CN111049410B - Control method of electric energy conversion device and electric energy conversion system - Google Patents
Control method of electric energy conversion device and electric energy conversion system Download PDFInfo
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- CN111049410B CN111049410B CN201911414733.9A CN201911414733A CN111049410B CN 111049410 B CN111049410 B CN 111049410B CN 201911414733 A CN201911414733 A CN 201911414733A CN 111049410 B CN111049410 B CN 111049410B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
- H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
- H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
Abstract
The application provides an electric energy system of changing, its characterized in that includes: the system comprises an inverter assembly, a transformer and a controller; the inverter assembly includes at least one inverter; the controller is used for acquiring the temperature of the transformer; the controller is further configured to control the power output by the inverter assembly to the transformer to be reduced when the temperature of the transformer is greater than or equal to a preset limit temperature. When the temperature of the transformer is too high, the power output to the transformer by the inverter assembly is reduced, and the running power of the transformer is reduced, so that the temperature of the transformer can be reduced.
Description
Technical Field
The application relates to the field of electric energy conversion, in particular to a control method of an electric energy conversion device and an electric energy conversion system.
Background
In a photovoltaic power station, a photovoltaic device generates Direct Current (DC) power, an inverter converts the DC power generated by a photovoltaic module into alternating current, and a transformer converts the output voltage (current) of the inverter into another voltage (current) with the same frequency or different values.
The service life of elements in the transformer is influenced by the overhigh operating temperature of the transformer. In addition, when a fault such as a short circuit occurs in the transformer, the temperature of the transformer rises. To avoid component burnout in the circuit that may result from a fault such as a short circuit and to improve the life of the transformer, a trip temperature may be set at the transformer. When the temperature of the transformer exceeds the trip temperature, the transformer trips and stops running.
When the ambient temperature is high, the heat dissipation of the transformer is slow, which easily causes the over-high temperature of the transformer and influences the normal operation of the transformer.
Disclosure of Invention
The application provides a method and an electronic device, which can avoid the over-high temperature of a transformer and enable the transformer to normally operate.
In a first aspect, an electric energy charging and discharging system is provided, which includes: the system comprises an inverter assembly, a transformer and a controller; the inverter assembly includes at least one inverter; the controller is used for acquiring the temperature of the transformer; the controller is further configured to control the power output by the inverter assembly to the transformer to be reduced when the temperature of the transformer is greater than or equal to a preset limit temperature.
When the temperature of the transformer is too high, the running power of the transformer is reduced by reducing the power output to the transformer by the inverter assembly, so that the temperature of the transformer can be reduced.
With reference to the first aspect, in some possible implementations, the controller is configured to control the output power of at least one target inverter of the at least one inverter to be reduced when the temperature of the transformer is greater than or equal to a preset limit temperature.
By reducing the output power of the inverter, components do not need to be added, the cost is low, and the problem of untimely response caused by the switch of the inverter is avoided.
With reference to the first aspect, in some possible implementations, the controller is further configured to send limitation indication information to each target inverter of at least one target inverter when the temperature of the transformer is greater than or equal to a preset limitation temperature, where the limitation indication information is used to instruct the target inverter to reduce the output power.
A controller is arranged in the electric energy conversion system to control the plurality of inverters, so that the cost is reduced.
With reference to the first aspect, in some possible implementations, the limitation indication information is used to indicate a limitation value of the output power of the target inverter.
With reference to the first aspect, in some possible implementations, the preset limit temperature is less than a trip temperature, and the trip temperature is a lowest temperature at which the transformer stops operating.
Before the temperature of the transformer reaches the tripping temperature, the power input into the transformer is reduced, so that the temperature of the transformer is reduced, and the tripping of the transformer is avoided.
With reference to the first aspect, in some possible implementation manners, the controller is further configured to stop reducing the power output to the transformer by the inverter component when the temperature of the transformer is less than a preset recovery temperature.
In a second aspect, a control method of an electric energy conversion apparatus is provided, the electric energy conversion apparatus includes an inverter assembly including at least one inverter, and a transformer; the method comprises the following steps: acquiring the temperature of the transformer; and when the temperature of the transformer is greater than or equal to a preset limit temperature, controlling the power output to the transformer by the inverter assembly to be reduced.
