Smoothing Capacitor Emergency Power for EV Inverter
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Solution Overview
Problem
In electric vehicle power conversion devices, there is a need to supply power to the controller of the inverter circuit during a collision without relying on a backup power supply, especially when the auxiliary battery is disconnected or broken, as existing systems require a backup power supply to ensure continuous operation.
Innovation Solution
A power conversion device that includes a main battery, an auxiliary battery, a step-up converter circuit, an inverter circuit, a smoothing capacitor, and a DC-DC converter, where the DC-DC converter supplies power from the smoothing capacitor to the controller and motor, eliminating the need for a dedicated backup power supply by using the power stored in the smoothing capacitor during a collision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a backup power supply is added to ensure continuous operation during collision, then reliability is improved, but device complexity and weight increase
Solution Approach 1:
The smoothing capacitor, originally designed solely for voltage smoothing during normal operation, is made to serve dual purposes: it continues to smooth voltage during normal operation and simultaneously serves as an emergency power source during collision. This multi-functionality eliminates the need for a separate backup power supply while ensuring continuous operation during collisions.
Solution Approach 2:
The system uses its own existing energy storage component (smoothing capacitor) to serve the emergency power supply need, rather than relying on an external backup power supply. The smoothing capacitor's stored energy is utilized to maintain inverter circuit operation during collision, making the system self-sufficient for emergency power needs.
2Reliability
If a backup power supply is added to ensure continuous operation during collision, then reliability is improved, but vehicle weight increases
Solution Approach 1:
The smoothing capacitor is designed to perform multiple functions including both voltage smoothing during normal operation and emergency power supply during collision. By making this existing component multi-functional, the patent eliminates the need for additional weight-bearing backup power supply components, thereby maintaining vehicle weight efficiency while ensuring reliability during collisions.
3Ease of operation
If the auxiliary battery is used to power the controller, then ease of operation is improved, but reliability deteriorates when the auxiliary battery is disconnected or broken
Solution Approach 1:
The smoothing capacitor acts as an intermediary energy storage component between the main battery and the inverter circuit. During collision when the auxiliary battery may be disconnected or broken, the smoothing capacitor provides intermediate power support to the controller, bridging the power supply gap and ensuring continuous operation without direct reliance on the auxiliary battery.
Solution Approach 2:
The smoothing capacitor is pre-charged with energy during normal operation, creating an energy buffer or cushion that is ready to be deployed during collision. This beforehand energy storage provides immediate power support to the controller when the auxiliary battery fails, cushioning against the reliability issue without affecting normal ease of operation.
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
Enables the inverter circuit to be driven using power from the smoothing capacitor, reducing the need for a backup power supply, thereby reducing vehicle weight and ensuring continuous operation during collisions without relying on auxiliary battery power.
Implementation Method 1
a smoothing capacitor connected between a high-potential wire of the high-voltage wiring and a low-potential wire of the high-voltage wiring
Implementation Method 2
a DC-DC converter connected to a high-potential wire of the main wiring, a low-potential wire of the main wiring, a high-potential wire of the subsidiary wiring, a low-potential wire of the subsidiary wiring, the high-potential wire of the high-voltage wiring and the low-potential wire of the high-voltage wiring
Implementation Method 3
a step-up converter circuit connected to the main battery. The step-up converter circuit is configured to step up a voltage of the main battery
Implementation Method 4
an inverter circuit connected to the step-up converter circuit. The inverter circuit is configured to convert an output of the step-up converter circuit into an alternate current and output the alternate current to a motor for running of a vehicle
Data Source
AI summary
A power conversion device includes a main battery, an auxiliary battery, an inverter circuit, a high-voltage wiring, a smoothing capacitor, a main wiring, a subsidiary wiring, a DC-DC converter and a controller. The DC-DC converter is connected to a high-potential wire of the main wiring, a low-potential wire of the main wiring, a high-potential wire of the subsidiary wiring, a low-potential wire of the subsidiary wiring, the high-potential wire of the high-voltage wiring and the low-potential wire of the high-voltage wiring. The controller is connected to the auxiliary battery and the DC-DC converter. The DC-DC converter is configured to supply a power stored in the smoothing capacitor to the controller through the DC-DC converter such that the controller drives the inverter circuit and that the power stored in the smoothing capacitor is supplied to the motor through the inverter circuit, when a collision of the vehicle is detected.