Bi-Stable Switch Discharge Circuit for High-Voltage Bus Safety
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power inverter systems face challenges in efficiently discharging electrical energy stored on high-voltage buses, particularly when the system is not in operation or experiences events like airbag deployment or high g-forces, leading to potential inadvertent discharge and energy loss.
Innovation Solution
A power inverter system with a passive discharge circuit that includes a bi-stable switch and low-impedance discharge resistor, triggered by activation signals from contactor circuits, allowing for rapid and controlled discharge of the high-voltage bus without consuming additional energy, even when the ignition is off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a passive discharge circuit with bi-stable switch is used, then discharge speed and control precision are improved, but device complexity increases
Solution Approach 1:
The bi-stable switch is pre-configured in a stable high-impedance state during normal operation. When discharge is needed, a trigger signal switches it to a stable low-impedance state, immediately connecting the discharge resistor to the DC bus. This preliminary configuration enables rapid discharge without requiring continuous control signals or complex real-time switching logic.
Solution Approach 2:
The bi-stable switch maintains its state without continuous external control, using only two stable states (high-impedance and low-impedance). Once triggered into the discharge state, it automatically maintains low-impedance connection through the discharge resistor until the bus voltage drops below the switch's break voltage, at which point it automatically returns to high-impedance state, providing self-regulating discharge control.
2Reliability
If continuous monitoring and active control are used to prevent inadvertent discharge, then safety is improved, but energy consumption increases
Solution Approach 1:
The discharge circuit operates passively without requiring continuous power for monitoring or control. The bi-stable switch only consumes energy during the brief transition moments when switching between states. During normal operation and discharge phases, the circuit relies on the inherent stability of the bi-stable switch and the passive discharge resistor, eliminating the need for continuous active control and associated energy consumption.
Solution Approach 2:
The invention extracts the active control function from the discharge circuit, removing the need for continuous monitoring and control systems. The discharge process is left to the passive characteristics of the bi-stable switch and discharge resistor, which naturally regulate the discharge based on voltage thresholds without requiring external power or control signals.
3Productivity
If high-voltage discharge is allowed during airbag deployment or high g-forces, then system responsiveness is improved, but harmful effects increase
Solution Approach 1:
The system is pre-configured with a discharge circuit that automatically activates under high-g or airbag deployment conditions. The bi-stable switch is designed to detect voltage drops associated with these events and automatically transition to the discharge state, counteracting the potential harmful effects of inadvertent discharge by controlling it through the low-impedance path of the discharge resistor rather than allowing uncontrolled discharge through other system components.
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
The system effectively and automatically discharges the high-voltage bus within a short time, preventing over-discharge and energy loss, while ensuring safety during events like airbag deployment or high g-forces, without requiring continuous power consumption.
Implementation Method 1
The bi-stable switch is controllable to provide a low-impedance electric current flow path through the discharge resistor between the positive and negative conductors of the high-voltage bus
Data Source
AI summary
A power inverter includes a multi-phase inverter circuit electrically connected to positive and negative conductors of the high-voltage bus. A bi-stable switch is electrically connected in series with a discharge resistor between the positive and negative conductors of the high-voltage bus, and a capacitor is electrically connected between the positive and negative conductors of the high-voltage bus. First and second trigger circuits are in communication with a gate of the bi-stable switch, and first and second contactors are controllable to electrically connect a respective one of the positive and negative conductors of the high-voltage bus to the high-voltage DC power source. The bi-stable switch is controllable to provide a low-impedance electric current flow path through the discharge resistor between the positive and negative conductors of the high-voltage bus in response to an activation signal from one of the first and second high-voltage DC contactor circuits.