Power Converter Phase Isolation for Motor Reliability
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Solution Overview
Problem
Existing motor driving devices face limitations in maintaining optimal motor output during abnormal states, such as failures in power converter systems, which affect continuous operation and efficiency.
Innovation Solution
A power converter design that includes an inverter connected to n-phase windings with low-side and high-side switching elements, phase separation relay circuits, and a neutral point leg, allowing for switching between power supply and windings or neutral point, enabling continuous motor operation by reconfiguring power distribution during failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a power supply relay cuts off power from a failed system to ensure safety, then reliability is improved, but motor output and productivity deteriorate because the motor cannot operate at full capacity
Solution Approach 1:
The patent divides the power supply system into separate controllable segments for each phase (U, V, W phases) using individual phase separation relay circuits. When a failure occurs in one phase, only that specific phase is isolated while the other phases remain operational, allowing the motor to continue running at reduced capacity rather than completely shutting down. This segmentation enables selective isolation of faulty components while preserving functionality of healthy components.
Solution Approach 2:
The patent implements dynamic reconfiguration of the power distribution system through the neutral point separation relay circuit and phase separation relay circuits. These relays dynamically adjust the connection state between the power supply, neutral point, and motor windings based on the operational status of each phase. This dynamic adaptation allows the system to transition from full three-phase operation to reduced two-phase or single-phase operation while maintaining safety, thereby preserving motor output under abnormal conditions.
2Reliability
If the motor operates using only one non-failed system when a failure occurs, then reliability is improved, but motor output and driving range deteriorate significantly
Solution Approach 1:
The patent segments the motor control into independent phase units with separate relay control for each phase. This allows the motor to operate using multiple healthy phases simultaneously rather than being forced to use only one system, thereby maintaining higher output power while ensuring continuous operation through selective phase isolation.
Solution Approach 2:
The patent enables dynamic reconfiguration of power distribution pathways through the neutral point separation relay circuit and phase separation relay circuits. This dynamic capability allows the system to adaptively maintain motor operation using available healthy phases, preserving driving range and output capacity while ensuring continuous operation even when some phases fail.
3Reliability
If four electrical isolation devices are installed in each inverter for complete isolation, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent implements multi-functional relay circuits that perform both phase separation and neutral point separation functions. The phase separation relay circuits and neutral point separation relay circuit work together to provide comprehensive isolation capability across all phases and the neutral point, replacing the need for four separate isolation devices per inverter with a more efficient multi-functional relay configuration that achieves the same reliability with reduced complexity.
Data Source
AI summary
A power converter to convert power from a power supply into power supplied to a motor including n-phase windings, where n is an integer of 3 or more, in which first ends thereof are Y-connected and includes an inverter connected to second ends of the n-phase windings, a phase separation relay circuit to switch connection and disconnection between the power supply and the n-phase windings for each phase, a neutral point leg connected to a neutral point node of the motor, in which the first ends of the n-phase windings are Y-connected, and a neutral point separation relay circuit to switch connection and disconnection between the power supply and the neutral point node.