Disclosure of Invention
The invention aims to provide a control system and a control method of a photovoltaic module and the photovoltaic system.
In order to solve the technical problem, the invention provides a control system of a photovoltaic module, which comprises a module breaker, a group string breaker and an alternating current idle switch, wherein the module breaker comprises:
a main switch;
the detection module is used for detecting the output parameter of the component breaker;
the control module is used for judging whether the photovoltaic module and the inverter are communicated or not according to the output parameters, if so, controlling the main switch to be conducted, and if not, controlling the main switch to be switched off;
and the power supply module is used for supplying power to the control module and the detection module.
Preferably, the output parameters include an output voltage and an output current;
correspondingly, the detection module comprises:
the voltage detection module is used for acquiring the output voltage;
and the current detection module is used for acquiring the output current.
Preferably, the control module is specifically configured to:
when the output current meets a transient conduction condition, controlling the main switch to be conducted transiently, and when the conduction time of the main switch is longer than a first preset time, controlling the main switch to be switched off;
judging whether an output parameter of the component breaker is greater than or equal to the preset conduction value when the main switch is conducted temporarily;
if yes, the photovoltaic module is judged to be communicated with the inverter, after the main switch is turned off, the main switch is controlled to be conducted, and until the output current of the module breaker is smaller than a turn-off preset value, the photovoltaic module is judged to be not communicated with the inverter, and the main switch is controlled to be turned off.
Preferably, the process of controlling the main switch to be turned on briefly includes:
and controlling the main switch to be switched on temporarily by sending a positive pulse signal.
Preferably, the process of determining whether the output parameter of the component breaker is greater than or equal to the preset conduction value when the main switch is turned on briefly includes:
judging whether the output current of the component breaker is greater than or equal to a first preset conduction value when the main switch is conducted temporarily;
or judging whether the output voltage of the component breaker is greater than or equal to a second conduction preset value when the main switch is conducted for a short time.
Preferably, when the output current of the module shutdown device is smaller than a shutdown preset value, it is determined that the photovoltaic module and the inverter are not connected, and a process of controlling the main switch to be turned off specifically includes:
acquiring the output current of the component breaker every second preset time;
and when the duration time that the output current of the component breaker is smaller than a preset turn-off value is longer than a third preset time, judging that the photovoltaic component is not communicated with the inverter, and controlling the main switch to turn off.
Preferably, the control module is further configured to:
when the closing time of the main switch reaches a fourth preset time, controlling the main switch to be turned off temporarily;
acquiring the output voltage variation of the component breaker after the main switch is turned off briefly;
judging whether the output voltage variation is smaller than or equal to a first preset value;
if yes, the photovoltaic module is judged to be communicated with the inverter, and the main switch is controlled to be closed;
if not, judging that the photovoltaic module is not communicated with the inverter, and controlling the main switch to be switched off;
and the fourth preset time is less than the second preset time.
Preferably, the process of controlling the main switch to be turned off temporarily specifically includes:
and controlling the main switch to be turned off temporarily by sending a negative pulse signal.
In order to solve the above technical problem, the present invention further provides a control method of a photovoltaic module, which is applied to the control module described in any one of the above paragraphs, and includes:
acquiring an output parameter of the component breaker;
and judging whether the photovoltaic module and the inverter are communicated or not according to the output parameters, if so, controlling the main switch to be conducted, and if not, controlling the main switch to be switched off.
In order to solve the technical problem, the invention further provides a photovoltaic system, which comprises the control system of the photovoltaic module as described in any one of the above, and further comprises an inverter.
The invention provides a control system of a photovoltaic module, which comprises a module breaker, a group string breaker and an alternating current idle switch, wherein the module breaker comprises a main switch; the detection module is used for detecting the output parameters of the component shutoff device; the control module is used for judging whether the photovoltaic module is communicated with the inverter or not according to the output parameters, if so, controlling the main switch to be conducted, and if not, controlling the main switch to be turned off; and the power supply module is used for supplying power to the control module and the detection module. Therefore, in practical application, by adopting the scheme of the invention, the control module in the component breaker controls the on or off of the component breaker according to the change of the output parameter of the component breaker detected by the detection module, so that the voltage output of the photovoltaic component is controlled, the reliability is high, the photovoltaic component does not depend on stable and reliable communication support, the application range is wide, and the stability of a photovoltaic system is improved. The invention also provides a control method of the photovoltaic module and a photovoltaic system, and the control method and the photovoltaic system have the same beneficial effects as the control system of the photovoltaic module.
