KR20220074769A - Integrated power supply for controlling voltage - Google Patents

Abstract

The integrated power supply device for voltage control according to the present invention includes a photovoltaic module for generating DC power by photoelectric reaction, a fuel cell module connected in parallel with the photovoltaic module and generating power, a photovoltaic module and fuel A parallel connection unit that measures the output of the cell module and prevents reverse current flow between the photovoltaic module and the fuel cell module, and a power conversion unit that receives and transmits power to the load as much as the sum of the outputs of the photovoltaic module and the fuel cell module Receives the output voltage (V _PV (t)) of the solar module, the output voltage (V _FC (t)) of the fuel cell module, and the output power (P _Total (t)) of the power converter from the parallel connection unit, and the load The input voltage command value (V* _Total (t)) and input current command value (I* _Total ) of the power conversion unit according to the change in the required power (P _Load (t)) and the output voltage (V _PV (t)) of the photovoltaic module. ₍ t)), and the power conversion unit can stably supply power required to the load by performing a constant voltage operation on the load according to the control of the control unit.

Description

Integrated power supply for controlling voltage

The present invention relates to a direct current output power generation system including a solar power generation device and a fuel cell power generation device, and more particularly, to an integrated power supply device for voltage control.

A number of renewable and new energy power generation methods have been proposed and used to reduce emissions of carbon dioxide, nitrogen oxides, and volatile organic compounds (VOCs), which are substances that generate a greenhouse effect and are mass-produced by the consumption of fossil fuels. These power generation methods are greatly affected by the natural environment such as climate, or are installed according to the possible or necessary scale due to economic or technical constraints on large-scale production. Microgrid-related technologies that consume electricity by themselves have attracted attention.

In the case of microgrids, the distance required for power transmission is shorter than that of the existing system, and the technology for easily adjusting the voltage of DC power using semiconductor devices has been commercialized, so microgrids based on DC power are being proposed and utilized. In this case, it is mainly composed of a power source that generates direct current.

Among new and renewable energy generation, solar power generation and fuel cell power generation have in common that their power generation output is in the form of direct current. has a low output voltage. In addition, since sunlight is a source of direct sunlight, it is limited in time and space and it is difficult to control the output, whereas fuel cells have limitations in the speed of output fluctuation, but the user can generate the desired output by adjusting the amount of fuel supplied.

In constructing a power system using fuel cells and solar power generation devices, each power generation device is equipped with a linkage inverter so that each power generation device can generate a grid AC output in order to connect it to a load using commercial AC power. It is generally configured to generate an AC output and a load to receive the output AC power. Even when composing a DC-based power system, a device for controlling the output for each power source is provided. In particular, in the case of a fuel cell power generation device, the entire fuel cell including the power converter is provided to control the auxiliary device (BOP) according to the output. to control

1 is a view showing the output characteristics and the maximum output point curve of a solar module.

The solar module has a property that the output increases according to the amount of insolation and the output decreases when the temperature rises. Under certain insolation and temperature conditions, when the current increases, the voltage tends to decrease. There is almost no decrease in the current up to a certain level, so the output increases linearly as the voltage increases. It has a decreasing property. Therefore, the power converter that delivers the solar output to the load operates by using the voltage at which the maximum output occurs as the input reference voltage to maximize the solar power generation efficiency, and this process is performed using the Maximum Power Point Tracking (MPPT) algorithm. ) is called The solar module output that tracks the maximum power point has a relationship that the voltage increases as the current increases.

2 is a diagram illustrating output characteristics of a fuel cell.

Meanwhile, in the case of the fuel cell stack, as the current increases, the output power decreases due to the internal resistance. The output tends to increase as the flow rate of gas passing through the anode and cathode increases within the maximum output range of the stack. If this phenomenon continues for a long time, damage to the stack may occur. Therefore, when the fuel cell stack is operated, the fuel supply exceeds a certain level compared to the equivalent to the electric output. The power converter for converting the DC output of the fuel cell can switch between current control and voltage control according to the characteristics of the circuit to be connected.

(Prior Document 1) Registration No. 10-1267803, Announced on May 31, 2013 Economical grid-connected PCS for interfacing between heterogeneous power grids

By effectively utilizing the output characteristics of the solar module and the fuel cell stack, an integrated power supply device that provides the power required for the load from a DC power connected in parallel through a power conversion device of a single configuration that controls the input voltage. to provide.

Rather than converting the outputs of the fuel cell stack and the solar module individually, the output terminals of the solar module and the fuel cell stack are connected in parallel and the combined DC output is supplied to the load through the power converter, simplifying the control step and providing a stable A method for securing current and voltage ranges is provided.

The integrated power supply device for voltage control according to the present invention includes a photovoltaic module for generating DC power by photoelectric reaction, a fuel cell module connected in parallel with the photovoltaic module and generating power, a photovoltaic module and fuel A parallel connection part that measures the output of the cell module and prevents reverse current flow between the photovoltaic module and the fuel cell module, and the output power of the photovoltaic module (P _PV (t)) and the output power of the fuel cell module (P _FC ( t)), the power conversion unit receives and transmits power to the load, and the output voltage of the solar module (V _PV (t)) and the output voltage of the fuel cell module (V _FC (t)) And it receives the input power (P _Total (t)) of the power converter, and according to the change in the required power (P _Load (t)) of the load and the change in the output voltage (V _PV (t)) of the solar module, the input of the power converter a control unit for calculating a voltage command value (V* _Total (t)) and an input current command value (I* _Total( t)) can be supplied stably.

