KR20170115999A - Anti-Start Air Conditioner Compressor L-C Resonant DC/DC Converter for Commercial Vehicle - Google Patents

Abstract

The present invention relates to a resonance type DC-DC converter for power supply used in an inverter of a neglected air conditioner compressor in the case of using an air conditioner of a commercial vehicle. The resonance type DC-DC converter includes a high frequency transformer for boosting the input battery voltage, A switching unit formed of first to fourth switches in a bridge form and alternately switched according to an input signal to provide the battery voltage to the high frequency transformer; a switch unit formed on a secondary side of the high frequency transformer, And a control unit including first and second capacitors to rectify the voltage boosted by the high frequency transformer and to turn on and off the first to fourth switches by receiving an output voltage output from the rectifier unit, Resonance occurs at the resonance frequency of the inductance and the first and second capacitors, thereby reducing the switching loss of the switch section, And more particularly, to an L-C resonance type DC-DC converter for an ignorable air conditioner compressor.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an L-C resonance type DC-DC converter for a commercial vehicle,

More particularly, the present invention relates to an L-C resonance type DC-DC converter for a neglected air conditioner compressor of a commercial vehicle.

Global automotive technology development is accelerating global warming, focusing on reducing greenhouse gases and reducing fuel consumption due to rising oil prices. In particular, commercial vehicles play a central role in the nation 's logistics industry as transportation means, which has a higher transportation efficiency than the overall vehicle market share. In addition, commercial vehicles are industrial sectors that support infrastructure such as urban construction, roads, bridges, and harbors. The average annual mileage of commercial vehicles is 3.4 times higher than that of passenger cars. As oil consumption and CO2 emissions are large, the need for environmentally friendly technology development and energy efficiency improvement is increasing.

A general automotive air conditioning system refers to a device that maintains the temperature of the vehicle interior desired by the driver by using energy generated by the operation (running or idling) of the engine.

The operation of this air conditioning system utilizes a part of the engine driving force and is related to the fuel efficiency of the automobile. Especially, in the case of a commercial vehicle where frequent summer work or nighttime sleep in the vehicle is frequently used, the usage rate of the air conditioner depends on the driving habit of the driver. Therefore, in the case of a commercial vehicle in which a large amount of air conditioner is used in the summer, excessive fuel consumption and environmental pollution due to exhaust gas are caused by driving a large engine frequently for cooling power. In addition, a vehicle released under the Euro III emission regulation is required to be equipped with a control system that automatically stops the engine if idling occurs for more than 5 minutes. Therefore, the problem of cooling when stopping a commercial vehicle such as a freight vehicle or a high-speed bus vehicle is a problem to be solved.

For commercial vehicles, a battery-based direct current system is used. A compressor of the air conditioner that can operate even in the ignition state of a vehicle requires a high voltage of 260 V or more, so a step-up converter is essential. Particularly, a resonance type converter having advantages such as reduction in loss due to high frequency switching is suitable for a power conversion system in which low voltage high current characteristics, high efficiency and high power density are required.

Conventional resonance type converters are equipped with inverters and converters for L-C resonance, which complicates the circuit and increases the size of the circuit, thereby increasing the size of the entire system. In addition, when the conventional resonant converter is used, there is a problem that the signal interference due to the resonant frequency becomes large in the peripheral circuit device.

The object of the present invention is to provide an L-C resonance type DC-DC converter for a commercial-vehicle air-conditioner compressor capable of increasing the pressure 10 times or more based on a low-voltage battery power used in a commercial vehicle.

Another object of the present invention is to provide an LC resonance type non-isolated air conditioner compressor for a commercial vehicle which can minimize the loss by reducing the switching frequency of the switches connected to the full bridge to a frequency equal to the resonance frequency, And a DC-DC converter.

In order to solve the above problems, the present invention provides a resonance type DC-DC converter for power supply used in an inverter of a neglected air conditioner compressor when using an air conditioner of a commercial vehicle, comprising: a high frequency transformer for boosting an input battery voltage to output; A switch unit having first to fourth switches formed in a full-bridge type on a primary side of the high-frequency transformer and alternately switched according to an input signal to provide the battery voltage to the high-frequency transformer; A rectifying unit formed on a secondary side of the high-frequency transformer and including first and second diodes and first and second capacitors to rectify a voltage boosted by the high-frequency transformer; And a control unit receiving the output voltage from the rectifying unit and turning on and off the first to fourth switches, wherein resonance occurs at a resonance frequency of the leakage inductance of the high frequency transformer and a resonance frequency of the first and second capacitors, DC resonant DC-DC converter for a non-commercial air-conditioner compressor for a commercial vehicle, characterized in that the switching loss is reduced.

In the high frequency transformer, the primary winding and the secondary winding are separated and wound, and a gap may be formed in the middle of the transformer.

