KR20210011684A - System for controlling solar power for vehicle - Google Patents

Abstract

The present invention relates to a solar power control system for a vehicle, which charges a battery in a stable manner by using sunlight acquired by the vehicle. According to one embodiment of the present invention, the solar power control system for a vehicle comprises: a solar power input unit which converts the solar heat energy acquired by a solar power panel into electric energy; a first converter unit which charges a first battery by using the electric energy inputted from the solar power input unit; a switching unit connected to the part between the first converter unit and the first battery; a second converter unit which converts the power supply provided from the first converter unit, and charges a second battery; and a control unit which controls the switching unit in accordance with the charged or discharged status of the first battery or the second battery.

Description

Solar power control system for vehicle {System for controlling solar power for vehicle}

The present invention relates to a power control system for a vehicle, and more particularly, to a solar power control system for a vehicle that performs stable battery charging using sunlight obtained from a vehicle.

Today, due to problems such as global warming and resource depletion, research on alternative energy is becoming more active. In particular, research on automobile energy sources, which is pointed out as the main culprit of air pollution, is active.

Among these studies, a representative one is the field of electric vehicle research that replaces fossil raw materials, which are automobile energy sources, with electric energy. Electric vehicles are vehicles that are driven by receiving power from secondary batteries instead of fossil materials, and their mileage is gradually increasing and speed is increasing. Such electric vehicles are emerging as a means to solve the problem of fossil fuel depletion, and are positioned as a next-generation means of transportation.

Further, a technology for charging a secondary battery while driving or stopping a vehicle using sunlight has appeared. That is, a solar panel is installed on the roof of the vehicle, and the secondary battery is charged using sunlight obtained from the solar panel.

However, since the vehicle continuously moves, charging using sunlight while driving is volatile. For example, when a vehicle enters a shaded area without sunlight, such as in a tunnel or in the shade of a high-rise building, the voltage input through the solar panel increases.

Accordingly, in the charging system using solar light, a separate device for controlling solar charging is mounted. However, such a separate device acts as a factor that increases the cost and volume of the system.

The present invention has been proposed in order to solve such a problem, and an object thereof is to provide a solar power control system for a vehicle having an inexpensive manufacturing cost, easy miniaturization, and improved stability.

Other objects and advantages of the present invention can be understood by the following description, and will be more clearly understood by examples of the present invention. In addition, it will be easily understood that the objects and advantages of the present invention can be realized by the means shown in the claims and combinations thereof.

A system for controlling power of solar light for a vehicle according to the present invention for achieving the above object includes: a solar light input unit for converting solar heat energy obtained from a solar panel into electric energy; A first converter unit charging the first battery by using the electric energy input from the solar input unit; A switching unit connected between the first converter unit and the first battery; A second converter configured to convert power supplied from the first converter to charge a second battery; And a controller for controlling the switching unit according to whether the first battery or the second battery is charged.

A buck converter may be used for the first converter, and a push-pull converter using a pair of switches may be used for the second converter.

The system further includes a discharge unit connected to the capacitor of the second converter to form a discharge path, including a discharge resistor and a discharge switch, and discharging the voltage of the capacitor by turning on the discharge switch under control of the controller. Can include.

The discharge unit may include a photo coupler connected to the input line of the control unit and connected to the discharge switch and the output line. In this case, when an input signal is received from the control unit, the photo coupler generates an output signal through the output line to turn on the discharge switch.

When an emergency situation occurs, the control unit may generate an input signal through the photo coupler to perform discharge through the discharge unit.

The controller may control a pair of switches included in the first converter unit through a pulse width modulation (PWM) signal based on a maximum power point tracking (MPPT).

The first converter unit may include an inductor disposed on a path connecting a positive electrode of the first battery and a first semiconductor switch; A first semiconductor switch having a source terminal connected to the solar input unit and a drain terminal connected to the inductor; And a second semiconductor switch in which a source terminal is connected to a negative electrode of the first battery and a drain terminal is connected to a path between the first semiconductor switch and the inductor.

The second converter unit may include a transformer module configured to convert a voltage output from the inductor into a predetermined voltage through switch control of a pair of switches; A rectifying module rectifying the transformed power; And a capacitor that accumulates the voltage rectified in the rectification module.

The second converter unit may further include a diode disposed between the capacitor and the second battery so that the current of the capacitor flows in the direction of the second battery.

