Multi-phase Power Converter Drift Current Detection
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Solution Overview
Problem
The detection accuracy of drift current in multi-phase converters is compromised due to the offsetting of currents detected by a single current sensor, which sums opposing currents, leading to reduced accuracy.
Innovation Solution
A power conversion device with a multi-phase converter that uses a single current sensor on the primary side to detect phase currents flowing through reactors when switching elements are in both on and off states, and a drift current detection unit that identifies drift current based on change point phase currents, with optional delay and current difference calculations to improve detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single current sensor is used to detect currents from multiple chopper circuits, then device complexity is reduced, but detection precision of drift current deteriorates due to current offsetting
Solution Approach 1:
The patent segments the detection process by identifying specific time points (change points) when switching elements transition between on and off states. At these segmented time points, the current sensor detects currents that do not offset each other, allowing accurate drift current measurement through temporal segmentation of the detection process.
Solution Approach 2:
The control unit preliminarily determines change points based on switching element states before current detection occurs. By anticipating when currents will not offset (at change points), the system prepares to capture accurate drift current measurements at these predetermined moments, improving detection accuracy without additional sensors.
2Measurement precision
If phase currents are detected when switching elements are in both on and off states, then drift current detection accuracy is improved, but detection complexity increases
Solution Approach 1:
The control unit continuously monitors switching element states and uses this feedback to identify change points. This feedback mechanism allows the system to dynamically determine when to capture current measurements for accurate drift current detection, managing complexity through intelligent control rather than hardware additions.
Solution Approach 2:
The system uses its own switching element state information to automatically identify detection opportunities. The control unit leverages existing state data to determine change points, making the system self-sufficient in identifying when accurate drift current measurements can be obtained without external assistance or complex additional components.
Data Source
AI summary
A power conversion device having a multi-phase converter in which a plurality of chopper circuits each including a switching element and a reactor connected to the switching element are connected in parallel is provided. The power conversion device includes a single current sensor that is provided on a primary side of the chopper circuit, and detects a phase current flowing through each of the reactors when the switching elements are in both an on state and an off state, and a drift current detection unit configured to detect a drift current of a phase current in the multi-phase converter on the basis of the phase current detected by the current sensor, wherein the current sensor detects a phase current such that directions of phase currents flowing through each of the reactors are the same as each other.