KR20120012522A - Charging device and method for automotive vehicles - Google Patents

Abstract

PURPOSE: A charging apparatus for a vehicle and a charging method thereof are provided to improve the charging efficiency of a converter charging a sub battery in a vehicle by changeably controlling the output of a converter. CONSTITUTION: The driving of a vehicle is detected(S1). A sub battery is operated in a charging mode(S2). The voltage state of the sub battery is checked(S3). Battery discharge warning is generated according to the voltage state of the sub battery(S4). The voltage of the sub battery is monitored according to the voltage state of the sub battery(S5). An output voltage is set in a range of the ±1V of the secondary battery voltage(S6). A detected output current is compared with that in a stable usage range(S7). The output voltage diminishes to 0.1V according to an output current of a converter(S8). The temperature in the converter is detected according to the output current of the converter(S9). The charge of the sub battery is determined according to the inner temperature of the converter(S10). The output of the converter is switched off according to the output current of the converter(S11). The output voltage of the converter is increased(S12).

Description

Charging device and method for vehicle {CHARGING DEVICE AND METHOD FOR AUTOMOTIVE VEHICLES}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle charging apparatus and method, and more particularly, to a vehicle charging apparatus and method for efficiently controlling a converter for charging an auxiliary battery employed in a hybrid electric vehicle or a fuel cell vehicle.

In general, a hybrid vehicle in a broad sense means to drive a vehicle by efficiently combining two or more different power sources.

However, in most cases, it means a vehicle that is driven by an electric motor driven by the power of the engine and the battery using the fuel driving power, which is commonly referred to as a hybrid electric vehicle (HEV).

In recent years, in response to the demand for improving fuel economy and developing more environmentally friendly products, research on hybrid electric vehicles has been actively conducted.

Hybrid electric vehicles (hereinafter, abbreviated as 'hybrid vehicles') can form a variety of structures using engines and electric motors as power sources. Most of the vehicles studied so far adopt either parallel or series type. have.

Among them, the parallel type engine is used to charge the battery, but to drive the vehicle directly with the electric motor.

The parallel type has the disadvantage that the structure is relatively more complicated than the serial type and the control logic is more complicated. However, the parallel type is widely adopted in passenger cars due to the advantage that the mechanical energy of the engine and the electric energy of the battery can be used simultaneously. It is becoming.

In particular, since the parallel type uses an optimal operating area of the engine and the electric motor, the fuel efficiency of the entire driving system is improved, as well as the energy is recovered by the electric motor during braking, thereby enabling efficient use of energy.

The hybrid vehicle is equipped with a vehicle control unit (HCU), and is provided with a controller for each device constituting the system.

For example, an engine control unit (ECU) for controlling the overall operation of the engine, a motor control unit (MCU) for controlling the overall operation of the electric motor, a transmission control unit (TCU) for controlling the transmission A battery management system (Battery Management System, BMS) that monitors and manages the battery status, and an air conditioner controller (Full Auto Temperature Controller, FATC) in charge of room temperature control are provided.

Here, the HCU is a top level controller that is in charge of driving control of each controller, hybrid driving mode setting, and overall vehicle control. Each of the controllers described above is connected to a high-speed CAN communication line around the HCU, which is the uppermost controller, and the upper controller transmits commands to the lower controller while exchanging information between the controllers.

In addition, the hybrid vehicle is essentially equipped with a high voltage battery (main battery) for providing the driving power of the electric motor, the high voltage battery while supplying the necessary power while repeatedly charging or discharging the vehicle.

In the motor assist, a high voltage battery supplies (discharges) electrical energy, and stores (charges) electrical energy when regenerative braking or driving an engine. At this time, the BMS transmits a battery state of charge (SOC), available charging power, and available discharge power to the HCU and the MCU to perform battery safety and life management.

On the other hand, the hybrid vehicle is equipped with a main battery (high voltage battery) for providing the driving power of the electric motor (driving motor) and a secondary battery (low voltage battery) for providing the driving power of the vehicle electronics.

A low voltage DC / DC converter (Low Voltage DC / DC Converter, LDC, LV DCDC, hereinafter referred to as “converter”) for output conversion between high voltage and low voltage is connected to the auxiliary battery.