Detailed Description
The core of the invention is to provide a control system and a control method of a photovoltaic module and the photovoltaic system, wherein the control module in the module breaker controls the on or off of the module breaker according to the change of the output parameter of the module breaker detected by the detection module, so that the voltage output of the photovoltaic module is controlled, the reliability is high, the system does not depend on stable and reliable communication support, the application range is wide, and the stability of the photovoltaic system is improved.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a control system of a photovoltaic module provided in the present invention, including a module shutdown device 1, a group string shutdown device 2, and an ac idle switch 3, where the module shutdown device 1 includes:
a main switch 11;
a detection module 12, configured to detect an output parameter of the component shutdown device 1;
the control module 13 is used for judging whether the photovoltaic module and the inverter are communicated or not according to the output parameters, if so, controlling the main switch 11 to be conducted, and if not, controlling the main switch 11 to be switched off;
and the power supply module 14 is used for supplying power to the control module 13 and the detection module 12.
It should be noted in advance that a photovoltaic system generally includes a plurality of photovoltaic modules, and therefore the module shutdown device 1 also includes a plurality of photovoltaic modules, the control system of the photovoltaic module provided by the present invention only uses one module shutdown device 1, the group string shutdown device 2, and the ac air switch 3 to describe the control process of the photovoltaic module, the control process of the control system for all other photovoltaic modules is the same as that of the control system, and the module shutdown device 1, the group string shutdown device 2, and the ac air switch 3 may be connected in other manners besides the connection as shown in fig. 1, the present invention is not limited herein, for example, the group string shutdown device 2 may also be integrated into an inverter.
Specifically, the structural schematic diagram of the string shutdown device 2 provided by the present invention is shown in fig. 2, and includes a string control module, a string switch, a resistor, and a resistor switch, where a state of the string switch and a state of the resistor switch are opposite, that is, when the string switch is turned on, the resistor switch is turned off, and when the string switch is turned off, the resistor switch is turned on, as can be seen from the connection structure shown in fig. 2, the string switch determines connection and disconnection of the photovoltaic module and the inverter, and the resistor switch is used to connect and disconnect the resistor.
Specifically, the control system of the photovoltaic module provided by the invention mainly controls the on/off of the module breaker 1 through the control module 13 in the module breaker 1, so as to control whether the photovoltaic module can output direct current. When the photovoltaic system is normally started and operated, namely the photovoltaic module is communicated with the inverter, and when the inverter converts direct current output by the photovoltaic module into alternating current for grid connection, the flow for controlling the normal starting of the photovoltaic system is as follows, firstly, the alternating current air switch 3 is closed, then, the resistance switch in the group string breaker 2 is disconnected, the group string switch in the group string breaker 2 is controlled to be conducted, and then, the control system in the component breaker 1 is used for controlling the conduction of the component breaker 1, so that the normal operation of the photovoltaic system is realized.
Specifically, the control system inside the module breaker 1 includes a main switch 11, a detection module 12, a control module 13, and a power module 14, the power module 14 supplies power to the control module 13 and the detection module 12 from the photovoltaic module, the detection module 12 is used for detecting an output parameter of the module breaker 1, and the control module 13 controls on/off of the main switch 11 according to the output parameter. Specifically, the detection module 12 in the component shutdown device 1 detects the output parameters of the component shutdown device 1 according to a preset rule, where the output parameters include output current and output voltage, and the detection according to the preset rule may refer to real-time detection or detection according to a preset period, as long as the control requirement of the present invention can be met. After the ac air switch 3 and the string switch are closed, the output parameter of the module shutdown device 1 may change, so the control module 13 inside the module shutdown device 1 may determine whether the photovoltaic module and the inverter are connected according to the output parameter of the module shutdown device 1, and if the photovoltaic module and the inverter are connected, it indicates that the main switch 11 of the module shutdown device 1 may be controlled to be closed, so that the photovoltaic module may normally output the dc power to the inverter.
Correspondingly, the flow for controlling the rapid turn-off of the photovoltaic system is as follows, firstly, the alternating current air switch 3 is switched off, the group string switches are switched off, the resistance switches are switched on, at the moment, the capacitor of the inverter discharges through the resistance to ensure that the voltage is reduced to the standard requirement within the required time after the component turn-off device 1 is turned off, and then the control system in the component turn-off device 1 controls the component turn-off device 1 to be turned off.
Specifically, after the ac air switch 3 and the string switch are disconnected, the output parameter of the module shutdown device 1 changes correspondingly, the control module 13 inside the module shutdown device 1 can determine whether the current photovoltaic module and the inverter are connected according to the output parameter, and if the current photovoltaic module and the inverter are not connected, the main switch 11 of the module shutdown device 1 is controlled to be disconnected, so that the voltage output of the photovoltaic module is switched off, and at this time, the photovoltaic string is changed from high voltage to low voltage.