The first and fourth switches are simultaneously turned on or off. When the first and fourth switches are turned on, the second and third switches are simultaneously turned off. When the first and fourth switches are turned off The second and third switches can be turned on.

In the LC resonant DC-DC converter for a commercial vehicle air-conditioner compressor, when the first and fourth switches are turned on at the same time, the first diode is turned on, the power of the battery is charged in the first capacitor, The inductance and the first capacitor may be in a series resonance state.

In the LC resonant DC-DC converter for a commercial vehicle air-conditioner compressor, when the second and third switches are simultaneously turned on, the second diode is turned on, the power of the battery is charged in the second capacitor, The inductance and the second capacitor may be in a series resonance state.

The controller may use the resonance frequency of the series resonance state as the switching frequency of the first to fourth switches.

The L-C resonant DC-DC converter for a commercial vehicle air-conditioner compressor according to an embodiment of the present invention is capable of stepping up (more than 10 times) by 260V or more based on 24V low-voltage battery power used in a commercial vehicle.

Also, the L-C resonance type DC-DC converter for a commercial vehicle air-conditioner compressor according to an embodiment of the present invention controls the switching frequency to be equal to the resonance frequency to minimize the loss, and the efficiency is about 95.6%.

The LC resonant DC-DC converter for a commercial vehicle air-conditioner compressor according to an embodiment of the present invention is characterized in that an inductor and a capacitor for LC resonance can be simplified by using a leakage inductor of a high frequency transformer and a capacitor of a rectifying part .

1 is a block diagram showing an LC resonant DC-DC converter for a commercial vehicle air-conditioner compressor according to an embodiment of the present invention;
Fig. 2 and Fig. 3 are diagrams showing the transition of the first operation mode and the second operation mode in the no-load state of the LC resonance type DC-DC converter; Fig.
4 is a waveform diagram showing the waveforms of the first operation mode and the second operation mode;
5 is a circuit diagram showing the AC equivalent circuit of FIG. 1;
6 is a circuit diagram showing an AC equivalent circuit of a secondary circuit of a high-frequency transformer;
7 is a waveform chart showing DC characteristics of an LC resonant DC-DC converter for a commercial vehicle air-conditioner compressor according to an embodiment of the present invention;
FIG. 8 to FIG. 10 are waveform diagrams showing simulation results to confirm the operation of an LC resonant DC-DC converter for a commercial vehicle air-conditioner compressor according to an embodiment of the present invention. FIG.
11 is a simulation waveform diagram showing input / output voltage and current.
12 is a photograph of an LC resonant DC-DC converter for a commercial vehicle air-conditioner compressor according to an embodiment of the present invention.
13 is a waveform diagram showing a switching signal (gate signal) applied to each switch of the switch section.
Fig. 14 is a waveform diagram showing a primary side resonance current waveform of a high-frequency transformer having a leakage inductance; Fig.
15 is a waveform diagram showing a resonance current waveform transmitted to the secondary side of the high frequency transformer;
16 is a waveform diagram showing a primary side resonance voltage waveform of the high frequency transformer;
17 is a waveform diagram showing input / output voltages and currents of an LC resonant DC-DC converter for a commercial vehicle air-conditioner compressor according to an embodiment of the present invention.
18 is a waveform diagram showing ripples of the output voltage and current;
19 is a waveform chart showing the efficiency of an LC resonant DC-DC converter for a commercial vehicle air-conditioner compressor according to an embodiment of the present invention.

Hereinafter, the description of the present invention with reference to the drawings is not limited to a specific embodiment, and various transformations can be applied and various embodiments can be made. It is to be understood that the following description covers all changes, equivalents, and alternatives falling within the spirit and scope of the present invention.

In the following description, the terms first, second, and the like are used to describe various components and are not limited to their own meaning, and are used only for the purpose of distinguishing one component from another component.

Like reference numerals used throughout the specification denote like elements.

As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. It is also to be understood that the terms " comprising, "" comprising, "or" having ", and the like are intended to designate the presence of stated features, integers, And should not be construed to preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 19 attached herewith.

1 is a block diagram showing an L-C resonance type DC-DC converter for a commercial vehicle air-conditioner compressor according to an embodiment of the present invention.

1, a LC resonant DC-DC converter for a commercial vehicle air-conditioner compressor according to an embodiment of the present invention includes a switch unit 20, a high-frequency transformer 30, a rectifying unit 40, and a controller 50 .

Specifically, the switch portion 20 is formed on the primary side of the high-frequency transformer 30. The switch unit 20 is connected to the battery 10 to supply the power charged in the battery 10 to the high frequency transformer 30. The switch unit 20 is connected in a full-bridge manner to the first to fourth switches 21 to 24. At this time, the first and fourth switches 21 and 24 are turned on or off at the same time, and the second and third switches 22 and 23 are simultaneously turned on or off. At this time, when the first and fourth switches 21 and 24 are turned on, the second and third switches 22 and 23 are turned off, and when the first and fourth switches 21 and 24 are turned off , The second and third switches 22 and 23 are turned on. The switch unit 20 may be a three terminal power switch that is turned on or off by the control unit 50.

