CN110690831B - Control method of double-inverter photovoltaic power generation system considering leakage current suppression - Google Patents

Control method of double-inverter photovoltaic power generation system considering leakage current suppression Download PDF

Info

Publication number
CN110690831B
CN110690831B CN201911056167.9A CN201911056167A CN110690831B CN 110690831 B CN110690831 B CN 110690831B CN 201911056167 A CN201911056167 A CN 201911056167A CN 110690831 B CN110690831 B CN 110690831B
Authority
CN
China
Prior art keywords
phase
terminal
current
terminals
voltage source
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
CN201911056167.9A
Other languages
Chinese (zh)
Other versions
CN110690831A (en
Inventor
张兴
王宝基
赵文广
洪剑峰
曹仁贤
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.)
Hefei University of Technology
Original Assignee
Hefei University of Technology
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 Hefei University of Technology filed Critical Hefei University of Technology
Priority to CN201911056167.9A priority Critical patent/CN110690831B/en
Publication of CN110690831A publication Critical patent/CN110690831A/en
Application granted granted Critical
Publication of CN110690831B publication Critical patent/CN110690831B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • H02M7/539—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 with automatic control of output wave form or frequency
    • H02M7/5395—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 with automatic control of output wave form or frequency by pulse-width modulation
    • 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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H02M1/0038—Circuits or arrangements for suppressing, e.g. by masking incorrect turn-on or turn-off signals, e.g. due to current spikes in current mode control
    • 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

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)

Abstract

The invention discloses a control method of a double-inverter photovoltaic power generation system considering leakage current suppression. According to the method, the direct-current side voltages of the two inverters are subjected to closed-loop control to obtain an active current given decoupling angle correction instruction of the system, and then a modulation wave for driving the two inverters is obtained through current closed-loop control and a 120-degree decoupling modulation strategy. The control method can independently control the direct-current side voltages of the two inverters, so that two paths of maximum power tracking can be realized, and meanwhile, the leakage current generated due to the existence of the ground distributed capacitance of the photovoltaic array can be inhibited. Compared with the existing method, the method provided by the invention has the advantages that the control target is realized, the electric energy quality of grid-connected current is not influenced, the control method is simple, and the engineering realization is easy.

