CN112636392A - Single-stage multi-terminal hybrid micro-grid structure suitable for low-voltage house and control method thereof - Google Patents

Single-stage multi-terminal hybrid micro-grid structure suitable for low-voltage house and control method thereof Download PDF

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CN112636392A
CN112636392A CN202011533450.9A CN202011533450A CN112636392A CN 112636392 A CN112636392 A CN 112636392A CN 202011533450 A CN202011533450 A CN 202011533450A CN 112636392 A CN112636392 A CN 112636392A
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CN112636392B (en
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陈元辉
何晋伟
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Hefei Institute Of Innovation And Development Tianjin University
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Hefei Institute Of Innovation And Development Tianjin University
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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
    • H02J3/388—Islanding, i.e. disconnection of local power supply from the network
    • 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
    • H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
    • 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
    • H02J3/28—Arrangements for balancing of the load in a network by storage of energy
    • H02J3/32—Arrangements for balancing of the load in a network by storage of energy using batteries with converting means
    • 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
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin

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Abstract

The invention discloses a single-stage multi-terminal hybrid micro-grid structure suitable for a low-voltage house and a control method thereof, wherein the single-stage multi-terminal hybrid micro-grid structure is formed by connecting a plurality of power modules in series, each power module comprises a direct current unit and a direct current/alternating current conversion circuit, and the direct current unit is formed by connecting a direct current bus capacitor and an energy storage system in parallel; the direct current/alternating current conversion circuit comprises a main power conversion circuit and a filter circuit, and also relates to a power and supply voltage electric energy quality control method of the micro-grid structure. The invention has the advantages that: the micro-grid structure only needs single-stage power conversion, the efficiency of the converter is improved, meanwhile, the low-bandwidth communication reduces the system cost, the control method can reasonably utilize the energy of a direct-current side power supply, reasonable power distribution among modules is automatically realized according to the state of the direct-current side, the service life of a direct-current unit is prolonged, overload protection of a basic module is automatically realized, and stable control of the frequency and the amplitude of a power supply voltage is automatically realized.

Description

Single-stage multi-terminal hybrid micro-grid structure suitable for low-voltage house and control method thereof
Technical Field
The invention relates to the technical field of low-voltage house power supply, in particular to a single-stage multi-terminal hybrid micro-grid structure suitable for a low-voltage house and a control method thereof.
Background
The power generation proportion of new energy is increased, and a large amount of distributed renewable energy and energy storage units thereof are connected to the microgrid, so that the development of the island medium-voltage microgrid is promoted. In past researches, an island-running micro-grid is formed by connecting a plurality of inverters in parallel, however, the voltage level of a distributed direct-current power supply is smaller than the grid-connected voltage level under common conditions, and the parallel inverters need to be boosted through two-stage power conversion to reach the grid-connected voltage level. The multi-inverter parallel system generally adopts droop control to realize power sharing without communication, but the droop control has the problems of instability, inaccurate reactive power distribution and the like. On the other hand, a series inverter has been proposed, which is an important means for connecting renewable energy to a power grid by connecting a low-voltage-class dc power supply in series after performing primary power conversion and then connecting the dc power supply to the grid.
Past research has focused on grid-connected operation of inverters, which are connected in series in multiple stages and then output from one voltage port, but for house power supply, output from multiple ports may be required simultaneously, and load power levels are different; the frequency and amplitude of the output voltage may be biased by only using the inverse power factor droop control; moreover, for the cascade-type converter, the available power of the energy storage at each direct current side is different, and the traditional mode of uniform power distribution is not applicable any more.
In order to overcome the difficulties of the house power supply of the cascade converter, a structure which only needs single-stage power conversion and has a plurality of output ports and a power distribution and supply voltage management control method with high reliability are urgently needed to be provided.
Disclosure of Invention
The invention aims to make up the defects of the prior art and provides a single-stage multi-terminal hybrid micro-grid structure suitable for a low-voltage house and a control method thereof.