With reference to the second aspect, in some possible implementations, the electric energy conversion device includes at least one inverter, output power of the at least one inverter is equal to input power of the transformer, and the controlling of the power reduction output from the inverter component to the transformer includes: and controlling the output power of at least one target inverter in the at least one inverter to be reduced.
With reference to the second aspect, in some possible implementations, the controlling of the output power reduction of at least one target inverter of the at least one inverter includes: transmitting limitation indication information to each target inverter of the at least one target inverter, wherein the limitation indication information is used for indicating the target inverter to reduce the output power.
With reference to the second aspect, in some possible implementations, the limitation indication information is used to indicate a limitation value of the output power of the target inverter.
With reference to the second aspect, in some possible implementations, the preset limit temperature is less than a trip temperature, and the trip temperature is a lowest temperature at which the transformer stops operating.
With reference to the second aspect, in some possible implementations, the method further includes: and when the temperature of the transformer is lower than a preset recovery temperature, stopping reducing the power output to the transformer by the inverter assembly.
In a third aspect, a control device for an electric energy conversion device is provided, the control device comprising various functional modules for performing the method according to the second aspect.
In a fourth aspect, a control device for a power conversion device is provided, the power conversion device comprising a memory for storing a program and a processor for performing the method of the first aspect when the program is executed.
In a fifth aspect, a computer program storage medium is provided having program instructions which, when run on an electronic device, cause the electronic device to perform the method of the second aspect.
In a sixth aspect, a chip system is provided, the chip system comprising at least one processor, which when executed by program instructions causes the chip system to perform the method of the second aspect.
Drawings
Fig. 1 is a schematic structural view of a photovoltaic power plant.
Fig. 2 is a schematic flowchart of a control method of an electric energy conversion device according to an embodiment of the present application.
Fig. 3 is a schematic flowchart of a control method of an electric energy conversion device according to an embodiment of the present application.
Fig. 4 is a schematic configuration diagram of an inverter.
Fig. 5 is a schematic structural diagram of an electric energy conversion device provided in an embodiment of the present application.
Fig. 6 is a schematic structural diagram of an electric energy conversion device provided in an embodiment of the present application.
Fig. 7 is a schematic structural diagram of an electric energy conversion system according to an embodiment of the present application.
Detailed Description
The technical solution in the present application will be described below with reference to the accompanying drawings.
Fig. 1 is a schematic structural view of a photovoltaic power plant.
In a photovoltaic power plant, an electric energy conversion device converts Direct Current (DC) electricity generated by a photovoltaic module to obtain Alternating Current (AC) electricity meeting requirements.
The photovoltaic module may comprise a plurality of photovoltaic panels for converting light energy into electrical energy.
The power conversion apparatus includes a plurality of inverters and transformers. Each inverter is used for AC-DC conversion to obtain alternating current. The transformer can adjust the voltage value of the alternating voltage.
On the one hand, when the transformer is operated at a high temperature for a long time, the life of the components inside the transformer will be affected. On the other hand, the transformer may be at risk of a short circuit, which would cause the temperature of the transformer to rise rapidly. The transformer can detect the temperature of the transformer. And when the temperature exceeds the preset safety temperature, tripping the transformer and stopping running. This preset safe temperature may also be referred to as a trip temperature.
At normal temperature, when the input power of the transformer is less than or equal to the rated power of the transformer, the transformer can work normally.
Under the low temperature environment, because the heat dissipation is very fast, the input power that can bear when transformer normal operating is higher. In a high-temperature environment, the input power which can be borne by the transformer during normal operation is low due to slow heat dissipation. In practical applications, the ambient temperature of the transformer may have a large difference.
In order to increase the efficiency of the transformer, the rated output power of the transformer in the photovoltaic power plant is usually less than the sum of the maximum output powers of the inverters connected to the inverter. When the sum of the output power of the plurality of inverters is greater than the rated power of the transformer, the inverter is called over-run. In this case, the output power of the plurality of inverters, that is, the input power of the transformer is large, and the transformer heat generation power is high. When the temperature of the environment is high, the heat dissipation of the transformer is slow, and the over-temperature tripping of the transformer is easily caused by the over-current running of the inverter.
