CN108321850B - Parallel connection method of H-bridge cascaded high-voltage shore power supply based on independent droop control - Google Patents
Parallel connection method of H-bridge cascaded high-voltage shore power supply based on independent droop control Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/40—Synchronising a generator for connection to a network or to another generator
- H02J3/42—Synchronising a generator for connection to a network or to another generator with automatic parallel connection when synchronisation is achieved
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M5/00—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases
- H02M5/40—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc
- H02M5/42—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters
- H02M5/44—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac
- H02M5/453—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal
- H02M5/458—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
- H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
- H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/493—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 the static converters being arranged for operation in parallel
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
- H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
- H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
- H02M7/5387—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 in a bridge configuration
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/0067—Converter structures employing plural converter units, other than for parallel operation of the units on a single load
- H02M1/007—Plural converter units in cascade
Abstract
The invention discloses a high-voltage shore power supply parallel connection method based on independent droop control, which realizes capacity expansion through the parallel connection method based on the droop control, realizes plug and play of equipment, can greatly improve the flexibility of a system, reduces the volume and the weight of a shore power supply system, avoids the problem of unbalanced module direct-current voltage caused by interphase circulation by adopting the independent droop control method, and improves the operation stability of the system.
Description
Technical Field
The invention relates to a parallel connection method of H-bridge cascaded high-voltage shore power supplies based on independent droop control, and belongs to the technical field of parallel connection control of the high-voltage shore power supplies.
Background
The demand of the modern society on a high-power shore power supply is larger and larger, the flexibility requirement is higher and stronger, and the shore power supply with high voltage and large capacity is connected in parallel to be used to become a new demand direction, because the mode can not only improve the purpose of larger capacity by connecting a plurality of power supplies in parallel, but also can meet the use of a large-capacity independent power supply. Meanwhile, the requirement on the quality of the output electric energy of the high-voltage shore power supply with large capacity is increasingly strict, and the contradiction between the working voltage of the power switching device and the switching frequency requirement thereof restricts the development and application of the inversion technology and the parallel technology. As is known, the H-bridge cascade inversion technology combined with the carrier phase shift SVPWM technology is an effective way for solving the inversion technical problem at present, but the high-voltage shore power supply parallel technology still has many unsolved problems. For example, if the output voltage frequency, phase and amplitude of each high-voltage shore power supply cannot be guaranteed to be the same, then circulating current will occur, which causes great system loss, even system breakdown, power interruption and other problems.
The method is suitable for a newly built system, the master-slave control equipment is added during design, but for a system needing capacity expansion, the problems of transformation and coordination among different equipment are considered, the method has certain limitation, a plug-and-play control method is adopted to realize parallel control of all high-voltage shore power supplies, and meanwhile, because the number of power modules of the H-bridge cascaded high-voltage shore power supplies is large, the problem of direct-current voltage balance of all phase power units exists, and the problem of overvoltage fault disconnection of circulation current during parallel connection is easy to occur, so that the stability of system operation is influenced.
Disclosure of Invention
In order to solve the defects of the prior art, the invention provides the parallel connection method of the H-bridge cascade high-voltage shore power supply based on the independent droop control, the capacity expansion is realized through the parallel connection method based on the droop control, the plug and play of the equipment are realized, the flexibility of the system can be greatly improved, the volume and the weight of the shore power supply system are reduced, the problem of unbalanced module direct-current voltage caused by interphase circulating current is avoided by adopting the independent droop control method, and the operation stability of the system is improved.