The converter converts the high voltage DC voltage from the high voltage battery of the hybrid vehicle into the low voltage DC voltage to charge the auxiliary battery and monitor the vehicle electric load.

Since some of the vehicle generated torque is used as the torque for generating the converter, a large amount of power generated by the converter is inferior in vehicle oscillation, and thus the auxiliary battery charging amount and driving feeling are inversely proportional.

In addition, converter control without considering the driving state of the vehicle or the voltage state of the auxiliary battery reduces the charging efficiency of the auxiliary battery and adversely affects fuel efficiency.

Therefore, there is a need for a method of improving fuel economy and driving comfort of the vehicle through control of the converter.

To this end, conventionally, a method of improving fuel efficiency by simply controlling the converter to an ON or OFF state according to a condition has been used.

That is, if the electric load exceeds the reference value after the electric load of the vehicle is generated and the battery is consumed, there is a risk of discharge. Therefore, the LDC is turned on to supply a constant output to charge the auxiliary battery. If it is less than or equal to the reference value, the LDC is turned off.

However, such a conventional method focuses on improving fuel economy, and the effect of improving fuel economy is excellent, but the LDC is frequently turned on or off, thereby adversely affecting the durability of the auxiliary battery.

In addition, it is pointed out that there is a risk of discharge during driving when the LDC is off in the low SOC state of the auxiliary battery.

The present invention is to solve the above problems of the prior art, an object of the present invention is to improve the charging efficiency of the converter for charging the auxiliary battery of the vehicle, and to improve the charging efficiency of the vehicle converter to minimize the load on the converter To provide.

The present invention for achieving the above object, the battery for providing a driving power of the vehicle electrical equipment; A converter for charging the battery; And a controller that controls the on / off operation of the converter according to the state of charge of the battery, and variably controls the output voltage of the converter by sensing the output voltage of the battery.

In addition, the present invention comprises the steps of checking the power of the battery when there is no abnormality of the battery and the vehicle; Turning on the converter when the state of charge of the battery is out of the normal range; Checking the output current of the converter to step down the output voltage of the converter when the determined current value exceeds the normal range and to increase the output voltage when the converter is below the normal range; Sensing an internal temperature of the converter and stepping down the output voltage of the converter when the temperature is equal to or greater than a set temperature value; And detecting the output current and the output voltage of the converter and stopping the output of the converter when the output voltage is within a preset range.

The present invention has a useful effect of not only improving the charging efficiency of the auxiliary battery, but also minimizing the load of the converter by controlling the output of the converter in accordance with the state of the auxiliary battery and the state of the converter.

In addition, the present invention not only improves fuel efficiency and driving performance by efficiently controlling the charging of the converter, but also has the effect of extending the life of the auxiliary battery and stably maintaining the state of the auxiliary battery.

1 is a flowchart illustrating a method of controlling an output voltage of a vehicle charging device according to the present invention in a normal mode.
2 is a flowchart illustrating a method of controlling an output voltage of a vehicle charging device according to the present invention in an emergency mode.
3 is a block diagram showing a vehicle charging device according to the present invention.

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

The vehicle of the present invention includes a hybrid vehicle having two or more different power sources, an electric vehicle powered by electric energy, a fuel cell vehicle powered by hydrogen, and the like.

The vehicle is equipped with a main battery (high voltage) for providing driving power of an electric motor and an auxiliary battery (low voltage) for providing driving power for a vehicle electrical appliance.

The converter of the present invention connects between the main battery and the auxiliary battery to supply a 12V electric load as an output conversion, and converts the DC high voltage output from the high voltage main battery into a DC low voltage to charge the auxiliary battery and monitor the vehicle electric load. It will perform the function.

1 is a flowchart illustrating a method of controlling an output voltage of a vehicle converter in a normal mode according to an exemplary embodiment of the present invention.

Hereinafter, a method of controlling an output voltage of a vehicle converter in a normal mode will be described with reference to FIG. 1.