The invention is realized by the following technical scheme:
the invention provides a single-stage multi-terminal hybrid micro-grid structure, which is applied to a single-phase micro-grid system which takes an H bridge unit formed by IGBTs as a main power inverter circuit to provide stable and continuous power supply for a load, the structure is formed by connecting three power modules in series, each power module comprises a direct current unit and a direct current/alternating current conversion circuit, and the direct current unit is formed by connecting a direct current bus capacitor and an energy storage system in parallel; the direct current/alternating current conversion circuit comprises a main power conversion circuit and a filter circuit, wherein the filter circuit consists of a filter inductor and a filter capacitor, the input end of the filter inductor is connected with one end of the main power inverter circuit, the output end of the filter inductor is connected with the input end of the filter capacitor and is connected to one end of an external heavy load connection point or the output end of the filter capacitor of another power module, and the output end of the filter capacitor is connected with the output end of the filter inductor of the other power module or is connected to the other end of the external heavy load connection point; the single-end multi-port hybrid microgrid system sampling circuit mainly comprises a basic unit module sampling circuit and a backup unit module sampling circuit. The basic unit module sampling circuit comprises a sampling circuit for outputting total current to the module, a sampling circuit for sampling the self-carried load current of the basic unit module, a sampling circuit for sampling the voltage between load connection points and an energy storage battery information sampling circuit in a corresponding direct current unit, and the information obtained by sampling is transmitted to the basic unit module controller; the backup unit module sampling circuit comprises a sampling circuit for outputting total current to the self module, a sampling circuit for outputting power supply current to the whole load, a sampling circuit for outputting voltage by a filter capacitor, and an energy storage battery information sampling circuit in the corresponding direct current unit, wherein information obtained by sampling is transmitted into the backup unit module controller.
Based on the low-voltage single-stage multi-terminal hybrid micro-grid structure, the invention also provides a control method based on the low-voltage single-stage multi-terminal micro-grid structure, which comprises the following steps: (1) the central controller obtains the active power of the unit module and the state of charge (SOC) of the battery at the direct current side, which are obtained by the unit module sampling circuit in a low-bandwidth communication mode, reasonably distributes the output among the cascaded unit modules by the proposed method for distributing the power based on the active functional energy at the direct current side, and sends the calculated power reference value of the unit module to the unit module controller at the next layer in the low-bandwidth communication mode. (2) The unit module controller samples the voltage of the filter capacitor output by the unit module, outputs total current, self-carried load current and outgoing current, calculates the output total apparent power, total active power, outgoing power and power factor of external overload of the corresponding unit module, uploads the output total active power information to the central controller, receives the power reference value calculated by the central controller, controls the power factor through the provided output power factor adjusting method and the reverse power factor droop control method, and utilizes the voltage current double closed loop to track and output control quantity, thereby achieving the effect of accurate power distribution. (3) The basic unit module calculates a power factor of the corresponding unit module to the external heavy load according to the voltage at two ends of the output capacitor of the unit module measured by the voltage measuring circuit and the total output current of the unit module measured by the current sensor, compares the power factor with a set limit power factor in real time, and sets a reference power factor value as the limit power factor value and sets a state of charge (SOC) and total output active power measured by the corresponding unit module as 0 once the real-time power factor is greater than the limit power factor, so as to perform over-power protection of the unit module.
Preferably, the step (1) specifically comprises the following steps: the central controller communicates with the unit module controllers in a low-bandwidth communication mode, acquires the total active power of each unit module and the state of charge (SOC) of the direct current battery from the unit module controllers, and determines the weighted average of each battery as:
Figure BDA0002852627470000031
wherein the SOC，i(i ═ 1,2,3) is the SOC of each cell. SOC，3The voltage of the backup unit module relative to the other two base unit modules is considered.
Finally, the central controller also derives three units Psi(i ═ 1,2,3) active power collectionPower information, and actual power is distributed according to the SOC.
Figure BDA0002852627470000032
Wherein P issoc，iIs the reference active power of converter i.