The number of inverters connected per transformer can be reduced. The rated power of the transformer can also be increased under the condition that the number of the inverters connected with each transformer is not changed, so that the rated power of the transformer is larger than or equal to the maximum output power of the inverters. Increasing the rated power of the transformers or increasing the number of transformers can make the operation reliable, the power generation of the photovoltaic power station is high, but the initial investment cost of the photovoltaic power station is increased.
The transformer cannot control the operating power. The transformer generally has a structure in which a primary coil and a secondary coil are wound around an iron core. An input ac voltage is applied across the primary coil, and due to electromagnetic induction effects, an induced voltage is generated in the secondary coil, which forms the output of the transformer. The ratio of the number of turns of the primary coil to the number of turns of the secondary coil is equal to the ratio of the input voltage to the output voltage. The current flowing through the coil causes losses that cause the transformer to generate heat.
When the power input into the transformer is high, the temperature of the transformer rises, and the normal operation of the transformer is influenced. Under the condition that the transformer is provided with the tripping temperature, the phenomenon of over-temperature tripping can occur, and the transformer does not have faults such as short circuit and the like, so that the total power generation amount of the photovoltaic power station is seriously influenced.
In order to solve the problem of overhigh temperature of a transformer caused by high power of an input transformer, the embodiment of the application provides a control method of an electric energy conversion device.
Fig. 2 is a schematic flowchart of a control method of an electric energy conversion device according to an embodiment of the present application. The power conversion device includes a transformer and an inverter assembly.
The inverter assembly includes at least one inverter. Each inverter may be used to convert a direct current voltage to an alternating current voltage.
The inverter assembly may further include at least one DC-DC converter. The DC-DC converter is used to convert a direct voltage. The DC-DC converter may be of a boost (boost) type or a buck (buck) type. The output end of the DC-DC converter is connected to an inverter, and the inverter can convert the direct current output from the DC-DC converter into alternating current.
The transformer may be used to convert an output voltage of the at least one inverter. The output end of each inverter is connected with the input end of the transformer.
In step S201, the temperature of the transformer is acquired.
The transformer may be an oil-immersed transformer or a dry-type transformer, etc. The temperature of the oil filled transformer may be the oil level temperature or the temperature of other parts. The temperature of the dry-type transformer may be the temperature of a certain power element or elements generating more heat or the temperature around the elements.
In step S202, when the temperature of the transformer reaches a preset limit temperature, the power output from the inverter assembly to the transformer is controlled to be reduced.
By reducing the power output by the inverter assembly to the transformer, the power input to the transformer is reduced, thereby reducing the operating power of the transformer.
The transformer may set the trip temperature. When the temperature of the transformer reaches the tripping temperature, the transformer trips and stops running. That is, the trip temperature is the highest temperature at which the transformer normally operates. When the transformer is set with the trip temperature, the preset limit temperature may be less than the trip temperature. Before the temperature of the transformer reaches the tripping temperature, the power input into the transformer is reduced, so that the temperature of the transformer is reduced, and the tripping of the transformer is avoided.
There are various ways to control the power output from the inverter assembly to the transformer to be reduced, i.e., the power input to the transformer to be reduced.
The number of inverters that can control the transformer connection is reduced. Control switches can be connected between the transformer and all or part of the inverters in the at least one inverter and are controlled to be disconnected, so that the number of the inverters connected with the transformer is reduced, and the power output to the transformer by the inverter assembly can be reduced. That is, the input power to the transformer may be less than or equal to the sum of the output power of each inverter in the inverter assembly. And the inverter disconnected from the transformer is the target inverter. The power input to the transformer is reduced by disconnecting the target inverter from the transformer, and a control switch needs to be added between the transformer and the target inverter, thereby increasing the cost.
Or may control portions of the inverter to shut down. And part of the inverters are shut down, so that the input power of the transformer is reduced. It takes a certain time for the inverter to operate normally from the shutdown state. Therefore, the power of the input transformer is reduced by controlling the shutdown of part of the inverter, and the inverter cannot sound in time when the inverter needs to recover to work normally.