When the power supply device supplies power to a static load that does not fluctuate, the control unit calculates the sum of the output power (P _PV (t)) of the solar module and the output power (P _FC (t)) of the fuel cell module to the load voltage ( The operation of the power converter can be controlled based on the output voltage (V _PV (t)) of the solar module while maintaining within a certain range regardless of V _Load (t)).

When the power supply device supplies power to a load having variability, the controller determines that the sum of the output current (I _PV (t)) of the solar module and the output current (I _FC (t)) of the fuel cell module is the load voltage (V). It is possible to control the operation of the power conversion unit based on the required power (P _Load (t)) of the load while responding to the change in _Load (t)).

It is connected in parallel to the output of the power conversion unit, when a difference between the input power (P _Total (t)) and the required power of the load (P _Load (t)) may further include a buffer for accommodating the excess or insufficient power.

The control unit controls the voltage output value of the solar module (V _PV (t)), the current output value of the solar module (I _PV (t)), the voltage output value of the fuel cell module (V _FC (t)), and the current output value of the fuel cell module. (I _FC (t)) is received, and according to the required power of the load (P _Load (t)) Calculate the amount of input current (I _Total (t)) of the power conversion unit, check the state of the solar module, and draw the output power (P _PV (t)) from the solar module to the maximum, but if sufficient power is supplied to the load Calculate the input voltage command value (V* _Total (t)) to make it _possible , and the output current command value (I* _PV (t)) of the solar module and the Calculate the output current command value (I* _FC (t)), and based on the output current command value (I* _FC (t)) of the fuel cell module, the output current of the fuel cell module (I _FC (t)) )) can be controlled.

The control unit is included in the fuel cell module to control the output current (I _FC (t)) of the fuel cell module so that the fuel supply amount is satisfied based on the output current command value (I* _FC (t)) of the fuel cell module. It is possible to adjust the output of the fuel supply to supply and the blower to supply oxygen.

When the output voltage (V _PV (t)) of the photovoltaic module is less than a predetermined reference value (V _{PV_Low} ) (V _PV (t)<V _{PV_Low} ), the control unit controls so that the power of the load is completely supplied by the fuel cell module. The load demand voltage (V _Load (t)) and load demand current (I _Load (t)) that generate the required power of the load can be specified as the output power command value (P* _FC (t)) of the fuel cell module. .

When the output voltage (V _PV (t)) of the solar module is higher than the predetermined reference value (V _{PV_Low} ) (V _PV (t)≥V _{PV_Low} ), the maximum output point voltage (V _PVMP ) of the solar module is set to the fuel cell module It can be specified as the output voltage command value (V* _FC (t)) of

The control unit receives the power storage amount of the buffer, and when the buffer power storage amount (P _Buffer (t)) is less than a certain level (P _{Buffer_Low} ), the maximum output point voltage (V _PVMP ) of the solar module is set to the voltage command value of the solar module (V* _PV (t)) and the voltage command value of the fuel cell module (V* _FC (t)), and when the amount of power stored in the buffer (P _Buffer (t)) is above a certain level (P _{Buffer_Low} ), the load demand Input voltage command value (V* _Total (t)), output current command value of solar module (I* _PV (t)) so that power (P _Load (t)) becomes input power (P _Total (t)) of the power conversion unit And by designating the output current command value (I* _FC (t)) of the fuel cell module, the output power of the solar module (P _PV (t)) and the output power of the fuel cell module (P _FC (t)) can be controlled. have.

According to the present invention, by effectively utilizing the output characteristics of the photovoltaic module and the fuel cell stack, the power required for the load is stably supplied from the DC power connected in parallel through the power conversion device of a single configuration that controls the input voltage. can provide

1 is a view showing the output characteristics and the maximum output point curve of a solar module.
2 is a diagram illustrating output characteristics of a fuel cell.
3 is a diagram showing the configuration of a power supply device according to an embodiment of the present invention.
4 is a diagram showing the configuration of a fuel cell module according to an embodiment of the present invention.
5A is a diagram illustrating an output current of a power supply device according to a voltage according to an embodiment of the present invention, and FIG. 5B is a diagram illustrating an output power of the power supply device according to an embodiment of the present invention.
6 is a diagram illustrating a change in internal power of a power supply device when a voltage of a solar module is increased according to an embodiment of the present invention.
7 is a diagram showing the configuration of a parallel connection unit according to an embodiment of the present invention.
8 is a diagram showing the configuration of a power supply to which a buffer is added according to an embodiment of the present invention.
9 is a diagram illustrating a control flow of a power supply device according to an embodiment of the present invention.
10 is a diagram illustrating a power distribution and output control flow of a power supply device according to an embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, if it is determined that a detailed description of a related well-known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, the terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to intentions or customs of users and operators. Therefore, the definition should be made based on the content throughout this specification.

3 is a view showing the basic configuration of the power supply device 10 according to an embodiment of the present invention.

The power supply device 10 includes a solar module 110 used as a power source, a fuel cell module 120 and a parallel connection unit 130 , a power conversion unit 140 , and a control unit 150 . The power supply device 10 supplies power generated from the photovoltaic module 110 and the fuel cell module 120 to the load 20 by using the power conversion unit 140 through the parallel connection unit 130 . The load 20 may be, for example, a device such as a lighting, an electric tool for camping, and the like. An inverter (not shown) may be connected to the rear end of the power supply device 10 to output alternating current, but hereinafter, a device used in a situation in which it is difficult to receive power from the grid will be mainly described.

