CN216436818U - Quick power limiting control system for photovoltaic grid-connected system - Google Patents

Quick power limiting control system for photovoltaic grid-connected system Download PDF

Info

Publication number
CN216436818U
CN216436818U CN202121805570.XU CN202121805570U CN216436818U CN 216436818 U CN216436818 U CN 216436818U CN 202121805570 U CN202121805570 U CN 202121805570U CN 216436818 U CN216436818 U CN 216436818U
Authority
CN
China
Prior art keywords
voltage
current
output
inverter
control unit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202121805570.XU
Other languages
Chinese (zh)
Inventor
冯夏云
陈星和
颜华俊
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
AFORE NEW ENERGY TECHNOLOGY (SHANGHAI) CO LTD
Original Assignee
AFORE NEW ENERGY TECHNOLOGY (SHANGHAI) CO LTD
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by AFORE NEW ENERGY TECHNOLOGY (SHANGHAI) CO LTD filed Critical AFORE NEW ENERGY TECHNOLOGY (SHANGHAI) CO LTD
Priority to CN202121805570.XU priority Critical patent/CN216436818U/en
Application granted granted Critical
Publication of CN216436818U publication Critical patent/CN216436818U/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Landscapes

  • Inverter Devices (AREA)
  • Control Of Electrical Variables (AREA)

Abstract

A rapid power limiting control system for a photovoltaic grid-connected system relates to the technical field of photovoltaic power generation grid-connected control. The photovoltaic grid-connected inverter comprises a two-stage inverter, a voltage and current sensor, a central control unit and a photovoltaic module, wherein the input end of the two-stage inverter is connected with the output end of the photovoltaic module, the output end of the two-stage inverter is three-phase alternating current or is merged into a power grid, the output end of the voltage and current sensor is connected with the input end of the central control unit, and the two-stage inverter is connected with the input end of the voltage and current sensor and the output end of the central control unit. The utility model has the advantages that: the power limiting control is carried out through a photovoltaic PV end power ring, and the dynamic response characteristic is good.

