Power Converter Control for Multiplex-Winding Motor PWM Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power converter control devices for multiplex-winding electric motors face instability during high-speed rotation due to complex timing calculations and phase deviations between carrier signals and voltage commands, leading to potential control instability and reduced efficiency.
Innovation Solution
A power converter control device that selectively switches between asynchronous and synchronous PWM control modes, using carrier signals synchronized with specific voltage commands to stabilize motor operation across various speed regions, ensuring stable control by adjusting carrier signals based on the motor's operation state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If synchronous PWM control is performed using two carrier signals for multiplex-winding electric motor, then switching loss is reduced, but timing calculation becomes complicated and control stability deteriorates
Solution Approach 1:
The patent merges the timing calculation for multiple carrier signals into a unified system where one carrier signal serves as a reference for calculating the phases of other carrier signals. This consolidation simplifies the overall timing calculation process while maintaining synchronous PWM control benefits for reducing switching loss in multiplex-winding electric motors.
Solution Approach 2:
The patent performs preliminary calculation of carrier signal phases based on a reference carrier signal before generating PWM waveforms. By pre-calculating the phase relationships and timing offsets, the system avoids complex real-time calculations during PWM generation, thereby simplifying timing management while maintaining control stability.
2Productivity
If carrier signal phase is changed to synchronize with voltage command, then PWM control efficiency is improved, but calculation time varies causing control instability
Solution Approach 1:
The patent implements feedback mechanisms that monitor the relationship between carrier signal phases and voltage command phases. Based on this feedback, the system dynamically adjusts carrier signal timing to maintain synchronization while ensuring that calculation times remain within stable ranges, thus preventing control instability.
Solution Approach 2:
The patent dynamically changes carrier signal phase parameters based on the voltage command phase while maintaining fixed timing calculation intervals. This approach allows the system to adapt to varying operating conditions and maintain PWM control efficiency without causing control instability through variable calculation times.
3Device complexity
If asynchronous PWM control is used for multiplex-winding electric motor, then control simplicity is maintained, but switching loss increases at high speed
Solution Approach 1:
The patent introduces dynamic carrier signal phase adjustment mechanisms that adapt to motor speed conditions. At low speeds, the system operates with simpler control similar to asynchronous PWM, but at high speeds, it dynamically transitions to synchronous PWM control by adjusting carrier phases, thereby reducing switching loss while maintaining control simplicity through automated adaptation.
Data Source
AI summary
A power converter control device performs PWM control for power converters which respectively supply power to a plurality of winding groups of a multiplex-winding electric motor including the plurality of winding groups, the power converter control device including a PWM control unit which performs control while selectively switching among an asynchronous PWM control mode using a carrier not synchronized with voltage commands for respective winding groups and both or one of a first synchronous PWM control mode in which voltage commands for respective winding groups are subjected to PWM control using a carrier synchronized with a voltage command for a specific winding group, and a second synchronous PWM control mode in which voltage commands for respective winding groups are subjected to PWM control using respective carriers synchronized with the respective voltage commands.