The high-frequency transformer 30 boosts the power of the battery 10 according to the operation of the switch unit 20 connected to the primary side, and delivers the power to the secondary side. In the high-frequency transformer 30, the primary winding N1 and the secondary winding N2 are wound at a ratio of 1:12, respectively. It is preferable that the high frequency transformer 30 isolates and winds the primary winding N1 and the secondary winding N2 in order to reduce the thermal stress due to the leakage inductance and the finsing effect. Further, an air gap is formed in the middle of the high-frequency transformer 30.

The rectifying part (40) is formed on the secondary side of the high frequency transformer (30). In the rectifying part 40, the first and second diodes 41 and 42 and the first and second capacitors 43 and 44 are connected. The rectifying part (40) can boost the voltage boosted by the high frequency transformer (30) and supply it to the load side.

The control unit 50 receives the voltage output from the rectifying unit 40 and controls the first to fourth switches 21 to 24 to be turned on or off. The control unit 50 applies the on / off switching frequencies of the first to fourth switches 21 to 24 to the same resonance frequency. This allows the impedance of the inductor and capacitor to be zero at the resonant frequency, resulting in the highest gain.

Hereinafter, the L-C resonance type DC-DC converter for a commercial vehicle air-conditioner compressor will be described in more detail with reference to FIG. 2 to FIG.

Fig. 2 and Fig. 3 are diagrams showing the transition of the first operation mode and the second operation mode in the no-load state of the LC resonance type DC-DC converter, Fig. 4 is a graph showing the waveforms of the first operation mode and the second operation mode Fig.

Referring to FIG. 2, in the first operation mode, the first and fourth switches 21 and 24 are turned on and the second and third switches 22 and 23 are turned off. In this case, the first operation mode of FIG. 4 is a period of T0 <t <T1 in the waveform diagram.

The input current is transmitted through the first and fourth switches 21 and 24 to the secondary side of the high frequency transformer 30 via the high frequency transformer 30. At the same time, the first diode (41) is turned on to charge the first capacitor (43) with the power supplied from the battery (10). At this time, the leakage inductance Lm and the first capacitor 43 form a series resonance type. Thereafter, the current charged in the first capacitor 43 is supplied to the load side.

Referring to FIG. 3, in the second operation mode, the second and third switches 22 and 23 are turned on, and the first and fourth switches 21 and 24 are turned off. In this case, the second operation mode of FIG. 5 is a section of T1 <t <T2 in the waveform diagram.

The input current is passed through the second and third switches 22 and 23 through the high frequency transformer 30 and the high frequency transformer 30 is transferred to the secondary side. At the same time, the second diode 42 is turned on to charge the battery 10 to the second capacitor 44. At this time, the leakage inductance Lm and the second capacitor 44 form a series resonance type. Thereafter, the current charged in the second capacitor 44 is supplied to the load side.

Here, the current waveform becomes a sinusoidal wave by the series resonance between the first operation mode and the second operation mode, and the switching loss and the write noise are reduced.

Fig. 5 is a circuit diagram showing the AC equivalent circuit of Fig. 1, and Fig. 6 is a circuit diagram showing an AC equivalent circuit of the secondary circuit of the high-frequency transformer. 5 is a circuit diagram showing that the leakage inductance Lm of the high-frequency transformer and the secondary-side resonant capacitor Cs1 are reduced to the primary side of the high-frequency transformer 30.

5 and 6, when the high-frequency transformer 30 is assumed to be ideal, the resonant frequency is calculated using Equations 1 to 5.

Value Input Voltage 24 [V] Output Voltage 260 [V] Resonant Frequency 30 [kHz] Resonant Capacitor 10 [uF] Snubber Capacitor 2.0 [uF] Resonant Inductor 1.0 [uH] Transformer Turn Ratio 1:12 Load Resistance 28 [Ω]

FIG. 8 is a waveform diagram showing switching signals applied to the first to fourth switches in the simulation, FIG. 9 is a waveform diagram showing the resonance voltage, and FIG. 10 is a waveform diagram showing the resonance current.

As shown in FIGS. 8 to 10, when gate signals (switch turn-on signals) are applied to the gates of the first to fourth switches 21 to 24 formed in the switch unit 20, The power of the battery 10 is transferred to the load side. At this time, the resonance inductance of the high-frequency transformer 30 and the capacitor provided on the secondary side operate at a point where the current of the main inductor is the highest, and the energy stored in the inductor is transmitted to the load when the switch is turned off.

