EV Charging Pre-Charge Module Layout for Low Inrush Current
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Solution Overview
Problem
Existing electric vehicle charging systems suffer from high inrush currents due to imbalances in Y capacitors and resistors, leading to prolonged cable check times and potential safety hazards during pre-charging.
Innovation Solution
Incorporating a separate pre-charge module that operates independently from the power module, minimizing Y capacitance and output impedance to prevent high inrush currents and enable efficient pre-charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pre-charge circuit with resistor and relay is used in parallel to the DC+ contactor, then pre-charging can be performed to charge the output voltage near to battery voltage, but high inrush current may occur when the vehicle battery is connected to the DC bus due to imbalances in resistors and capacitors
Solution Approach 1:
The patent segments the pre-charge function from the main power module by introducing a separate pre-charge module that is electrically connected to the DC bus but independent from the power module. This separation allows the pre-charge module to handle pre-charging operations with minimized Y capacitance, preventing high inrush currents when the vehicle battery connects to the DC bus, while the power module handles main charging operations.
2Quantity of substance
If Y capacitance in the power module, DC bus and output is increased, then energy storage capacity is improved, but the cable check time is prolonged due to measurement of AC signal amplitude and phase shift
Solution Approach 1:
The patent extracts the Y capacitance function from the main power module by implementing a separate pre-charge module with minimized Y capacitance. This extraction allows the cable check to be performed quickly on the pre-charge module without the burden of large Y capacitance, while the main power module retains sufficient energy storage capacity for charging operations.
3Object-generated harmful factors
If a separate pre-charge module is introduced that is electrically connected to the DC bus and independent from the power module, then inrush currents are prevented and cable check time is shortened, but device complexity increases
Solution Approach 1:
The separate pre-charge module is designed to perform multiple functions: it conducts the cable check, performs pre-charging of the output voltage, and prevents inrush currents. By consolidating these functions in a single module with minimized Y capacitance, the patent avoids the need for separate complex circuits for each function, thereby reducing overall system complexity while achieving the desired technical effects.
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
Reduces inrush currents, shortens cable check times, and enhances user safety by minimizing energy storage in capacitors, while allowing for higher charging currents and voltages.
Implementation Method 1
charging the internal capacitors at the output to prevent a high inrush current when the vehicle battery is connected to the DC bus
Implementation Method 2
a power module configured for providing electrical energy to charge the electric vehicle... converts the received AC into a direct current, DC
Data Source
AI summary
Described herein is an electric vehicle charging arrangement for charging an electric vehicle, including an electric vehicle supply equipment (EVSE), where the EVSE includes: a power module configured to provide electrical energy to charge the electric vehicle, an output configured to connect the power module to the electric vehicle for charging the electric vehicle, and a direct current (DC) bus provided between and connected to the power module and the output and configured to transport electric energy from the power module to the output, where the electric vehicle supply equipment includes a pre-charge module configured to pre-charge the output, and where the pre-charge module is separate from the power module and electrically connected to the DC bus.