Some of the at least one inverter may also be controlled to disconnect from the input power source. For example, the input power of the inverter may be provided by the photovoltaic module. Some of the at least one inverter may be disconnected from the photovoltaic module. Similarly, disconnecting a part of the inverter from the input power source of the inverter requires a control switch to be added between the inverter and the input power source of the inverter, which increases the circuit cost.
The output power reduction of at least one target inverter of the at least one inverter to which the transformer is connected may also be controlled. The at least one target inverter is all or part of the at least one inverter. By reducing the output power of the at least one target inverter, the power output by the inverter assembly to the transformer, i.e. the power input to the transformer, may be reduced, thereby reducing the operating power of the transformer. The input power to the transformer is equal to the sum of the output power of each inverter in the inverter assembly. It should be understood that equal may also be understood as approximately equal. By means of the mode of reducing the output power of the target inverter, components do not need to be added, cost is low, and the response speed of the inverter is improved.
Steps S201 to S202 may be performed by all or part of the in-inverter control unit. Each target inverter in the at least one target inverter is the inverter where the control unit is located. A temperature sensor or the like in the transformer can detect the temperature of the transformer. The transformer may send temperature information to the at least one target inverter, the temperature information indicating a temperature of the transformer. And receiving the temperature of the transformer, namely acquiring the temperature of the transformer. And the control unit in each target inverter judges the temperature of the transformer and the preset limit temperature. When the temperature of the transformer is greater than or equal to the preset limit temperature, the control unit controls the target inverter to reduce the output power. The manner in which the inverter reduces the output power can be seen in the description of fig. 4.
Steps S201 to S202 may also be executed by a system-level control unit such as a monitor in the power conversion apparatus or a control unit corresponding to the transformer.
The power conversion device may include a plurality of transformers. The transformers may correspond one-to-one to the control units. A temperature sensor or the like in the transformer can detect the temperature of the transformer. When the temperature of the transformer is greater than or equal to the preset limit temperature, the control unit corresponding to the transformer may send limit indication information to the at least one target inverter, where the limit indication information is used to instruct the at least one target inverter to reduce the output power. The limitation indication information may also be referred to as the power limitation scheduling instruction. And after each target inverter in the at least one target inverter receives the limitation indication information, reducing the output power.
The power conversion device may include a plurality of transformers. A system-level control unit such as a monitor may correspond to the plurality of transformers. The temperature of the transformer can be measured, and temperature information sent by the transformer can also be received, wherein the temperature information is used for indicating the temperature of the transformer. The system level control unit may determine a magnitude relationship between the temperature of the transformer and a preset limit temperature. And when the temperature of the transformer is greater than or equal to the preset limit temperature, sending limit indication information to at least one target inverter, wherein the limit indication information is used for indicating the target inverter to reduce the output power. And after each target inverter in the at least one target inverter receives the limitation indication information, reducing the output power.
The limit indication information may also be used to indicate a value of the output power of the target inverter. The limit indication information transmitted to each target inverter is used to indicate a limit value of the output power of the target inverter. Each target inverter may adjust the output power according to the value of the output power indicated by the limitation indication information. The values of the output powers indicated by the limitation indication information transmitted for each target inverter may be equal or different. It should be understood that equal may also be understood as approximately equal.
It should be understood that for a control unit or system level control unit corresponding to the transformer, the control unit may determine the target inverter from the at least one inverter. The control unit may also determine a value of the output power of each target inverter. The control unit may determine the input power limit value of the transformer according to one or more of a temperature change rate of the transformer, an ambient temperature, an input power of the transformer, and the like. The output power limit value of each target inverter may be determined according to the input power limit value of the transformer, the number of target inverters, the number of inverters other than the target inverter, and the output power or the maximum output power of the inverters other than the target inverter. The control unit corresponding to the transformer may store the maximum output power of each inverter.
After step S202, when the temperature of the transformer is less than a preset recovery temperature, the reduction of the power input to the transformer may be stopped.
And a control unit in the inverter receives the temperature information sent by the transformer and judges the size relation between the temperature of the transformer and the preset recovery temperature. When the temperature of the transformer is lower than the preset recovery temperature, the control unit in the inverter controls the inverter to stop reducing the output power.