11 is a simulation waveform diagram showing input / output voltage and current.

11, an output voltage of 260 [V] and an output current of 9 [A] are generated with a voltage of 24 [V] as an input. The average output voltage is stable at about 10 times as much as the input voltage As shown in Fig.

12 to 16 are diagrams showing experimental results of manufacturing an L-C resonance DC-DC converter for a commercial vehicle air-conditioner compressor according to an embodiment of the present invention.

FIG. 12 is a photograph of an LC resonance type DC-DC converter for a commercial-air-vehicle ignition air conditioner compressor according to an embodiment of the present invention, FIG. 13 is a waveform diagram showing a switching signal (gate signal) 15 is a waveform diagram showing a resonance current waveform transmitted to the secondary side of the high-frequency transformer, and FIG. 16 is a waveform diagram of the resonance current waveform of the high- Fig. 7 is a waveform diagram showing a primary side resonance voltage waveform of the resonator shown in Fig.

The parameters used in the experiment are as shown in Table 2. The test was performed using a 250 kW battery simulator from Horiba.

Parameters Value Input Voltage 24 [V] Output Voltage 280 [V] Resonant Frequency 39 [kHz] Resonant Capacitor 17 [uF] Snubber Capacitor 2.0 [uF] Resonant Inductor 1.0 [uH] Transformer Turn Ratio 1:12 Load Resistance 28 [Ω] Output Power 2.8 [kW]

As shown in Figs. 12 to 16, the first and fourth switches and the second and third switches are alternately turned on / off. At this time, as shown in FIG. 14, it can be confirmed that the resonance is constantly performed while the first switch is turned on / off.

17 is a waveform diagram showing the input / output voltage and current of the LC resonant DC-DC converter for a commercial vehicle air-conditioner compressor according to the embodiment of the present invention, and FIG. 18 is a waveform diagram showing ripples of the output voltage and current to be.

As shown in FIG. 17, an output voltage of 280 [V] and a current of 10 [A] are generated by inputting a voltage of 24 [V] and the average output voltage is stably boosted to about 10 times the input voltage .

Further, as shown in FIG. 18, it can be seen that the ripple is very small at an output voltage of 280 V, and the output current has a very small ripple.

19 is a waveform chart showing the efficiency of an L-C resonance type DC-DC converter for a commercial vehicle air-conditioner compressor according to an embodiment of the present invention.

As shown in FIG. 19, an efficiency of about 95.6% was measured at an output power range of 1 kW to 3 kW, which shows that the energy utilization efficiency of the present invention is very high.

10: Battery
20:
30: High frequency transformer
40: rectification part

Claims (1)

1. A power supply resonance type DC-DC converter for use in an inverter of a compressor for air conditioner,
A high frequency transformer for boosting the input battery voltage and outputting the boosted voltage;
A switch unit having first to fourth switches formed in a full-bridge type on a primary side of the high-frequency transformer and alternately switched according to an input signal to provide the battery voltage to the high-frequency transformer;
And a rectifying part which is formed on a secondary side of the high frequency transformer and includes first and second diodes and first and second capacitors to rectify a voltage boosted by the high frequency transformer and supply the boosted voltage to the load side again, ; And
DC converter according to an embodiment of the present invention; FIG. 4 is a circuit diagram of a DC-DC converter according to a first embodiment of the present invention; FIG. And a controller for reducing ripple of the output current,
The high-
The primary winding and the secondary winding are separately wound at a ratio of 1:12 to reduce thermal stress due to the leakage inductance and the finsing effect, a gap is formed in the middle of the transformer,
The switch unit
The first and fourth switches are simultaneously turned on or off and the remaining second and third switches are simultaneously turned off when the first and fourth switches are turned on and when the first and fourth switches are turned off, And the third switch are turned on,
When the first and fourth switches are turned on at the same time, the first diode is turned on, the power of the battery is charged in the first capacitor, the leakage inductance and the first capacitor become a series resonance state,
When the second and third switches are turned on at the same time, the second diode is turned on, the power of the battery is charged in the second capacitor, the leakage inductance and the second capacitor are brought into a series resonance state,
The control unit
Wherein resonance frequency of the series resonance state is used as a switching frequency of the first to fourth switches to serially resonate at a resonance frequency of the leakage inductance of the high frequency transformer and a resonance frequency of the first and second capacitors, The write noise is reduced,
When a voltage of 24 [V] is input, an output voltage of 260 ~ 280 [V] and a current of 9 ~ 10 [A]
Assuming that the high-side transformer is ideal, the resonant frequency is derived by the following equations (1) to (5)
Wherein the switch unit is a three-terminal power switch that is turned on or off by the control unit.
[Equation 1]

&Quot; (2) &quot;

&Quot; (3) &quot;

&Quot; (4) &quot;

&Quot; (5) &quot;

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