Description

Quick power limiting control system for photovoltaic grid-connected system
Technical Field
The utility model relates to the technical field of photovoltaic power generation grid-connected control, in particular to a rapid power limiting control system for a photovoltaic grid-connected system.
Background
Energy is an important material basis for national economic development and improvement of the living standard of people, energy shortage and environmental pollution in the world become two important factors restricting the sustainable development of the human society, and the rapid development of new alternative energy becomes urgent; the research and experimental results of solar power generation show that the solar power generation has the advantages which are not possessed by other conventional energy sources, such as sufficient cleanness, absolute safety, relative universality and sufficiency of resources, long service life, maintenance-free property and the like, and shows no wider development space and application prospect. Photovoltaic grid-connected power generation also receives increasing attention as one of the main forms of solar power generation.
The electric energy output of the photovoltaic system has nonlinear characteristics and is related to the external temperature, the illumination condition and the power load; in order to obtain more electric energy under the dynamic environment condition, the Maximum Power Point Tracking (MPPT) technology is applied to the photovoltaic Power generation system, so that the energy conversion efficiency of the photovoltaic Power generation system can be greatly improved. However, under the influence or requirement of many factors such as power grid dispatching requirement, power factor limitation, power limitation, voltage overrun and the like: photovoltaic systems do not always operate at the maximum power point. Seemingly, these limiting factors affect the return on investment, and are, in fact, the necessary means to ensure that the grid is stable, or that the load requirements are met, and that even occasionally the system is guaranteed to operate properly by limiting power. The traditional power limiting control method is used for reducing the output power of an inverter by disturbing the reference voltage at the PV end of a photovoltaic module to enable a PV power point to be far away from the PV maximum power. However, the method has a slow control speed and poor dynamic response. At present, a method and a system for controlling the fast power limit with consideration of the control speed and the dynamic response are not available in the technical field.
SUMMERY OF THE UTILITY MODEL
The utility model aims to provide a rapid power limiting control system for a photovoltaic grid-connected system aiming at the defects and shortcomings in the prior art, the system carries out power limiting control through a photovoltaic PV end power ring, and has good dynamic response characteristics.
In order to achieve the purpose, the utility model adopts the following technical scheme: the utility model provides a quick limit power control system to photovoltaic grid-connected system, it includes two-stage inverter 1, voltage current sensor 2, central control unit 3, photovoltaic module 4, two-stage inverter 1's input is connected with photovoltaic module 4's output, and two-stage inverter 1's output is three-phase alternating current or merges into the electric wire netting, central control unit 3's input is connected to voltage current sensor 2's output, and two-stage inverter 1 connects its voltage current sensor 2's input and central control unit 3's output.
Preferably, the two-stage inverter 1 includes a DC/DC converter 11, a DC/AC inverter 12, and a voltage stabilizing capacitor 13, the DC/DC converter 11, the DC/AC inverter 12, and the voltage stabilizing capacitor 13 are sequentially connected in parallel, an input end of the DC/DC converter 11 is connected in parallel to an output end of the photovoltaic module 4, and the DC/AC inverter 12 outputs three-phase power.
Preferably, the voltage and current sensor 2 comprises a voltage probe 21, a current probe 22 and a signal level conversion circuit 23, wherein the voltage probe 21 and the current probe 22 are connected in series with the signal level conversion circuit 23.
Preferably, the central control unit 3 includes a signal receiving subunit 31, a control decision subunit 32, and a decision output subunit 33, where the signal receiving subunit 31, the control decision subunit 32, and the decision output subunit 33 are connected in series.
More optimally, the input end of the voltage and current sensor 2 is a voltage probe and a current probe in the two-stage inverter 1 circuit, the output end of the voltage and current sensor 2 is a central control unit 3 unit, and the voltage and current sensor 2 is responsible for providing key voltage and current signals in the two-stage inverter 1 for the central control unit 3 in real time.
More optimally, the input end of the central control unit 3 is connected to the output end of the voltage and current sensor 2, the output end of the central control unit 3 is connected to the driving circuit of the two-stage inverter 1, and the central control unit 3 realizes the rapid power-limiting control inversion function of the two-stage inverter 1 according to the voltage and current signals fed back by the voltage and current sensor 2.
The working principle of the utility model is as follows: the input end of a two-stage inverter 1 is the output end of a photovoltaic component 4, the output end of the two-stage inverter 1 is three-phase alternating current or is merged into a power grid, the two-stage inverter 1 converts electric energy generated by the photovoltaic component 4 into stable and reliable three-phase electricity, so that a photovoltaic system meets the requirements of power supply and grid connection, the input end of a voltage and current sensor 2 is a voltage and current probe in a circuit of the two-stage inverter 1, the output end of the voltage and current sensor 2 is a central control unit 3 unit, the voltage and current sensor 2 is responsible for providing key voltage and current signals in the two-stage inverter 1 for the central control unit 3 in real time, the input end of the central control unit 3 is connected with the output end of the voltage and current sensor 2, the output end of the central control unit 3 is connected with a driving circuit of the two-stage inverter 1, and the central control unit 3 feeds back voltage, current and voltage signals according to the voltage and current sensors 2, The current signal realizes the fast power-limiting control inversion function of the two-stage inverter 1, the DC/DC converter 11, the DC/AC inverter 12 and the voltage-stabilizing capacitor 13 are sequentially connected in parallel, the input end of the DC/DC converter 11 is connected in parallel with the output end of the photovoltaic component 4, the DC/AC inverter 12 outputs three-phase power to realize grid connection or supply power for a load, the input end of the DC/DC converter, the input end and the output end of the DC/AC inverter 12 