Power Supply Device Non-Overlapping Switching Control
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Solution Overview
Problem
In on-vehicle power supply devices for plug-in hybrid electric vehicles and electric vehicles, switching elements are prone to malfunction due to noise-induced erroneous turning on or off, leading to potential overcurrent issues as a result of closely arranged switching circuits and increasing switching frequencies.
Innovation Solution
A power supply device design featuring a first switching circuit with high and low side switching elements connected in series, a second switching circuit with a variable ON time point, and a control unit that ensures non-overlapping ON time points between the switching elements to prevent simultaneous activation and thereby avoid overcurrent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If switching frequency is increased to improve power supply efficiency, then productivity is improved, but switching elements are more prone to malfunction due to noise
Solution Approach 1:
The control unit preemptively prevents switching element malfunction by controlling the ON time points of high side and low side switching elements to be non-overlapping. This preliminary anti-action against noise-induced erroneous switching maintains reliability while allowing high switching frequencies for improved efficiency.
2Device complexity
If switching circuits are closely arranged to reduce device size, then device complexity is reduced, but noise-induced malfunction risk increases
Solution Approach 1:
By implementing non-overlapping ON time point control, the system preemptively counteracts the increased malfunction risk from closely arranged circuits. This allows compact circuit design while maintaining switching element reliability through proactive noise mitigation.
3Reliability
If dead-time is extended to prevent simultaneous switching, then switching element reliability is improved, but power supply efficiency deteriorates
Solution Approach 1:
The control unit dynamically adjusts the ON time points of switching elements based on real-time operating conditions. This dynamic control achieves non-overlapping switching without excessive dead-time extension, maintaining both reliability and efficiency by optimizing the balance between these competing requirements.
4Reliability
If ON time point control is implemented to prevent overlap, then switching element reliability is improved, but device complexity increases
Solution Approach 1:
The control unit performs multiple functions: it manages switching element ON time points to prevent overlap, controls dead-time duration, and adapts to varying operating conditions. This multi-functionality achieves reliable non-overlapping switching without requiring separate dedicated circuits for each control aspect, thereby limiting the increase in device complexity.
Data Source
AI summary
A power supply device comprises: a first switching circuit that includes a series circuit, connected between a predetermined voltage level and a ground level, having a high side switching element and a low side switching element connected in series that are alternately turned on and off at a predetermined frequency; a second switching circuit that includes a switching element controlled between on and off, the switching element having one end being connected to the ground level, and that makes an ON time point of the switching element variable; and a control unit that performs control such that ON time points of the switching element and the high side switching element are not overlapped with each other.