A high-voltage electrical battery in HEV/EVs is used to energy the traction inverter and different high-voltage hundreds such because the AC compressor. To attach the battery to the masses, the battery energy strains are routed by means of electronically managed, high-voltage switches referred to as contactors.

Determine 1 reveals a typical high-power car boardnet with contactors within the battery disconnect unit (BDU) and energy distribution field (PDB).

Determine 1: Typical high-voltage energy boardnet with contactors in HEV/EVs

The high-voltage contactor is electronically managed by powering a low-voltage coil contained in the contactor. The low-voltage contactor management circuit, referred to as the economizer, drives this low-voltage coil contained in the contactor and is powered by the low-voltage bus within the car; for instance 12-V bus. Additional, the management indicators for switching the high-voltage contactors on or off are generated by management modules such because the car management unit (VCU) or the HVAC management module within the car.

Determine 2 reveals the profile of the present within the low-voltage coil. This present profile, referred to as a pull-in-and-hold profile; when the contactor is first switched on, the present within the coil is initially excessive. That is the pull-in present, represented by ipull in Determine 2. The pull-in present is adopted by constant-hold present, represented by imaintain in Determine 2, for the rest of time that contactor is on. The pull-in present ensures that the contact is made whereas the maintain present ensures the contacts stay in place.

As proven in Determine 2, one of many key capabilities of an economizer is to control the present within the low-voltage management coil. Texas Devices extensive portfolio of present mode PWM controllers that features units such because the UC2843A-Q1 and UCC28C43-Q1 and LED drivers reminiscent of TPS92691-Q1 and TPS92692-Q1 are nicely suited to control the present within the low-voltage coil.

The present PWM controllers characteristic a easy but efficient management structure. With solely eight pins, the UC2843A-Q1 and UCC28C43-Q1 can drive MOSFET gates immediately. Moreover, these industry-proven units supply a versatile and scalable controller resolution for the high-voltage to low-voltage conversion and also can help wide-input vary purposes. Determine 3 reveals a circuit idea for an economizer with the PWM controller.

The LED drivers are fixed-frequency present regulators and therefore combine the present management characteristic. Each the TPS92691-Q1 and TPS92692-Q1 have an enter pin that’s used to set the present set level. Additional, the TPS92692-Q1 integrates unfold spectrum which helps with EMI mitigation. Determine 4 reveals a circuit idea for economizer with a LED driver.

Determine 3: Present mode PWM controller proven in contactor economizers

Determine 4: LED driver proven in contactor economizers

The economizers in Determine 3 and Determine 4 additionally embrace energy provide and present set level generator blocks. These blocks might be simply realized by utilizing Texas Devices extensive portfolio of LDOs, analog multiplexers, operational amplifiers and comparators.

Courtsey- Texas Devices 

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