Preferably, the step (2) comprises the following steps: the unit control module receives reference power from the central controller through low-bandwidth communication, and the angular speed of the instantaneous reference voltage can be calculated according to the power and the anti-power factor droop control method:
Figure BDA0002852627470000033
wherein DPFIs the reverse sag factor, SiAnd λiIs the apparent power and power factor of cell i. PloadiIs the external load power of both base unit modules.
At the same time, the amplitude of the instantaneous reference voltage can also be determined:
Ei＝120(i＝1,2) (1-3)
Figure BDA0002852627470000034
wherein EiIs a reference for the amplitude of the output voltage of each basic cell module. Reference voltage and V of backup unit module for compensating terminal voltage of heavy-load interfacecIn connection with, VcIs the total voltage of the series connected power cells. k is a radical ofpIs the proportional gain, kiIs the integral gain.
To avoid the effect of power factor caused by line current ripple, λiFiltering with Low Pass Filter (LPF) with time constant of omegacut
Figure BDA0002852627470000041
The reference voltage of each unit module obtained through (1-4) to (1-6) is:
Figure BDA0002852627470000042
finally, accurate voltage tracking is ensured by a voltage-current double closed-loop controller:
Figure BDA0002852627470000043
Figure BDA0002852627470000044
wherein, VcIs the measured cell module output voltage, kp，vIs the proportional control gain, ki，vIs the resonant controller gain, and ωcIs the cut-off frequency in radians. k is a radical ofinnerIs the proportional gain, I, of the inner loop controllersiIs the measured cell module converter output current.
Preferably, the step (3) includes the following steps: the basic unit module measures and obtains the voltage of the output capacitor end of the unit module and the total current output by the module, so as to calculate the power factor of the module to the external heavy load, and makes a difference with the set limit power factor, when the actual power factor is larger than the limit power factor, the reference power factor is forced to be the limit power factor, and the battery state of charge (SOC) and the output active power measured by the corresponding unit module are set to be zero, so as to keep the current power output, and the protected state is as follows:
ωi＝ω*+DPF·(λi-λi-lim)(i＝1,2) (1-11)
SoCi(i＝1,2)＝0 (1-12)
Psi(i＝1,2)＝0 (1-13)
when the power required by heavy load is increased, the output power of the basic unit module is not increased, and the increased power is completely provided by the backup unit module.
The invention has the advantages that:
1. the low-voltage single-stage multi-terminal micro-grid structure formed by serially connecting the power unit modules is different from the traditional inverter mode in that a plurality of power modules are connected in series, and a DC/DC boost conversion link in the traditional micro-grid structure is omitted, so that the system cost is reduced, and the operation efficiency of the power modules is improved.
2. The single-stage power conversion specific to the series structure reduces the requirement of the power module on the level of the direct current side input voltage, improves the utilization rate of new energy, and reduces the requirement of the micro-grid system on the new energy.
3. For external heavy load, the inherent circuit property of the series connection mode between the power modules ensures that the output currents of the power modules are constant and equal, the problem of circulation does not exist, the use of the traditional circulation restraining equipment is avoided, and the cost is reduced.
4. The power control and power supply voltage management method has the characteristics of simplicity and practicality, does not need communication among power modules, automatically realizes reasonable power distribution among unit modules, automatically realizes power supply voltage control, and can protect the power of a basic unit module from overload, thereby solving the problems of accurate power distribution and power supply voltage management of the traditional island micro-grid under low-bandwidth communication.
Drawings
Fig. 1 is a schematic diagram of a low-voltage house power supply microgrid structure provided in an embodiment of the present invention;
fig. 2 is a flow chart of a hierarchical control of a low-voltage single-stage multi-terminal microgrid structure according to an embodiment of the present invention;
fig. 3 is a flowchart illustrating an overload protection control of a basic cell module according to an embodiment of the present invention;
fig. 4 is a waveform diagram of simulation provided by the embodiment of the present invention.
Detailed Description
Referring to fig. 1, the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Referring to fig. 1, fig. 2, and fig. 3 and fig. 4, fig. 1 is a schematic diagram of a low-voltage house power supply microgrid structure according to an embodiment of the present invention; fig. 2 is a flowchart illustrating a hierarchical control of a low-voltage house power supply microgrid structure according to an embodiment of the present invention; fig. 3 is a flowchart of basic unit module overload protection control according to an embodiment of the present invention. FIG. 4 is a waveform diagram of simulation provided by an embodiment of the present invention.