The above object of the present invention is achieved by the following technical means: a parallel connection method of H-bridge cascaded high-voltage shore power supplies based on independent droop control is suitable for parallel connection control of high-voltage shore power variable-frequency power supplies of cascaded H-bridge topologies, wherein the high-voltage shore power variable-frequency power supplies of the cascaded H-bridge topologies comprise a grid-connected switch G1, a pre-charging module M1, a rectifying link, a direct-current voltage link, an alternating-current inversion link, an output filtering link and a voltage and current detection and control link, wherein the rectifying link comprises a phase-shifting transformer T1 and uncontrolled rectifying units 1-18; the direct-current voltage link comprises direct-current voltage units 1-18 and chopper units 1-18, and the alternating-current inversion link comprises H-bridge cascade inversion units 1-18; the output filtering link comprises an isolation transformer T2, filtering capacitors C1-C3, filtering reactances L1-L3 and an output switch G2.
The voltage and current detection and control link comprises a main power supply module and a control link of a slave power supply module, wherein the control link of the main power supply module comprises a main module voltage and current detection and a constant voltage and constant frequency controller; the control link of the slave power supply module comprises slave module voltage and current detection, an active and reactive decoupling controller and a current inner loop controller.
The rectification link adopts a phase-shifting transformer rectification technology, so that stable direct current bus voltage is provided for the alternating current inversion link, and harmonic waves are reduced; the bus capacitor pre-charging device comprises a pre-charging module and a phase-shifting transformer T1 module, wherein the pre-charging module is responsible for smoothly charging the bus capacitor, and impact current influence caused by high-speed charging is avoided.
The direct-current voltage link can rapidly act when the direct-current voltage is over-voltage and stabilize the direct-current voltage, and comprises a direct-current side voltage detection module and a chopping unit module.
The alternating current inversion link adopts an H-bridge cascade topological structure, provides stable power output for a load, and consists of a carrier phase-shifting SVPWM modulator and a filtering unit module, wherein the carrier phase-shifting SVPWM modulator is matched with the H-bridge cascade topological structure for use, so that equivalent switching frequency is improved, and harmonic pollution is reduced;
the control unit of the shore power supply comprises a driving and protecting circuit; the control unit adjusts the output frequency and the output voltage of the corresponding shore power supply according to the signal provided by the parallel control module, so that the output power of the parallel shore power supply can be evenly divided, and the method comprises the following specific steps:
(1) obtaining the given control voltage V of the current ship according to the voltage system of the connected ship0And given control frequency f0；
(2) Each phase voltage u sampled and output by data acquisition unit of high-voltage shore power supplya,ub,ucSampling the output current i of each phasea,ib,icCalculating to obtain effective voltage value V of each phasea,Vb,VcFrequency real time value fa,fb,fcActive power P of each phasea,Pb,PcReactive power Q of each phasea,Qb,Qc；
(3) According to the output phase voltage u of each phase in a mode of a software phase-locked loopa,ub,ucDetermining the phase angle theta on the AC side0And starting output by taking the angle as an initial angle to realize the shore power supply for controlling each droopThe pre-synchronization is started;
(4) calculating to obtain a frequency-active droop curve of three-phase active power and three-phase frequency by adopting a formula (1), wherein f0For frequency of each phase given value, ma，mb，mcIs the frequency-active droop curve coefficient;
(5) calculating to obtain a voltage-reactive droop curve of three-phase reactive power and three-phase voltage by adopting a formula (2), wherein V0Given values of effective voltage values, n, for each phasea，nb，ncIs a voltage-reactive droop curve coefficient;
(6) will f isa′，fb′，fc' controlling the frequency of each phase, V, as a given frequency value to a frequency controller of each phase of the H-bridge cascadea′，Vb′，VcThe three-phase voltage effective value is taken as a given value of a three-phase voltage effective value to be sent to a voltage controller, and the output effective value of each phase voltage is controlled;
(7) the output of the frequency controller and the voltage controller forms a three-phase modulation wave signal, and after the three-phase modulation wave signal is compared with a pulse signal of a phase-shifted carrier, SPWM control signals of all modules are generated to drive all power modules of a high-voltage shore power supply of the cascaded H bridge, so that output voltage for supplying power to the ship is formed.
