Polyphase Inverter Zero-Sequence Supply for Auxiliary Power
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Solution Overview
Problem
Current electrical power systems for electric vehicles require complex conversion systems to supply auxiliary networks, often involving multiple converters to achieve balanced power, which complicates the supply of auxiliary electrical networks without disturbing the main electrical load.
Innovation Solution
An electrical power system that generates polyphase voltage with a non-zero homopolar component, allowing the auxiliary network to be supplied indirectly through a connection module that exploits this component, simplifying the power distribution and eliminating the need for multiple converters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a DC-DC converter is used to supply the auxiliary network from the main battery, then the auxiliary network can be powered, but the system complexity increases and galvanic isolation is required
Solution Approach 1:
The patent combines the auxiliary power supply function with the main motor power supply system by using the same inverter to generate both the polyphase voltage for the motor and the zero-sequence voltage for the auxiliary network. This eliminates the need for separate DC-DC converters and reduces system complexity while maintaining reliable power supply to the auxiliary network.
Solution Approach 2:
The inverter is designed to perform multiple functions: it supplies polyphase voltage to the motor for propulsion and simultaneously generates zero-sequence voltage to power the auxiliary network. This multi-functionality reduces the number of components needed and simplifies the overall power conversion system.
2Reliability
If multiple converters are used to draw balanced power from three phases, then the auxiliary network can be powered, but the device complexity and number of components increase
Solution Approach 1:
Instead of using multiple separate converters to extract power from each phase, the patent merges all power extraction into a single unified approach using the zero-sequence voltage generated by the inverter. This single-point extraction method maintains balanced power supply while eliminating the need for multiple converters.
Solution Approach 2:
The patent extracts the auxiliary power supply function from the multi-converter approach and consolidates it into a single extraction point at the inverter output through the zero-sequence voltage. This extraction method provides balanced power without requiring multiple separate conversion devices.
3Reliability
If a conversion system is positioned between the motor power supply and electric motor, then the auxiliary network can be powered, but it disrupts the main electrical load supply
Solution Approach 1:
The patent introduces the zero-sequence voltage as an intermediary that allows auxiliary power extraction without interfering with the main motor supply. The inverter generates this intermediate voltage component that can be used for auxiliary purposes while the main polyphase voltage continues to supply the motor without disruption.
Solution Approach 2:
The inverter output is segmented into two independent components: the polyphase voltage for motor propulsion and the zero-sequence voltage for auxiliary network power. This segmentation allows both functions to operate independently without interfering with each other, maintaining main load supply stability while enabling auxiliary power supply.
Data Source
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AI summary
This power supply system (15) includes a main power supply device (20) generating, from a main network (14), at least one polyphase voltage to supply at least one load (12); each load (12) having one winding (30) for each phase, the windings (30) being connected in a star configuration at a midpoint (32); and an auxiliary power supply device (25) for an auxiliary network (28) having a first (60) and a second (62) supply terminals. The main power supply device (20) is configured to generate at least one polyphase voltage with at least one non-zero zero-sequence component; and the auxiliary power supply device (25) includes a connection module (65) of the first power supply terminal (60) with the midpoint (32) and of the second power supply terminal (62) with a reference point (68), to supply the auxiliary network (28) via at least one zero-sequence component from the midpoint (32).