Vehicle Power Conversion Rectification Phase Control
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Solution Overview
Problem
Conventional vehicle electric-power conversion apparatuses face challenges in maintaining high-efficiency rectification operations due to load fluctuations, which affect the phase control of switching elements in vehicle rotating electric machines.
Innovation Solution
The apparatus includes a diode-conduction-state detection unit and a gate-command creation unit to detect and adjust the on/off timings of switching elements based on real-time load changes, ensuring stable operation by generating gate command signals for the switching elements, thereby maintaining high-reliability power conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If phase control for switching element on/off operation is performed based on rotor position detection, then rectification efficiency can be enhanced, but the system cannot cope with load fluctuations that cause the mechanical rotation position to vary in real time
Solution Approach 1:
The patent implements feedback by detecting the actual on/off timings of diodes and using this information to adjust the gate command signals for switching elements. The control unit continuously monitors diode conduction states and modifies switching timings based on detected variations, creating a closed-loop control system that adapts to load fluctuations in real time.
Solution Approach 2:
The patent makes the switching control dynamic by adjusting the on/off timings of switching elements based on real-time detection of diode conduction states and rotor position variations. Instead of using fixed phase control, the system dynamically modifies switching timings to compensate for load-induced mechanical position variations, enabling adaptive operation under varying load conditions.
2Loss of energy
If switching elements are used as rectification elements to reduce loss, then rectification efficiency is improved, but the system becomes more complex requiring precise phase control
Solution Approach 1:
The patent applies self-service by using the diodes themselves to provide timing information for the switching elements. The diode conduction state detection unit extracts timing signals from the natural operation of the diodes, and this information is directly used to control the switching elements. This eliminates the need for separate complex phase control circuits, as the system uses its own operational characteristics to generate control signals.
Solution Approach 2:
The patent makes the diodes serve multiple functions: they act as rectification elements during normal operation and simultaneously serve as timing reference sources for controlling the switching elements. The same diode conduction events that perform power rectification also provide the synchronization signals needed for precise switching control, reducing the need for separate control infrastructure.
Data Source
AI summary
The objective of the present invention is to obtain a vehicle electric-power conversion apparatus in which high-efficiency rectification operation can be realized, by detecting in real time a change, due to a fluctuation in a load, in a phase at which a switching element is turned on/off and by changing the phase at which the switching element is turned on/off, in response to the change. A diode-on timing and a diode-off timing corresponding to the diode conduction state of a diode connected in parallel with a switching element are detected; the values of rotor-position signals corresponding to the timings are sequentially stored; based on the stored values of rotor-position signals, a switching-element-on timing and a switching-element-off timing are calculated; and based on the timings, a gate command signal for the switching element is created.