The invention realizes the parallel connection of high-voltage shore power supplies based on H-bridge cascade connection, each shore power supply is provided with an independent control loop, the modulation signals of each phase module are independently controlled, the output voltage and the load sharing power can be accurately adjusted at the same time, the control structure is simple, and the precision is very high.
Compared with the prior art, the invention has the advantages that:
(1) under the actual complex operating conditions that a shore power supply parallel control system is provided with a nonlinear load and the like, the shore power supply can still provide stable voltage and frequency support for the load on the common bus, and the harmonic voltage distortion rate on the common bus is obviously reduced.
(2) The circulation between the shore power supplies can be restrained, the power is equally divided and controlled, and the stable operation of a plurality of shore power supply parallel power equally dividing control systems is ensured.
(3) The reference voltage phase angle output by the droop control system is used for replacing the phase angle of the common bus voltage after coordinate transformation processing, so that the time delay of the sampling process is avoided, and the calculation amount of the phase angle is reduced.
(4) And by adopting an independently controlled droop method, the circulation current generated between the modules when three phases are unbalanced is avoided, and the stability of the direct-current voltage of each power unit is improved.
Drawings
FIG. 1 is a topological diagram of a high-voltage shore power supply system based on H-bridge cascade connection;
FIG. 2 is a diagram of a high-voltage shore power supply parallel system structure based on droop control;
FIG. 3 shows simulated waveforms of output voltages of two shore power supplies;
FIG. 4 is a simulated waveform of output current from the No. 1 shore power supply;
FIG. 5 is a simulated waveform of output current from the station shore power supply of FIG. 2;
FIG. 6 shows simulated waveforms of active power output by two shore power sources;
FIG. 7 shows a high-voltage shore power supply parallel experimental structure;
fig. 8 shows the output voltage current waveform of the high-voltage shore power supply in parallel operation (start-up operation of # 2 shore power supply);
fig. 9 shows the output voltage current waveform of the high-voltage shore power supply in parallel operation (2# shore power supply quits operation).
Detailed Description
The present invention will be described in more detail with reference to examples.
As shown in fig. 2, according to the parallel connection method of the H-bridge cascaded high-voltage shore power supply based on the independent droop control, the whole shore power supply parallel connection control system comprises a power outer ring, a voltage ring and a current inner ring setAnd (4) obtaining. The power ring is used as the outer ring of the whole system and is used for supplying output voltage U of each shore power supplyn(n is a, b and c), and calculating the active power P of each phase output by the shore power supply in real timenAnd reactive power QnAccording to the droop control equations of P-f and Q-U, giving out the amplitude and frequency of each phase reference voltage when the system works stably; the voltage loop adopts a PI regulator, so that the output voltage of the shore power supply can be ensured to quickly and accurately track the reference voltage, and the output voltage is maintained to be stable; the current loop is used as the system inner loop, and the PI regulator is also adopted to control the current I flowing into the filter inductornAnd (n is a, b and c), so that the output of the voltage loop can be accurately tracked, and the dynamic response performance of the whole system is further improved.
The high-voltage shore power supply parallel connection method based on independent droop control is suitable for parallel connection control of a high-voltage shore power variable-frequency power supply of a cascade H-bridge topology, and as shown in figure 1, the high-voltage shore power variable-frequency power supply of the cascade H-bridge topology comprises a grid-connected switch G1, a pre-charging module M1, a rectifying link, a direct-current voltage link, an alternating-current inversion link, an output filtering link and a voltage and current detection and control link. The rectifying link comprises a phase-shifting transformer T1 and uncontrolled rectifying units 1-18; the direct-current voltage link comprises direct-current voltage units 1-18 and chopper units 1-18, and the alternating-current inversion link comprises H-bridge cascade inversion units 1-18; the output filtering link comprises an isolation transformer T2, filtering capacitors C1-C3, filtering reactances L1-L3 and an output switch G2.