The solar power control system for a vehicle according to an embodiment of the present invention has an advantage of supplying stable power to a battery using a plurality of converters without having a DC-DC converter dedicated to solar power.

In addition, the solar power control system for a vehicle according to an embodiment of the present invention has the advantage of reducing the cost and miniaturization of the product by reducing the number of components input to the entire system.

In addition, the solar power control system for a vehicle according to an embodiment of the present invention, when an emergency occurs, by discharging the voltage charged in the capacitor through the discharge path connected to the second converter, electric shock caused by a vehicle accident, etc. Or, there is an advantage of preventing a fire caused by a short.

The following drawings attached to the present specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of the present invention together with specific details for carrying out the invention, so the present invention is described in such drawings. It is limited only to matters and should not be interpreted.
1 is a view showing a conventional vehicle solar power control system.
2 is a view showing a solar power control system for a vehicle according to an embodiment of the present invention.
3 is a view showing an internal circuit of a solar power control system for a vehicle according to an embodiment of the present invention.

The above-described objects, features, and advantages will become more apparent through the following detailed description in connection with the accompanying drawings, whereby those of ordinary skill in the technical field to which the present invention pertains can easily implement the technical idea of the present invention. There will be. In addition, in describing the present invention, when it is determined that a detailed description of a known technology related to the present invention may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In general, since a vehicle to which the solar charging technology is applied does not stay in one place, but moves in a tunnel, a shade, etc., a component capable of controlling solar charging is required.

Accordingly, a solar power control system as shown in FIG. 1 may be considered.

1 is a view showing a conventional vehicle solar power control system.

The conventional solar power control system 100 for a vehicle according to FIG. 1 includes a photovoltaic input unit 110 for converting photovoltaic energy into electrical energy using a photovoltaic panel 111, and a photovoltaic DC-DC converter 121 It includes a photovoltaic control unit 120 for charging the photovoltaic battery 123 by using, and a converter control unit 130 for converting power from the photovoltaic battery 123 to power. The converter control unit 130 converts the power of the solar battery 123 to a high voltage to charge the high voltage battery 141 and converts the power of the high voltage DC-DC converter 131 and the solar battery 123 to a low voltage It includes a low voltage DC-DC converter 132 for charging the battery 142.

However, when the solar control unit 120 including the solar DC-DC converter 121 and the solar battery 123 is mounted on a vehicle, the weight and volume of the entire power system increase, and the material cost increases significantly. can do. In addition, due to the nature of sunlight, MPPT (Maximum Power Point Tracking)-based control must be performed. When the MPPT-based control is performed by the solar DC-DC converter 121 or the high voltage DC-DC converter 131, the vehicle It can be difficult to estimate the solar characteristics that change with driving.

2 is a view showing a solar power control system for a vehicle according to an embodiment of the present invention.

As shown in FIG. 2, the solar power control system 200 for a vehicle according to an embodiment of the present invention includes a solar input unit 210, a first converter unit 220, a first battery 240, and a first battery. It includes a two converter unit 230, a second battery 250, and a switching unit 260. In addition, as shown in FIG. 3, the vehicle solar power control system 200 may further include a discharge unit 260 and controllers 271 and 272.

The solar input unit 210 includes a solar panel 213 that converts solar energy into electrical energy. The solar panel 213 is installed at a portion of a vehicle that can acquire the most sunlight, such as a roof of a vehicle. The photovoltaic input unit 210 transfers the electric energy converted through the photovoltaic panel 213 to the first converter unit 220.

The first battery 240 is a battery mounted in a vehicle. The first battery 240 may supply power to various load devices in a vehicle operating at a low voltage. The first battery 240 may be a 12V lithium ion battery.

The second battery 250 is another battery mounted in the vehicle, and may supply power to various load devices in the vehicle operating at a high voltage. The second battery 250 may supply power in connection with braking devices. The second battery 250 may be a 48V lithium ion battery.

The first converter unit 220 converts the electric energy input from the photovoltaic input unit 210 into a preset low-voltage power source (eg, 12V power), and charges the first battery 240 or the second converter unit 230 ) Can be provided. The first converter unit 220 operates as a buck converter to provide stable power to the first battery 240. At this time, the first converter unit 220 performs a PWM (Pulse Width Modulation) control based on MPPT (Maximum Power Point Tracking) for a pair of switches (Q1 and Q2 in FIG. 3) that are switched to operate in the buck mode. do. The first converter unit 220 uses a field effect transistor (FET) switch as a pair of switches (Q1 and Q2 in FIG. 3). In other words, if the diode is used at the point where the second switch Q2 of FIG. 3 is disposed, the efficiency decreases accordingly due to the voltage drop, and improved efficiency than the diode can be obtained by using the FET switch.