The photovoltaic module 110 is a photovoltaic device organized to have a desired voltage and current output through a series-parallel connection of cells. The photovoltaic module 110 generates direct current power by a photoelectric reaction.

The fuel cell module 120 generates electric power through an electrochemical reaction between the fuel and the oxidizing agent.

The parallel connection unit 130 measures the outputs of the solar module 110 and the fuel cell module 120 and prevents reverse current flow between the solar module 110 and the fuel cell module 120 .

The power conversion unit 140 is connected to the parallel connection unit 130 and the control unit 150 . The power conversion unit 140 receives power as much as the sum of the output power (P _PV (t)) of the solar module 110 and the output power (P _FC (t)) of the fuel cell module 120 to receive the load ( 20) is transmitted. When the loss of the conversion process is not taken into account, the sum of the output powers from the power conversion unit 140 is equal to the sum of the input powers of the power conversion unit 140 .

Hereinafter, P _Total (t) represents the input power of the power conversion unit 140 , P _Load (t) is the output power of the power conversion unit 140 , and represents the required power of the load 20 .

The control unit 150 includes the output voltage (V _PV (t)) of the solar module 110, the output voltage (V _FC (t)) of the fuel cell module 120 and the power conversion unit 140 in the parallel connection unit 130 . ) of the input power (P _Total (t)) is received. The control unit 150 is the input voltage command value of the power conversion unit 140 according to the change in the required power (P _Load (t)) of the load 20 and the output voltage (V _PV (t)) change of the solar module 110 (V* _Total (t)) and input current command value (I* _Total( t)) can be calculated and changed. The power conversion unit 140 may perform a constant voltage operation on the load 20 according to the control of the control unit 150 to stably supply power P _Load (t) required to the load 20 .

The configuration, voltage, and current specifications of the solar module 110 and the fuel cell module 120 may be changed according to characteristics of the corresponding load 20 . Since the available voltage of the load is generally defined through the standard, for example, in the case of an electric device required for camping, a multiple of 12 such as 24 [V] is the minimum voltage, and the rating of the solar module 110 and the fuel cell module 120 is Voltage can be specified, and when it is necessary to supply power to a load having various voltages, the middle of the voltage range is set as the rating of the solar module 110 and the fuel cell module 120, and the power converter 140 is rated It may be configured to further include a voltage adjustment circuit for outputting each load voltage higher or lower than the corresponding one.

4 is a diagram showing the configuration of a fuel cell module 120 according to an embodiment of the present invention.

The fuel cell module 120 is a fuel cell stack 121 , a fuel supply 122 , a blower 123 , a moisture separator 124 , and a cooler 125 , etc. Auxiliary for smoothly supplying fuel/oxidant and power output It consists of devices.

The fuel supply 122 receives hydrogen as fuel and delivers it to the water separator 124 .

The cooler 125 supplies coolant to the fuel cell stack 121 from a coolant tank (not shown) in which coolant is stored.

The blower 123 supplies oxygen to the fuel cell stack 121 .

The fuel cell stack 121 outputs DC power using hydrogen supplied from the fuel supply unit 122 and oxygen supplied from the blower 123 . The fuel cell stack 121 is composed of a plurality of stacked sensors, and is designed to supply water, fuel, air, etc. to each cell.

The moisture separator 124 discharges moisture generated in the fuel cell stack 121 .

The control unit 140 of FIG. 3 controls the output current (I _FC (t)) of the fuel cell module 120 to satisfy the fuel supply amount based on the output current command value (I* _FC (t)) of the fuel cell module 120 . ), the outputs of the fuel supply unit 122 and the blower 123 of the fuel cell module 120 may be adjusted.

Referring again to FIG. 3 , in FIG. 3 , one solar module 110 and one fuel cell module 120 are shown to be connected for clarity, but a plurality of modules having the same characteristics may be connected. For example, the plurality of photovoltaic modules 110-1 to 110-m may be connected to each other in parallel, and the plurality of fuel cell modules 120-1 to 120-n may be connected to each other in parallel.

When a plurality of photovoltaic modules (110-1 to 110-m) are connected in parallel, power generated from a plurality of power sources connected in parallel is preferential from a power source having a high voltage (solar module 110 having a high voltage) However, it may be designed such that the output voltages of the plurality of solar modules 110-1 to 110-m and the output voltages of the plurality of fuel cell modules 120-1 to 120-n are substantially the same.

V_PV

V_FC)하다. Therefore, when the MPPT operation region of the solar module 110 and the voltage of the ohmic region of the fuel cell module 120 are configured to match, the sun constituting the input voltage (V _Total (t)) of the power conversion unit 140 The output voltage (V _PV (t)) of the optical module 110 and the output voltage (V _FC (t)) of the fuel cell module 120 are the same (V _Total )

V _PV

V _FC ).