The voltage and current detection and control link comprises a main power supply module and a control link of a slave power supply module, wherein the control link of the main power supply module comprises a main module voltage and current detection and a constant voltage and constant frequency controller; the control link of the slave power supply module comprises slave module voltage and current detection, an active and reactive decoupling controller and a current inner loop controller.
The rectification link adopts a phase-shifting transformer rectification technology, provides stable direct current bus voltage for the alternating current inversion link, and reduces harmonic waves. The bus capacitor pre-charging device comprises a pre-charging module and a phase-shifting transformer T1 module, wherein the pre-charging module is responsible for smoothly charging the bus capacitor, and impact current influence caused by high-speed charging is avoided.
The direct-current voltage link can rapidly act when the direct-current voltage is over-voltage and stabilize the direct-current voltage, and comprises a direct-current side voltage detection module and a chopping unit module.
The alternating current inversion link adopts an H-bridge cascade topological structure, provides stable power output for a load, and consists of a carrier phase-shifting SVPWM modulator and a filtering unit module, wherein the carrier phase-shifting SPWM modulation is matched with the H-bridge cascade topological structure for use, so that the equivalent switching frequency is improved, and the harmonic pollution is reduced.
The control unit of the shore power supply comprises a driving and protecting circuit. The control unit adjusts the output frequency and the output voltage of the corresponding shore power supply according to the signal provided by the parallel control module, so that the output power of the parallel shore power supply can be evenly divided. The method comprises the following specific steps:
(1) obtaining the given control voltage V of the current ship according to the voltage system of the connected ship0And given control frequency f0。
(2) Each phase voltage u sampled and output by data acquisition unit of high-voltage shore power supplya,ub,ucSampling the output current i of each phasea,ib,icCalculating to obtain effective voltage value V of each phasea,Vb,VcFrequency real time value fa,fb,fcActive power P of each phasea,Pb,PcReactive power Q of each phasea,Qb,Qc。
(3) According to the output phase voltage u of each phase in a mode of a software phase-locked loopa,ub,ucDetermining the phase angle theta on the AC side0Starting output by taking the angle as an initial angle to realize pre-synchronous starting of each droop-controlled shore power supply;
(4) calculating to obtain a frequency-active droop curve of three-phase active power and three-phase frequency by adopting a formula XX, wherein f0For frequency of each phase given value, ma，mb，mcIs the frequency-active droop curve coefficient;
(5) calculating to obtain a voltage-reactive droop curve of three-phase reactive power and three-phase voltage by adopting a formula XX, wherein V0Given values of effective voltage values, n, for each phasea，nb，ncIs a voltage-reactive droop curve coefficient;
(6) will f isa′，fb′，fc' controlling the frequency of each phase, V, as a given frequency value to a frequency controller of each phase of the H-bridge cascadea′，Vb′，VcThe three-phase voltage effective value is taken as a given value of a three-phase voltage effective value to be sent to a voltage controller, and the output effective value of each phase voltage is controlled; the voltage controller takes the given value and the actual value as input, and the output is the given value of the current inner ring, as shown in the following formula.
The formula is as follows:
wherein k ispuIs the proportionality coefficient of the voltage controller, kiuIs the integral coefficient of the voltage controller.
The given current value enters a current inner loop controller to form a modulation voltage, and the modulation voltage is output to an SPWM modulator to generate a corresponding control pulse, wherein the formula is as follows:
wherein k ispiIs the proportionality coefficient of the current controller, kiiIs the integral coefficient of the current controller.
(7) The output of the frequency controller and the voltage controller forms a three-phase modulation wave signal, and after the three-phase modulation wave signal is compared with a pulse signal of a phase-shifted carrier, SPWM control signals of all modules are generated to drive all power modules of a high-voltage shore power supply of the cascaded H bridge, so that output voltage for supplying power to the ship is formed.
Example 1
And simulating two high-voltage shore power supply parallel control systems through matlab simulation software.