Description

Control method of double-inverter photovoltaic power generation system considering leakage current suppression
Technical Field
The invention belongs to a control technology of a double-inverter based on an open winding structure in the field of electrical engineering, and particularly relates to a control method of a double-inverter photovoltaic power generation system considering leakage current suppression.
Background
The multi-level inverter has the advantages of high efficiency, large capacity, low harmonic content of output voltage and the like, and is widely applied to medium and high power occasions. Among various multi-level inverter topologies, a double-inverter topology (hereinafter referred to as a double inverter) based on an open winding structure has the advantages of higher direct-current voltage utilization rate, higher redundancy and the like, and therefore has attracted extensive attention in the fields of motor driving, new energy grid-connected power generation and the like. When the topology is applied to the field of photovoltaic grid-connected power generation, the two inverters can adopt an independent direct-current bus design, namely, the direct-current sides are respectively connected with one photovoltaic array, and also can adopt a common direct-current bus design, namely, the direct-current sides of the two inverters are connected with the same group of photovoltaic arrays after being connected in parallel. The design of the independent direct current bus can realize two paths of Maximum Power Point Tracking (MPPT), has higher generated energy and obviously higher application value, but also brings higher requirements on a control strategy of the system. For example, in this scheme, a dual-inverter photovoltaic power generation system needs to be capable of independently controlling the dc side voltages of two inverters to realize two-way independent MPPT, and meanwhile, since a photovoltaic array has a ground-based distributed capacitance, a leakage current loop exists in the system, and thus leakage current in the system needs to be suppressed.
In order to solve the problems, researchers at home and abroad research the problems. For example, an article entitled "Dual inverter configuration for grid-connected photovoltaic generation systems", Grandi G, Ostojic D, Rossi c. "International electronic communication Energy transfer 2007. intelecec, 2007,29th, 880-885." ("Dual inverter structure of photovoltaic grid-connected power generation system" ("International Telecommunications Energy conference" 2007 29th,880-885 page) proposes a control method, in which dc-side voltages of two inverters are controlled by two dc-side voltage controllers, respectively, to output respective active current commands, and modulated waves are distributed by the ratio of each inverter active current command to a total active current command, so that independent control of the dc-side voltages of the two inverters can be realized, but the method does not consider suppression of leakage current in the system.
Entitled "A new multilevel conversion structures for grid-connected PVapplications", Grandi, G.; rossi, c.; ostojic, d.; the article of "a novel multilevel topology applied to a photovoltaic grid-connected system", IEEE industrial Electronics, 2009, 11, 4416-.
The subject is a novel double-inverter photovoltaic grid-connected converter capable of realizing independent MPPT control of two groups of cell plates, and an article of Yijing Yuan, Jinxinmin, Yanjie, Wu Zhi, Li jin Ke, the report of electrotechnical Commission, volume 30, No. 2015, No. 12, page 97-105 proposes a control method, which suppresses leakage current in a system by adopting 120-degree decoupling modulation, stabilizes direct-current side voltages of two inverters by a control method of mutually switching modulation waves of the two inverters at a certain frequency, can independently control the direct-current side voltages of the two inverters, and can suppress leakage current in the system.
In summary, the prior art mainly has the following disadvantages:
1. the existing control method for distributing modulation waves based on active current instructions can realize independent control of direct-current side voltages of two inverters, but does not consider the suppression of leakage current in a system;
2. the existing control method based on the average voltage controller and the balance voltage controller can not realize the independent control of the DC side voltages of the two inverters, and the suppression of leakage current in the system is not considered;
3. the existing control method based on 120-degree decoupling modulation and mutual switching of modulation waves of two inverters at a certain frequency can realize independent control of direct-current side voltages of the two inverters, and leakage current in a system is also inhibited.
Disclosure of Invention
The invention aims to overcome the limitations of the various technical schemes, and provides a control method which can realize the independent control of the direct-current side voltages of two inverters and can inhibit the leakage current in a system aiming at a double-inverter photovoltaic power generation system.
In order to realize the purpose of the invention, the adopted technical scheme is as follows:
examination deviceThe control method of the leakage current suppression-considered double-inverter photovoltaic power generation system comprises a first photovoltaic array PV1, a second photovoltaic array PV2 and a first distribution capacitor Cpv1_pA second distributed capacitor Cpv1_nAnd a third distributed capacitor Cpv2_pA fourth distributed capacitor Cpv2_nA first DC capacitor Cdc1A second DC capacitor Cdc2The three-phase power supply type inverter circuit comprises a first three-phase voltage source type inverter INV1, a second three-phase voltage source type inverter INV2, a three-phase filter inductor L, a three-phase filter capacitor C and a three-phase open winding transformer T; the first distributed capacitor Cpv1_pIs the distributed capacitance between the anode of the first photovoltaic array PV1 and the ground GND, one end of the distributed capacitance is connected to the anode of the first photovoltaic array PV1, and the other end of the distributed capacitance is connected to the ground GND; the second distributed capacitor Cpv1_nThe distributed capacitance between the negative electrode of the first photovoltaic array PV1 and the ground GND is formed, one end of the distributed capacitance is connected to the negative electrode of the first photovoltaic array PV1, and the other end of the distributed capacitance is connected to the ground GND; the third distributed capacitor Cpv2_pIs the distributed capacitance between the anode of the second photovoltaic array PV2 and the ground GND, one end of the distributed capacitance is connected to the anode of the second photovoltaic array PV2, and the other end of the distributed capacitance is connected to the ground GND; the fourth distributed capacitor Cpv2_nOne end of the distributed capacitance between the negative electrode of the second photovoltaic array PV2 and the ground GND is