When the temperature of the transformer is lower than the preset recovery temperature, the control unit or the system-level control unit corresponding to the transformer sends recovery indication information to each target inverter in the at least one target inverter, and the recovery indication information is used for indicating the target inverter to stop reducing the output power.
Through steps S201 to S202, the input power of the transformer is reduced, so as to reduce the operating power of the transformer, thereby reducing the temperature of the transformer, so that the transformer can operate normally.
Fig. 3 is a schematic flowchart of a control method of an electric energy conversion device according to an embodiment of the present application.
The electrical energy conversion device includes a transformer and at least one inverter. The inverter is used for carrying out DC-AC conversion, and the transformer is used for adjusting the output voltage of at least one inverter.
In step S301, the controller acquires the temperature of the transformer.
The transformer may be an oil-filled transformer. The transformer oil has low viscosity and good heat transfer performance, can well protect the iron core and the coil from the influence of moisture in the air, can protect the insulating paper and the insulating paper board from the action of oxygen, reduces the aging of insulating materials and prolongs the service life of the transformer.
In step S302, the controller determines a magnitude relationship between the temperature of the transformer and a preset limit temperature.
The preset limit temperature is a temperature value preset in the controller.
When the temperature of the transformer is less than the preset limit temperature, the step S301 is performed, and the controller acquires the temperature of the transformer again. Through steps S301 and S302, the controller can monitor the temperature of the transformer in real time.
When the temperature of the transformer is greater than or equal to the preset limit temperature, step S303 is performed.
In step S303, the controller transmits limitation indication information to each of the at least one inverter to which the transformer is connected. The limit indication information may be used to instruct the inverter to reduce the output power.
After receiving the limitation instruction information transmitted from the controller, the inverter performs step S321 to start derating operation.
The limit indication information may also be used to indicate an output power limit value of the inverter. The inverter limits the output power according to the limitation indication information, so that the output power of the inverter does not exceed the output power limit value of the inverter indicated by the limitation indication information.
Before step S303, the controller may calculate an output power limit value of each inverter. The input power limit value of the transformer is divided by the number of inverters to which the transformer is connected, i.e. the output power limit value of each inverter.
In some embodiments, when the temperature of the transformer is greater than the preset limit temperature, the controller determines the input power limit value of the transformer to be a fixed value, and the controller may determine the output power limit value of each inverter according to the number of inverters connected to the transformer.
In other embodiments, the controller may determine the output power limit value of each inverter according to a temperature rise rate of the transformer, or the like, when the temperature of the transformer is greater than a preset limit temperature. The controller may store a one-to-one correspondence between the temperature rise rate of the transformer and the input power limit value of the transformer, and determine the output power limit value of each inverter according to the number of inverters connected to the transformer.
In still other embodiments, the controller may step down the output power of each inverter to which the transformer is connected when the temperature of the transformer is greater than a preset limit temperature. In step S321, the inverter reduces the output power by a preset step size. After step S303, the controller may obtain the transformer temperature and determine a magnitude relationship between the transformer temperature and the preset limit temperature, and if the transformer temperature is greater than or equal to the preset limit temperature, further reduce the output power of the inverter. The controller sends the limitation indication information to the inverter again, and instructs the inverter to reduce the output power. The inverter performs step S321 to reduce the output power according to a preset step. And stopping further reducing the output power of the inverter until the output power of the inverter enables the temperature of the transformer to be less than the preset limit temperature.
After step S303, the controller continues to monitor the temperature of the transformer.
In step S304, the controller acquires the temperature of the transformer.
In step S305, the controller determines a magnitude relationship between the temperature of the transformer and a preset recovery temperature.
The preset recovery temperature is a temperature value preset in the controller.
When the temperature of the transformer is greater than or equal to the preset recovery temperature, the step S304 is performed, and the controller acquires the temperature of the transformer again.
When the temperature of the transformer is greater than or equal to the preset recovery temperature, the step S306 is performed.
In step S306, the controller transmits recovery indication information to each of the at least one inverter to which the transformer is connected. The recovery indication information may be used to instruct the inverter to stop the reduction of the output power.