The parameters of the main circuit of the high-voltage shore power supply connected in parallel are shown in the following table:
| NO. | parameter name | Parameter value | Unit of |
| 1 | Input voltage | 6000 | |
| 2 | Input frequency | 50 | |
| 3 | Rated |
2 | |
| 4 | DC bus voltage | 900 | |
| 5 | Output voltage | 6600 | |
| 6 | |
60 | Hz |
| 7 | |
5 | mH |
| 8 | |
1 | μF |
Taking a set of sag coefficients m as 1 × 10-6,n＝1×10-6And observing the parallel operation condition of the two shore power supplies.
After the two high-voltage shore power supplies start in no-load and stably operate, when t is 0.2s, the contactor is connected in parallel to be switched on, the two shore power supplies operate in parallel, the impact is small at the moment of parallel connection, and the two shore power supplies enter a stable operation state and are very gentle. When t is 0.25s, 1MW load is suddenly added to the common bus terminal, at this time, the two shore power supplies based on droop control can quickly respond and change, the current changes of the two power supplies are stable, the waveforms are as shown in fig. 4 and fig. 5, and when the output currents of the two power supplies rapidly rise from 0A to 60A, the parallel control system shows a good load power sharing function. At t of 0.35s, the load is cut off, and the impact is small at the moment of cutting off. The power waveforms of the two shore power supplies in the whole process are shown in fig. 6, and it can be seen through the waveforms that the high-voltage shore power supplies based on droop control are connected in parallel to achieve load power equalization well, and meanwhile, the output voltage waveforms (fig. 3) of the two shore power supplies show that the dynamic performance of the output voltage is good when the load suddenly changes.
Example 2
The parallel connection effect of the two high-voltage shore power supplies adopting the independent droop control method is verified by building an actual system. The experimental block diagram is shown in fig. 7, two high-voltage shore power supplies input with 10kV voltage, output is connected in parallel through two high-voltage switches, after the 1# shore power supply is started to operate at constant voltage and constant frequency, a simulated ship load is input, the 1# shore power supply operates with a load, the 2# shore power supply is started to operate in parallel with the 1# shore power supply through pre-synchronization as shown in fig. 8, load current is gradually equalized, when the 2# shore power supply is withdrawn, the load is borne by the 1# shore power supply, and the withdrawal process is shown in fig. 9.
The foregoing detailed description is exemplary only, and is intended to better enable others skilled in the art to understand the invention, and is not intended to limit the scope of the invention; any equivalent alterations or modifications made in accordance with the spirit of the present disclosure are within the scope of the present invention.
Claims (1)
1. A parallel connection method of H-bridge cascaded high-voltage shore power supplies based on independent droop control is suitable for parallel connection control of high-voltage shore power variable-frequency power supplies of cascaded H-bridge topologies, wherein the high-voltage shore power variable-frequency power supplies of the cascaded H-bridge topologies comprise a grid-connected switch G1, a pre-charging module M1, a rectifying link, a direct-current voltage link, an alternating-current inversion link, an output filtering link and a voltage and current detection and control link, wherein the rectifying link comprises a phase-shifting transformer T1 and uncontrolled rectifying units 1-18; the direct-current voltage link comprises direct-current voltage units 1-18 and chopper units 1-18, and the alternating-current inversion link comprises H-bridge cascade inversion units 1-18; the output filtering link comprises an isolation transformer T2, filtering capacitors C1-C3, filtering reactors L1-L3 and an output switch G2;
the voltage and current detection and control link comprises a main power supply module and a control link of a slave power supply module, wherein the control link of the main power supply module comprises a main module voltage and current detection and a constant voltage and constant frequency controller; the control link of the slave power supply module comprises slave module voltage and current detection, an active and reactive decoupling controller and a current inner loop controller;