connected to the negative electrode of the second photovoltaic array PV2, and the other end of the distributed capacitance is connected to the ground GND; the direct current side of the first three-phase voltage source inverter INV1, a first photovoltaic array PV1 and a first direct current capacitor Cdc1Parallel connection; the direct current side of the second three-phase voltage source inverter INV2, a second photovoltaic array PV2 and a second direct current capacitor Cdc2Parallel connection; the primary three-phase winding of the three-phase open winding transformer T is in an open state, and the A-phase winding has two terminals which are respectively marked as a terminal A1And terminal A2The winding of phase B has two terminals, respectively denoted as terminal B1And terminal B2The C-phase winding has two terminals, respectively denoted as terminal C1And terminal C2Setting terminal A1Terminal B1And terminal C1On the same side of the primary winding of the three-phase open-winding transformer T and using the three terminals as the primary windingInput terminal, terminal A of primary winding of T-shaped open winding transformer2Terminal B2And terminal C2The three terminals are used as output terminals of the primary winding of the three-phase open winding transformer T on the other side of the primary winding of the three-phase open winding transformer T; the three-phase filter inductor L is provided with 6 terminals, two terminals of each phase are respectively marked as a terminal A3And terminal A4And the two terminals of phase B are respectively denoted as terminal B3And terminal B4And the two terminals of the C phase are respectively marked as terminals C3And terminal C4Setting terminal A3Terminal B3And terminal C3At the same side of the three-phase filter inductor L and using the three terminals as the input terminal of the three-phase filter inductor L, the terminal A4Terminal B4And terminal C4The three terminals are used as output terminals of the three-phase filter inductor L on the other side of the three-phase filter inductor L; the three-phase filter capacitor C has 6 terminals, two terminals of each phase, and two terminals of the A phase are respectively marked as a terminal A5And terminal A6And the two terminals of phase B are respectively denoted as terminal B5And terminal B6And the two terminals of the C phase are respectively marked as terminals C5And terminal C6Setting terminal A5Terminal B5And terminal C5At the same side of the three-phase filter capacitor C and using the three terminals as the input terminals of the three-phase filter capacitor C, the terminal A6Terminal B6And terminal C6The three terminals are used as output terminals of the three-phase filter capacitor C on the other side of the three-phase filter capacitor C; terminal A of the three-phase filter inductor L3Terminal B3And terminal C3Connected to the AC output side of the first three-phase voltage source inverter INV1, terminal A4Terminal B4And terminal C4Are respectively connected with primary winding terminals A of a three-phase open winding transformer T1Terminal B1And terminal C1And terminal A of three-phase filter capacitor C5Terminal B5And terminal C5Connecting; terminal A of primary winding of T-shaped three-phase open winding transformer2Terminal B2Terminal C2Respectively connected with terminals A of three-phase filter capacitor C6Terminal B6And terminal C6After being connected, the three-phase voltage source inverter is connected to the alternating current output side of the second three-phase voltage source inverter INV 2; the secondary side of the three-phase open winding transformer T is connected into a power grid E in a star connection or a triangular connection mode;
the control method is characterized by comprising the following steps of controlling the direct-current side voltage of a first three-phase voltage source type inverter INV1, controlling the direct-current side voltage of a second three-phase voltage source type inverter INV2, controlling grid-connected current and decoupling and modulating the strategy at 120 degrees in the double-inverter photovoltaic power generation system:
step 1, collecting a direct-current side voltage v of a first three-phase voltage source type inverter INV1dc1D.c. side current idc1Collecting the direct-current side voltage v of a second three-phase voltage source type inverter INV2dc2D.c. side current idc2Collecting and recording the voltage of the three-phase filter capacitor C as the voltage v of the three-phase filter capacitorca、vcb、vccCollecting the current of the input end of the three-phase filter inductor L and recording the current as the bridge arm side inductor current ia、ib、ic；
Step 2, according to the direct-current side voltage v of the first three-phase voltage source type inverter INV1 obtained in the step 1dc1And a direct side current idc1Obtaining a direct-current side voltage instruction v of the first three-phase voltage source inverter INV1 after maximum power point trackingdc1_ref(ii) a According to the direct-current side voltage v of the second three-phase voltage source type inverter INV2 obtained in the step 1dc2And a direct side current idc2Obtaining a direct-current side voltage instruction v of a second three-phase voltage source inverter INV2 after maximum power point trackingdc2_ref(ii) a Then obtaining an active current instruction i of the double-inverter photovoltaic power generation system through a direct-current side voltage closed-loop control equationd_refAnd a decoupling angle correction command δ;
the direct current side voltage closed-loop control equation is as follows:
Figure BDA0002255711490000041
Figure BDA0002255711490000042
in the formula, Kp_dFor commanding the proportional coefficient, K, of the PI regulator for the active current of the DC voltage loopi_dIntegral coefficient, K, for direct current voltage loop active current instruction PI regulatorp_δCorrection of the proportionality coefficient, K, of the command PI regulator for the decoupling angle of the DC voltage loopi_δThe integral coefficient of a direct current voltage loop decoupling angle correction instruction PI regulator is obtained, and s is a Laplace operator;
step 3, obtaining the three-phase filter capacitor voltage v according to the step 1ca、vcb、vccObtaining the phase angle theta of the three-phase filter capacitor voltage and the dq component v of the three-phase filter capacitor voltage through a phase-locked loopcd、vcq；
The calculation equation of the voltage phase angle theta of the three-phase filter capacitor is as follows:
Figure BDA0002255711490000051
in the formula, ω0Rated angular frequency, K, of three-phase filter capacitor voltagep_PLLIs the proportionality coefficient, K, of a phase-locked loop PI regulatori_PLLIs an integral coefficient, v 'of a phase-locked loop PI regulator'cqThe q component v ' obtained by carrying out synchronous rotation coordinate transformation on the phase angle theta ' of the three-phase filter capacitor voltage calculated according to the previous control period 'cqIs calculated as follows:
Figure BDA0002255711490000052
wherein, θ' is the phase angle of the three-phase filter capacitor voltage obtained in the previous control period;