The second converter unit 230 may charge the second battery 250 by converting the power received from the first converter unit 220 into a preset high voltage power source (eg, 48V power).

The second converter unit 230 charges the second battery 250 in a push-pull method. In other words, when charging the second battery 250, the conventional flyback method is used. However, when the second battery 250 is charged in the flyback method, product efficiency is lowered. In order to overcome this drawback, the vehicle solar power control system 200 according to the embodiment of the present invention secures efficiency and controllability by using converter units 220 and 230 in which a buck converter and a push-pull method are mixed. .

The switching unit 260 is disposed between the first converter unit 220 and the first battery 240. When the switching unit 260 is turned on, the first battery 240 is charged, and when the switching unit 260 is turned off, the second battery 250 is charged.

3 is a view showing an internal circuit of a solar power control system for a vehicle according to an embodiment of the present invention.

Referring to FIG. 3, the solar input unit 210 includes the above-described solar panel 213, solar cell 211, and semiconductor switch 212. The solar panel 213 converts solar energy into electric energy, and the solar cell 211 stores the converted electric energy. The semiconductor switch 212 is disposed between the first converter unit 220 and the solar cell 211 and is turned on or off according to the control of the first controller 271.

The first converter unit 220 includes a plurality of current sensors 221 and 222, a pair of switches Q1 and Q2, a plurality of resistors 223a to 223b, and an inductor 225.

The first current sensor 221 is disposed in a path between the first switch Q1 and the semiconductor switch 212 of the solar input unit 210, and measures a current generated in the path to the first control unit 271. To pass.

The second current sensor 222 is disposed in a path between the inductor 225 and the first battery 240, measures the current generated by the inductor 225 and transmits it to the first control unit 271.

As the first current sensor 221 and the second current sensor 222, a hall sensor, a current sensing resistor, or the like may be used.

The pair of switches Q1 and Q2 is turned on or turned off by the control of the first control unit 271. The pair of switches Q1 and Q2 are complementary to each other, and are respectively turned on or turned off based on a Pulse Width Modulation (PMW) signal based on MPPT (Maximum Power Point Tracking) of the first controller 271. do. The pair of switches Q1 and Q2 operate in a buck mode under the control of the first controller 271 to supply power input from the solar input unit 210 to the first battery 240. . As the first switch Q1 and the second switch Q2, a FET-based semiconductor switch may be used.

The inductor 225 included in the first converter unit 220 is disposed on a path through which the anode of the first battery 240 and the first switch Q1 are connected. In addition, the first switch Q1 has a source terminal connected to the solar input unit 210 and a drain terminal connected to the inductor 225. In addition, the source terminal of the second switch Q2 is connected to the negative electrode of the first battery 240, and the drain terminal of the second switch value Q2 is connected to a path formed between the first switch Q1 and the inductor. do.

The plurality of resistors 223a to 223b are arranged in a pair in a specific path, and a voltage generated between the pair of resistors is transmitted to the first control unit 271. That is, the plurality of resistors 223a to 223b is used as a means for measuring voltage.

A power branch point OUTPUT1 is generated in a path between the inductor 225 and the switching unit 260, and power is supplied to the second converter unit 230 through the power branch point.

The second converter unit 230 operates as a push-pull converter, a pair of switches Q3 and Q4, a transformer module 231, a rectifier module 232, an inductor 233, and a capacitor. 234), a diode 235, and a plurality of resistors 236a to 236e.

The pair of switches Q3 and Q4 are turned on or off according to the control of the first control unit 271. Power applied from the first converter 220 passes through the transformer module 231 according to the operation of the pair of switches Q4 and Q4. The pair of switches Q3 and Q4 are alternately turned on so that the power supplied from the first converter 220 passes through the transformer module 231.

The transformer module 231 converts the voltage supplied from the first converter 220 into a voltage having a predetermined size according to the operation of the third switch Q3 and the fourth switch Q4. Since the second converter unit 230 operates as a push-pull converter, the input voltage level is not reduced by half, and the input voltage level is output from the transformer module 231 as it is and transferred to the rectification module 232 Can be.