The invention provides a control system of a photovoltaic module, which comprises a module breaker, a group string breaker and an alternating current idle switch, wherein the module breaker comprises a main switch; the detection module is used for detecting the output parameters of the component shutoff device; the control module is used for judging whether the photovoltaic module and the inverter are communicated or not according to the output parameters, if so, controlling the main switch to be conducted, and if not, controlling the main switch to be switched off; and the power supply module is used for supplying power to the control module and the detection module. Therefore, in practical application, by adopting the scheme of the invention, the control module in the component breaker controls the on or off of the component breaker according to the change of the output parameter of the component breaker detected by the detection module, so that the voltage output of the photovoltaic component is controlled, the reliability is high, the photovoltaic component does not depend on stable and reliable communication support, the application range is wide, and the stability of a photovoltaic system is improved.
On the basis of the above-described embodiment:
as a preferred embodiment, the output parameters include output voltage and output current;
accordingly, the detection module 12 comprises:
the voltage detection module is used for acquiring output voltage;
and the current detection module is used for acquiring the output current.
Specifically, the current detection module 12 may specifically obtain the output current of the component breaker 1 through a sampling resistor.
As a preferred embodiment, the control module 13 is specifically configured to:
when the output current meets the transient on condition, controlling the main switch 11 to be on transiently, and when the on time of the main switch 11 is longer than a first preset time, controlling the main switch 11 to be off;
judging whether the output parameter of the component breaker 1 when the main switch 11 is turned on momentarily is larger than or equal to a preset on-state value;
if yes, the photovoltaic module is judged to be communicated with the inverter, after the main switch 11 is turned off, the main switch 11 is controlled to be conducted, and until the output current of the module breaker 1 is smaller than a turn-off preset value, the photovoltaic module is judged to be not communicated with the inverter, and the main switch 11 is controlled to be turned off.
As a preferred embodiment, the process of controlling the main switch 11 to be turned on briefly includes:
the main switch 11 is controlled to be briefly turned on by sending a positive pulse signal.
As a preferred embodiment, the process of determining whether the output parameter of the component shutdown device 1 when the main switch 11 is turned on briefly is greater than or equal to the preset on-state value specifically includes:
judging whether the output current of the component breaker 1 when the main switch 11 is turned on momentarily is greater than or equal to a first preset turn-on value;
or whether the output voltage of the pack shutdown 1 when the main switch 11 is turned on for a short time is greater than or equal to a second on preset value.
Specifically, after the ac air switch 3 is closed, the string control module in the string breaker 2 controls the resistance switch to be turned off and controls the string switch to be turned on. The control module 13 determines whether the output current of the device shutdown device 1 meets the transient conduction condition, if so, the control module 13 inside the device shutdown device 1 generates a short positive pulse signal (millisecond level) to briefly conduct the main switch 11, the first preset time can be set to 15ms, that is, the conduction time of the main switch 11 exceeds 15ms, the control module 13 controls the main switch 11 to be turned off, the detection module 12 detects the output current and the output voltage of the device controller 1 within 15ms, if the output current is greater than or equal to the first conduction preset value or the output voltage is greater than or equal to the second conduction preset value, it indicates that the connection between the photovoltaic device and the inverter is conducted, at this time, the main switch 11 is controlled to be closed, so that the photovoltaic string is raised from low voltage to high voltage, the inverter is started, the photovoltaic system enters a normal working state, if the output current is less than the first conduction preset value or the output voltage is less than the second conduction output voltage, the main switch 11 is again controlled to be briefly turned on and the above-described steps are performed. After the photovoltaic system normally works, the control module 13 obtains the output parameter of the module shutdown device 1 detected by the detection module 12 every second preset time to judge the connection state of the photovoltaic module and the inverter, and controls the main switch 11 to be switched off to realize the fast shutdown of the photovoltaic system when judging that the photovoltaic module and the inverter are not connected, that is, the output parameter is smaller than a shutdown preset value, wherein the second preset time can be set to 5 s.
Specifically, the process of detecting the output current includes a positive direction and a negative direction, the current in the normal working mode is positive, the current in the reverse flow mode is negative, and the process of determining whether the output current of the component breaker 1 meets the transient conduction condition by the control module 13 specifically includes:
when the output current is positive and is greater than or equal to a threshold value Ith2, entering a normal working mode; if the output current is negative and is less than a threshold value-Ith 4, entering a reverse flow mode; the control module 13 controls the main switch 11 to be closed in both the normal working mode and the reverse flow mode, if the absolute value of the output current is smaller than the threshold Ith3 at the moment, the detection and judgment of the fast turn-off mode are carried out, after the condition of the fast turn-off mode is met, the main switch 11 is controlled to be turned off, and at the moment, the output current is judged to meet the transient conduction condition.
