KR20070045404A - Relay control system and method of a hev - Google Patents

Abstract

A relay control system and method for a hybrid electric vehicle according to the present invention, comprising the steps of measuring the voltage of a high-voltage battery, "on" (-) stage main relay, delayed by a predetermined first time "Turning on" the precharge relay; measuring the voltage of the DC link capacitor; "turning on" the positive main relay if the voltage of the DC link capacitor is equal to or greater than the first reference voltage; It is configured to include the step of delaying by a predetermined second time, and the step of "off" the precharge relay, there is an effect of ensuring the stability of the circuit by preventing the generation of an arc during the main relay connection.

Description

Relay control system and method of hybrid electric vehicle {Relay control system and method of a HEV}

1 is a circuit diagram of a relay control system of a hybrid electric vehicle according to the present invention;

2 is a flowchart of a relay control method of a hybrid electric vehicle according to the present invention;

3 is an operation timing diagram of a relay control system and method of a hybrid electric vehicle according to the present invention.

<Explanation of symbols for the main parts of the drawings>

1: High voltage battery 2-1: (+) stage main relay

2-2: (-) stage main relay 2-3: precharge relay

3: controller 4: inverter

5: DC link capacitor 6: motor / generator

7 bidirectional DC-DC converter 8 low voltage battery

9: first voltage sensor 10: second voltage sensor

R: resistance

The present invention relates to a hybrid electric vehicle, and more particularly, to a relay control system and method for pre-charging a DC link capacitor using a precharge relay and a resistor before connecting the main relay.

Recently, hybrid electric vehicles have been developed and used as eco-friendly vehicles. Such a hybrid electric vehicle uses a combination of an internal combustion engine and a battery as a power source. In general, a hybrid electric vehicle runs by using only an electric motor at start and start, and runs in conjunction with an electric motor and an internal combustion engine during normal driving.

When driving a car by using the electric motor, the main relay is connected so that the battery power is supplied to the inverter through the main relay and the DC link capacitor, and the DC is switched to AC by the operation of the inverter to operate the motor / generator. Let's do it.

However, as described above, when the main relay is connected, an arc is generated at the contact portion, and thus, the contact is damaged and the accumulation of the contact causes a malfunction of the relay.

Accordingly, the present invention is a relay control system and method of the hybrid electric vehicle to ensure the stability of the circuit by preventing the arc generated during the main relay connection by charging the DC link capacitor through the precharge relay and the resistance before the main relay connection The purpose is to provide.

Relay control system of a hybrid electric vehicle according to the present invention for achieving the above object, the high voltage battery is stored a high voltage power, and the direct current output from the high voltage battery is converted into alternating current and transferred to a motor / generator or An inverter for converting the alternating current generated by the motor / generator to a direct current and transferring the alternating current to the high voltage battery, a positive terminal main relay provided at a positive power line connecting the high voltage battery and the inverter, and the high voltage battery (-) Stage main relay which is installed on the (-) power line connecting the inverter and the inverter, precharge relay connected in parallel with the (+) stage main relay, and the rear end of the precharge relay A resistor, a DC link capacitor connected in parallel to the front end of the inverter, and preset when connecting the relays Depending on the control program (-) as the only main relay, the precharge relay, characterized in that it is configured to (+) as a single main relay net comprises a controller that sequentially connected.

The relay control method of the hybrid electric vehicle according to the present invention for achieving the above object, the step of measuring the voltage of the high voltage battery, the step of "on" (-) stage main relay, Delaying by the first time, " turning on the precharge relay ", measuring the voltage of the DC link capacitor, and if the voltage of the DC link capacitor is equal to or greater than the first reference voltage, " On ", delaying by a predetermined second time, and" off "the precharge relay.

And measuring a high voltage battery and a DC link capacitor voltage after a predetermined third time delay after the precharge relay is “off,” and determining a failure if the DC link capacitor voltage is not equal to the second reference voltage. It is done.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a circuit diagram of a relay control system of a hybrid electric vehicle according to the present invention.

As shown in FIG. 1, the high voltage battery 1 stores a high voltage power supply, and includes (+) main relay 2-1 and (−) stage main relay 2-2 and precharge relay 2. -3) is configured to electrically connect or disconnect the high voltage battery 1 and the inverter 4 under the control of the controller 3.

DC link capacitors 5 are connected to the front end of the inverter 4 in parallel, and the inverter 4 operates under the control of the controller 3 to exchange direct current output from the high voltage battery 1. Is converted to the motor / generator 6, or the alternating current generated by the motor / generator 6 is converted into direct current and transferred to the high voltage battery 1.