As shown in fig. 1 and 2, the low-voltage single-stage multi-port microgrid structure formed by serially connecting power modules is formed by serially connecting two basic unit modules and a standby unit module, wherein the unit modules comprise direct current units and direct current/alternating current conversion circuits. The direct current unit is formed by connecting a direct current bus capacitor and an energy storage battery in parallel; the DC/AC conversion circuit comprises a main power conversion circuit and a filter circuit, wherein the filter circuit comprises a filter inductor L and a filter capacitor CfThe input end of the filter inductor L is connected with one end of the main power inverter circuit, and the output end of the filter inductor L is connected with the filter capacitor CfIs connected to one end of an external heavy-load connection point or a filter capacitor C of another power modulefOf the filter capacitor CfAnd the filter inductance L of another power modulefThe output end of the connecting rod is connected with or connected to the other end of the external heavy load connecting point; the low-voltage single-stage multi-port microgrid system sampling circuit is divided into a basic unit controller sampling circuit and a backup unit controller sampling circuit. The basic unit module sampling circuit comprises a sampling circuit for outputting total current to the module, a sampling circuit for sampling the self-carried load current of the basic unit module, a sampling circuit for sampling the voltage between load connection points and an energy storage battery information sampling circuit in a corresponding direct current unit, and the information obtained by sampling is transmitted to the basic unit module controller; the backup unit module sampling circuit comprises a sampling circuit for outputting total current to the self module, a sampling circuit for supplying current to the whole load, a sampling circuit for outputting voltage by the filter capacitor and an energy storage battery information sampling circuit in the corresponding direct current unitAnd the circuit is used for transmitting the information obtained by sampling into the backup unit module controller.
Aiming at the low-voltage single-stage multi-terminal micro-grid layered control technology formed by connecting the power modules in series, the invention comprises the following basic steps:
firstly, the central controller communicates with the basic unit module controller and the backup module controller through low bandwidth communication, the central controller obtains the total active power of each unit module from the unit module controller and the state of charge (SOC) of the direct current measurement battery, and the weighted average of each battery is determined as follows:
Figure BDA0002852627470000061
wherein the SOC，i(i ═ 1,2,3) is the SOC of each cell. SOC，3The voltage of the backup unit module relative to the other two base unit modules is considered.
Finally, the central controller also derives three units Psi(i-1, 2,3) collecting active power information and distributing actual power according to the SOC.
Figure BDA0002852627470000062
Wherein P issoc，iIs the reference active power of converter i.
Secondly, the unit control module receives reference power from the central controller through low bandwidth communication, and the angular speed of the instantaneous reference voltage can be calculated according to the power and the anti-power factor droop control method:
Figure BDA0002852627470000063
wherein DPEIs the reverse sag factor, SiAnd λiIs the apparent power and power factor of cell i. PloadiIs the output power of two basic unit modules to the external heavy load。
At the same time, the amplitude of the instantaneous reference voltage can also be determined:
Ei＝120(i＝1,2) (1-3)
Figure BDA0002852627470000071
wherein EiIs a reference for the amplitude of the output voltage of each basic cell module. Reference voltage and V of backup unit module for compensating voltage of external heavy loadcIn connection with, VcIs the total voltage of the series connected power cells. k is a radical ofpIs the proportional gain, kiIs the integral gain.
To avoid the effect of power factor caused by line current ripple, λiFiltering with Low Pass Filter (LPF) with time constant of omegacut
Figure BDA0002852627470000072
The reference voltage of each unit module can be obtained by equations (4) to (6):
Figure BDA0002852627470000073
finally, accurate voltage tracking is ensured by a voltage-current double closed-loop controller:
Figure BDA0002852627470000074
Figure BDA0002852627470000075
wherein, VcIs the measured cell module output voltage, kp，vIs the proportional control gain, ki，vIs the resonant controller gain, and ωcIs the cut-off frequency in radians. k is a radical ofinnerIs the proportional gain, I, of the inner loop controllersiIs the measured cell module converter output current.
