Solution Approach 1:
The control device dynamically switches between PWM drive control and rectangular wave drive control based on the detected rotation speed of the synchronous electric motor. At high rotation speeds where induced voltage is high, rectangular wave drive control is applied to maximize voltage utilization. At low rotation speeds where induced voltage is low, PWM drive control is applied to prevent overcurrent. This dynamic adaptation resolves the contradiction by adjusting the control mode according to operating conditions.
3Device complexity
If drive control switching is based only on voltage command without considering rotation speed, then device complexity is reduced, but appropriate control selection becomes impossible
Solution Approach 1:
The control device incorporates a rotation speed detector that provides real-time feedback on the motor's rotation speed. The drive control switching determination unit uses this feedback information to intelligently select between PWM drive control and rectangular wave drive control. This feedback mechanism enables accurate adaptation to operating conditions while maintaining reasonable device complexity through automated decision-making based on detected parameters.
Data Source
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AI summary
A control device 1 for a synchronous electric motor that switches a drive control of the synchronous electric motor to a PWM drive control and a rectangular wave drive control includes a PWM signal generator 14 configured to generate a PWM signal, a rectangular wave signal generator 22 configured to generate a rectangular wave signal, a rotation speed detector 40 configured to detect a rotation speed of the motor 2, a signal switching determination part 50 configured to determine, according to at least the rotation speed, whether the PWM signal or the rectangular wave signal is used as a control signal when controlling the drive of the motor 2, and a drive controller 30 configured to control the drive of the motor 2 using a signal determined by the signal switching determination part 50 to be used as the control signal.