are sampled by the voltage probe 21 and the current probe 22 to obtain the output voltage V of the photovoltaic component 4PVOutput current IPVDc bus voltage VbusInverting output voltage VgOutputting electrical signals such as current I and the like; the signal grade conversion circuit performs voltage grade conversion on the electric signal obtained by initial sampling, the converted electric signal is more suitable for the central control unit 3 to process, and the signal receiving subunit 31 receives the analog signal transmitted by the signal grade conversion circuit and performs analog-to-digital conversion; the control decision subunit 32 processes and judges the digital signal obtained by the signal receiving subunit 31 to obtain a control decision of the two-stage inverter 1, that is, a driving signal of the power switching device; the decision output subunit 33 outputs a decision signal for controlling the decision subunit 32 to the two-stage inverter 1, and performs fast power limit control through a PV end power loop in a power limit required condition, wherein the specific implementation steps of the power loop include: (1) sampling inversion output powerPressure VgOutputting current I; (2) obtaining power P through an active calculation link; (3) comparing the power P with a limit power PrefObtaining a reference value I of the output current of the power ring at the photovoltaic PV end through an active control link by taking a smaller valuePV_ref2The voltage and current double closed-loop control implementation steps of the DC/DC converter 11 of the DC conversion circuit include: (1) MPPT algorithm for obtaining photovoltaic PV end output voltage reference value VPV_ref(ii) a (2) Photovoltaic PV terminal output voltage reference value VPV_refAnd the actual output voltage value VPVObtaining a photovoltaic PV end voltage ring output current reference value I through a PV voltage control linkPV_ref1(ii) a (3) Comparing the output current reference value I of the PV end voltage ringPV_ref1And PV power loop output current reference value IPV_ref2Obtaining the output current reference value I of the PV end through a current selection linkPV_ref＝min{IPV_ref1,IPV_ref2}; 4PV end output current reference value IPV_refAnd the actual output current value IPVThe DC/DC circuit driving signal is obtained through the current control link, and the DC/DC circuit link outputs the DC bus voltage Vbus，IPVThe sampling can be obtained, and the voltage and current double closed-loop control implementation steps of the inverter circuit DC/AC inverter 12 comprise: (1) DC bus voltage reference value Vbus_refAnd the actual value V of the DC bus voltagebusObtaining an inversion output current reference value I through a voltage control linkref(ii) a (2) Reference value of inverter output current IrefAnd the actual value I of the inversion output current obtains a DC/AC circuit driving signal through a current control link; (3) the driving signal controls the output current I of the DC/AC inversion link, wherein the DC/DC converter 11 of the primary DC conversion circuit of the two-stage inverter 1 adopts voltage and current double closed-loop control and respectively outputs voltage V to the PV photovoltaic modulePVVoltage ring and photovoltaic module output current IPVA ring; the other stage of inverter circuit DC/AC inverter 12 completes AC/DC conversion, converts PV DC energy into grid-connected AC energy, and adopts voltage and current double closed-loop control to respectively obtain DC bus voltage VbusThe voltage loop and the inversion output current I current loop are adopted, the DC/DC converter 11 performs conversion of the output voltage grade of the photovoltaic module, and Maximum Power Point Tracking (MPPT) and Maximum Power Point Tracking (Maximum Power Point Tracking) control are metGenerally, a Boost circuit is adopted, and a Buck-Boost circuit, a Cuk circuit, a double-tube Buck-Boost circuit and the like can also be adopted.
After the technical scheme is adopted, the utility model has the beneficial effects that: compared with a single two-stage inverter structure, the two-stage inverter structure can realize the independent control of the maximum power point tracking and the power limiting of the photovoltaic device and the grid-connected work of the inverter, avoid the influence of the grid-connected work of the inverter on the output power of the photovoltaic device, adopt a photovoltaic PV end power ring to carry out the power limiting control and have good dynamic response characteristic; under the working condition that power limitation is needed, power limitation control is realized, and under other working conditions, Maximum Power Point Tracking (MPPT) control is realized; the system gives consideration to stability and economic benefit, and the DC/DC circuit and the DC/AC circuit respectively carry out double closed-loop control on voltage and current, so that the system has good dynamic and steady-state voltage and current characteristics.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a block diagram of a fast power limit control system according to the present invention.
Fig. 2 is a schematic structural diagram of the voltage-current sensor 2 according to the present invention.
Fig. 3 is a schematic structural diagram of the central control unit 3 according to the present invention.
Fig. 4 is a schematic diagram of the power ring assembly of the photovoltaic module 4PV end of the present invention.
Fig. 5 is a schematic diagram of the voltage-current double closed loop of the DC/DC converter 11 according to the present invention.
Fig. 6 is a schematic diagram of the voltage-current double closed loop composition of the DC/AC inverter 12 of the present invention.
Description of reference numerals: the photovoltaic module comprises a two-stage inverter 1, a voltage and current sensor 2, a central control unit 3, a photovoltaic module 4, a DC/DC converter 11, a DC/AC inverter 12, a voltage stabilizing capacitor 13, a voltage probe 21, a current probe 22, a signal level conversion circuit 23, a signal receiving subunit 31, a control decision subunit 32 and a decision output subunit 33.
Detailed Description
Referring to fig. 1 to fig. 3, the technical solution adopted by the present embodiment is: it includes two-stage inverter 1, voltage current sensor 2, central control unit 3, photovoltaic module 4, two-stage inverter 1's input is connected with photovoltaic module 4's output, and two-stage inverter 1's output is three-phase alternating current or merges the electric wire netting into, central control unit 3's input is connected to voltage current sensor 2's output, and two-stage inverter 1 connects its voltage current sensor 2's input and central control unit 3's output.
