EV Charging Relay Segmentation to Isolate Inverter Capacitors
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Solution Overview
Problem
Existing electric vehicles experience unnecessary voltage application to electrically powered system-based electronic devices during battery charging, leading to increased capacitor loads and potential deterioration, without a way to reduce these loads without increasing component count.
Innovation Solution
The implementation of a relay-based system that disconnects the charging system electronic device from the electrically powered system-based electronic device during charging, using pre-charge relays and junction relays to manage voltage and prevent inrush currents, thereby reducing loads on capacitors and extending their service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the charging system electronic device and electrically powered system-based electronic device are connected in parallel to the main battery, then the charging function is achieved, but unnecessary voltage is applied to the electrically powered system-based electronic device during charging, increasing capacitor loads
Solution Approach 1:
The patent divides the electrical connection into separate segments by introducing a first junction relay that can independently connect or disconnect the charging system electronic device from the main battery, and a second junction relay that can independently connect or disconnect the electrically powered system-based electronic device from the main battery. This segmentation allows the charging device to be isolated from the electrically powered system-based electronic device during charging operations, preventing unnecessary voltage application while maintaining independent functionality of each system.
2Object-affected harmful factors
If junction relays are added to isolate circuits during charging, then unnecessary voltage application is prevented, but the number of components increases
Solution Approach 1:
The patent designs the first and second junction relays to serve multiple functions: they act as isolation relays to prevent unnecessary voltage application during charging, serve as pre-charge relays to control inrush currents when connecting to the main battery, and enable independent operational control of different electronic devices. By making the relays multi-functional, the patent reduces the need for additional separate components while achieving comprehensive circuit protection and control.
Solution Approach 2:
The patent implements pre-charge relays that are activated before the main junction relays to gradually charge the capacitor loads in the electronic devices before full power connection. This preliminary action prevents inrush currents that would otherwise occur when connecting directly to the main battery, protecting the relays and electronic devices from current surges while maintaining a compact relay-based control structure.
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 effectively reduces the load on electrically powered system-based electronic devices during charging without increasing the number of components, suppressing inrush currents and preventing capacitor deterioration, thus enhancing the service life of relays and capacitors.
Implementation Method 1
it is possible to suppress an inrush current to capacitors which are located on the main battery side of the charging system electronic device
Implementation Method 2
by the first pre-charge relay being in a closed state before the first junction relay is closed
Implementation Method 3
a first junction relay capable of isolating the first high-voltage electric wire; and a second junction relay capable of isolating the second high-voltage electric wire
Implementation Method 4
an inverter configured to convert direct-current power of the main battery into alternating-current power, thereby driving a motor for travelling
Data Source
AI summary
An electric vehicle may include a main battery, a charging system electronic device, an electrically powered system-based electronic device, a first high-voltage electric wire; and a second high-voltage electric wire. The electrically powered system-based electronic device and the charging system electronic device may be sequentially disposed in parallel. The electric vehicle may further include a first junction relay capable of isolating the first high-voltage electric wire; and a second junction relay capable of isolating the second high-voltage electric wire. The first junction relay is disposed between the main battery and the charging system electronic device, and a first pre-charge relay which bypasses the first junction relay is disposed in parallel with the first junction relay, and the second junction relay is disposed between the charging system electronic device and the electrically powered system-based electronic device.