dq component v of the three-phase filter capacitor voltagecd、vcqThe calculation equation of (a) is:
Figure BDA0002255711490000053
step 4, according to the bridge arm side inductive current i obtained in the step 1a、ib、icAnd step 3, obtaining the dq component i of the bridge arm side inductive current through a single synchronous rotation coordinate transformation equation according to the phase angle theta of the three-phase filter capacitor voltage obtained in the stepd、iq；
The transformation equation of the single synchronous rotation coordinate is as follows:
Figure BDA0002255711490000054
step 5, firstly setting a reactive current instruction iq_refThen according to the active current command i obtained in the step 2d_refAnd 3, obtaining dq component v of the three-phase filter capacitor voltage in the step 3cd、vcqAnd dq component i of the bridge arm side inductive current obtained in step 4d、iqAnd obtaining dq component v of the master control signal of the double-inverter photovoltaic power generation system through a current closed-loop control equationd、vq；
The current closed-loop control equation is as follows:
Figure BDA0002255711490000055
in the formula, Kp_iIs the proportionality coefficient, K, of a current loop PI regulatori_iThe integral coefficient of the current loop PI regulator is shown, omega is the fundamental angular frequency, and L is the filter inductance value;
step 6, according to the dq component v of the total control signal of the double-inverter photovoltaic power generation system obtained in the step 5d、vqObtaining dq component v of control signal of first three-phase voltage source inverter INV1 through control signal decoupling equationd1、vq1And dq component v of control signal of second three-phase voltage source inverter INV2d2、vq2；
The control signal decoupling equation is as follows:
Figure BDA0002255711490000061
Figure BDA0002255711490000062
Figure BDA0002255711490000063
Figure BDA0002255711490000064
step 7, correcting the command delta according to the decoupling angle obtained in the step 2, the phase angle theta of the three-phase filter capacitor voltage obtained in the step 3 and the dq component v of the control signal of the first three-phase voltage source type inverter INV1 obtained in the step 6d1、vq1And dq component v of control signal of second three-phase voltage source inverter INV2d2、vq2At an angle, respectively
Figure BDA0002255711490000065
And
Figure BDA0002255711490000066
performing inverse transformation of single synchronous rotation coordinate to obtain three-phase control components v of control signals of the first three-phase voltage source inverter INV1a1、vb1、vc1And a three-phase control component v of a control signal of a second three-phase voltage source inverter INV2a2、vb2、vc2；
The single synchronous rotation coordinate inverse transformation equation is as follows:
Figure BDA0002255711490000067
Figure BDA0002255711490000071
step 8, according to the control signal of the first three-phase voltage source inverter INV1 obtained in step 7Three-phase control component va1、vb1、vc1Multiply by 2/v, respectivelydc1Obtaining a modulation wave signal m of the first three-phase voltage source type inverter INV1a1、mb1、mc1The three-phase control component v of the control signal of the second three-phase voltage source inverter INV2 obtained in step 7a2、vb2、vc2Are multiplied by-2/v respectivelydc2Obtaining a modulation wave signal m of a second three-phase voltage source type inverter INV2a2、mb2、mc2Respectively generating PWM control signals PWM1 and PWM2 for driving switching tubes of a first three-phase voltage source inverter INV1 and a second three-phase voltage source inverter INV2 through a modulation strategy;
the modulated wave signal ma1、mb1、mc1And modulated wave signal ma2、mb2、mc2The calculation equations of (a) are:
Figure BDA0002255711490000072
Figure BDA0002255711490000073
compared with the prior art, the invention has the following beneficial effects:
1. the implementation method is simple, the independent control of the DC side voltages of the two inverters can be realized only by adjusting the structure of the DC voltage loop, and the leakage current in the system can be inhibited at the same time;
2. the harmonic voltage distortion rate of grid-connected current is not influenced, and the advantage of low output harmonic of the double inverters is reserved.
Drawings
Fig. 1 is a main circuit block diagram of a dual-inverter photovoltaic power generation system in an embodiment of the present invention.
Fig. 2 is a block diagram of a control method of the dual inverter photovoltaic power generation system in consideration of leakage current suppression, which is proposed in the embodiment of the present invention.
Fig. 3 is a simulation waveform of the dc-side voltages of the two inverters when the dc-side voltage command of the two inverters changes in the embodiment of the present invention.
Fig. 4 is a simulation waveform of the system leakage current when the dc side voltage commands of the two inverters change in the embodiment of the present invention.
Fig. 5 is a simulation waveform of the grid-connected current of the dual inverters when the direct-current side voltage command of the dual inverters changes in the embodiment of the invention.
Detailed Description
The invention is described in further detail below with reference to the figures and examples.
Fig. 1 is a main circuit block diagram of a dual-inverter photovoltaic power generation system in an embodiment of the present invention. From fig. 1 it can be seen that the dual inverter photovoltaic power generation system to which the present control method relates comprises a first photovoltaic array PV1, a second photovoltaic array PV2, a first distribution capacitor Cpv1_pA second distributed capacitor Cpv1_nAnd a third distributed capacitor Cpv2_pA fourth distributed capacitor Cpv2_nA first DC capacitor Cdc1A second DC capacitor Cdc2The three-phase open-winding transformer comprises a first three-phase voltage source inverter INV1, a second three-phase voltage source inverter INV2, a three-phase filter inductor L, a three-phase filter capacitor C and a three-phase open-winding transformer T.
The first distributed capacitor Cpv1_pIs the distributed capacitance between the anode of the first photovoltaic array PV1 and the ground GND, one end of the distributed capacitance is connected to the anode of the first photovoltaic array PV1, and the other end of the distributed capacitance is connected to the ground GND; the second distributed capacitor Cpv1_nThe distributed capacitance between the negative electrode of the first photovoltaic array PV1 and the ground GND is formed, one end of the distributed capacitance is connected to the negative electrode of the first photovoltaic array PV1, and the other end of the distributed capacitance is connected to the ground GND; the third distributed capacitor Cpv2_pIs the distributed capacitance between the anode of the second photovoltaic array PV2 and the ground GND, one end of the distributed capacitance is connected to the anode of the second photovoltaic array PV2, and the other end of the distributed capacitance is connected to the ground GND; the fourth distributed capacitor Cpv2_nOne end of the distributed capacitance between the negative electrode of the second photovoltaic array PV2 and the ground GND is connected to the negative electrode of the second photovoltaic array PV2, and the other end of the distributed capacitance is connected to the ground GND.