The two-stage inverter 1 comprises a DC/DC converter 11, a DC/AC inverter 12 and a voltage-stabilizing capacitor 13, the DC/DC converter 11, the DC/AC inverter 12 and the voltage-stabilizing capacitor 13 are sequentially connected in parallel, the input end of the DC/DC converter 11 is connected in parallel with the output end of the photovoltaic module 4, the DC/AC inverter 12 outputs three-phase power, the voltage and current sensor 2 comprises a voltage probe 21, a current probe 22 and a signal level conversion circuit 23, the voltage probe 21 and the current probe 22 are connected in series with the signal level conversion circuit 23, the central control unit 3 comprises a signal receiving subunit 31, a control decision subunit 32 and a decision output subunit 33, the signal receiving subunit 31, the control decision subunit 32 and the decision output subunit 33 are connected in series, the input end of the voltage and current sensor 2 is the voltage in the two-stage inverter 1 circuit, The current probe, voltage current sensor 2's output is 3 units of central control unit, voltage current sensor 2 is responsible for providing key voltage, the current signal in the two-stage inverter 1 for central control unit 3 in real time, central control unit 3's input access voltage current sensor 2's output, central control unit 3's output access two-stage inverter 1's drive circuit, central control unit 3 realizes the quick limit power control contravariant function of two-stage inverter 1 according to voltage, the current signal of voltage current sensor 2 feedback.
The working principle of the utility model is as follows: the input end of a two-stage inverter 1 is the output end of a photovoltaic component 4, the output end of the two-stage inverter 1 is three-phase alternating current or is merged into a power grid, the two-stage inverter 1 converts electric energy generated by the photovoltaic component 4 into stable and reliable three-phase electricity, so that a photovoltaic system meets the requirements of power supply and grid connection, the input end of a voltage and current sensor 2 is a voltage and current probe in a circuit of the two-stage inverter 1, the output end of the voltage and current sensor 2 is a central control unit 3 unit, the voltage and current sensor 2 is responsible for providing key voltage and current signals in the two-stage inverter 1 for the central control unit 3 in real time, the input end of the central control unit 3 is connected with the output end of the voltage and current sensor 2, the output end of the central control unit 3 is connected with a driving circuit of the two-stage inverter 1, and the central control unit 3 feeds back voltage, current and voltage signals according to the voltage and current sensors 2, The current signal realizes the fast power-limiting control inversion function of the two-stage inverter 1, the DC/DC converter 11, the DC/AC inverter 12 and the voltage-stabilizing capacitor 13 are sequentially connected in parallel, the input end of the DC/DC converter 11 is connected in parallel with the output end of the photovoltaic component 4, the DC/AC inverter 12 outputs three-phase power to realize grid connection or supply power for a load, the input end of the DC/DC converter, the input end and the output end of the DC/AC inverter 12 are sampled by the voltage probe 21 and the current probe 22 to obtain the output voltage V of the photovoltaic component 4PVOutput current IPVDc bus voltage VbusInverting output voltage VgOutputting electrical signals such as current I and the like; the signal grade conversion circuit performs voltage grade conversion on the electric signal obtained by initial sampling, the converted electric signal is more suitable for the central control unit 3 to process, and the signal receiving subunit 31 receives the analog signal transmitted by the signal grade conversion circuit and performs analog-to-digital conversion; the control decision subunit 32 processes and judges the digital signal obtained by the signal receiving subunit 31 to obtain a control decision of the two-stage inverter 1, that is, a driving signal of the power switching device; the decision output subunit 33 outputs a decision signal for controlling the decision subunit 32 to the two-stage inverter 1, and performs fast power limit control through the PV-side power loop when the power limit is needed, so as to implement the specific steps of the power loopThe method comprises the following steps: (1) sampling inversion output voltage VgOutputting current I; (2) obtaining power P through an active calculation link; (3) comparing the power P with a limit power PrefObtaining a reference value I of the output current of the power ring at the photovoltaic PV end through an active control link by taking a smaller valuePV_ref2The voltage and current double closed-loop control implementation steps of the DC/DC converter 11 of the DC conversion circuit include: (1) MPPT algorithm for obtaining photovoltaic PV end output voltage reference value VPV_ref(ii) a (2) Photovoltaic PV terminal output voltage reference value VPV_refAnd the actual output voltage value VPVObtaining a photovoltaic PV end voltage ring output current reference value I through a PV voltage control linkPV_ref1(ii) a (3) Comparing the output current reference value I of the PV end voltage ringPV_ref1And PV power loop output current reference value IPV_ref2Obtaining the output current reference value I of the PV end through a current selection linkPV_ref＝min{IPV_ref1,IPV_ref2}; 4PV end output current reference value IPV_refAnd the actual output current value IPVThe DC/DC circuit driving signal is obtained through the current control link, and the DC/DC circuit link outputs the DC bus voltage Vbus，IPVThe sampling can be obtained, and the voltage and current double closed-loop control implementation steps of the inverter circuit DC/AC inverter 12 comprise: (1) DC bus voltage reference value Vbus_refAnd the actual value V of the DC bus voltagebusObtaining an inversion output current reference value I through a voltage control linkref(ii) a (2) Reference value of inverter output current IrefAnd the actual value I of the inversion output current obtains a DC/AC circuit driving signal through a current control link; (3) the driving signal controls the output current I of the DC/AC inversion link, wherein the DC/DC converter 11 of the primary DC conversion circuit of the two-stage inverter 1 adopts voltage and current double closed-loop control and respectively outputs voltage V to the PV photovoltaic modulePVVoltage ring and photovoltaic module output current IPVA ring; the other stage of inverter circuit DC/AC inverter 12 completes AC/DC conversion, converts PV DC energy into grid-connected AC energy, and adopts voltage and current double closed-loop control to respectively obtain DC bus voltage VbusThe voltage loop and the inversion output current I current loop are adopted, and the DC/DC converter 11 performs conversion of the output voltage grade of the photovoltaic module to meet the requirement of maximum power point trackingMPPT (Maximum Power Point Tracking) is controlled by a Boost circuit generally, and a Buck-Boost circuit, a Cuk circuit, a double-tube Buck-Boost circuit and the like can also be adopted.
The above description is only for the purpose of illustrating the technical solutions of the present invention and not for the purpose of limiting the same, and other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention should be covered within the scope of the claims of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims (5)