[Equation 1]

When the input voltage (V _PV (t)) of the solar module 110 of the power conversion unit 140 increases, the output current (I _PV (t)) of the solar module 110 is the maximum output point (I _{PV_MPP} ) ), and when the input voltage V _FC (t) of the fuel cell module 120 increases, the output current I _FC (t) of the fuel cell module 120 decreases. The total input current (I _Total (t)) received by the power converter 140 is the output current (I _PV (t)) of the solar module 110 and the output current (I _FC ( t)) is the sum of

[Equation 2]

The total input power (P _Total = P _PV + P _FC = V _Total ·I _Total ) of the power conversion unit 140 may be maintained within a certain range. The output current (I _PV ) of the photovoltaic module 110 is proportional to the input voltage (V _Total ), and the output current (I _FC ) of the fuel cell module 120 is inversely proportional, so the predetermined range is each module 110, 120), it can be defined as a positive value smaller than the maximum value among the output currents.

[Equation 3]

5A is a diagram illustrating an output current of the power supply device 10 according to a voltage according to an embodiment of the present invention, and FIG. 5B is a diagram illustrating an output power of the power supply device 10 according to an embodiment of the present invention. .

As described above, the input current (I _Total (t)) of the power conversion unit 140 is the maximum output point current (I _{PV_MPP} ) which is the output current (I _PV (t)) of the solar module 110 and the fuel cell It may be expressed as the sum of the output currents I _FC (t) of the module 120 .

The input power (P _Total (t)) of the power conversion unit 140 is the maximum output point power (P _{PV_MPP} ) which is the output power (P _PV (t)) of the solar module 110 and the fuel cell module 120 . It can be expressed as the sum of the output power (P _FC ).

When the solar output power (P _PV (t)) rises, the output state before and after may be represented as shown in FIG. 6 .

6 is a diagram illustrating an internal power change of the power supply device 10 when the voltage (V _PV (t)) of the solar module 110 is increased according to an embodiment of the present invention.

As shown by reference numeral 610, the amount of insolation increases.

Then, the voltage (V _PV (t)) of the photovoltaic module 110 and the current (I _PV (t)) of the photovoltaic module 110 increase as shown by reference numeral 620 . This can be expressed as Equation (4).

[Equation 4]

As shown in reference numeral 630 , the output current I _FC (t) of the fuel cell module 120 decreases due to an increase in the voltage of the fuel cell module 120 connected to the parallel connection unit 130 .

[Equation 5]

Accordingly, the voltage V _FC of the fuel cell module 120 increases (V _FC (t)>V _FC (t-1)).

Then, as shown in reference numeral 640, the input voltage (V _Total (t)) to the power conversion unit 140 increases, and the input current (I _Total (t)) is maintained.

As the voltage (V _PV (t)) of the solar module 110 increases, the output current (I _PV (t)) of the solar module 110 and the output current (I _FC (t)) of the fuel cell 120 When the input current (I _Total (t)) to the power converter 140, which is the sum of , is maintained, the output power (P _Total (t)) to the power converter 140 may be increased. Otherwise, that is, when the output voltage (V _PV (t)) of the solar module 110 is maintained, the output current (I _FC (t)) of the fuel cell decreases and the total input current (I _Total (t)) ) is maintained, the output power (P _Total (t)) to the power conversion unit 140 will be maintained. This can be expressed by Equation (5).

[Equation 5] Variation of the output current (I _Total (t)) and output power (P _Total (t)) to the power conversion unit 140 by increasing the voltage of the solar module 110

7 is a diagram illustrating an example of a configuration of the parallel connection unit 130 and a connection state with the control unit 140 according to an embodiment of the present invention.

The parallel connection unit 130 combines the DC output (P _PV (t)) of the solar module 110 and the DC output (P _FC (t)) of the fuel cell module 120 and delivers it to the power conversion unit 140 , , has a configuration in which the anode and the cathode are connected in parallel.

There is a difference in the output change rate of the photovoltaic module 110, and when a reverse current occurs as an electrical device, the first diode 710 and the first relay to block the possibility that an abnormality may occur in the operation of the photovoltaic module 110 (712) may be added. In addition, the first voltage sensor 714 or the first current sensor 716 may be connected to clearly grasp the output of the solar module 110 .

In addition, there is a difference in the output change rate of the fuel cell module 120 and, as an electrical device, when a reverse current occurs, the second diode 730 and the second diode 730 are used to block the possibility of abnormal operation of the fuel cell module 120 . Two relays 732 may be added. In addition, a second voltage sensor 734 or a second current sensor 736 may be connected to clearly grasp the output of the fuel cell module 120 .

The voltage output value (V _PV (t)) of the solar module 110 detected by the first voltage sensor 714, the current output value (I _PV ) of the solar module 110 detected by the first current sensor 716 ( t)), the voltage output value (V _FC (t)) of the fuel cell module 120 output by the second voltage sensor 734, and the current output value of the fuel cell module 120 detected by the second current sensor 736 (I _FC (t)) is transmitted to the control unit 150 .

In addition, when there is a first relay 712 and a second relay 732 in the parallel connection unit 130 as shown in FIG. 7 , the control unit 150 uses the first relay control signal S _PV as necessary. Thus, the opening and closing of the first relay 712 may be controlled, and the opening and closing of the second relay 732 may be controlled using the second relay control signal S _FC .

V_PV

V_FC)을 부하(20)에 필요한 전압(V_Load)으로 변환하는 역할을 수행한다. 전력변환부(140)는 부하(20)측에서 역조류가 발생할 가능성을 최소화하기 위해 절연형 회로를 구성하는 것이 안전하지만, 병렬연결부(130)의 상태 및 부하(20)의 성질을 추가로 감안하여 회로 구성을 결정할 수 있다. The power conversion unit 140 of FIG. 3 is the input voltage (V _Total ) of the solar module 110 and the fuel cell module 120 .