After receiving the restoration instruction information transmitted from the controller, the inverter performs step S322 to end the derating operation and restore the normal operation.
It should be appreciated that the preset recovery temperature may be less than the preset limit temperature. That is, after the derated operation of the inverter, if the temperature of the transformer is lowered, the inverter may cancel the derated operation and resume the normal operation.
The preset limit temperature may be less than a trip temperature of the transformer. And when the temperature of the transformer reaches the preset limit temperature, reducing the input power of the transformer and preventing the temperature of the transformer from continuously rising to the trip temperature. The difference between the trip temperature and the preset limit temperature may be small, and when the temperature of the transformer approaches the trip temperature, the input power of the transformer is reduced.
The transformer cannot adjust the input power, and therefore, the output power of the previous stage circuit of the transformer, i.e., the input power of the transformer, may also be referred to as the operating power of the transformer. And at least one inverter connected with the transformer is a previous-stage circuit of the transformer. Under the condition of not changing the power of the input transformer and the number of the inverters connected with the transformer, the purpose of adjusting the running power of the inverters is achieved by adjusting the output power of the inverters.
The transformer and the at least one inverter may be applied in a photovoltaic power plant as shown in fig. 1. Total power of at least one inverter output
Fig. 4 is a schematic configuration diagram of the inverter.
The inverter assembly provided by the embodiment of the application can be equipment for converting direct current generated by a photovoltaic assembly in a solar photovoltaic power station. The inverter components may be in a string-type architecture, a centralized architecture, or a distributed architecture. The centralized architecture generally employs a DC-AC one-stage conversion circuit to convert the DC power. The group-string architecture and the distributed architecture generally adopt a DC-DC boost and DC-AC full-bridge inversion two-stage conversion circuit to convert the direct current. Fig. 4 illustrates a two-stage circuit of DC-DC boost and single-phase DC-AC inversion in a string architecture. It should be understood that the inverter assembly may also employ a multi-phase DC-AC inverter circuit to convert DC power to multi-phase AC power. For example, a three-phase DC-AC inverter circuit may be used to convert DC power to three-phase AC power.
In the inverter module, a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) device, an Insulated Gate Bipolar Transistor (IGBT), an Integrated Gate Commutated Thyristor (IGCT), or the like may be used as the switching tube.
The boost (boost) type DC-DC converter includes an inductor L1, a diode D1, a switching tube Q5, and an output capacitor C1. The first end of the inductor L1 is used for receiving the dc voltage Vdc, the second end of the inductor L1, the anode of the diode D1, and the first end of the switching tube Q5 are connected, the cathode of the diode D1 is connected to the first end of the output capacitor C1, and the second end of the output capacitor C1 is grounded to the second end of the switching tube Q5.
When the switch Q5 is turned on, the switch Q5 short-circuits the capacitor and the diode, and the power supply charges the inductor. When the switch tube Q5 is turned off, the inductor discharges and the inductor and the power supply jointly charge the capacitor.
The output power of the DC-DC converter can be changed by adjusting the duty ratio of the switching tube Q5. Reducing the on-time of the switching tube Q5 can reduce the output power of the DC-DC converter.
The DC-AC converter includes switching tubes Q1 through Q4. The first terminals of the switching tube Q1 and the switching tube Q3 are connected to the positive terminal of the input voltage, i.e., the first terminal of the output capacitor C1, and the first terminals of the switching tube Q2 and the switching tube Q4 are connected to the negative terminal of the input voltage, i.e., the second terminal of the output capacitor C1. The connection point of the second terminal of the switching tube Q1 and the second terminal of the switching tube Q2 is a node a, and the connection point of the second terminal of the switching tube Q3 and the second terminal of the switching tube Q4 is a node B, and the voltage Vac between the node a and the node B can be used as the output of the DC-AC converter.
The switch Q1 is turned on and off simultaneously with the switch Q4. The switch Q2 is turned on and off simultaneously with the switch Q3. When the switching tube Q1 and the switching tube Q4 are in a conducting state, the switching tube Q2 and the switching tube Q3 are in a cut-off state; when the switching tube Q2 and the switching tube Q3 are in a conducting state, the switching tube Q1 and the switching tube Q4 are in a non-conducting state.
