Voltage Conversion Circuit Soft Start for Bus Capacitor Precharge
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Solution Overview
Problem
The existing power supply circuits in vehicles require a precharge circuit to charge the high-voltage bus capacitor, which reduces the reliability of the power supply and increases costs.
Innovation Solution
A voltage conversion circuit that includes a failure isolation module, a soft start module, and a voltage conversion module, which allows a low-voltage direct current from a battery to be converted into a high-voltage direct current to charge the high-voltage bus capacitor, eliminating the need for a precharge circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a precharge circuit is disposed in the power supply circuit to charge the high-voltage bus capacitor, then the high-voltage bus capacitor can be charged when the vehicle is started, but the reliability of the power supply circuit is reduced
Solution Approach 1:
The patent combines the precharge function with the DC/DC converter by integrating a second switch and a precharge resistor into the existing converter circuit. This merging eliminates the need for a separate precharge circuit, thereby improving reliability while maintaining the charging capability of the high-voltage bus capacitor.
Solution Approach 2:
The DC/DC converter is designed to perform multiple functions: it serves as both the voltage conversion device and the precharge circuit. The second switch and precharge resistor enable the converter to charge the high-voltage bus capacitor during vehicle startup, in addition to its normal voltage conversion function, thus eliminating the need for a dedicated precharge circuit.
2Ease of manufacture
If a precharge circuit is disposed in the power supply circuit, then the high-voltage bus capacitor can be charged, but the costs of the power supply circuit increase
Solution Approach 1:
The patent merges the precharge function with the DC/DC converter circuit, eliminating the need for a separate precharge circuit. This integration reduces the total number of components and lowers manufacturing costs while simultaneously improving reliability by removing an additional circuit that could potentially fail.
3Reliability
If the soft start module connects the first battery and the output filter capacitor, then the first battery can charge the output filter capacitor, but additional components are added to the circuit
Solution Approach 1:
The soft start module uses a controllable switch that can dynamically change its state between on and off. This dynamic control allows the circuit to adapt to different operating conditions: during startup, the switch is on to charge the output filter capacitor; during normal operation, the switch is off to prevent unwanted current flow. This dynamic behavior eliminates the need for additional permanent 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
This solution improves the reliability of the vehicle's power supply circuit by eliminating the need for a precharge circuit and potentially reducing costs if the soft start module is less expensive.
Implementation Method 1
a voltage conversion module, wherein the voltage conversion module includes an output filter capacitor
Implementation Method 2
The soft start module is configured to connect the first battery and the output filter capacitor, so that the first battery charges the output filter capacitor
Implementation Method 3
the voltage conversion module converts a low-voltage direct current output by the first battery into a high-voltage direct current to charge the high-voltage bus capacitor
Data Source
AI summary
Embodiments of this application provide a voltage conversion circuit, a control method, a DC/DC converter and a device. The voltage conversion circuit includes a failure isolation module, a soft start module, and a voltage conversion module. The voltage conversion module includes an output filter capacitor. Both a first terminal of the failure isolation module and a first terminal of the soft start module are connected to a positive electrode of a first battery, both a second terminal of the failure isolation module and a second terminal of the soft start module are connected to a first terminal of the output filter capacitor, and a second terminal of the output filter capacitor is connected to a negative electrode of the first battery. The soft start module is configured to connect the first battery and the output filter capacitor, so that the first battery charges the output filter capacitor.