A regulator (not shown in the drawing) stabilizing the voltage transformed into the transforming module 231 to a constant voltage and supplying the stabilized voltage to the rectifying module 232 is further included in the second converter 230. I can.

The rectification module 232 includes a plurality of diodes, and the power output from the transformer module 231 flows through the diodes through a path in which the inductor 233 is disposed.

The capacitor 234 is connected to the rectification module 232, receives power from the rectification module 232, and accumulates a voltage.

The diode 235 is disposed so that the current generated by the capacitor 234 or the rectifying module 232 flows only to the second battery 250. The diode 235 also blocks a reverse polarity current that may occur in the second battery 250.

A plurality of resistors 236a to 236d are arranged in a pair in a specific path, and a voltage generated between the pair of resistors is measured by the second controller 272. Meanwhile, among the resistors, a resistor having the reference numeral 236e may be disposed alone, and a voltage generated around the resistor 236e is measured by the second controller 272.

The switching unit 260 is disposed between a path connecting the inductor 225 of the first converter unit 220 and the first battery 240 and is turned on or off by the first control unit 271. A relay or the like may be used as the switching unit 260. When the switching unit 260 is turned on, power supplied from the first converter unit 220 charges the first battery 240. Conversely, when the switching unit 260 is turned off, the power transferred from the first converter unit 220 to the second converter unit 230 is converted to a high voltage to charge the second battery 250. That is, one of the low voltage battery 240 and the second battery 250 is selectively charged according to the open/closed state of the switching unit 260.

The solar power control system 200 for a vehicle according to an embodiment of the present invention may further include a discharge unit 260.

The discharge unit 260 includes a photocoupler 261, a discharge switch Q5, and a discharge resistor 262.

When the photo coupler 261 receives an input signal from the first control unit 271, the photo coupler 261 generates an output signal to turn on the discharge switch Q5. The input part of the photo coupler 261 is connected to the first control part 271, and the output part of the photo coupler 261 is connected to the gate terminal of the discharge switch Q5. That is, when an input signal is applied through the input unit, the port coupler 261 generates an output signal to the output unit to turn on the discharge switch Q5. Meanwhile, the first control unit 271 may directly turn on the discharge switch Q5 by directly connecting to the discharge switch Q5 without using the photo coupler 261. When the first control unit 271 turns on the discharge switch Q5 using the photo coupler 261, the discharge switch Q5 may be turned on more quickly.

The discharge switch Q5 is turned on during rapid discharge and performs a function of rapidly discharging the voltage accumulated in the capacitor 234. In other words, the discharge switch Q5 has a branched discharge path formed in the second converter 230 in the path where power is supplied from the capacitor 234 to the second battery 250, and a discharge resistance in the discharge path 262 and a discharge switch Q5 are arranged. The discharge resistor 262 is designed to have a resistance value that sufficiently discharges the voltage discharged from the capacitor 234. Further, the source terminal of the discharge switch Q5 is grounded, and the drain terminal is connected to one end of the discharge resistor 262. Also, the other end of the discharge resistor 262 is connected to one end of the capacitor 234.

The second control unit 272 is a processor such as a microcontroller unit (MCU), and measures a voltage generated at each point in the second converter unit 230 and also measures a voltage generated at an output. The second control unit 272 transfers the measured voltages to the first control unit 271.

The first control unit 271 is a processor such as a microcontroller unit (MCU), and controls the operation of each switch (Q1, Q2, Q3, Q4, Q5, 212) and the switching unit 260, and together with the photo coupler 261 ) To generate an input signal. The first control unit 2721 controls the operation of each switch (Q1, Q2, Q3, Q4, Q5, 212) and the switching unit 260 based on the current value and voltage value measured at each point. Overall control such as charging the first battery 240 or charging the second battery 250 is performed. Also, the first control unit 271 may communicate with various devices of the vehicle through controller area network (CAN) communication.

In particular, the first control unit 271 generates an MPPT-based PWM signal with the Q1 switch and the Q2 switch, so that stable power generated from the solar input unit 210 is transferred to the first battery 240 or the second converter unit 230. Let it be supplied. At this time, the first control unit 271 turns on the switching unit 260 to charge the first battery 240. In addition, the first control unit 271 turns off the switching unit 260 and generates a PWM signal with the Q3 switch and the Q4 switch, so that the transformed and rectified power is supplied to the second battery 250 to provide the second battery. 250 is controlled to be charged. That is, the first control unit 271 prevents simultaneous charging of the first battery 240 and the second battery 250, and the first battery 240 and the second battery 250 are You can choose to charge.