The output power of the DC-AC converter can be changed by adjusting the duty ratio from the switching tube Q1 to the switching tube Q4. The output power of the DC-DC converter can be reduced by reducing the conducting time from the switching tube Q1 to the switching tube Q4.
Fig. 5 is a control device of an electric energy conversion device according to an embodiment of the present application.
The electric energy conversion device comprises an inverter assembly and a transformer, wherein the inverter assembly comprises at least one inverter.
The control device includes: an acquisition module 501 and a control module 502.
The obtaining module 501 is configured to obtain the temperature of the transformer.
The control module 502 is configured to control the power output from the inverter component to the transformer to be reduced when the temperature of the transformer is greater than or equal to a preset limit temperature.
Optionally, the control module 502 is configured to control the output power of at least one target inverter of the at least one inverter to be reduced when the temperature of the transformer is greater than or equal to a preset limit temperature.
Optionally, the control module 502 is configured to send limitation indication information to each target inverter of the at least one target inverter when the temperature of the transformer is greater than or equal to a preset limitation temperature, where the limitation indication information is used to instruct the target inverter to reduce the output power.
Optionally, the limitation indication information is used for indicating a limitation value of the output power of the target inverter.
Optionally, the preset limit temperature is less than a trip temperature, and the trip temperature is a maximum temperature at which the transformer normally operates.
Optionally, the control module 502 is further configured to stop reducing the power output by the inverter component to the transformer when the temperature of the transformer is less than a preset recovery temperature.
Fig. 6 is a control device of an electric energy conversion device according to an embodiment of the present application.
The electric energy conversion device comprises an inverter assembly and a transformer, wherein the inverter assembly comprises at least one inverter.
The control device includes: memory 601, processor 602. The memory 601 is used to store programs which, when executed, the processor 602 is used to: acquiring the temperature of the transformer; and when the temperature of the transformer is greater than or equal to a preset limit temperature, controlling the power output to the transformer by the inverter assembly to be reduced.
Optionally, the processor 602 is configured to control the output power of at least one target inverter of the at least one inverter to be decreased when the temperature of the transformer is greater than or equal to a preset limit temperature.
Optionally, the processor 602 is configured to send limitation indication information to each target inverter of the at least one target inverter when the temperature of the transformer is greater than or equal to a preset limitation temperature, where the limitation indication information is used to instruct the target inverter to reduce the output power.
Optionally, the limitation indication information is used for indicating a limitation value of the output power of the target inverter.
Optionally, the preset limit temperature is less than a trip temperature, and the trip temperature is a maximum temperature at which the transformer normally operates.
Optionally, the processor 602 is further configured to stop reducing the power output by the inverter assembly to the transformer when the temperature of the transformer is less than a preset recovery temperature.
Fig. 7 is a schematic structural diagram of an electric energy conversion system according to an embodiment of the present application. The power charging system 700 includes: an inverter assembly 701, a transformer 702, a controller 703.
The inverter assembly 701 comprises at least one inverter, the output of each of which is connected to the input of a transformer 702;
the controller 703 is configured to obtain a temperature of the transformer 702;
the controller 703 is further configured to control the power output from the inverter component 701 to the transformer 702 to be reduced when the temperature of the transformer 702 is greater than or equal to a preset limit temperature.
It should be understood that the controller may be a control unit in the apparatus in which the inverter or the transformer is located. The controller may also be located in other devices.
Optionally, the controller 703 is configured to control the output power of at least one target inverter of the at least one inverter to be reduced when the temperature of the transformer 702 is greater than or equal to a preset limit temperature.
Optionally, the controller 703 is further configured to send limitation indication information to each target inverter of the at least one target inverter when the temperature of the transformer 702 is greater than or equal to a preset limitation temperature, where the limitation indication information is used to instruct the target inverter to reduce the output power.
Optionally, the limitation indication information is used for indicating a limitation value of the output power of the target inverter.
Optionally, the preset limit temperature is less than a trip temperature, which is the maximum temperature at which the transformer 702 operates normally.
Optionally, the controller 703 is further configured to stop reducing the power output by the inverter component 701 to the transformer 702 when the temperature of the transformer 702 is less than a preset recovery temperature.
