Integrated Solid-State Relay with Pre-Charge Circuit
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Solution Overview
Problem
Existing electronic systems for connecting and disconnecting loads in electric or hybrid traction vehicles face issues with high current flow due to voltage differences, requiring complex external pre-charge and diagnosis systems that are costly and cumbersome.
Innovation Solution
An integrated electronic device with a solid-state relay and pre-charge circuit that includes a measurement, command, and diagnosis module to equalize terminal voltages before connection, providing a status signal for pre-charge completion and simplifying the system by integrating switch, pre-charge, and diagnosis functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a pre-charge circuit is integrated into the relay, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent integrates the pre-charge circuit directly into the relay device, combining previously separate components (relay and external pre-charge circuit) into a single unified device. This merging eliminates the need for external pre-charge circuits and their associated diagnosis systems, thereby reducing overall system complexity while accepting increased manufacturing precision requirements for the integrated structure.
2Measurement precision
If external diagnosis systems are used to verify pre-charge operation, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts the diagnosis function from external systems and integrates it directly into the relay device. The relay now includes internal circuitry to monitor and verify pre-charge operation, eliminating the need for separate external diagnosis systems. This extraction maintains measurement precision for pre-charge verification while significantly reducing device complexity by removing external diagnostic components.
3Power
If high voltage batteries are used in electric vehicles, then power is increased, but harmful factors increase due to overcurrent during connection
Solution Approach 1:
The patent implements a pre-charge circuit that activates before the main relay closes, preliminarily charging the load capacitance to match the battery voltage. This preliminary action equalizes the voltage between battery and load, preventing the voltage difference that would otherwise cause harmful overcurrent when the main connection is established. The pre-charge operation ensures safe connection of high power batteries without overcurrent damage.
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 solution effectively reduces the complexity and cost of pre-charge systems, ensuring safe and efficient terminal connections while eliminating the need for external diagnosis systems, enhancing compactness and reliability in vehicle applications.
Implementation Method 1
a pre-charge electrical circuit (2) connected between said first (11) and second (12) device terminals and comprising at least one impedance element (21) and at least one pre-charge electronic switch (M2), arranged in series. The pre-charge electrical circuit (2) is configured to carry out, based on said command signal (CMD), a pre-charge operation, aimed at equalizing the electrical potentials (V1, V2) present at the first terminal (11) and second terminal (12) of the device
Implementation Method 2
a measurement, command and diagnosis module (3) configured to detect a voltage difference (ΔV) between the first (11) and second device terminal (12) and to generate said enabling signal (ENB) as a function of the detected voltage difference (ΔV)
Data Source
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AI summary
An electronic device 1 for electrically connecting and disconnecting, based on a command signal CMD, a first device terminal 11 and a second device terminal 12 is described. The device 1 comprises at least one main electronic switch M1, an electrical pre-charge circuit 2 and a measurement, command and diagnosis module 3. The main electronic switch M1 has a first electrical terminal D1 connected to the first device terminal 11, a second electrical terminal S1 connected to the second terminal of the device 12, and a main driving terminal G1. The main electronic switch M1 is configured to take, based on a driving signal DRV, depending on the command signal CMD and on an enabling signal ENB, a closed condition or an open condition, wherein the first electrical terminal D1 is respectively connected to or disconnected from the second electrical terminal S1. The pre-charge electrical circuit 2 is connected between said first 11 and second device terminal 12, and comprises at least one impedance element 21 and at least one pre-charge electronic switch M2, arranged mutually in series. The pre-charge electrical circuit 2 is configured to carry out, based on the command signal CMD, a pre-charge operation, aimed at equalizing the electric potentials (V1, V2) of the first and second terminals of the device, before the main electronic switch M1 takes a closed condition, upon of a transition from the open condition. The aforesaid main electronic switch (M1) and the electronic pre-charge switch (M2) are solid-state power switches (i.e., relays). The measurement, command and diagnosis module (3) is configured to detect a voltage difference ΔV between the first 11 and the second device terminal 12, and to generate said aforesaid enabling signal ENB based on the detected voltage difference ΔV. The measurement, command and diagnosis module 3 is further configured to generate, based on the detected voltage difference ΔV and on the command signal CMD, a status signal STS indicative of a start phase, of an in-progress phase and of a completion phase of the pre-charge operation carried out by the pre-charge electrical circuit 2 The measurement, command and diagnosis module (3) comprises a comparator module (30), a command module (31) and a diagnosis module (32).