Conventionally, since MPPT is performed in a high-voltage DC-DC converter, it is difficult to track the rapidly changing solar power characteristics when the vehicle is driven, but the vehicle solar power control system 200 according to the present invention includes a first converter unit 220 capable of high-speed switching. ), MPPT-based switching is performed, so the solar characteristics can be quickly followed.

Meanwhile, the first control unit 271 applies an input signal to the photo coupler 261 when it receives an emergency matter such as a vehicle rollover or a vehicle accident from an external device or detects an emergency through its own algorithm. can do. Then, a signal is output to the output of the photo coupler 261 to turn on the discharge switch Q5, and accordingly, the voltage accumulated in the capacitor 234 is rapidly transferred through the discharge resistor 262 and the discharge switch Q5. Discharged. In addition, when an emergency such as a vehicle accident occurs, the voltage accumulated in the capacitor 234 may cause an accident such as an electric shock. Accordingly, when it is determined that an emergency has occurred, the first control unit 271 turns on the discharge switch Q5 by applying a signal to the photo coupler 261, so that the accumulated voltage of the capacitor 234 is reduced to the discharge resistance ( By rapidly discharging through 262 and the discharging switch Q5, energy in the capacitor 234 is consumed.

Meanwhile, in the above-described embodiment, it has been described that the first control unit 271 and the second control unit 272 are separated from each other, but the first control unit 271 and the second control unit 272 may be integrated into one implementation. .

As described above, the vehicle solar power control system 200 provides stable power using the first converter unit 220 and the second converter unit 230 without having a DC-DC converter dedicated to sunlight. Can be supplied by battery. In addition, the solar power control system 200 for a vehicle according to an embodiment of the present invention has the advantage of reducing the cost and miniaturization of the product by reducing the number of components input to the entire system.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those of ordinary skill in the technical field to which the present invention belongs. It is not limited by the drawings.

210: solar input unit
220: first converter unit
230: second converter unit
240: first battery
250: second battery
260: switching unit

Claims (9)

In the system for controlling the power of solar light for vehicles,
A solar light input unit for converting solar heat energy obtained from the solar panel into electric energy;
A first converter unit charging the first battery by using the electric energy input from the solar input unit;
A switching unit connected between the first converter unit and the first battery;
A second converter configured to convert power supplied from the first converter to charge a second battery; And
And a control unit for controlling the switching unit according to whether the first battery or the second battery is charged. The method of claim 1,
The first converter part is a buck converter,
The second converter unit solar power control system for a vehicle, characterized in that the push-pull converter using a pair of switches. The method of claim 1,
A discharge unit connected to the capacitor of the second converter to form a discharge path, including a discharge resistor and a discharge switch, and discharging the voltage of the capacitor by turning on the discharge switch under control of the control unit Vehicle solar power control system. The method of claim 3,
The discharge unit includes a photo coupler connected to the input line of the control unit and connected to the discharge switch and the output line,
The photo coupler, when an input signal is received from the control unit, generates an output signal through the output line to turn on the discharge switch. The method of claim 4,
The control unit,
When an emergency situation occurs, the photo coupler generates an input signal and discharges through the discharging unit. The method of claim 1,
The control unit,
A solar power control system for a vehicle, comprising controlling a pair of switches included in the first converter unit through a Pulse Width Modulation (PWM) signal based on a maximum power point tracking (MPPT). The method of claim 1,
The first converter unit,
An inductor disposed on a path through which the anode of the first battery and the first semiconductor switch are connected;
A first semiconductor switch having a source terminal connected to the solar input unit and a drain terminal connected to the inductor; And
And a second semiconductor switch having a source terminal connected to the negative electrode of the first battery and a drain terminal connected to a path between the first semiconductor switch and the inductor. The method of claim 7,
The second converter unit,
A transformer module converting a voltage output from the inductor into a predetermined voltage through switch control of a pair of switches;
A rectifying module rectifying the transformed power; And
And a capacitor that accumulates the voltage rectified in the rectification module. The method of claim 8,
The second converter unit,
A vehicle solar power control system further comprising a diode disposed between the capacitor and the second battery so that the current of the capacitor flows in the direction of the second battery.

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