An embodiment of the present application further provides a control device for an electric energy conversion device, including: a memory for storing a program and a processor, the program, when executed in the at least one processor, causing the control apparatus to perform the method hereinbefore.
Embodiments of the present application further provide a computer program storage medium, which is characterized by having program instructions, when the program instructions are directly or indirectly executed, the method in the foregoing is implemented.
An embodiment of the present application further provides a chip system, where the chip system includes at least one processor, and when a program instruction is executed in the at least one processor, the method in the foregoing is implemented.
Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.
It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
In the description of the embodiments of the present application, "/" means "or" unless otherwise specified, for example, a/B may mean a or B; "and/or" herein is merely an association relationship describing an associated object, and means that there may be three relationships, for example, a and/or B, and may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of the present application, "a plurality" means two or more than two unless otherwise specified.
The terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.
In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.
The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application or portions thereof that substantially contribute to the prior art may be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the methods described in the embodiments of the present application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a read-only memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.
The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.
Claims (14)
1. An electrical energy charging system, comprising: the inverter assembly comprises a plurality of inverters, the inverters are used for converting direct current into alternating current, the output end of each inverter in the inverters is connected to the input end of the transformer, and the transformer is used for adjusting the voltage of the alternating current;
the controller is connected to the transformer and used for acquiring the temperature of the transformer;
the controller is further connected to the inverter assembly and is used for controlling the power output from at least one target inverter in the plurality of inverters to be reduced to the transformer when the temperature of the transformer is greater than or equal to a preset limit temperature.
2. The system of claim 1, wherein the controller is further configured to send limitation indication information to each target inverter of the at least one target inverter when the temperature of the transformer is greater than or equal to a preset limitation temperature, the limitation indication information being configured to instruct the target inverter to reduce the output power.
3. The system according to claim 2, wherein the limit indication information indicates a limit value of the output power of the target inverter.
4. The system according to any of claims 1-3, wherein the preset limit temperature is less than a trip temperature, the trip temperature being a maximum temperature at which the transformer operates normally.
5. The system of any one of claims 1-3, wherein the controller is further configured to stop reducing the power output by the inverter assembly to the transformer when the temperature of the transformer is less than a preset recovery temperature.
6. A control method of an electric energy conversion apparatus, characterized in that the electric energy conversion apparatus includes an inverter assembly, a transformer, and a controller, the inverter assembly includes a plurality of inverters for converting direct current into alternating current, an output terminal of each of the plurality of inverters is connected to an input terminal of the transformer, the transformer is used for adjusting a voltage of the alternating current, the controller is connected to the transformer, and the controller is also connected to the inverter assembly;
the method is performed by the controller and comprises:
acquiring the temperature of the transformer;
and when the temperature of the transformer is greater than or equal to a preset limit temperature, controlling the power output from at least one target inverter in the plurality of inverters to the transformer to be reduced.
7. The method of claim 6, wherein the controlling the power reduction of the output of the at least one target inverter of the plurality of inverters to the transformer comprises:
transmitting limitation indication information to each target inverter of the at least one target inverter, wherein the limitation indication information is used for indicating the target inverter to reduce the output power.
8. The method according to claim 7, wherein the limitation indication information is used to indicate a limitation value of the output power of the target inverter.
9. The method according to any of claims 6-8, wherein the preset limit temperature is less than a trip temperature, the trip temperature being a maximum temperature at which the transformer operates normally.
10. The method according to any one of claims 6-8, further comprising:
and when the temperature of the transformer is less than a preset recovery temperature, stopping reducing the power output by the inverter assembly to the transformer.
11. A control device of an electric energy conversion device, characterized by comprising respective functional modules for performing the method according to any one of claims 6 to 10.
12. A control apparatus for an electric energy conversion apparatus, comprising a memory for storing a program and a processor for performing the method of any one of claims 6 to 10 when the program is executed.
13. A computer storage medium having computer instructions which, when run on an electronic device, cause the electronic device to perform the method of any one of claims 6-10.
14. A chip system, characterized in that the chip system comprises at least one processor, which when program instructions are executed in the at least one processor causes the chip system to carry out the method according to any one of claims 6 to 10.
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