Capacitor Discharge Circuit Using Transistor Feedback
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Solution Overview
Problem
Existing capacitor discharge methods, such as those involving mechanical conductors or resistors, are inefficient or wasteful, particularly when the power module is disconnected or during electrical faults, as they either require mechanical components or continuously consume current.
Innovation Solution
An electrical system with a current-consuming circuit using a transistor to stabilize and control the discharge current, which enters and exits through its terminals, optionally including Zener diodes and resistors, to efficiently discharge a capacitor without mechanical elements or continuous current consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resistor is connected to the terminals of a capacitor to discharge it, then the capacitor can be discharged when the power module is disconnected, but the resistor continuously consumes substantial current even when the power module is connected
Solution Approach 1:
The patent applies the dynamics principle by making the discharge circuit dynamically controllable through a transistor switch. The transistor is controlled by a control signal that activates the discharge path only when needed (when the power module is disconnected or during faults), rather than maintaining a continuous discharge path with a resistor. This dynamic switching eliminates continuous current consumption while preserving discharge capability when required.
2Ease of operation
If a mechanical conductor is used to short a controlled switch to deactivate the current-consuming circuit, then the circuit can be deactivated, but the solution requires the presence of a mechanical element on the power-module side
Solution Approach 1:
The patent replaces the mechanical conductor system with an electrical control system. Instead of using a mechanical element to physically short the switch, the invention uses an electrical control signal applied to the transistor's control terminal to electronically switch the discharge circuit on or off. This substitution eliminates mechanical components while achieving the same circuit deactivation function.
3Object-affected harmful factors
If a current-consuming electrical circuit is activated to consume constant discharge current, then the capacitor can be discharged to prevent electric shocks, but the circuit requires mechanical disconnection to activate
Solution Approach 1:
The patent implements feedback by using a detection circuit that monitors the connection state of the power module and automatically controls the transistor switch accordingly. When the detection circuit detects that the power module is disconnected or a fault condition exists, it automatically activates the discharge circuit through the transistor, eliminating the need for manual mechanical disconnection to activate the safety function.
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 efficiently discharges capacitors by maintaining a constant current flow, reducing losses and ensuring safety, even when the power supply is disconnected, and can be used in electric motor vehicles to manage high-voltage capacitors.
Implementation Method 1
the current-consuming electrical circuit includes a transistor arranged such that the consumed current enters via a current input terminal of the transistor and exits via a current output terminal of the transistor, and in that the current output terminal is connected to a control terminal of the transistor in order to stabilize the transistor
Implementation Method 2
the current-consuming electrical circuit includes a Zener diode connected between the current output terminal of the transistor and the control terminal of the transistor in order to stabilize the transistor
Implementation Method 3
the current-consuming electrical circuit includes a resistor connected between the control terminal of the transistor and the first interface terminal
Data Source
AI summary
The electrical system (100) includes: —a capacitor (C); —an electrical power supply device (102); —an electrical power receiving device (104); —a current-consuming electrical circuit (108) designed to consume a current (i) entering via a first interface terminal (BA) and exiting via a second interface terminal (BB). The electrical system (100) being designed such that the current-consuming electrical circuit (108) consumes the discharge current (i) when the electrical power supply device (102) is connected to the terminals of the capacitor (C).The current-consuming electrical circuit (108) includes a transistor (Q1) arranged such that the consumed current (i) enters via a current input terminal (C1) of the transistor (Q1) and exits via a current output terminal (E1) of the transistor (Q1), and in that the current output terminal (E1) is connected to a control terminal (B1) of the transistor (Q1) in order to stabilize the transistor (Q1).