V _PV

V _FC ) serves to convert the voltage (V _Load ) required for the load 20 . The power conversion unit 140 is safe to configure an insulated circuit in order to minimize the possibility that a reverse current occurs on the load 20 side, but additionally consider the state of the parallel connection unit 130 and the nature of the load 20 . to determine the circuit configuration.

The control unit 150 is a voltage output value (V _PV (t)) of the solar module 110 that the first voltage sensor 714 of the parallel connection unit 130 outputs, the sunlight output from the first current sensor 716 The current output value (I _PV (t)) of the module 110, the voltage output value (V _FC (t)) of the fuel cell module 120 output by the second voltage sensor 734, and the second current sensor 736 are Receives the current output value I _FC (t) of the fuel cell module 120 to be sensed. The control unit 150 is the input voltage command value (V * _Total (t)) of the power conversion unit 140 according to the output voltage (V _PV (t)) of the solar module 110 and the input of the power conversion unit 140 Determine the current command value (I* _Total (t)), and control the operation of the power conversion unit 140 according to the input voltage command value (V* _Total (t)) and the input current command value (I* _Total (t)). can

In addition, the control unit 150, the output voltage command value (V * _PV (t)) of the photovoltaic module 110, the _photovoltaic module ( 110) of the output current command value (I* _PV (t)), the output voltage command value of the fuel cell module 120 (V* _FC (t)), and the output power command value of the fuel cell module 120 (I* _FC (t)) )), and according to the output voltage command value (V* _PV (t)) of the solar module 110 and the output current command value (I* _PV (t)) of the solar module 110, the solar module 110 ), and according to the output voltage command value (V* _FC (t)) of the fuel cell module 120 and the output power command value (I* _FC (t)) of the fuel cell module 120, the fuel cell module ( 120) can be controlled.

When the power supply device 10 supplies power to the static load 20 with no fluctuation, the power supply device 10 sets the solar module 110 and the fuel cell module 120 within a certain range regardless of the voltage fluctuation. It can be operated to maintain within. To this end, the control unit 150 is the output power (P _PV (t)) of the solar module 110 and the output power (P _FC (t)) of the fuel cell module 120 is the sum of the input voltage command value (V* _Total (t)), it is possible to control the operation of the power conversion unit 140 based on the output voltage (V _PV (t)) of the solar module 110 while making it constant according to the voltage.

In the solar module 110, the output voltage (V _PV (t)) and the output power (P _PV (t)) are proportional, and the fuel cell module 120 has the output voltage (V _FC (t)) and the output power ( Since P _FC (t)) is inversely proportional, the power supply device 110 combining the solar module 110 and the fuel cell module 120 increases the output voltage (V _Total (t)) and the output power (P _Total ) (t)) is not proportional. Therefore, the output power (P _Total (t)) of the power supply device 10 is the input output voltage (V _PV (t)) of the solar module 110 and the output voltage (V _FC () of the fuel cell module 120) t)) varies, but is larger than the sum of the minimum output powers of the solar module 110 and the fuel cell module 120 and appears within a range smaller than the sum of the maximum output powers.

On the other hand, when power is supplied to the load 20 in which the power consumed by the power supply device 10 changes, the power supply device 10 is output current (I _PV (t)) of the solar module 110 at this time. When the sum of the output current I _FC (t) of the fuel cell module 120 and the fuel cell module 120 is configured to be maintained regardless of the output voltage V _PV (t) of the photovoltaic module 110, the load 20 The output power (P _Total ) can be changed according to the required power (P _Load (t)). To this end, the controller 150 determines that the sum of the output current I _PV (t) of the solar module 110 and the output current I _FC (t) of the fuel cell module 120 is the solar module 110 . It is possible to control the operation of the power conversion unit 140 based on the required power (P _Load (t)) of the load 20 while making it constant regardless of the output voltage (V _PV (t)) of the.

For example, between the input voltage command value (V* _Total (t)) and the output voltage (V _PV (t)) of the photovoltaic module 110 to generate the required power due to the sudden drop off of the load 20 If the difference between , the output current (I _PV (t)) of the solar module 110 is reduced to maintain the input voltage command value (V* _Total (t)) or the output current (I of the fuel cell module 120) is reduced. _FC (t)) can be increased.

8 is a connection diagram of the power supply device 10 including the buffer 160 according to an embodiment of the present invention.

As shown in FIG. 8 , power conversion is performed to alleviate the shock caused by the start/stop of the load 20 and maintain the maximum efficiency of the solar module 110 and the fuel cell module 120 for a predetermined output. A buffer 160 may be connected to an output terminal of the unit 140 . The buffer 160 may be connected in parallel to the power converter 140 . The buffer 160 may perform over/under power when there is a difference between the power (P _Total (t)) transmitted from the power conversion unit 140 and the required power (P _Load (t)) of the load 20 . . The buffer 160 is a power storage device having the voltage of the load 20 as a rated voltage, and may be a capacitor, a secondary battery, or a flow battery.

The buffer 160 controls the charging state (P _Buffer (t)), or the output voltage (V _Buffer (t)) of the buffer 160 and the output current (I _Buffer (t)) of the buffer 160 to the controller 150 The control unit 150 utilizes the output voltage (V _Buffer (t)) of the buffer 160 and the output current (I _Buffer (t)) of the buffer 160 as a variable to the solar module 110, It is possible to adjust the output of the fuel cell module 120 and the power conversion unit 140).

As described above, the control unit 150 may receive the power storage amount (P _Buffer (t)) or the storage level of the buffer 160 . When the power storage amount (P _Buffer (t)) of the buffer 160 is less than a certain level (P _{Buffer_Low} ), the control unit 150 sets the maximum output point voltage (V _PVMP ) of the solar module 110 to the solar module 110 ) of the voltage command value (V* _PV (t)) and the voltage command value of the fuel cell module 120 (V* _FC (t)). When the power storage amount 160 of the buffer 160 is equal to or greater than a certain level (P _{Buffer_Low} ), the control unit 150 determines that the required power (P _Load (t)) of the load 20 is the output (P _Total ) of the power conversion unit 140 . (t)), the output power (P _PV (t)) of the solar module 110 and the output power (P _FC (t)) of the fuel cell module 120 can be controlled.

Hereinafter, in the DC-based power supply device 10 having the above configuration, the required power is supplied to the static load 20 with little change in the required power, while the solar module 110 and the fuel cell module 120 ) based on the operation method of the control unit 150 to increase the efficiency and stability of the renewable energy output will be described.

9 illustrates a method in which the control unit 150 of the power supply device 10 having the configuration of FIG. 3 controls the output through the power conversion unit 140 .

The control unit 150 includes a voltage output value (V _PV (t)) of the solar module 110, a current output value (I _PV (t)) of the solar module 110, and a voltage output value (V) of the fuel cell module 120 . _FC (t)) and the current output value I _FC (t) of the fuel cell module 120 is received ( 910 ).

The control unit 150 calculates the output current amount (I _Total (t)) of the power conversion unit 140 according to the required power (P _Load (t)) of the load 20, and determines the state of the solar module 110 Confirm (920).

The control unit 150 draws the output power (P _PV (t)) from the solar module 110 to the maximum, but sets the input voltage command value (V * _Total (t)) to provide sufficient power to the load 20 . Calculate (930).

The control unit 150 controls the output current command value (I* _PV (t)) of the solar module 110 and the output current command value (I*) of the fuel cell module 120 according to the input voltage command value (V* _Total (t)) _FC (t)) is calculated (940).

The control unit 150 controls the output current I _FC (t) of the fuel cell module 120 so that the fuel supply amount is satisfied based on the output current command value I* _FC (t) of the fuel cell module 120 . do. To this end, the control unit 150 adjusts the outputs of the fuel supply unit 122 and the blower 123 of the fuel cell module 120 of FIG. 4 ( 950 ).

10 is a diagram illustrating a power distribution and output control flow of the controller 150 of the power supply device 10 according to an embodiment of the present invention.

At the input/output terminal, the control unit 150 includes an output voltage (V _PV (t)) of the solar module 110, an output voltage (V _FC (t)) of the fuel cell module 120, and a required output voltage of the load 20 . (V _Load (t)) and the output current of the solar module 110 (I _PV (t)), the output current of the fuel cell module 120 (I _FC (t)), the required output current of the load 20 (I _Load ) is received (1010).

The control unit 150 calculates the required power (P _Load (t)) of the load 20 from the product of the required output voltage (V _Load (t)) and the required output current (I _Load (t)) of the load (20). Check, and designate the required power (P _Load (t)) of the load 20 as the output power command value (P * _Total (t)) of the power conversion unit 140 (P * _Total (t) = P _Load ( t)= V _Load (t)*I _Load (t))(1012). The controller 150 then adjusts the current input power (P _PV (t) + P _FC (t)) to be greater than or equal to the required power (P _Load (t)) of the load 20 .

Specifically, when the output is generated when the solar voltage (V _PV (t)) is less than the predetermined reference value (V _{PV_Low} ) (V _PV (t) < V _{PV_Low} ) 1014, the control unit 150 controls the load ( 20) is controlled to be completely supplied by the fuel cell module 120 (P* _PV (t)=0, P* _FC (t)=P* _Total (t)) (1016).

To this end, the control unit 150 corresponds to the load demand voltage value (V _Load (t)) and the load demand current value (I _Load (t)) generating the required power (P _Load (t)) of the load 20 . The input voltage command value (V* _Total (t)) of the power conversion unit 140 is designated as the output voltage command value (V* _FC (t)) of the fuel cell module 120, and the input of the power conversion unit 140 is The input current command value (I* _Total (t)) of the power conversion unit 140 is designated according to the voltage command value (V* _Total (t)).

In detail, the control unit 150 instructs a voltage command value according to the characteristics of the fuel cell module 120 (V * _Total (t) = V * _FC (t)) 1018 , and instructs a current command value (I) * _FC (t)=P* _FC (t)/V* _FC (t), I* _PV (t)=0, I* _Total (t)=I* _FC (t))(1020). If there is a first relay device 712 shown in FIG. 7, if the output does not occur or the output cannot be expected because the voltage does not match the output possible range as described above, the first connected to the solar module 110 1 By adding an open signal (S _PV = 0) to the relay 712 , it is possible to block the reverse current flowing to the module.

If the solar output is sufficient (V _PV (t)≥V _{PV_Low} ) (1014), the control unit 150 sets the required power command value (P* _Total ) of the load 20 to the output power command value ( Calculate as the sum of P* _PV (t)) and the output power command value (P* _FC (t)) of the fuel cell module 120 (P* _Total (t)=P* _PV (t)+P* _FC ( t)), the output power command value (P* _PV (t)) of the solar module 110 is the output voltage (V _PV (t)) and the output current (I _PV (t)) of the solar module 110 Calculate by product (1022).

When the solar output is sufficient, the output voltage (V _PV (t)) of the solar module 110 is greater than or equal to a predetermined reference value (V _{PV_Low} ) (V _PV (t)≥V _{PV_Low} ), the solar A maximum output point voltage value (V _PVMP (t)) of the optical module 110 is designated as an output voltage command value (V* _FC (t)) of the fuel cell module 120 . In detail, the current output voltage command value (V * _PV (t)) of the solar module 110 is temporarily designated as the output voltage (V _PV (t)) of the solar module 110 (V * _Total (t)) )=V* _PV (t)=V _PV (t))(1024).

In addition, the control unit 150 changes to increase the output voltage command value (V* _PV (t)) of the solar module 110 by a predetermined unit (ΔV) (V* _PV (t) ← V* _PV (t) ) + ΔV), maximize the output of the solar module 110 (I* _PV (t) = I _PVMP (t)) (1030). Here, I _PVMP (t) is the maximum output point current of the photovoltaic module 110 when the output of the photovoltaic module 110 is maximum, and under a specific voltage, indicated by the characteristics of the photovoltaic module 110 . It means the maximum current that can be produced (I _PVMP (t)=F[V* _PV (t)]) (1030).

The output setpoint of the solar module 110 (P* _PV (t)=V* _PV (t)×I* _PV (t)) is (P* _PV (t)=V* _PV (t)×I* _PVMP (t)) is fixed (1026), the controller 150 controls the fuel cell module 120 to take charge of the remaining output. In detail, the control unit 150 includes the input voltage command value (V * _Total (t)) of the power conversion unit 140 is the voltage command value (V * _FC (t)) of the fuel cell module 120 and the solar module ( 110) of the voltage command value (V* _PV (t)), and set the current command value (I* _Total (t)) of the power conversion unit 140 to the power command value (P* _Total () of the power conversion unit 140) t)) is calculated by dividing the voltage command value (V* _PV (t)) of the solar module 110 (I* _Total (t)= P* _Total (t)/V* _PV (t)) (1028) .

The control unit 150 converts the current command value (I* _FC (t)) of the fuel cell module 120 to the current command value (I* _Total (t)) of the power conversion unit 140 to the maximum output of the solar module 110 . It is designated as a value obtained by subtracting the point current (I _PVMP (t)) (1032).

After the output power command value (P* _FC (t)) of the fuel cell module 120 is determined, the control unit 140 determines the fuel flow rate (Q* _H2 (t)) and the oxidant supply amount (Q* _O2 ) capable of producing the specified output. (t)) is determined (1034).

The control unit 140 multiplies the fuel flow rate (Q* _H2 (t)) by a predetermined ratio (m) determined by an electrochemical reaction by the current command value (I* _FC (t)) of the fuel cell module 120, and the fuel It can be calculated by adding a surplus (α) for the uniformity of the reaction of the electrodes in the battery module 120 . The control unit 140 multiplies the oxidizing agent supply amount (Q* _O2 (t)) by the current command value (I* _FC (t)) of the fuel cell module 120 by a predetermined ratio (n) determined by an electrochemical reaction, and the fuel It can be calculated by adding the surplus β for the uniformity of the reaction of the electrodes in the battery module 120 (1034).

Finally, although not shown, the control unit 150 turns on/off the fuel supply 122 and the blower 123 to command the fuel flow rate (Q* _H2 (t)) and the oxidant supply amount (Q* _O2 (t)) Time adjustment, etc. can be performed.

V_PVMP)할 수 있다. When the buffer 160 is added to the output side of the power converter 140, even if there is no load 20, it can be stored in the buffer 160 instead, so when the storage amount of the buffer 160 is within a predetermined level, the load ( Instead of calculating the command value (V ^* _Total (t)) of the input voltage based on the required power (P _Load (t)) of 20), input based on the MPPT voltage (V _PVMP ) of the solar module 110 Derive voltage setpoint (V ^* _Total (t)) (V ^* _Total (t)

V _PVMP ) can be done.

When the output power (P _PV (t)) of the solar module 110 is not generated, the control unit 150 controls the output power command value (P * _FC (t)) of the fuel cell module 120 to the load 20 It can be determined by adding a predetermined power required for charging to the required power (P _Load (t)). If the storage amount of the buffer 160 is less than a predetermined level, the output is adjusted according to the required power (P _Load (t)) of the load 20 , so the controller 150 controls the control method when the buffer 160 is not present and can be controlled in the same way.

When the amount of power stored in the buffer 160 exceeds a predetermined level, when the required power (P _Load (t)) of the load 20 decreases, the input power command value (P * _Total (t)) is set to the required power of the load. (P _Load (t)) should be decreased with the decrease.

An aspect of the present invention may be implemented as computer-readable codes on a computer-readable recording medium. Codes and code segments implementing the above program can be easily inferred by a computer programmer in the art. The computer-readable recording medium includes all types of recording devices in which data readable by a computer system is stored. Examples of the computer-readable recording medium include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical disk, and the like. In addition, the computer-readable recording medium may be distributed in network-connected computer systems, and may be stored and executed as computer-readable codes in a distributed manner.

The above description is merely an embodiment of the present invention, and those of ordinary skill in the art to which the present invention pertains will be able to implement it in a modified form without departing from the essential characteristics of the present invention. Accordingly, the scope of the present invention should not be limited to the above-described embodiments, but should be construed to include various embodiments within the scope equivalent to the content described in the claims.

10: power supply 20: load
110: solar module 120: fuel cell module
130: parallel connection unit 140: power conversion unit
150: control unit

Claims (9)

A photovoltaic module that generates DC power by photoelectric reaction;
a fuel cell module connected in parallel with the solar module and generating power;
a parallel connection unit that measures the output of the solar module and the fuel cell module and prevents reverse current flow between the solar module and the fuel cell module;
a power conversion unit that receives and transmits power to a load as much as the sum of the output power (P _PV (t)) of the solar module and the output power (P _FC (t)) of the fuel cell module;
Receives the output voltage (V _PV (t)) of the photovoltaic module, the output voltage (V _FC (t)) of the fuel cell module, and the input power (P _Total (t)) of the power converter from the parallel connection unit, and receives the load request According to the change in power (P _Load (t)) and the change in the output voltage (V _PV (t)) of the solar module, the input voltage command value (V* _Total (t)) and the input current command value (I* _{Total (} t) of the power conversion unit )) a control unit for calculating; including,
The power conversion unit performs a constant voltage operation on the load according to the control of the controller to stably supply the required power to the load. 2. The method of claim 1
When the power supply device supplies power to a static load that does not change, the controller controls the sum of the output power (P _PV (t)) of the photovoltaic module and the output power (P _FC (t)) of the fuel cell module within a certain range. An integrated power supply device for voltage control, characterized in that it controls the operation of the power conversion unit based on the output voltage (V _PV (t)) of the solar module while maintaining 2. The method of claim 1
When the power supply device supplies power to a load having variability, the controller determines that the sum of the output current (I _PV (t)) of the solar module and the output current (I _FC (t)) of the fuel cell module is the load voltage (V). An integrated power supply device for voltage control, characterized in that the operation of the power converter is controlled based on the required power (P _Load (t)) of the load while responding to the variation of _Load (t)). The method of claim 1,
a buffer connected in parallel to the output of the power conversion unit and accommodating excess or insufficient power when a difference between the input power (P _Total (t)) and the required power of the load (P _Load (t)) occurs; An integrated power supply for voltage control, characterized in that it further comprises. The method of claim 1, wherein the control unit
Voltage output value of solar module (V _PV (t)), current output value of solar module (I _PV (t)), voltage output value of fuel cell module (V _FC (t)), current output value of fuel cell module (I receive _FC (t)),
Calculate the input current (I _Total (t)) of the power converter according to the required power of the load (P _Load (t)), check the state of the solar module,
The output power (P _PV (t)) from the solar module is drawn to the maximum, but the input voltage command value (V* _Total (t)) is calculated so that sufficient power can be supplied to the load,
Calculate the output current command value (I* _PV (t)) of the solar module and the output current command value (I* _FC (t)) of the fuel cell module according to the input voltage command value (V* _Total (t)),
Integrated power with voltage control, characterized in that the output current (I _FC (t)) of the fuel cell module is controlled so that the fuel supply amount is satisfied based on the output current command value (I* _FC (t)) of the fuel cell module supply device. 6. The method of claim 5,
The control unit is included in the fuel cell module to control the output current (I _FC (t)) of the fuel cell module so that the fuel supply amount is satisfied based on the output current command value (I* _FC (t)) of the fuel cell module. An integrated power supply device with voltage control, characterized in that it adjusts the outputs of a fuel supply supplying fuel and a blower supplying oxygen. 6. The method of claim 5,
When the output voltage (V _PV (t)) of the photovoltaic module is less than a predetermined reference value (V _{PV_Low} ) (V _PV (t)<V _{PV_Low} ), the control unit controls so that the power of the load is completely supplied by the fuel cell module. Designating the load demand voltage (V _Load (t)) and load demand current (I _Load (t)) that generate the required power of the load as the output power command value (P* _FC (t)) of the fuel cell module An all-in-one power supply with voltage control. 8. The method of claim 7,
When the output voltage (V _PV (t)) of the solar module is higher than the predetermined reference value (V _{PV_Low} ) (V _PV (t)≥V _{PV_Low} ), the maximum output point voltage (V _PVMP ) of the solar module is set to the fuel cell module An integrated power supply device for voltage control, characterized in that it is specified as the output voltage command value (V* _FC (t)) of 5. The method of claim 4,
The control unit receives the power storage amount of the buffer,
When the amount of power stored in the buffer (P _Buffer (t)) is less than a certain level (P _{Buffer_Low} ), the maximum output point voltage (V _PVMP ) of the photovoltaic module is compared with the voltage setpoint of the photovoltaic module (V* _PV (t)) and the fuel Designate as the voltage command value (V* _FC (t)) of the battery module,
When the amount of power stored in the buffer ( _{P Buffer} ( _t )) is above a certain level (P _{Buffer_Low} ), the input voltage command value ( By specifying V* _Total (t)), the output current command value of the solar module (I* _PV (t)), and the output current command value of the fuel cell module (I* _FC (t)), the output power (P An integrated power supply device with voltage control, characterized in that it controls the _PV (t)) and the output power (P _FC (t)) of the fuel cell module.

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