Automotive Excessive-Voltage Interlock Loop Reference Design

The HVIL reference design enhances security in high-voltage environments with complete fault analysis, configurable settings, and strong interlock options.

In hybrid or electrical automobiles (HEVs, EVs), programs similar to battery administration, traction inverters, DC-DC converters, and onboard chargers function at excessive voltages and subsequently require a high-voltage interlock loop (HVIL). This loop is a low-voltage, low-current circuit that screens the integrity of the connectors. It checks whether or not connectors and wires are correctly related, disconnected, have a short-to-battery fault, or a short-to-ground fault. When the HVIL detects a fault, it sends a sign to the car’s security system to make sure the high-voltage parts are safely managed. This setup encompasses each the technology and monitoring points of the HVIL system. Texas Devices (TI) has launched an HVIL reference design to streamline the design course of.

The HVIL reference design gives a complete set of options for interlock loop fault analysis, full with LED indicators to show varied states: closed connection for regular operation, open connection, quick to battery, and quick to floor. It consists of configurable fixed present technology and choices for both analog or digital output indicators. Moreover, the system permits for adjustable thresholds in fault state monitoring and employs a unidirectional interlock system.

HVIL connectors are engineered to maintain the HVIL sign circuit separate from the excessive voltage energy supply circuit. As connectors are indifferent, the HVIL sign circuit is interrupted earlier than the excessive voltage energy, alerting the battery administration system (BMS) to any disconnections. This immediate notification permits the BMS to chop off excessive voltage energy swiftly, stopping arcing and defending in opposition to potential hazards from free wires.

The HVIL system’s performance hinges on a low-voltage, fixed present sign that travels independently by means of the cables connecting the excessive voltage battery to numerous subsystems. Its design features a fixed present generator, a present sensing block, load connectors and clamps, a modified window comparator, and digital logic gates, with every element’s design and performance detailed all through the reference design.

Past automotive purposes, HVIL know-how can also be employed in varied industrial settings that contain excessive voltages, similar to in heavy equipment in factories, high-voltage sensible grids, and different heavy electrical installations. Its use in these contexts helps stop hurt to each people and gear throughout operation.

The a number of subsystems, together with the traction inverter, DC-DC converters, and onboard charger, are related in collection to the HVIL circuit, every working underneath excessive voltage with a requisite interlock loop. Alternatively, these subsystems can every be geared up with their very own distinctive HVIL circuit, connecting to at least one subsystem at a time to make sure security and performance.

TI has examined this reference design. It comes with a invoice of supplies (BOM), schematics, meeting drawing, printed circuit board (PCB) structure, and extra. The corporate’s web site has extra information in regards to the reference design. To learn extra about this reference design, click on right here.