First, the start of the vehicle is sensed to detect whether the vehicle is running. (Step S1) At this time, when the start of the vehicle is detected, power is supplied to the controller.

Then, in the normal mode, it operates in Mode 1 for charging the auxiliary battery through the converter under the control of the controller (step S2).

After determining the normal mode, check the power state of the auxiliary battery. That is, when the state of charge of the auxiliary battery is 80% or more or the equivalent voltage, the voltage state of the auxiliary battery is checked without turning on the converter output (step S3).

At this time, when the voltage state of the auxiliary battery is less than the predetermined voltage (for example, 10.5V), a battery discharge warning is generated.

That is, when the voltage detected in the process of checking the voltage of the auxiliary battery is a voltage exceeding the general use range of the auxiliary battery, an abnormal signal is output to the controller side.

On the other hand, when the voltage state of the auxiliary battery is higher than or equal to a preset voltage (for example, 13 V), the battery output is stopped and the voltage of the auxiliary battery is monitored (step S5).

That is, the output of the converter is turned ON only when the state of charge of the auxiliary battery is less than or equal to 80%, and the output voltage is set to be ± 1 V of the auxiliary battery voltage (step S6).

In an embodiment of the present invention, when the state of charge of the auxiliary battery is between 10.5V to 13V, the output of the converter is turned on.

Subsequently, after confirming the output current of the converter, it is determined whether the detected output current exceeds the stable use range (step S7).

If the output current of the converter exceeds the stable use range, the output voltage is decreased by 0.1 V. (Step S8) At this time, the output voltage of the converter is not lowered below a predetermined minimum limit. Here, the preset minimum limit voltage is preferably set to 12V.

Thereafter, when the output current of the converter does not exceed the stable use area, the temperature inside the converter is sensed (step S9). Here, the stable use area of the output current is preferably set to less than 70 degrees.

If the detected internal temperature of the converter is equal to or higher than the prescribed temperature value, the output voltage of the converter is decreased by 0.1 V. (Step S7) At this time, the output voltage is set so as not to fall below the minimum limit, and the output Also set the lower limit so that the current does not go below it.

On the other hand, if the internal temperature of the converter is less than the specified temperature value, it is determined whether the charging of the auxiliary battery is completed according to the output current (step S10).

If the charging of the auxiliary battery is completed according to the output current of the converter, the output of the converter is turned off (step S11). In step S3, the charging voltage of the auxiliary battery is checked again.

On the other hand, when charging of the auxiliary battery is not completed, the output voltage of the converter is increased (step S12). Here, it is preferable to increase the output voltage of the converter by 0.1V. Thereafter, the process returns to step 7 to determine again whether the output current of the converter has exceeded the set range.

2 is a flowchart illustrating a method of controlling an output voltage of a vehicle converter in an emergency mode according to an exemplary embodiment of the present invention.

The controller determines whether the auxiliary battery is abnormal or the vehicle is in an abnormal state, and when an abnormality occurs, the controller enters emergency mode 2 that adjusts the voltage of the converter or outputs a fixed voltage according to the controller signal (step S20). If there is no error, the output voltage of the converter is controlled to be variable according to the output voltage of the auxiliary battery.

If the auxiliary battery is removed, or if the auxiliary battery is in an abnormal state or an abnormal state of the vehicle, it is recognized as an emergency mode and the controller adjusts the voltage of the converter or outputs a fixed voltage (step S21).

3 is a configuration diagram schematically showing a charging method of an auxiliary battery according to the present invention.

An embodiment of the present invention includes a converter 100, a controller 200, a relay R, a pulse adjusting unit 300, and an auxiliary battery B.

The controller 200 described above maintains an on-operation state after the vehicle is started or when the driver is operating the vehicle. The output on / off operation of the converter 100 always operates preferentially by the control signal of the controller 200 over other conditions. In addition, the controller 200 continuously checks the voltage state of the above-described auxiliary battery B, and controls the on / off operation of the converter 100 in response to the check result.

In the case where the auxiliary battery B is a lead acid battery, as the charging / discharging cycle is repeated, sulfation occurs to reduce the life of the battery. In order to overcome this, the embodiment of the present invention extends the life of the battery by charging the auxiliary battery B through a trickle charging method.