Thirdly, the basic unit module measures and obtains the voltage of the output capacitor end of the unit module and the current output to the external heavy load by the unit module, so as to calculate the power factor of the unit module to the external heavy load, and makes a difference with a preset limit power factor, when the actual power factor to the external heavy load is larger than the limit power factor, the reference power factor is forced to be the limit power factor, and the battery state of charge (SOC) and the output active power measured by the corresponding unit module are set to be zero, so as to keep the current power output, and the protected state is as follows:
ωi＝ω*+DPF·(λi-λi-lim)(i＝1,2) (1-11)
SoCi(i＝1,2)＝0 (1-12)
Psi(i＝1,2)＝0 (1-13)
when the power required by heavy load is increased, the current output power of the basic unit module is kept, and the power required to be increased is completely provided by the backup unit module.
In conclusion, the method realizes that the multi-port voltage is effectively managed under the condition without a high-frequency communication line, particularly the external heavy-load voltage is effectively compensated, the basic unit modules can be subjected to over-power protection, the energy of a direct-current side power supply can be reasonably utilized among the power modules, and the reasonable distribution of the power in the system is automatically realized.
As shown in the simulation waveform of fig. 4, the dc-side battery state of charge (SOC) is set to 100% for the basic unit module 1 and 60% for the basic unit module 2 and 80% for the backup unit module, with 5 seconds as a boundary. The traditional fixed amplitude and fixed frequency control is adopted before 5 seconds, and the control is carried out by the method provided by the text after 5 seconds. As can be seen from the first row and column waveform diagrams, with constant amplitude, the power output during constant frequency control is: the output 2028W of the basic unit module 1, the output 2312W of the backup unit module by the basic unit module 2, after the method provided by the text is executed after 5 seconds, the output 2330W of the basic unit module 1, and the output 1873W of the backup unit module by the basic unit module 2 have the same proportion with the direct current side SOC, which proves that the scheme can effectively realize the accurate power distribution among the unit modules according to the direct current side state; meanwhile, the frequency waveform diagram of the first row and the second row shows that the voltage frequency of the external heavy-load terminal is always kept constant, and the output voltage frequency of the unit module only slightly changes at the switching moment of the control scheme. The second row and column are the output voltage of the unit module and the output heavy load current to the outside under the traditional control scheme, and the second row and column are the module voltage and the output heavy load current under the control of the method provided by the invention, and the comparison shows that: under the traditional control mode, the voltages of the basic modules 1 and 2 are basically the same, and the output voltage of the backup unit module is smaller; after the method provided by the invention is adopted, the output voltage phase of the basic unit module has obvious difference, and the voltage amplitude output by the backup unit is obviously improved. The last behavior is the basic module overload protection waveform, and it can be seen that the output power can not be increased any more in the later period of the basic unit overload, the power factor for the external overload is kept constant, and the operation safety and stability of the basic power unit are ensured.
The present invention is not limited to the above-described embodiments. The foregoing description of the specific embodiments is intended to describe and illustrate the technical solutions of the present invention, and the above specific embodiments are merely illustrative and not restrictive. Those skilled in the art can make many changes and modifications to the invention without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (5)

1. The utility model provides a be adapted to single-stage multiterminal little electric wire netting structure that mixes in low pressure house which characterized in that: the power module comprises a direct current unit and a direct current/alternating current conversion circuit, wherein the direct current unit is formed by connecting a direct current bus capacitor and an energy storage battery in parallel; the direct current/alternating current conversion circuit comprises a main power conversion circuit and a filter circuit, wherein the filter circuit consists of a filter inductor and a filter capacitor, the input end of the filter inductor is connected with one end of the main power conversion circuit, the output end of the filter inductor is connected with the input end of the filter capacitor and is connected to one end of an external heavy load connection point or the output end of the filter capacitor of another power module, and the output end of the filter capacitor is connected with the output end of the filter inductor of the other power module or is connected to the other end of the external heavy load;
the sampling circuit comprises a basic unit module sampling circuit and a backup unit module sampling circuit, wherein the basic unit module sampling circuit comprises a sampling circuit for outputting total current to a module per se, a sampling circuit for the current of the load carried by the basic unit module per se, a sampling circuit for the voltage between load connection points and an energy storage battery information sampling circuit in a corresponding direct current unit, and the information obtained by sampling is transmitted to a basic unit module controller; the backup unit module sampling circuit comprises a sampling circuit for outputting total current to the self module, a sampling circuit for outputting power supply current to the whole load, a sampling circuit for outputting voltage by the filter capacitor and an energy storage battery information sampling circuit in the corresponding direct current unit, and information obtained by sampling is transmitted to the backup unit module controller.
