Partitioned DC-Link Inverter Layout for Common-Mode Noise Cancellation
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Solution Overview
Problem
Typical motor drive systems are hindered by the weight and volume of passive components like EMI filters and DC link capacitors, which contribute to over 60% of the total system weight and volume, limiting system density and being critical for aviation applications where weight affects fuel efficiency and performance.
Innovation Solution
A multi-three-phase motor drive system with a power distribution network featuring a partitioned DC link and a motor drive unit comprising inverter units connected in parallel with the DC link portions, utilizing phase-shifted carrier signals to achieve common-mode noise cancellation and reduced DC ripple.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional EMI filters and DC link capacitors are used to meet EMI and power quality standards, then electromagnetic compatibility and power quality requirements are satisfied, but system weight and volume increase by over 60%
Solution Approach 1:
The patent changes the electrical parameters by using a multi-three-phase configuration with phase-shifted carrier signals. This transforms the common-mode voltage characteristics, enabling cancellation of electromagnetic interference without requiring traditional bulky EMI filters and DC link capacitors, thus reducing passive component weight while maintaining EMI compliance
Solution Approach 2:
The patent converts the harmful common-mode voltage into a beneficial cancellation mechanism. By using phase-shifted carrier signals in a multi-three-phase system, the common-mode voltages from different phases interfere destructively, canceling each other out. This eliminates the need for heavy passive EMI filtering components while meeting electromagnetic compatibility requirements
2Reliability
If traditional EMI filters and DC link capacitors are used to meet EMI and power quality standards, then electromagnetic compatibility and power quality requirements are satisfied, but system volume increases by over 60%
Solution Approach 1:
The patent changes the electrical parameters by using a multi-three-phase configuration with phase-shifted carrier signals. This transforms the common-mode voltage characteristics, enabling cancellation of electromagnetic interference without requiring traditional bulky EMI filters and DC link capacitors, thus reducing passive component volume while maintaining EMI compliance
Solution Approach 2:
The patent converts the harmful common-mode voltage into a beneficial cancellation mechanism. By using phase-shifted carrier signals in a multi-three-phase system, the common-mode voltages from different phases interfere destructively, canceling each other out. This eliminates the need for heavy passive EMI filtering components while meeting electromagnetic compatibility requirements
3Weight of stationary object
If multi-three-phase configuration with phase-shifted carrier signals is used, then passive component weight is reduced by up to 80%, but system complexity increases
Solution Approach 1:
The patent segments the single three-phase system into multiple three-phase systems (e.g., upper and lower inverter groups). Each inverter unit operates independently with its own carrier signal, allowing modular design and control. This segmentation enables weight reduction through common-mode cancellation while managing complexity through modular architecture
Solution Approach 2:
The patent makes the inverter units universal by having them perform multiple functions: motor drive control, common-mode voltage generation for cancellation, and ripple current reduction. This multi-functionality reduces the need for separate dedicated components, offsetting the increased control complexity with functional integration
4Loss of energy
If multi-three-phase configuration with phase-shifted carrier signals is used, then DC capacitor ripple current is reduced by about 60%, but control complexity increases
Solution Approach 1:
The patent uses periodic carrier signals with specific phase shifts (e.g., 180 degrees between upper and lower groups) to control the inverter units. This periodic action with carefully chosen phase relationships creates destructive interference of ripple currents, reducing DC capacitor stress while maintaining manageable control complexity through repetitive patterns
Solution Approach 2:
The patent converts the harmful ripple current into a beneficial cancellation effect. By coordinating phase-shifted carrier signals across multiple inverter units, the ripple currents are made to interfere destructively, canceling each other out at the DC capacitor. This reduces energy loss and component stress while the control complexity is managed through systematic signal coordination
Data Source
AI summary
A multi-three-phase motor drive system includes a power distribution network, a motor drive unit, and a motor network. The power distribution network includes a partitioned direct current (DC) link connected between a positive voltage rail and a negative voltage rail. A connection between the positive voltage rail and a mid-point node defines an upper portion of the partitioned DC link and a connection between negative voltage rail and the mid-point node defines a lower portion of the partitioned DC link. The motor drive unit includes a plurality of inverter units, and the motor network includes a plurality of motor windings which are each connected to a respective inverter unit. A first group of the inverter units is connected in parallel with the upper portion of the portioned DC link, and a second group of the inverter units is connected in parallel with the lower portion of the partitioned DC link.