Accordingly, the component shutdown device 1 may further continuously detect the output current, and after the absolute value of the output current is smaller than the threshold Ith3, if an overcurrent sudden change and a continuous small current occur, the fast shutdown mode is entered, and if no overcurrent sudden change and a continuous small current occur, the control module 13 may send a negative pulse signal (in milliseconds) to briefly shut down the main switch 11, detect the variation of the output voltage, and if the variation is larger than the first preset value, the fast shutdown mode may be triggered.
As a preferred embodiment, when the output current of the module shutdown device 1 is smaller than the shutdown preset value, it is determined that the photovoltaic module and the inverter are not connected, and the process of controlling the shutdown of the main switch 11 specifically includes:
acquiring the output current of the component shutoff device 1 every second preset time;
when the duration that the output current of the module shutdown device 1 is smaller than the shutdown preset value is longer than the third preset time, it is determined that the photovoltaic module and the inverter are not communicated, and the main switch 11 is controlled to be turned off.
Specifically, considering that the influence of environmental factors may cause the output current to be smaller than the turn-off preset value in a short time, if the output current is smaller than the turn-off preset value, the fast turn-off is executed, and the working efficiency of the photovoltaic system may be reduced.
As a preferred embodiment, the control module 13 is further configured to:
when the closing time of the main switch 11 reaches the fourth preset time, controlling the main switch 11 to be turned off temporarily;
acquiring the output voltage variation of the component breaker 1 after the main switch 11 is turned off for a short time;
judging whether the output voltage variation is smaller than or equal to a first preset value;
if yes, the photovoltaic module is judged to be communicated with the inverter, and the main switch 11 is controlled to be closed;
if not, judging that the photovoltaic module is not communicated with the inverter, and controlling the main switch 11 to be switched off;
and the fourth preset time is less than the second preset time.
As a preferred embodiment, the process of controlling the main switch 11 to turn off briefly is specifically as follows:
the main switch 11 is controlled to be turned off briefly by sending a negative pulse signal.
Specifically, considering that after the main switch 11 is closed, the control module 13 intermittently (e.g. every 5s) determines whether the output current is smaller than the preset turn-off value, if, in the morning or in low light situations, the output current is affected, and correspondingly decreases, then after the main switch 11 is closed, a situation may arise in which the photovoltaic system is quickly switched off after 5s, the operating efficiency of the photovoltaic system is reduced to some extent, and it is considered that the present invention detects the connection state of the photovoltaic module and the inverter by the variation amount of the output voltage before 5s, if the two are connected, the main switch 11 is controlled to be conductive, after which the inverter is started, then, the control module 13 determines whether the current output current is greater than a second preset value, and if so, enters a normal working state.
Specifically, after the main switch 11 is closed and a period of time is waited, for example, 4s seconds (less than a second preset time), the internal switch controller of the component breaker 1 generates a very short negative pulse signal (millisecond level) to turn off the main switch 11 for a short time, the short off time may be set to 60ms, the control module 13 determines whether the output voltage variation of the component breaker within 60ms is less than or equal to a first preset value, if so, the main switch 11 is controlled to be turned on, then the inverter is started, the control module 13 determines whether the current output current is greater than a second preset value, and if so, the control module enters a normal operating state. If the voltage is less than the second preset value, the negative pulse signal is sent again to turn off the main switch 11, and then the step of starting the positive pulse signal to control the main switch 11 to be turned on briefly is restarted.
Of course, the main switch 11, the string switch, and the resistor switch in the present invention may be switches such as a relay, a MOS transistor, or an IGBT, and the present invention is not limited herein.
Referring to fig. 3, fig. 3 is a flowchart illustrating steps of a control method for a photovoltaic module according to the present invention, applied to a control module according to any one of the above embodiments, including:
step 1: acquiring an output parameter of the component breaker;
step 2: and judging whether the photovoltaic module and the inverter are communicated or not according to the output parameters, if so, controlling the main switch to be switched on, and if not, controlling the main switch to be switched off.
Correspondingly, the invention also provides a photovoltaic system, which comprises the control system of the photovoltaic module as any one of the above, and an inverter.
The control method of the photovoltaic module and the photovoltaic system provided by the invention have the same beneficial effects as the control system of the photovoltaic module.
For the introduction of the control method of the photovoltaic module and the photovoltaic system provided by the present invention, please refer to the above embodiments, and the description of the present invention is omitted here.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.