The direct current side of the first three-phase voltage source inverter INV1 is connected with a first photovoltaic array PV1 and a first direct currentCapacitor Cdc1Parallel connection; the direct current side of the second three-phase voltage source inverter INV2, a second photovoltaic array PV2 and a second direct current capacitor Cdc2And (4) connecting in parallel.
The primary three-phase winding of the three-phase open winding transformer T is in an open state, and the A-phase winding has two terminals which are respectively marked as a terminal A1And terminal A2The winding of phase B has two terminals, respectively denoted as terminal B1And terminal B2The C-phase winding has two terminals, respectively denoted as terminal C1And terminal C2Setting terminal A1Terminal B1And terminal C1The three terminals are arranged on the same side of the primary winding of the three-phase open winding transformer T and are used as input terminals of the primary winding of the three-phase open winding transformer T, and the terminal A2Terminal B2And terminal C2And the three terminals are arranged on the other side of the primary winding of the three-phase open winding transformer T and are used as output terminals of the primary winding of the three-phase open winding transformer T.
The three-phase filter inductor L is provided with 6 terminals, two terminals of each phase are respectively marked as a terminal A3And terminal A4And the two terminals of phase B are respectively denoted as terminal B3And terminal B4And the two terminals of the C phase are respectively marked as terminals C3And terminal C4Setting terminal A3Terminal B3And terminal C3At the same side of the three-phase filter inductor L and using the three terminals as the input terminal of the three-phase filter inductor L, the terminal A4Terminal B4And terminal C4And the three terminals are arranged on the other side of the three-phase filter inductor L and are used as output terminals of the three-phase filter inductor L.
The three-phase filter capacitor C has 6 terminals, two terminals of each phase, and two terminals of the A phase are respectively marked as a terminal A5And terminal A6And the two terminals of phase B are respectively denoted as terminal B5And terminal B6And the two terminals of the C phase are respectively marked as terminals C5And terminal C6Setting terminal A5Terminal B5And terminal C5At the same side of the three-phase filter capacitor C and using the three terminals as the input terminals of the three-phase filter capacitor C, the terminal A6Terminal B6And terminal C6And the three terminals are arranged on the other side of the three-phase filter capacitor C and are used as output terminals of the three-phase filter capacitor C.
Terminal A of the three-phase filter inductor L3Terminal B3And terminal C3Connected to the AC output side of the first three-phase voltage source inverter INV1, terminal A4Terminal B4And terminal C4Are respectively connected with primary winding terminals A of a three-phase open winding transformer T1Terminal B1And terminal C1And a three-phase filter capacitor C terminal A5Terminal B5And terminal C5Connecting; terminal A of primary winding of T-shaped three-phase open winding transformer2Terminal B2Terminal C2Respectively connected with terminals A of three-phase filter capacitor C6Terminal B6And terminal C6After being connected, the three-phase voltage source inverter is connected to the alternating current output side of the second three-phase voltage source inverter INV 2; and the secondary side of the three-phase open winding transformer T is connected into a power grid E in a star connection or a triangular connection mode.
In the embodiment of the invention, a double-three-level inverter is adopted in a double-inverter topology, the rated power of a system is 1MW, the rated power of each inverter is 500kW, the switching frequency is 5kHz, and a first direct current capacitor Cdc1And a second DC capacitor Cdc2Are all 2.5mF, a first distributed capacitance Cpv1_pA second distributed capacitor Cpv1_nAnd a third distributed capacitor Cpv2_pAnd a fourth distributed capacitor Cpv2_nThe three-phase filter inductance L is 0.1mH, the three-phase filter capacitance C is 400 muF, the phase voltage transformation ratio of the open winding transformer T is 364V/10kV, the short-circuit impedance is 6 percent, and the effective value of the power line voltage is 10kV/50 Hz.
Referring to fig. 2, the control method of the invention includes the control of the direct-current side voltage of a first three-phase voltage source inverter INV1, the control of the direct-current side voltage of a second three-phase voltage source inverter INV2, grid-connected current control and a 120-degree decoupling modulation strategy in a double-inverter photovoltaic power generation system, and specifically includes the following steps:
step 1, collecting the first threeDC side voltage v of phase voltage source inverter INV1dc1D.c. side current idc1Collecting the direct-current side voltage v of a second three-phase voltage source type inverter INV2dc2D.c. side current idc2Collecting and recording the voltage of the three-phase filter capacitor C as the voltage v of the three-phase filter capacitorca、vcb、vccCollecting the current of the input end of the three-phase filter inductor L and recording the current as the bridge arm side inductor current ia、ib、ic；
Step 2, according to the direct-current side voltage v of the first three-phase voltage source type inverter INV1 obtained in the step 1dc1And a direct side current idc1Obtaining a direct-current side voltage instruction v of the first three-phase voltage source inverter INV1 after Maximum Power Point Tracking (MPPT)dc1_ref(ii) a According to the direct-current side voltage v of the second three-phase voltage source type inverter INV2 obtained in the step 1dc2And a direct side current idc2Obtaining a direct-current side voltage instruction v of a second three-phase voltage source inverter INV2 after Maximum Power Point Tracking (MPPT)dc2_ref(ii) a Then obtaining an active current instruction i of the double-inverter photovoltaic power generation system through a direct-current side voltage closed-loop control equationd_refAnd a decoupling angle correction command δ;
the direct current side voltage closed-loop control equation is as follows:
Figure BDA0002255711490000101
Figure BDA0002255711490000102
in the formula, Kp_dFor commanding the proportional coefficient, K, of the PI regulator for the active current of the DC voltage loopi_dIntegral coefficient, K, for direct current voltage loop active current instruction PI regulatorp_δCorrection of the proportionality coefficient, K, of the command PI regulator for the decoupling angle of the DC voltage loopi_δAnd (4) an integral coefficient of a direct current voltage loop decoupling angle correction instruction PI regulator is obtained, and s is a Laplace operator. In this embodiment, Kp_d＝2，Ki_d＝1000，Kp_δ＝0.005，Ki_δ＝1。