Such a charging method may act as a noise while the vehicle is being driven or when power is supplied to other electronic devices. Therefore, it is charged for several minutes only when the state of the auxiliary battery B is not good by the driver's operation or the command of the host controller 200 after the start of the vehicle is turned off or after the operation is finished.

At this time, the charging current is preferably limited to 5A or less in consideration of safety, and it is preferable not to perform charging when the state of the high voltage main battery is bad.

In the above charging method, the output relay R of the converter 100 is opened and the output of the converter 100 is turned on at a fixed voltage of 14 V according to the control signal output from the controller 200.

Then, the pulse adjusting unit 300 connected to the output terminal of the converter 100 and the power terminal of the auxiliary battery B is controlled. In addition, the pulse adjusting unit 300 includes a switching element SW connected to both ends of the relay R and controlled according to a pulse width modulation signal PWM (Pulse Width Modulation).

Here, the switching element SW preferably includes a field effect transistor (FET) element, and controls the switching element SW to repeat the on / off operation at a 10 kHz period. In addition, the above-described pulse width modulated signal is preferably generated from the controller 200.

Therefore, the present invention not only improves fuel efficiency and driving performance by efficiently controlling the output of the converter 100, but also extends the life of the auxiliary battery and stably maintains the state of the auxiliary battery.

Claims (13)

A battery for providing driving power for the vehicle electronics; A converter for charging the battery; In the charging device for a vehicle comprising a controller for controlling the on / off operation of the converter in accordance with the state of charge of the battery, and detects the output voltage of the battery to variably control the output voltage of the converter,
The controller short-circuits the connection with the battery when a control signal requiring a fixed voltage output is applied from the outside and controls the output voltage of the converter according to an external control signal.
And a relay for selectively blocking the connection of the converter and the battery according to the control of the controller,
When the relay is open, the converter is a vehicle charging device, characterized in that the fixed voltage is output. The vehicle charging device of claim 1, further comprising a pulse adjuster connected to both ends of the relay and controlled according to a pulse width modulated signal generated by the controller. The vehicle charging device of claim 1, wherein the controller turns off the converter and checks a voltage state of the battery when the state of charge of the battery is within a normal state range. The charging device for a vehicle according to claim 1, wherein the controller turns on the converter when the state of charge of the battery is out of a normal state range and increases the output voltage of the battery by a predetermined voltage. The charging device for a vehicle according to claim 1, wherein the controller transmits an abnormal signal to the outside when the output voltage of the battery is out of a predetermined range. The charging device for a vehicle according to claim 1, wherein the controller senses the output current of the converter and steps down the output voltage of the converter when it is out of a preset range. The charging device for a vehicle according to claim 1, wherein the controller senses the internal temperature to step down the output voltage of the converter when the internal temperature is greater than or equal to a preset temperature range. The charging device for a vehicle according to claim 1, wherein the controller maintains an on state when the vehicle is in operation. Checking the power of the battery when there is no problem with the battery and the vehicle;
Turning on the converter when the state of charge of the battery is out of the normal range;
Checking the output current of the converter to reduce the output voltage of the converter when the determined current value exceeds the normal range and to increase the output voltage when the converter is below the normal range;
Sensing the internal temperature of the converter and stepping down the output voltage of the converter when it is above a set temperature value;
Detecting the output current and the output voltage of the converter and stopping the output of the converter when the output voltage is within a preset range. The method of claim 9,
And determining an abnormality of the battery and an abnormal state of the vehicle, and adjusting a voltage of the converter according to a control signal of a controller when an abnormality occurs. 10. The method of claim 9, wherein stepping or increasing the output voltage
And the output voltage of the converter is adjusted to be ± 1 V of the battery voltage. The method of claim 9,
Vehicle charging method further comprises the step of charging a trickle with an output current of a predetermined current or less while the output voltage of the converter is fixed to a constant voltage when the battery is turned off after the vehicle is turned off. . The vehicle charging device of claim 9, further comprising transmitting an abnormal signal to the outside when the output voltage of the battery is out of a predetermined range.

Images