2. A control method of a single-stage multi-terminal hybrid micro-grid structure suitable for a low-voltage house is characterized by comprising the following steps of: the method specifically comprises the following steps:
(1) the central controller obtains corresponding battery charge state and output power from the unit module controller in a low-bandwidth communication mode, then determines actual power distribution by weighted average of the charge state, and transmits a distributed power reference value to the unit module controller in a low-bandwidth communication mode;
(2) the module controller samples the output total current of the module, the voltage of a filter capacitor at a port, the load current of the module and the current additionally sent to a common load, the output total power calculated by the module is transmitted to an upper-layer central controller through a low-bandwidth communication system, an active power reference value is obtained from the central controller, and finally power distribution among the series-connected units is realized through the module controller, wherein a backup unit module is used for compensating the voltage and the power of a heavy-load port, the reference voltage of a basic unit module is a constant value, and the reference voltage of the backup unit module is changed along with the change of the load condition;
(3) the output power of the basic unit module is limited, specific parameters are set, the power of the unit module is controlled not to exceed a limit value, the unit module is protected, and the power requirement of the load which is continuously increased is provided by the backup unit module.
3. The method for controlling the single-stage multi-terminal hybrid microgrid structure adapted to a low-voltage house according to claim 2, characterized in that: the step (1) specifically comprises the following steps:
a) sampling the voltage of a filter capacitor output by a unit module by using a voltage sensor, sampling the total current output by the unit module by using a current sensor, simultaneously acquiring the charge state information of a battery at a direct current side, calculating the total power output by the unit module, and finally transmitting the calculated output active power and the charge state of the battery to a central controller in a low-bandwidth communication mode, wherein in the central controller, the weighted average SOC of each battery is determined as follows:
Figure FDA0002852627460000021
wherein the SOC，i(i-1, 2,3) is the SOC per cell, SOC，3The voltage of the backup unit module relative to the other two basic unit modules is considered;
b) the active power information P obtained by the transmission of the central controller through the lower layer unit module controllersi(i is 1,2,3) and the power distribution among the modules is carried out according to the charge state of the battery,
Figure FDA0002852627460000022
wherein P issoc，iIs the reference active power of converter i.