Step 3, obtaining the three-phase filter capacitor voltage v according to the step 1ca、vcb、vccObtaining the phase angle theta of the three-phase filter capacitor voltage and the dq component v of the three-phase filter capacitor voltage through a phase-locked loop (PLL)cd、vcq。
The calculation equation of the voltage phase angle theta of the three-phase filter capacitor is as follows:
Figure BDA0002255711490000111
in the formula, ω0Rated angular frequency, K, of three-phase filter capacitor voltagep_PLLIs the proportionality coefficient, K, of a phase-locked loop PI regulatori_PLLFor the integral coefficient of the phase-locked loop PI regulator, in this embodiment, ω0＝100πrad/s，Kp_PLL＝0.2，Ki_PLL＝2。
v′cqThe q component v ' obtained by carrying out synchronous rotation coordinate transformation on the phase angle theta ' of the three-phase filter capacitor voltage calculated according to the previous control period 'cqIs calculated as follows:
Figure BDA0002255711490000112
and theta' is the phase angle of the three-phase filter capacitor voltage obtained in the previous control period.
Dq component v of the three-phase filter capacitor voltagecd、vcqThe calculation equation of (a) is:
Figure BDA0002255711490000113
step 4, according to the bridge arm side inductive current i obtained in the step 1a、ib、icAnd step 3, obtaining the dq component i of the bridge arm side inductive current through a single synchronous rotation coordinate transformation equation according to the phase angle theta of the three-phase filter capacitor voltage obtained in the stepd、iq。
The transformation equation of the single synchronous rotation coordinate is as follows:
Figure BDA0002255711490000114
step 5, firstly setting a reactive current instruction iq_refThen according to the active current command i obtained in the step 2d_refAnd 3, obtaining dq component v of the three-phase filter capacitor voltage in the step 3cd、vcqAnd dq component i of the bridge arm side inductive current obtained in step 4d、iqAnd obtaining dq component v of the master control signal of the double-inverter photovoltaic power generation system through a current closed-loop control equationd、vq；
The current closed-loop control equation is as follows:
Figure BDA0002255711490000121
in the formula, Kp_iIs the proportionality coefficient, K, of a current loop PI regulatori_iThe integral coefficient of the current loop PI regulator is shown, omega is the angular frequency of the fundamental wave, and L is the inductance value of the filter. In this embodiment, ω ═ 100 π rad/s, Kp_i＝0.3，Ki_i＝100。
Step 6, according to the dq component v of the total control signal of the double-inverter photovoltaic power generation system obtained in the step 5d、vqObtaining dq component v of control signal of first three-phase voltage source inverter INV1 through control signal decoupling equationd1、vq1And dq component v of control signal of second three-phase voltage source inverter INV2d2、vq2；
The control signal decoupling equation is as follows:
Figure BDA0002255711490000122
Figure BDA0002255711490000123
Figure BDA0002255711490000124
Figure BDA0002255711490000125
step 7, correcting the command delta according to the decoupling angle obtained in the step 2, the phase angle theta of the three-phase filter capacitor voltage obtained in the step 3 and the dq component v of the control signal of the first three-phase voltage source type inverter INV1 obtained in the step 6d1、vq1And dq component v of control signal of second three-phase voltage source inverter INV2d2、vq2At an angle, respectively
Figure BDA0002255711490000126
And
Figure BDA0002255711490000127
performing inverse transformation of single synchronous rotation coordinate to obtain three-phase control components v of control signals of the first three-phase voltage source inverter INV1a1、vb1、vc1And a three-phase control component v of a control signal of a second three-phase voltage source inverter INV2a2、vb2、vc2；
The single synchronous rotation coordinate inverse transformation equation is as follows:
Figure BDA0002255711490000131
Figure BDA0002255711490000132
step 8, obtaining three-phase control component v of control signal of first three-phase voltage source inverter INV1 according to step 7a1、vb1、vc1Multiply by 2/v, respectivelydc1Obtaining a modulation wave signal m of the first three-phase voltage source type inverter INV1a1、mb1、mc1The second three-phase voltage source obtained according to step 7Three-phase control component v of control signal of inverter INV2a2、vb2、vc2Are multiplied by-2/v respectivelydc2Obtaining a modulation wave signal m of a second three-phase voltage source type inverter INV2a2、mb2、mc2Respectively generating PWM control signals PWM1 and PWM2 for driving switching tubes of a first three-phase voltage source inverter INV1 and a second three-phase voltage source inverter INV2 through a modulation strategy;
the modulated wave signal ma1、mb1、mc1And modulated wave signal ma2、mb2、mc2The calculation equations of (a) are:
Figure BDA0002255711490000133
Figure BDA0002255711490000134
FIG. 3 is a simulated waveform of DC side voltages of two inverters when the DC side voltage commands of the two inverters change, and a DC side voltage command v of a first three-phase voltage source inverter INV1 at the command change timedc1_refChanging from 730V to 700V, and changing the direct-current side voltage command V of the second three-phase voltage source type inverter INV2dc2_refWhen the voltage of the direct current side of the two inverters is changed from 730V to 670V, the direct current side voltage of the two inverters can be found to be quickly matched with respective instruction values, and the two inverters can be proved to be capable of realizing independent control of the direct current side voltage.
The grid-connected standard "NBT 32004 photovoltaic grid-connected inverter technical specification" specifies an inverter with rated output power greater than 30kVA, the leakage current should not be greater than 10mA/kVA, for this embodiment (rated output power 1MW), the effective value of the leakage current should not be greater than 10A, from the simulation waveform of the leakage current shown in fig. 4, the effective value of the leakage current before the dc side voltage instruction is changed is 2.79A, and the effective value of the leakage current after the dc side voltage instruction is changed is 5.5A, both meeting the grid-connected standard, which indicates that the proposed method can realize effective suppression of the system leakage current.
Fig. 5 is a simulation waveform of the grid-connected current of the two inverters when the direct-current-side voltage commands of the two inverters change, and it can be found that the power quality of the grid-connected current is not affected before and after the direct-current-side voltage commands of the two inverters change. In conclusion, the simulation result proves the correctness and effectiveness of the control method of the double-inverter photovoltaic power generation system considering leakage current suppression.