Then, the bidirectional DC-DC converter 7 operates under the control of the controller 3 to charge the low voltage battery 8 or to boost the voltage of the low voltage battery 8 to supply the high voltage battery 1 to the side. It is connected between the relay 2 and the direct current link capacitor 5.

In addition, the first voltage sensor 9 detects the voltage of the high voltage battery 1 and inputs it to the controller 3, and the second voltage sensor 10 senses the voltage of the DC link capacitor 5. To the controller 3.

When the controller 3 is connected to the main relay 2, the controller 3 first connects the main relay 2-2, and then connects the precharge relay 2-3 to attenuate the current through the resistor R. While charging the DC link capacitor 5 first, and then the voltage of the DC link capacitor 5 sensed by the second voltage sensor 10 is a first reference voltage, that is, by the first voltage sensor 9. When the voltage of the sensed high voltage battery 1 is multiplied by a weight (for example, 0.98), the positive terminal main relay 2-1 is connected.

The operation and effects of the relay control system and method of the hybrid electric vehicle according to the present invention configured as described above will be described in detail with reference to FIGS. 2 and 3.

2 is a flowchart of a relay control method of a hybrid electric vehicle according to the present invention, and FIG. 3 is an operation timing diagram of the relay control system and method of the hybrid electric vehicle according to the present invention.

As shown in FIG. 2, in step S1, the first voltage sensor 9 measures the voltage of the high voltage battery 1 and inputs it to the controller 3.

In step S2, the controller 3 " on " the main relay 2-2 on the negative stage, and in step S3, the first time (t1, FIG. Preferably 10 msec).

In step S4, the controller 3 turns on the precharge relay 2-3, so that the current of the high voltage battery 1 flows through the precharge relay 2-3 and the resistor R1. The capacitor 5 starts to be charged.

In step S5, the second voltage sensor 10 measures the voltage of the DC link capacitor 5 and inputs it to the controller 3, and in step S6, the controller 3 of the DC link capacitor 5 If the voltage is equal to or greater than the first reference voltage, that is, the voltage of the high voltage battery 1 measured in the step S1 is multiplied by the weight (0.98), and if the voltage is equal to or greater than the first reference voltage, perform step S7. If not, repeat the step (S5).

In step S7, the controller 3 "turns on" the positive main relay 2-1, and in step S8, the controller 3 remains in the second time (t2-t3 in FIG. 3, preferably Preferably 100msec).

Subsequently, in step S9, the controller 3 “offs” the precharge relay 2-3, and in step S10, the controller 3 remains in the third time (t3-t4 in FIG. 3, preferably 1 sec), and in step S11, the first voltage sensor 9 and the second voltage sensor 10 measure the voltages of the high voltage battery 1 and the DC link capacitor 5 and input them to the controller 3. do.

In step S12, the controller 3 determines that the voltage of the DC link capacitor 5 measured in step S11 is a second reference voltage (preferably the high voltage battery 1 measured in step S11). And if it is equal, the process is terminated. If not, the controller 3 determines that the relay system has failed in step S13.

As described above, according to the present invention, the DC link capacitor is charged through the precharge relay and the resistor before the main relay is connected, thereby preventing arcs from occurring when the main relay is connected, thereby securing stability of the circuit.

Claims (3)

A high voltage battery in which high voltage power is stored, and an inverter converting direct current output from the high voltage battery into alternating current and transferring the alternating current generated from the motor / generator to direct current and converting the alternating current generated from the motor / generator into direct current; (+) Stage main relay installed on the (+) power line connecting the high voltage battery and the inverter, (-) stage main relay installed on the (-) power line connecting the high voltage battery and the inverter; A precharge relay connected in parallel with the (+) stage main relay, a resistor connected to a rear end of the precharge relay, a DC link capacitor connected in parallel to the front end of the inverter, and the relays According to the preset program at the time of connection, (-) stage main relay, precharge relay, (+) stage main relay Relay control system of a hybrid electric vehicle, characterized in that configured to include the air. Measuring the voltage of the high voltage battery, " turning on " the main relay, &lt; RTI ID = 0.0 &gt; delaying &lt; / RTI &gt; for a predetermined first time, " turning on the precharge relay, &quot; Measuring the voltage of the circuit; if the voltage of the DC link capacitor is equal to or greater than the first reference voltage, turning on the main terminal (+); delaying the precharge relay by a predetermined second time; And “off” the relay control method of the hybrid electric vehicle. The method of claim 1, further comprising: measuring a high voltage battery and a DC link capacitor voltage after a predetermined third time delay after the precharge relay is “off”, and determining that the DC link capacitor voltage is not equal to the second reference voltage. Relay control method of a hybrid electric vehicle, characterized in that further comprises.

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