1. The utility model provides a quick limit power control system to photovoltaic grid-connected system which characterized in that: it includes two-stage inverter (1), voltage current sensor (2), central control unit (3), photovoltaic module (4), the input of two-stage inverter (1) is connected with the output of photovoltaic module (4), and the output of two-stage inverter (1) is three-phase alternating current or merges the electric wire netting into, the input of central control unit (3) is connected to the output of voltage current sensor (2), and the input of its voltage current sensor (2) and the output of central control unit (3) are connected to two-stage inverter (1).
2. The fast power limiting control system for the photovoltaic grid-connected system according to claim 1, characterized in that: the two-stage inverter (1) comprises a DC/DC converter (11), a DC/AC inverter (12) and a voltage stabilizing capacitor (13), wherein the DC/DC converter (11), the DC/AC inverter (12) and the voltage stabilizing capacitor (13) are sequentially connected in parallel, the input end of the DC/DC converter (11) is connected in parallel with the output end of the photovoltaic module (4), and the DC/AC inverter (12) outputs three-phase power.
3. The fast power limiting control system for the photovoltaic grid-connected system according to claim 1, characterized in that: the voltage and current sensor (2) comprises a voltage probe (21), a current probe (22) and a signal grade conversion circuit (23), wherein the voltage probe (21) and the current probe (22) are connected in series with the signal grade conversion circuit (23).
4. The fast power limiting control system for the photovoltaic grid-connected system according to claim 1, characterized in that: the input end of the voltage and current sensor (2) is a voltage probe and a current probe in a two-stage inverter (1) circuit, the output end of the voltage and current sensor (2) is a central control unit (3) unit, and the voltage and current sensor (2) is responsible for providing key voltage and current signals in the two-stage inverter (1) for the central control unit (3) in real time.
5. The fast power limiting control system for the photovoltaic grid-connected system according to claim 1, characterized in that: the input end of the central control unit (3) is connected with the output end of the voltage and current sensor (2), and the output end of the central control unit (3) is connected with the driving circuit of the two-stage inverter (1).
CN202121805570.XU 2021-08-04 2021-08-04 Quick power limiting control system for photovoltaic grid-connected system Active CN216436818U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202121805570.XU CN216436818U (en) 2021-08-04 2021-08-04 Quick power limiting control system for photovoltaic grid-connected system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202121805570.XU CN216436818U (en) 2021-08-04 2021-08-04 Quick power limiting control system for photovoltaic grid-connected system

Publications (1)

Publication Number Publication Date
CN216436818U true CN216436818U (en) 2022-05-03

Family

ID=81314897

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202121805570.XU Active CN216436818U (en) 2021-08-04 2021-08-04 Quick power limiting control system for photovoltaic grid-connected system

Country Status (1)

Country Link
CN (1) CN216436818U (en)

Similar Documents

Publication Publication Date Title
CN101714763B (en) High-efficiency stable multifunctional single-stage photovoltaic single-phase grid-connected control method
CN101710716A (en) Grid-connected inverter capable of reducing electrolytic capacitance
CN202001202U (en) Non-grid-connected wind-driven generating set used for hydrogen manufacturing
CN101860270A (en) Access system for adequately utilizing wind energy and solar energy and realization method thereof
CN102780398A (en) Intelligent component optimizer for solar photovoltaic cell panel and control method thereof
CN102856969B (en) A kind of solar photovoltaic generation system
CN104242790A (en) Wind-solar hybrid power generation system
CN103515974A (en) High-efficiency stable photovoltaic single-phase grid connected control method with double MPPT functions
CN104319806B (en) Inverting control system applicable to well sites of oil fields and used for photovoltaic power generation grid connection, and work method
CN108695886A (en) A kind of grid-connected inverting system of fuel cell and solar cell mixed power generation
CN108899987B (en) Solar charging control circuit with MPPT function
CN103812140A (en) Wind energy, solar energy and commercial power complementary electric vehicle charging system
CN113644695B (en) Rapid power limiting control system for photovoltaic grid-connected system
CN112290580A (en) New energy hydrogen production system
CN206932191U (en) Wind-light storage hybrid power system
CN216436818U (en) Quick power limiting control system for photovoltaic grid-connected system
CN201656848U (en) Access system for fully utilizing wind energy and solar energy
CN204967698U (en) Power supply device for internet of things
CN107069924B (en) Charge-discharge circuit of solar cell-super capacitor device sharing aluminum electrode and control method thereof
CN107154730B (en) A kind of generation of electricity by new energy two-way changing circuit and control method
CN207732485U (en) A kind of high power wind-mill generating equipment
CN215646333U (en) Multi-energy complementary intelligent off-grid power supply system
CN201138758Y (en) Intelligence control system for renewable energy resources and commercial electric power
CN206611184U (en) A kind of combined type photovoltaic generating system
CN205753400U (en) A kind of household DC micro-capacitance sensor mu balanced circuit

Legal Events

Date Code Title Description
GR01 Patent grant
GR01 Patent grant