Claims (1)

1. A control method of a double-inverter photovoltaic power generation system considering leakage current suppression is provided, wherein the double-inverter photovoltaic power generation system related to the control method comprises a first photovoltaic array PV1, a second photovoltaic array PV2 and a first distribution capacitor Cpv1_pA second distributed capacitor Cpv1_nAnd a third distributed capacitor Cpv2_pA fourth distributed capacitor Cpv2_nA first DC capacitor Cdc1A second DC capacitor Cdc2The three-phase power supply type inverter circuit comprises a first three-phase voltage source type inverter INV1, a second three-phase voltage source type inverter INV2, a three-phase filter inductor L, a three-phase filter capacitor C and a three-phase open winding transformer T; the first distributed capacitor Cpv1_pIs the distributed capacitance between the anode of the first photovoltaic array PV1 and the ground GND, one end of the distributed capacitance is connected to the anode of the first photovoltaic array PV1, and the other end of the distributed capacitance is connected to the ground GND; the second distributed capacitor Cpv1_nThe distributed capacitance between the negative electrode of the first photovoltaic array PV1 and the ground GND is formed, one end of the distributed capacitance is connected to the negative electrode of the first photovoltaic array PV1, and the other end of the distributed capacitance is connected to the ground GND; the third distributed capacitor Cpv2_pIs the distributed capacitance between the anode of the second photovoltaic array PV2 and the ground GND, one end of the distributed capacitance is connected to the anode of the second photovoltaic array PV2, and the other end of the distributed capacitance is connected to the ground GND; the fourth distributed capacitor Cpv2_nOne end of the distributed capacitance between the negative electrode of the second photovoltaic array PV2 and the ground GND is connected to the negative electrode of the second photovoltaic array PV2, and the other end of the distributed capacitance is connected to the ground GND; the direct current side of the first three-phase voltage source inverter INV1, a first photovoltaic array PV1 and a first direct current capacitor Cdc1Parallel connection; the direct current side of the second three-phase voltage source inverter INV2, a second photovoltaic array PV2 and a second direct current capacitor Cdc2Parallel connection; the primary three-phase winding of the three-phase open winding transformer T is in an open state, and the A-phase winding is provided withTwo terminals, respectively designated as terminal A1And terminal A2The winding of phase B has two terminals, respectively denoted as terminal B1And terminal B2The C-phase winding has two terminals, respectively denoted as terminal C1And terminal C2Setting terminal A1Terminal B1And terminal C1The three terminals are arranged on the same side of the primary winding of the three-phase open winding transformer T and are used as input terminals of the primary winding of the three-phase open winding transformer T, and the terminal A2Terminal B2And terminal C2The three terminals are used as output terminals of the primary winding of the three-phase open winding transformer T on the other side of the primary winding of the three-phase open winding transformer T; the three-phase filter inductor L is provided with 6 terminals, two terminals of each phase are respectively marked as a terminal A3And terminal A4And the two terminals of phase B are respectively denoted as terminal B3And terminal B4And the two terminals of the C phase are respectively marked as terminals C3And terminal C4Setting terminal A3Terminal B3And terminal C3At the same side of the three-phase filter inductor L and using the three terminals as the input terminal of the three-phase filter inductor L, the terminal A4Terminal B4And terminal C4The three terminals are used as output terminals of the three-phase filter inductor L on the other side of the three-phase filter inductor L; the three-phase filter capacitor C has 6 terminals, two terminals of each phase, and two terminals of the A phase are respectively marked as a terminal A5And terminal A6And the two terminals of phase B are respectively denoted as terminal B5And terminal B6And the two terminals of the C phase are respectively marked as terminals C5And terminal C6Setting terminal A5Terminal B5And terminal C5At the same side of the three-phase filter capacitor C and using the three terminals as the input terminals of the three-phase filter capacitor C, the terminal A6Terminal B6And terminal C6The three terminals are used as output terminals of the three-phase filter capacitor C on the other side of the three-phase filter capacitor C; terminal A of the three-phase filter inductor L3Terminal B3And terminal C3Connected to the AC output side of the first three-phase voltage source inverter INV1, terminal A4Terminal B4And terminal C4Are respectively connected with primary winding terminals A of a three-phase open winding transformer T1Terminal B1And terminal C1And terminal A of three-phase filter capacitor C5Terminal B5And terminal C5Connecting; terminal A of primary winding of T-shaped three-phase open winding transformer2Terminal B2Terminal C2Respectively connected with terminals A of three-phase filter capacitor C6Terminal B6And terminal C6After being connected, the three-phase voltage source inverter is connected to the alternating current output side of the second three-phase voltage source inverter INV 2; the secondary side of the three-phase open winding transformer T is connected into a power grid E in a star connection or a triangular connection mode;
the control method is characterized by comprising the following steps of controlling the direct-current side voltage of a first three-phase voltage source type inverter INV1, controlling the direct-current side voltage of a second three-phase voltage source type inverter INV2, controlling grid-connected current and decoupling and modulating the strategy at 120 degrees in the double-inverter photovoltaic power generation system:
step 1, collecting a direct-current side voltage v of a first three-phase voltage source type inverter INV1dc1D.c. side current idc1Collecting the direct-current side voltage v of a second three-phase voltage source type inverter INV2dc2D.c. side current idc2Collecting and recording the voltage of the three-phase filter capacitor C as the voltage v of the three-phase filter capacitorca、vcb、vccCollecting the current of the input end of the three-phase filter inductor L and recording the current as the bridge arm side inductor current ia、ib、ic；
Step 2, according to the direct-current side voltage v of the first three-phase voltage source type inverter INV1 obtained in the step 1dc1And a direct side current idc1Obtaining a direct-current side voltage instruction v of the first three-phase voltage source inverter INV1 after maximum power point trackingdc1_ref(ii) a According to the direct-current side voltage v of the second three-phase voltage source type inverter INV2 obtained in the step 1dc2And a direct side current idc2Obtaining a direct-current side voltage instruction v of a second three-phase voltage source inverter INV2 after maximum power point trackingdc2_ref(ii) a And then obtaining a double-inverter photovoltaic power generation system through a direct-current side voltage closed-loop control equationActive current command id_refAnd a decoupling angle correction command δ;
the direct current side voltage closed-loop control equation is as follows:
Figure FDA0002255711480000021
Figure FDA0002255711480000022
in the formula, Kp_dFor commanding the proportional coefficient, K, of the PI regulator for the active current of the DC voltage loopi_dIntegral coefficient, K, for direct current voltage loop active current instruction PI regulatorp_δCorrection of the proportionality coefficient, K, of the command PI regulator for the decoupling angle of the DC voltage loopi_δThe integral coefficient of a direct current voltage loop decoupling angle correction instruction PI regulator is obtained, and s is a Laplace operator;
step 3, obtaining the three-phase filter capacitor voltage v according to the step 1ca、vcb、vccObtaining the phase angle theta of the three-phase filter capacitor voltage and the dq component v of the three-phase filter capacitor voltage through a phase-locked loopcd、vcq；
The calculation equation of the voltage phase angle theta of the three-phase filter capacitor is as follows:
Figure FDA0002255711480000031
in the formula, ω0Rated angular frequency, K, of three-phase filter capacitor voltagep_PLLIs the proportionality coefficient, K, of a phase-locked loop PI regulatori_PLLIs an integral coefficient, v 'of a phase-locked loop PI regulator'cqThe q component v ' obtained by carrying out synchronous rotation coordinate transformation on the phase angle theta ' of the three-phase filter capacitor voltage calculated according to the previous control period 'cqIs calculated as follows:
Figure FDA0002255711480000032
wherein, θ' is the phase angle of the three-phase filter capacitor voltage obtained in the previous control period;
dq component v of the three-phase filter capacitor voltagecd、vcqThe calculation equation of (a) is:
Figure FDA0002255711480000033
step 4, according to the bridge arm side inductive current i obtained in the step 1a、ib、icAnd step 3, obtaining the dq component i of the bridge arm side inductive current through a single synchronous rotation coordinate transformation equation according to the phase angle theta of the three-phase filter capacitor voltage obtained in the stepd、iq；
The transformation equation of the single synchronous rotation coordinate is as follows:
Figure FDA0002255711480000034
step 5, firstly setting a reactive current instruction iq_refThen according to the active current command i obtained in the step 2d_refAnd 3, obtaining dq component v of the three-phase filter capacitor voltage in the step 3cd、vcqAnd dq component i of the bridge arm side inductive current obtained in step 4d、iqAnd obtaining dq component v of the master control signal of the double-inverter photovoltaic power generation system through a current closed-loop control equationd、vq；
The current closed-loop control equation is as follows:
Figure FDA0002255711480000041
in the formula, Kp_iIs the proportionality coefficient, K, of a current loop PI regulatori_iThe integral coefficient of the current loop PI regulator is shown, omega is the fundamental angular frequency, and L is the filter inductance value;
step 6, according to the dq component v of the total control signal of the double-inverter photovoltaic power generation system obtained in the step 5d、vqObtaining dq component v of control signal of first three-phase voltage source inverter INV1 through control signal decoupling equationd1、vq1And dq component v of control signal of second three-phase voltage source inverter INV2d2、vq2；
The control signal decoupling equation is as follows:
Figure FDA0002255711480000042
Figure FDA0002255711480000043
Figure FDA0002255711480000044
Figure FDA0002255711480000045
step 7, correcting the command delta according to the decoupling angle obtained in the step 2, the phase angle theta of the three-phase filter capacitor voltage obtained in the step 3 and the dq component v of the control signal of the first three-phase voltage source type inverter INV1 obtained in the step 6d1、vq1And dq component v of control signal of second three-phase voltage source inverter INV2d2、vq2At an angle, respectively
Figure FDA0002255711480000046
And
Figure FDA0002255711480000047
performing inverse transformation of single synchronous rotation coordinate to obtain three-phase control components v of control signals of the first three-phase voltage source inverter INV1a1、vb1、vc1And a three-phase control component v of a control signal of a second three-phase voltage source inverter INV2a2、vb2、vc2；
The single synchronous rotation coordinate inverse transformation equation is as follows:
Figure FDA0002255711480000051
Figure FDA0002255711480000052
step 8, obtaining three-phase control component v of control signal of first three-phase voltage source inverter INV1 according to step 7a1、vb1、vc1Multiply by 2/v, respectivelydc1Obtaining a modulation wave signal m of the first three-phase voltage source type inverter INV1a1、mb1、mc1The three-phase control component v of the control signal of the second three-phase voltage source inverter INV2 obtained in step 7a2、vb2、vc2Are multiplied by-2/v respectivelydc2Obtaining a modulation wave signal m of a second three-phase voltage source type inverter INV2a2、mb2、mc2Respectively generating PWM control signals PWM1 and PWM2 for driving switching tubes of a first three-phase voltage source inverter INV1 and a second three-phase voltage source inverter INV2 through a modulation strategy;
the modulated wave signal ma1、mb1、mc1And modulated wave signal ma2、mb2、mc2The calculation equations of (a) are:
Figure FDA0002255711480000053
Figure FDA0002255711480000054
CN201911056167.9A 2019-10-31 2019-10-31 Control method of double-inverter photovoltaic power generation system considering leakage current suppression Active CN110690831B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201911056167.9A CN110690831B (en) 2019-10-31 2019-10-31 Control method of double-inverter photovoltaic power generation system considering leakage current suppression

