Precharging Resistor Dual-Function Discharge Circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for discharging high-voltage capacitors in hybrid and electric vehicles are inefficient, requiring separate discharge circuits and resulting in longer discharge times, which pose safety risks and reduce vehicle availability.
Innovation Solution
Utilizing the existing precharging resistor, already present in the battery, for both charging and discharging the intermediate circuit capacitors, eliminating the need for additional discharge circuits and reducing installation space, while ensuring rapid discharge times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate discharge circuit with an ohmic discharge resistor is used, then the intermediate circuit can be discharged after switching off, but the discharge time is long and additional installation space is required
Solution Approach 1:
The precharging resistor is designed to serve dual functions: charging the DC link capacitor during system startup and discharging it during system shutdown or emergency situations. This eliminates the need for a separate discharge circuit, reducing component count and installation space while achieving rapid discharge times that meet safety requirements
2Reliability
If a separate discharge circuit is added, then discharge capability is provided, but device complexity and installation space increase
Solution Approach 1:
The precharging resistor serves as both a charging resistor during system startup and a discharge resistor during system shutdown or emergency situations. This multi-functional design eliminates the need for separate discharge circuits, reducing overall system complexity and component count
Solution Approach 2:
The charging and discharging functions are merged into a single circuit path using the precharging resistor. By controlling the switching elements, the same resistor handles both charging the DC link capacitor and discharging it, simplifying the overall circuit architecture
3Productivity
If precharging resistors are dimensioned for fast charging, then vehicle availability is ensured, but discharge capability must also be maintained
Solution Approach 1:
The resistance value of the precharging resistor is specifically selected to provide adequate charging current for fast DC link charging while simultaneously enabling rapid discharge. The switching elements control the resistor's connection timing to optimize both charging speed and discharge performance according to system requirements
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 allows for safe and rapid discharge of capacitors, significantly reducing the risk of high-voltage exposure and ensuring high vehicle availability by achieving discharge times ten times shorter than prior art solutions, while reducing costs and installation space.
Implementation Method 1
the DC link capacitor is charged via a precharging resistor
Implementation Method 2
an ohmic discharge resistor that is permanently connected in parallel with the intermediate circuit capacitor
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention describes methods and associated apparatuses for discharging the high-voltage supply system, in particular of a DC voltage intermediate circuit, in which switching means are used to discharge the capacitors of the high-voltage supply system, said switching means being situated between the capacitors and at least one precharging resistor and a high-voltage battery, and the switching means being switches with a predefinable arrangement of the switching contacts or switching devices or relays or contactors which can be switched by means of a control device. The switching devices are operated such that the at least one precharging resistor is simultaneously used to charge and discharge the DC voltage intermediate circuit.