Motor Driving Device Pre-Charge Timing Control
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Solution Overview
Problem
In motor driving devices with multiple driver circuits, simultaneous activation of pre-charge circuits for failure diagnosis increases current consumption and peak current, leading to higher costs and potential delays in startup due to increased resistance values needed to limit charging currents.
Innovation Solution
Implementing a control unit to manage the timing of pre-charge circuits so they charge power supply stabilizing capacitors at different timings or alternately, reducing peak charging currents and eliminating the need for increased resistor values or semiconductor ratings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple pre-charge circuits are simultaneously activated for failure diagnosis, then failure diagnosis capability is improved, but current consumption and peak current increase
Solution Approach 1:
The control unit activates pre-charge circuits in a periodic or sequential manner rather than simultaneously, controlling them to operate at mutually different timings. This reduces the peak current and overall current consumption while still enabling failure diagnosis of all relay circuits.
2Use of energy by moving object
If resistor values are increased to limit charging currents, then current consumption is reduced, but startup time increases
Solution Approach 1:
The pre-charge circuits charge the power supply stabilizing capacitors before the relay circuits are activated. This preliminary charging action ensures that when the relay circuits switch on, the capacitors are already charged, preventing inrush currents without requiring high resistance values that would delay startup.
3Reliability
If multiple pre-charge circuits are simultaneously activated, then failure diagnosis is enabled, but semiconductor element ratings must be increased
Solution Approach 1:
By controlling pre-charge circuits to operate at different timings rather than simultaneously, the peak current demand on any single semiconductor element is reduced. This allows the use of semiconductor elements with lower ratings while still achieving comprehensive failure diagnosis coverage.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces current consumption and costs while ensuring prompt startup of the motor driving device by controlling the charging of pre-charge circuits to avoid peak current surges, maintaining efficient operation without delaying the motor's response.
Implementation Method 1
the greater the resistance values are, the more time it takes to charge the power supply stabilizing capacitors
Data Source
AI summary
A motor driving device is operable with low current consumption at low cost and can be started up without delay. The motor driving device includes inverter circuits, relay circuits, power supply stabilizing capacitors, pre-charge circuits, and a control unit. The inverter circuits individually drive coil sets of a motor. Each relay circuit is provided between a power supply and a corresponding one of the inverter circuits. Each capacitor is provided between a corresponding one of the relay circuits and a corresponding one of the inverter circuits. The pre-charge circuits, which are provided corresponding individually to the capacitors, each charge a corresponding one of the capacitors before the relay circuits are driven. The control unit controls the pre-charge circuits so that the pre-charge circuits charge the capacitors at mutually different timings or alternately when failure diagnosis is performed on the relay circuits.