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201911056167.9A CN110690831B (en) 2019-10-31 2019-10-31 Control method of double-inverter photovoltaic power generation system considering leakage current suppression

Publications (2)

Publication Number Publication Date
CN110690831A CN110690831A (en) 2020-01-14
CN110690831B true CN110690831B (en) 2020-06-30

Family

ID=69115159

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201911056167.9A Active CN110690831B (en) 2019-10-31 2019-10-31 Control method of double-inverter photovoltaic power generation system considering leakage current suppression

Country Status (1)

Country Link
CN (1) CN110690831B (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106981976A (en) * 2017-03-24 2017-07-25 江苏固德威电源科技股份有限公司 The method that T-shaped three-level three-phase inverter suppresses center line common mode current
CN108418226A (en) * 2018-03-26 2018-08-17 合肥工业大学 Open the power-less compensation control method of winding twin inverter photovoltaic generating system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106981976A (en) * 2017-03-24 2017-07-25 江苏固德威电源科技股份有限公司 The method that T-shaped three-level three-phase inverter suppresses center line common mode current
CN108418226A (en) * 2018-03-26 2018-08-17 合肥工业大学 Open the power-less compensation control method of winding twin inverter photovoltaic generating system

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
"一种可实现两组池板独立MPPT控制的新型双逆变器光伏并网变流器";尹婧元 等;《电工技术学报》;20150625(第12期);97-105 *
"基于双三电平逆变器的开绕组PMSM直接转矩控制系统";薛硕;《中国优秀硕士学位论文全文数据库 工程科技Ⅱ辑》;20180315;C042-304 *

Also Published As

Publication number Publication date
CN110690831A (en) 2020-01-14

Similar Documents

Publication Publication Date Title
CN110350564B (en) High-voltage direct-hanging energy storage device and power control method
CN103475029B (en) Three-phase LCL type grid-connected inverter control system and method based on pole assignment
CN103151785B (en) Multi-converter parallel circulating current restraining method with quick and reactive support
CN105048788B (en) The multiport electric power electric transformer and its control method of a kind of Mixed cascading structure
CN103956911A (en) Modularized H-bridge cascade multilevel mutual-balance power electronic transformer
CN108988343B (en) Global high-frequency oscillation suppression method for multi-inverter grid-connected system under weak grid
CN204835971U (en) Multiport power electronic transformer
CN103346689B (en) Grid-connected inverter parallel system circulating current restraining method under imbalance condition of inductance
CN203827197U (en) Modular H bridge cascaded multilevel mutually-balanced electric power electronic transformer
CN103227581A (en) Inverter parallel harmonic wave ring current restraining method for controlling harmonic wave droop
CN104158211B (en) Based on many power grids system control method of Modular multilevel converter
CN116260348B (en) MMC-based high-capacity electrolytic hydrogen production hybrid rectifier and control method
CN103973121A (en) Single-phase power electronic transformer
Shen et al. Transformer-less three-port grid-connected power converter for distribution power generation system with dual renewable energy sources
CN101567567A (en) Carrier shifting inversion large power photovoltaic grid-connection system and control method thereof
CN104993713A (en) Control method for double PWM solid-state transformer
CN107681892B (en) Direct current converter
Farhadi-Kangarlu et al. Performance improvement of single-phase transformer less grid-connected PV inverters regarding the CMV and LVRT
Amin et al. Practical Implementation of High-Efficiency Multiple-Input Converter Embedding Renewables and Energy Storage For DC-Microgrid Applications
Sędłak et al. Operation of four-leg three-level flying capacitor grid-connected converter for RES
CN110854905B (en) Power sharing control method for open-winding double-inverter photovoltaic power generation system
CN116632902A (en) Multi-port flexible direct current transmission system based on PWM current source converter
CN110690831B (en) Control method of double-inverter photovoltaic power generation system considering leakage current suppression
Teng et al. Power mismatches elimination strategy for MMC-based photovoltaic system and lightweight design
CN203827195U (en) Single phase power electronic transformer

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant