Multi-phase Converter Common-mode Injection for Independent DC-Links
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
State-of-the-art modulation schemes for multi-phase power converters, particularly those based on H-bridge topologies, fail to optimize the utilization of dc-link voltage when each phase voltage is generated from an independent dc-link source, leading to sub-optimal output voltage and increased dc-link capacitance requirements.
Innovation Solution
A method is introduced to calculate a common-mode injection voltage by determining the difference between positive and negative dc-link voltages for each phase, averaging these differences across all phases, and adding the result to the reference voltage to generate an adjusted reference voltage for each phase, allowing for optimal utilization of independent dc-link voltages in multi-phase converters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If state-of-the-art modulation schemes are used for multi-phase converters with independent dc-link sources, then the converter can operate with isolated phase paths, but the utilization of dc-link voltage is sub-optimal, reducing output voltage and requiring bulky dc-link capacitors
Solution Approach 1:
The patent transforms the modulation approach by changing the reference voltage parameters through common-mode voltage injection. This allows the system to utilize the full range of independent dc-link voltages more effectively, converting the limitation of independent dc-links into an advantage for voltage optimization and output power enhancement.
2Reliability
If state-of-the-art modulation schemes are used for multi-phase converters with independent dc-link sources, then the converter can operate with isolated phase paths, but the utilization of dc-link voltage is sub-optimal, requiring bulky dc-link capacitors
Solution Approach 1:
By implementing common-mode voltage injection and optimizing the reference voltage calculation, the patent improves voltage utilization efficiency. This reduces the voltage ripple and energy storage requirements, allowing for smaller dc-link capacitors while maintaining stable operation with independent dc-link sources.
3Power
If common-mode voltage injection is used to optimize dc-link voltage utilization, then output power increases, but the modulation scheme becomes more complex for independent dc-link topologies
Solution Approach 1:
The patent applies local quality by implementing phase-specific reference voltage adjustments based on each phase's independent dc-link voltage levels. The common-mode injection is calculated and applied locally to each phase path, allowing optimized voltage utilization without requiring a complete redesign of the overall modulation architecture.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A multi-phase converter includes a plurality of phase paths. Each phase path includes at least one dc-link that is independent from every other phase path dc-link such that each output phase voltage is generated from a corresponding dc-link voltage source that can be different from every other phase voltage dc-link voltage source. A total dc-link voltage level is determined for each output phase voltage. A common-mode injection voltage is calculated based on all dc-link voltage levels and all phase reference voltages. Each phase path reference voltage is then adjusted based on the calculated common-mode injection voltage, such that each generated output phase voltage level is adjusted in response to its corresponding adjusted reference voltage.