Multilevel Regeneration Drive System With Disconnected Wye Transformer
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Solution Overview
Problem
Conventional motor drive systems with transformers are complex and costly, requiring multiple devices and voltage/current detection circuits, especially when trying to control the speed of three-phase AC motors with regeneration capabilities.
Innovation Solution
A transformer with a disconnected wye configuration on the secondary side simplifies the system, allowing for improved control using the average or combination of DC bus voltages from inverters for each load phase, eliminating the need for a shared neutral point and reducing the complexity of the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a transformer with multiple secondary isolation windings is used to obtain higher drive voltage, then the drive voltage is increased, but the system complexity and cost increase due to requiring multiple devices and voltage/current detection circuits
Solution Approach 1:
The patent divides the three-phase power conversion into three separate single-phase conversions, with each phase having its own converter and DC bus. This segmentation allows each phase to be independently controlled and simplified, eliminating the need for complex multi-winding transformers while achieving the same voltage transformation function.
Solution Approach 2:
The patent transitions from a traditional three-phase unified conversion approach to a dimensionally separated approach where each phase operates independently on its own DC bus. This dimensional separation in the electrical domain simplifies the transformer requirements and reduces system complexity.
2Device complexity
If a shared neutral point is used in the transformer secondary, then the system structure is simplified, but the control capability and precision are reduced
Solution Approach 1:
By eliminating the shared neutral point and creating separate DC buses for each phase, the patent achieves both structural simplification and enhanced control capability. Each phase can be controlled independently without interference from other phases, improving control precision while maintaining structural simplicity.
3Measurement precision
If multiple voltage/current detection circuits are used to monitor each phase, then the control precision is improved, but the system cost and complexity increase
Solution Approach 1:
The patent segments the detection function into independent units for each phase, where each single-phase converter has its own simplified detection circuit. This segmentation reduces the overall complexity compared to a unified three-phase detection system while maintaining the precision needed for each individual phase control.
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 configuration simplifies the motor drive system, reduces costs, and enhances control capabilities by utilizing the average DC bus voltages for feedback control, improving efficiency and reducing the number of devices needed.
Implementation Method 1
Where a transformer is used between the power source and the driver circuit to obtain a higher drive voltage
Implementation Method 2
a driver circuit is commonly used to convert the original AC power source signal (which is typically fixed) to a desired driving frequency and/or voltage
Implementation Method 3
the other for performing the regeneration function, which receives energy back from the motor
Data Source
AI summary
A drive system for driving a multi-phase motor (such as a three-phase AC motor) or other load. Where a transformer is used, the transformer may have a disconnected wye configuration on the secondary side. The system may also utilize the average or other combination of DC bus voltages of inverters for each load phase, to provide feedback control.