the rectification link adopts a phase-shifting transformer rectification technology, so that stable direct current bus voltage is provided for the alternating current inversion link, and harmonic waves are reduced; the pre-charging module is responsible for smoothly charging a bus capacitor, so that impact current influence caused by quick charging is avoided;
the direct-current voltage link can quickly act when the direct-current voltage is over-voltage and stabilize the direct-current voltage, and comprises a direct-current side voltage detection module and a chopping unit module;
the alternating current inversion link adopts an H-bridge cascade topological structure, provides stable power output for a load, and consists of a carrier phase-shifting SVPWM modulator and a filtering unit module, wherein the carrier phase-shifting SVPWM modulator is matched with the H-bridge cascade topological structure for use, so that equivalent switching frequency is improved, and harmonic pollution is reduced;
the control unit of the shore power supply comprises a driving and protecting circuit; the control unit adjusts the output frequency and the output voltage of the corresponding shore power supply according to the signal provided by the parallel control module, so that the output power of the parallel shore power supply can be evenly divided, and the method comprises the following specific steps:
(1) obtaining the given control voltage V of the current ship according to the voltage system of the connected ship0And given control frequency f0；
(2) Each phase voltage u sampled and output by data acquisition unit of high-voltage shore power supplya,ub,ucSampling the output current i of each phasea,ib,icCalculating to obtain effective voltage value V of each phasea,Vb,VcFrequency real time value fa,fb,fcActive power P of each phasea,Pb,PcReactive power Q of each phasea,Qb,Qc；
(3) Tong (Chinese character of 'tong')The mode of the software phase-locked loop is based on the output phase voltage ua,ub,ucDetermining the phase angle theta on the AC side0Starting output by taking the angle as an initial angle to realize pre-synchronous starting of each droop-controlled shore power supply;
(4) calculating to obtain a frequency-active droop curve of three-phase active power and three-phase frequency by adopting a formula (1), wherein f0For frequency of each phase given value, ma，mb，mcIs the frequency-active droop curve coefficient;
(5) calculating to obtain a voltage-reactive droop curve of three-phase reactive power and three-phase voltage by adopting a formula (2), wherein V0Given values of effective voltage values, n, for each phasea，nb，ncIs a voltage-reactive droop curve coefficient;
(6) will f isa′，fb′，fc' controlling the frequency of each phase, V, as a given frequency value to a frequency controller of each phase of the H-bridge cascadea′，Vb′，VcThe three-phase voltage effective value is taken as a given value of a three-phase voltage effective value to be sent to a voltage controller, and the output effective value of each phase voltage is controlled;
(7) the output of the frequency controller and the voltage controller forms a three-phase modulation wave signal, and after the three-phase modulation wave signal is compared with a pulse signal of a phase-shifted carrier, SPWM control signals of all modules are generated to drive all power modules of a high-voltage shore power supply of the cascaded H bridge, so that output voltage for supplying power to the ship is formed.
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| GB2483879A (en) * | 2010-09-22 | 2012-03-28 | Qingchang Zhong | Proportional load sharing for inverters |
| CN105071405A (en) * | 2015-08-26 | 2015-11-18 | 电子科技大学 | Microgrid system with asymmetric non-linear load and power balancing control method |
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| GB2483879A (en) * | 2010-09-22 | 2012-03-28 | Qingchang Zhong | Proportional load sharing for inverters |
| CN105071405A (en) * | 2015-08-26 | 2015-11-18 | 电子科技大学 | Microgrid system with asymmetric non-linear load and power balancing control method |
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| 岸电系统并车方法及控制策略研究;盛晓东等;《电气技术》;20170831;第36卷(第16期);全文 * |
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Address after: 201210 3rd floor, building 1, No.400, Fangchun Road, China (Shanghai) pilot Free Trade Zone, Pudong New Area, Shanghai Patentee after: Chengrui Power Technology (Shanghai) Co. Address before: 201315 3rd floor, building 1, No.400, Fangchun Road, China (Shanghai) pilot Free Trade Zone, Pudong New Area, Shanghai Patentee before: CHENGRUI ELECTRIC POWER TECHNOLOGY (SHANGHAI) CO.,LTD. |