KR102301613B1 - Power optimizer with protection circuit for solar power generation system - Google Patents

Abstract

The present invention relates to a power optimizer for a solar power generation system embedded with a protection circuit, which can protect a device from overvoltage, overcurrent, and overtemperature caused by instantaneous power failure, sudden environmental change, electric spark, lightning, hotspot, system malfunction, etc. by grafting hardware and software technologies with a power optimizer installed in each solar panel of a solar power generation system. To this end, the power optimizer of the present invention comprises: a sensing means for detecting an input current and voltage of an input terminal associated with a light concentrating panel, a temperature of the light concentrating panel, and an output current and voltage of an outer terminal associated with an external inverter; a DC/DC converter for performing DC/DC conversion on the voltage input through the input terminal; a gate driver for selectively driving the DC/DC converter in accordance with a predetermined control signal; and an MCU for controlling the DC/DC converter to be isolated from a panel and an inverter by transmitting a switching signal for a protection operation to the gate driver when it is determined that an input value of a sensing means is abnormal while performing an MPPT function on the basis of input voltage and current values and output voltage and current values from the sensing means by driving a predetermined program.

Description

POWER OPTIMIZER WITH PROTECTION CIRCUIT FOR SOLAR POWER GENERATION SYSTEM

The present invention relates to a power optimizer for a photovoltaic power generation system with a built-in protection circuit, and more particularly, overvoltage, overcurrent, and overvoltage by combining hardware and software technology to a power optimizer installed in each photovoltaic panel in a photovoltaic power generation system. It relates to a power optimizer for a solar power generation system with a built-in protection circuit with a built-in temperature protection circuit.

In general, the solar power generation system is a member of the development of alternative energy to promote the expansion and dissemination of new and renewable energy. Thanks to the pollution-free and indefinite nature of solar energy, it is a global environmental problem and a measure to diversify future energy sources in advanced countries. Research and development are being actively carried out, and recently, the efficiency of the solar power generation system and the practical use of the optimized power generation device are being spurred.

The photovoltaic power generation system directly converts the light energy of the sun into electric energy using a photoelectric converter called a photovoltaic module, that is, connects a plurality of photovoltaic power modules in series and parallel and connects to a power converter. will do

At this time, since the output voltage of one photovoltaic module alone is very low, in order to boost the voltage to the input voltage required for the power conversion device, a plurality of photovoltaic modules are connected in series in a string manner, and a plurality of arrays connected in series again are configured to obtain final power by connecting them in parallel.

Here, in the solar power generation system to which the conventional string method is applied, when overcurrent, overvoltage, and overtemperature occur due to instantaneous power failure, sudden environmental change, electric spark, lightning strike, hotspot, etc. on the specific panel side, the connection panel and inverter In addition, when overvoltage or overcurrent occurs due to instantaneous power failure, electric spark, lightning strike, system malfunction, etc. on the inverter side, a problem of causing damage to the entire photovoltaic power generation system occurs.

Domestic Registered Patent No. 10-1857916 Domestic Registered Patent No. 10-1149473

Therefore, the present invention has been devised to improve the conventional problems as described above, and its purpose is to embed a protection circuit combining hardware and software technology in a power optimizer installed in each solar panel of a solar power generation system. To provide a power optimizer for a solar power generation system with a built-in protection circuit to protect the device from overvoltage, overcurrent, and overtemperature caused by instantaneous power failure, sudden environmental change, electric spark, lightning strike, hot spot, system malfunction, etc. will be.

The power optimizer for a photovoltaic power generation system with a built-in protection circuit according to the present invention for achieving the above object, the input current, voltage and temperature of the input terminal associated with the collecting panel and the output terminal associated with the external inverter sensing means for detecting the output current and voltage; a DC/DC converter for performing DC/DC conversion on the voltage input through the input terminal; a gate driver selectively driving the DC/DC converter according to a predetermined control signal; The MPPT function is performed based on the input voltage and current values and the output voltage and current values from the sensing means through driving of a predetermined program, and when it is determined that the input value from the sensing means is in an abnormal state, the and an MCU for controlling the DC/DC converter to be isolated from the panel and the inverter by transmitting a switching signal for the protection operation.

Preferably, the sensing means further comprises a temperature sensor for detecting overtemperature due to a hot spot of a panel connected to the input terminal in addition to the Hall sensor for detecting the current and voltage values of the input terminal and the output terminal.

Preferably, when it is determined that the input value from the sensing means is in an abnormal state, the MCU transmits a "High Side = Low, Low Side = High" switching signal for the operation of the protection circuit to the gate driver. , High Side FET = OFF, Low Side FET = ON state of the DC/DC converter is characterized in that the control is made to operate.

Preferably, the process of operating the protection circuit when overvoltage, overcurrent, or overtemperature occurs through the control of the MCU is when the input voltage is less than a certain value in the power on state according to the application of power, the output power is turned off ) a startup mode (Startup mode) step to maintain the state; When the input voltage in the startup mode is above a certain value, it is determined whether the value input from the sensing means is normal or abnormal. Sends a Low signal to the LSGD (Low Side Gate Driver) & a High signal to the Low Side FET so that the High Side FET is turned OFF. a standby mode (Standby mode) step of determining whether the MPPT function is activated by determining whether it is abnormal; After the standby mode step, it is determined again whether the value input from the sensing means is normal or abnormal, and if it is in an abnormal state, a control signal is applied so that the High Side FET is in an OFF state, while the input value of the sensing means is normal a through mode step in which PWM is set so that the panel voltage is output as a voltage corresponding to the input value in a normal state by determining whether or not the voltage value of the corresponding panel is normal; It is determined again whether the value input from the sensing means is normal or abnormal, and if it is in an abnormal state, a control signal is applied so that the High Side FET is in the OFF state, while in the normal state of the sensing means input value, PWM adjustment for MPPT After this is done, it is determined whether the input voltage is a stable voltage equal to or greater than a certain value, and the voltage is increased through PWM adjustment so that the operating voltage is maintained when a voltage drop occurs. It is characterized in that it consists of an MPPT mode step of determining whether or not it is a predetermined value or more.

More preferably, it is determined that the value input from the sensing means is in an abnormal state in the standby mode step, the through mode step, or the MPPT mode step, so that the Low signal and the LSGD & Low Side of HSGD & High Side FETs After the High Side FET is turned OFF according to the High signal of the FET and the corresponding panel and inverter are completely isolated from the shutdown mode step, it is determined whether the input value from the sensing means is restored to normal and the startup mode is restored. It is characterized in that the control is made so that the power optimization function is sequentially re-executed by returning to the step.

According to the present invention made as described above, there is an effect of preventing damage to the device due to instantaneous power failure, electric spark, lightning, sudden environmental change, system malfunction, over temperature, etc. in the photovoltaic power generation system, and through this, the photovoltaic power plant It is possible to obtain the effect of increasing the amount of power generated by the improvement of the power efficiency of

In addition, by embedding a protection circuit that combines hardware and software technology in the power optimizer of the solar power generation system, it is possible to build an IP for solar system protection that can protect the device from overvoltage, overcurrent, and overtemperature. .

1 is a view showing a schematic configuration of a photovoltaic power generation system to which a power optimizer for a photovoltaic power generation system with a built-in protection circuit according to the present invention is applied;
2 is a block diagram showing the configuration of a power optimizer for a solar power generation system with a built-in protection circuit according to the present invention;
3 is a flowchart showing an operation process of a power optimizer for a solar power generation system having a built-in protection circuit according to the present invention;
4 is a view showing the operating state of the protection circuit when an over-condition factor of a solar panel or inverter occurs in the power optimizer for a solar power generation system with a built-in protection circuit according to the present invention;
5 is a view showing the operation results when overvoltage, overcurrent, and overtemperature occurs through the power optimizer for a solar power generation system having a built-in protection circuit according to the present invention.

Hereinafter, the present invention configured as described above will be described in detail with reference to the accompanying drawings.

1 is a view showing a schematic configuration of a photovoltaic power generation system to which a power optimizer for a photovoltaic power generation system with a built-in protection circuit according to the present invention is applied, and FIG. 2 is a photovoltaic power generation system with a built-in protection circuit according to the present invention 3 is a block diagram showing the configuration of the power optimizer. FIG. 3 is a flowchart showing the operation process of the power optimizer for a solar power generation system having a built-in protection circuit according to the present invention.

First, the power optimizer for a photovoltaic power generation system with a built-in protection circuit according to the present invention is a power optimizer 40 installed in each photovoltaic panel of the photovoltaic power generation system with a protection circuit grafted with hardware and software technology to the MCU Built in (50) is implemented to enable protection of the device through the power optimizer (40) in the event of overvoltage, overcurrent, and overtemperature.

A photovoltaic power generation system to which a power optimizer for a photovoltaic power generation system with a built-in protection circuit according to the present invention is applied, is installed in a predetermined place and produces a predetermined voltage and current by the photoelectric effect; , a plurality of power optimizers 40 and a plurality of power optimizers installed in conjunction with each solar panel 10 to control the maximum power output by tracking the maximum power point from the voltage and current input from the corresponding panel A gateway 20 that receives voltage and current data and power data of each solar panel 10 output from 40 and transmits them to the outside, and each solar panel 10 received through the gateway 20 It is configured to include a monitoring server 30 and the like in which real-time monitoring information is processed.

The monitoring server 30 is linked to a PC or smart phone for control, so that the manager can check the status information of each power optimizer 40 in real time through a predetermined terminal device.

Here, the input terminal 42 of the power optimizer 40 is connected to each photovoltaic panel 10 so that a predetermined power is input, and the output terminal 44 of the power optimizer 40 is connected to a connection panel. It is connected to the external inverter 60 through 62 or a plurality of power optimization 40 are connected to each other so that a predetermined power input through the input terminal 42 is output through the DC/DC converter 54 .

In addition, when the output terminals 44 of a plurality of power optimizers 40 are connected to each other, the output terminals 44 of the power optimizers 40 located at the ends are connected to the external inverter 60 through the connection panel 62 . done so as to

The power optimizer 40 is connected with predetermined sensing means 46a, 46b, and 46c, a DC/DC converter 54, a gate driver 52, an MCU 50 having a built-in protection circuit, and the input terminal 42 It is configured to include a power supply 48 and the like.

The sensing means is connected to the input terminal 42 associated with a predetermined panel, the input-side sensing means 46a consisting of a Hall sensor for detecting the current and voltage values produced by the solar panel 10, and the output terminal 44 ) output-side sensing means (46b) consisting of a Hall sensor for detecting current and voltage values output through, and a temperature sensor ( 46c) and the like.

The DC/DC converter 54 is configured to operate according to a command of the gate driver 52 to perform a DC/DC conversion function for the voltage input through the input terminal 42 , and the gate driver Reference numeral 52 is configured to perform a function of selectively driving the DC/DC converter 54 according to a control signal from the MCU 50 .

The MCU 50 operates autonomously according to the driving of a built-in predetermined program, the input voltage and current values from the input-side sensing means 46a, and the output voltage and current from the output-side sensing means 46b. Based on the value, the MPPT function is selectively performed to perform a series of controls to enable optimal power generation.

That is, the MCU 50 tracks the maximum power point based on the voltage and current values of the corresponding solar panel 10 sensed through the input-side sensing means 46a, and then PWM for output of the maximum power It is generated by controlling the duty signal, and accordingly, as the PWM duty signal is transmitted from the MCU 50 to the gate driver 52 and the DC/DC converter 54 side, the DC/DC converter 54 is Control is performed to output maximum power while repeatedly being turned ON/OFF by the gate driver 52 .

In addition, according to the present invention, the MCU 50 has a predetermined protection circuit and a predetermined program for controlling the operation of the protection circuit, so that the input values from the above-described sensing means 46a, 46b, and 46c are abnormal. When it is determined to be, a switching signal for protection operation is transmitted to the gate driver 52 so that the DC/DC converter 54 is completely isolated from the solar panel 10 and the inverter 60 so that the control is performed. is composed

That is, the MCU 50 is a Hall sensor that is the sensing means 46a and 46b connected to the input terminal 42 or the output terminal 44 , or the temperature sensing means 46c connected to the solar panel 10 . When it is determined that the input value from the detection sensor is in an abnormal state, a "High Side = Low, Low Side = High" switching signal for the operation of the protection circuit is transmitted to the gate driver 52 through driving of a predetermined program. , and thus the DC/DC converter 54 is operated in a state of High Side FET = OFF and Low Side FET = ON, while the Low FET performs only a bypass operation (refer to FIGS. 4 and 5 ).

Accordingly, the photovoltaic panel 10 and the inverter 60 are completely isolated from each other, and no current and voltage of the corresponding panel, which is a problem, are supplied to the inverter 60 side. 60 can be protected, and as the current supply to the inverter 60 is cut off, the corresponding panel 10 is also switched to an OFF state.

In the MCU 50, the voltage value and current value of the input terminal 42 and the output terminal 44 which are detected and inputted through each sensing means 46a, 46b, and 46c, and the temperature value of the solar panel 10 are respectively If it is 75 [V] or more, 15 [A] or more, or 110° C. or more, it is determined that it is in an abnormal state and the shutdown mode is performed.

At this time, the values of the voltage value, the current value, and the temperature value for which the shutdown mode is performed based on the detection value of the sensing means can be easily changed and designed by modifying the program of the MCU according to the conditions of each system. .

Next, the operation of the present invention configured as described above will be described in detail with reference to FIGS. 1 to 3 .

First, the power optimizer for a photovoltaic system with a built-in protection circuit according to the present invention is the MCU based on the detection value from the sensing means 46a, 46b, and 46c in the power on state according to the application of power (S 1). Based on the control signal from (50) startup mode (Startup mode) step (S 2), standby mode (Standby mode) step (S 3), mode determination step (S 4), through mode ( Through mode) step (S5), MPPT mode (Maximum Power Point Tracking mode) step (S6), and the shutdown mode step (S7) and the like are performed.

In the power on state (Boot up & Initialization) in which a predetermined power is supplied to the power optimizer 40 (S 1), in the startup mode step (S 2), the input terminal detected from the sensing means When the voltage value is 15 [V] or less, while maintaining the startup mode step of maintaining the off state of the output power, when it is determined that the voltage value of the input terminal exceeds 15 [V] , the control is made to enter the standby mode (Standby mode) step (S 2-1 and S 2-2).

Thereafter, in the standby mode step S3, sensing means 46a, 46b, 46c such as a Hall sensor or a temperature sensor connected to the input terminal 42 or the output terminal 44 through the MCU 50 ), the process of determining whether the input value is normal (S 3-1), that is, the voltage value of the input terminal 42 and the output terminal 44 is 75 [V] or more, or the current value is 15 [ A] or more, or when the temperature values of the panel 10 and the inverter 60 are 110° C. or higher, it is determined that an abnormal state is present and the shutdown mode step S7 is performed.

In the shutdown mode step (S 7), a predetermined program is driven by the MCU 50 to transmit a "High Side = Low, Low Side = High" switching signal for the operation of the protection circuit to the gate driver 52 to be controlled. is made, and accordingly, as the High Side FET of the DC/DC converter 54 is switched to the OFF state, the solar panel 10 and the inverter 60 are completely separated, and the current and voltage supply from the panel is completely It can be blocked (S 7-1).

In addition, in the shutdown mode step (S7), it is determined by continuously monitoring whether the input values from the plurality of sensing means 46a, 46b, and 46c are normally restored, and the input signal from the sensing means is restored to a normal state. In this case, it returns to the start-up mode (S2) step and control is made so that the power optimization function is performed again (S7-2).

Meanwhile, in the standby mode step (S2), sensing means 46a, 46b, 46c such as a Hall sensor or a temperature sensor connected to the input terminal 42 or the output terminal 44 through the MCU 50 If it is determined that the input value from is normal, it is determined whether the current input voltage exceeds 10 [V] again through the 'S 3-2 and S 3-3' process, and the current input voltage is 10 [V] In the following cases, the control is made to return to the startup mode step (S2).

If the input voltage exceeds 10 [V] as a result of the determination of 'S 3-2 and S 3-3', in the standby mode step (S 3), after the self-activation of the MPPT function is made after a certain time elapses (S 3-4), to determine whether to proceed to the through mode step or the MPPT mode (Maximum Power Point Tracking mode) step depending on whether the panel voltage state maintenance mode is used in the mode determination step 'S 4' the process will proceed.

In the through mode step (S5), after the process of determining whether the input values from the sensing means (46a, 46b, 46c) are normal through the MCU (50) (S5-1), the abnormal state If it is determined that , the process proceeds to the shutdown mode step (S7) and control is performed so that the supply of current and voltage from the corresponding panel 10 is completely cut off.

In the through mode step (S5), when it is determined that the input values from the sensing means 46a, 46b, and 46c are in a normal state, it is determined whether the input voltage of the corresponding panel exceeds 10 [V]. (S 5-2), when the corresponding voltage is 10 [V] or less, the return to the startup mode step (S 2) is made, while when the corresponding voltage exceeds 10 [V], the panel voltage is higher than the input voltage After the PWM is set to output at a voltage of about 95% (S 5-3), check whether the output current of the panel exceeds 0.2 [A] and check the normal photovoltaic power generation state (S 5- 4), the control is made to enter the MPPT mode (S6).

In the MPPT mode step (S6), after the process of determining whether the input value from the sensing means (46a, 46b, 46c) is normal through the MCU (50) (S6-1), the abnormal state If it is determined that , the process proceeds to the shutdown mode step (S7) and control is performed so that the supply of current and voltage from the corresponding panel 10 is completely cut off.

In the MPPT mode step (S 6), if it is determined that the input values from the sensing means (46a, 46b, 46c) are in a normal state, the process proceeds to 'S 6-2' and PWM adjustment for the MPPT of the corresponding panel is performed. As a result of the determination in 'S 6-3', it is checked whether the input voltage exceeds 20 [V] to determine whether the stable operating voltage is restored.

That is, as a result of checking the input voltage in 'S 6-3', if the value is 20 [V] or less, when an instantaneous voltage drop occurs, control is performed to increase the voltage through PWM adjustment to maintain the operating voltage. (S 6-4), and after that, when the operating voltage is stably returned, it is checked whether the input current exceeds 0.2 [A] and whether the input voltage exceeds 10 [V] After the process of determining the current state of the panel and the voltage state of the solar panel is performed (S 6-5 and S 6-6), control is made to selectively return to the startup mode step (S 2) .

The operating state of the power optimizer 40 with the built-in protection circuit as described above is transmitted in real time to the monitoring server 30 through the gateway 20, and the manager of the system can control each power optimizer 40 in real time. It is possible to check the status information using various terminal devices including a smart phone associated with the monitoring server 30 .

On the other hand, although preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above, and technology to which the present invention pertains within the scope not departing from the gist of the present invention as claimed in the claims Various modifications and modifications are possible by those of ordinary skill in the art, and these modifications and modified inventions should not be individually understood from the technical spirit or perspective of the present invention.

10: solar panel, 20: gateway,
30: monitoring server, 40: power optimizer,
42: input terminal, 44: output terminal,
46a, 46b, 46c: sensing means, 48: power supply,
50: MCU, 52: gate driver,
54: DC/DC converter, 60: inverter,
62: junction panel.

Claims (5)

sensing means for detecting an input current, voltage and temperature of an input terminal associated with the light collecting panel, and an output current and voltage of an output terminal associated with an external inverter;
a DC/DC converter for performing DC/DC conversion on the voltage input through the input terminal;
a gate driver selectively driving the DC/DC converter according to a predetermined control signal;
The MPPT function is performed based on the input voltage and current values and the output voltage and current values from the sensing means through driving of a predetermined program. On the other hand, when it is determined that the input value from the sensing means is in an abnormal state, the and an MCU controlling the DC/DC converter to be isolated from the panel and the inverter by transmitting a switching signal for protection operation;
The process of operating the protection circuit when overvoltage, overcurrent, and overtemperature occurs through the control of the MCU,
A startup mode (Startup mode) step of maintaining an off (off) state of the output power when the input voltage is less than or equal to a predetermined value in the power on (on) state according to the application of power;
When the input voltage in the startup mode is above a certain value, it is determined whether the value input from the sensing means is normal or abnormal. Sends a Low signal to the LSGD (Low Side Gate Driver) & a High signal to the Low Side FET so that the High Side FET is turned OFF. a standby mode step of determining whether the MPPT function is activated by determining whether it is abnormal;
After the standby mode step, it is determined again whether the value input from the sensing means is normal or abnormal, and if it is in an abnormal state, a control signal is applied so that the High Side FET is in an OFF state, while the input value of the sensing means is normal a through mode step in which PWM is set so that the panel voltage is output as a voltage corresponding to the input value in a normal state by determining whether or not the voltage value of the corresponding panel is normal;
It is determined again whether the value input from the sensing means is normal or abnormal, and if it is in an abnormal state, a control signal is applied so that the High Side FET is in an OFF state, while in a normal state of the sensing means input value, PWM adjustment for MPPT After this is done, it is determined whether the input voltage is a stable voltage equal to or greater than a certain value, and the voltage is increased through PWM adjustment so that the operating voltage is maintained when a voltage drop occurs. Power optimizer for a solar power generation system with a built-in protection circuit, characterized in that; The method of claim 1,
The sensing means further comprises a temperature sensor for detecting overtemperature due to a hot spot of a panel connected to the input terminal in addition to the Hall sensor for detecting the current and voltage values of the input terminal and the output terminal. Power optimizer for photovoltaic systems. 3. The method of claim 1 or 2,
The MCU is
When it is determined that the input value from the sensing means is in an abnormal state, by transmitting a "High Side = Low, Low Side = High" switching signal for the operation of the protection circuit to the gate driver, the DC/DC converter High Side FET = OFF, Low Side FET = Power optimizer for solar power generation system with a built-in protection circuit, characterized in that the control is made to operate in the ON state. delete The method of claim 1,
In the standby mode step, the through mode step, or the MPPT mode step, it is determined that the value input from the sensing means is in an abnormal state, so that the Low signal of the HSGD & High Side FET and the High signal of the LSGD & Low Side FET are After the High Side FET is turned OFF and the corresponding panel and inverter are completely isolated from the shutdown mode step, it is determined whether the input value from the sensing means is restored to normal, and returns to the startup mode step when normal recovery occurs. A power optimizer for a solar power generation system with a built-in protection circuit, characterized in that the control is made to sequentially re-perform the power optimization function.

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