4. The method for controlling the single-stage multi-terminal hybrid microgrid structure adapted to a low-voltage house according to claim 3, characterized in that: the step (2) specifically comprises the following steps:
a) power reference P calculated by the central controller via the bandwidth communication systemsoc，iThe power sharing is realized by the unit module controllers; to obtain a voltage transient reference, the voltage amplitude is determined as:
Ei＝120(i＝1,2) (1-3)
Figure FDA0002852627460000023
wherein EiIs a reference of voltage amplitude of basic unit module, and in order to compensate heavy-load terminal voltage, reference voltage and voltage V of backup unit modulecIn connection with, VcIs the voltage of the series power cell, Kp3Is the proportional gain, Ki3Is the integral gain;
b) ) using the inverse power droop control to obtain a reference phase angle:
Figure FDA0002852627460000031
wherein DPFIs the reverse sag factor, SiAnd λiIs the apparent power and power factor, ω, of cell i*Representing a given angular frequency, WSoC，iRepresenting the weighted average coefficient, P, of each cellloadiIs the internal self-load power of two basic unit modules;
power factor lambdaiFiltering with low-pass filter with time constant of omegacutAnd s represents an integration factor
Figure FDA0002852627460000032
Wherein theta isiIs the power factor angle of the unit module;
the reference voltage of each unit module is determined by equations (1-4) to (1-5):
Figure FDA0002852627460000033
c) after the instantaneous reference voltage is obtained by the unit control module, the voltage at two ends of the filter capacitor output by the unit module measured by the voltage sensor and the total current output by the unit module measured by the current sensor are combined, and the voltage and current double closed-loop control is adopted to realize accurate voltage tracking;
Figure FDA0002852627460000034
Figure FDA0002852627460000035
wherein G isV(s) represents the voltage loop control transfer function, VPCRepresenting a reference voltage, V, of each unit blockcThe voltage k at two ends of the filter capacitor output by the measuring unit modulep，vIs the proportional control gain, ki，vIs the resonant controller gain, and ωcCutoff frequency in radians; gI(s) represents the current loop control transfer function, kinnerIs the proportional gain, I, of the inner loop controllersiIs the measured total output current of the unit module.
5. The method for controlling the single-stage multi-terminal hybrid microgrid structure adapted to a low-voltage house according to claim 4, characterized in that: the step (3) specifically comprises the following steps:
from the power distribution, it is concluded that the power factor is positively correlated with the unit module output current, namely:
λi-lim∝Isi (1-10)
wherein λiFor each unit module power factor, IsiSetting the power factor lambda corresponding to the power limit for outputting the total current for each unit modulei-limBy determining the power factor lambda in real timeiPerforming overpower protection control in relation to the magnitude thereof; when the real-time power factor is larger than the limit power factor, the instantaneous reference angular velocity calculation formula of the basic unit module becomes:
ωi＝ω*+DPF·(λi-λi-lim)(i＝1,2) (1-11)
simultaneously transmitting the battery charge state and the output active power P of the corresponding unit module controller to the central controllers2And meanwhile, setting the voltage to be 0 to realize the over-power protection of the basic unit module, wherein the part of the increased load power is completely provided by the backup unit module.
CN202011533450.9A 2020-12-23 2020-12-23 Single-stage multi-terminal hybrid micro-grid structure suitable for low-voltage house and control method thereof Active CN112636392B (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113541173A (en) * 2021-07-06 2021-10-22 北京朗信智能科技有限公司 Battery energy storage system cluster control device and control method under weak power grid condition
CN117895572A (en) * 2024-03-14 2024-04-16 深圳市宝安任达电器实业有限公司 Island cascade H-bridge control method adopting hybrid power module modulation

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110572067A (en) * 2019-08-19 2019-12-13 天津大学 Island energy storage type power unit series micro-grid structure and control method
CN110571796A (en) * 2019-08-29 2019-12-13 天津大学 Island operation cascade H-bridge micro-grid structure decentralized interleaving and layered harmonic wave treatment method
CN110690727A (en) * 2019-09-20 2020-01-14 天津大学 Cascading H-bridge converter flexible grid-connection method based on hierarchical voltage control

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110572067A (en) * 2019-08-19 2019-12-13 天津大学 Island energy storage type power unit series micro-grid structure and control method
CN110571796A (en) * 2019-08-29 2019-12-13 天津大学 Island operation cascade H-bridge micro-grid structure decentralized interleaving and layered harmonic wave treatment method
CN110690727A (en) * 2019-09-20 2020-01-14 天津大学 Cascading H-bridge converter flexible grid-connection method based on hierarchical voltage control

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113541173A (en) * 2021-07-06 2021-10-22 北京朗信智能科技有限公司 Battery energy storage system cluster control device and control method under weak power grid condition
CN117895572A (en) * 2024-03-14 2024-04-16 深圳市宝安任达电器实业有限公司 Island cascade H-bridge control method adopting hybrid power module modulation
CN117895572B (en) * 2024-03-14 2024-05-28 深圳市宝安任达电器实业有限公司 Island cascade H-bridge control method adopting hybrid power module modulation

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