CN108512229B - Fuzzy coordination control method for alternating current-direct current section in alternating current-direct current hybrid micro-grid - Google Patents
Fuzzy coordination control method for alternating current-direct current section in alternating current-direct current hybrid micro-grid Download PDFInfo
- Publication number
- CN108512229B CN108512229B CN201810373603.4A CN201810373603A CN108512229B CN 108512229 B CN108512229 B CN 108512229B CN 201810373603 A CN201810373603 A CN 201810373603A CN 108512229 B CN108512229 B CN 108512229B
- Authority
- CN
- China
- Prior art keywords
- frequency
- voltage
- signal
- controller
- adaptive inverse
- 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.)
- Expired - Fee Related
Links
- 238000000034 method Methods 0.000 title claims abstract description 55
- 230000002457 bidirectional effect Effects 0.000 claims abstract description 69
- 230000003044 adaptive effect Effects 0.000 claims description 80
- 238000001514 detection method Methods 0.000 claims description 46
- 238000006243 chemical reaction Methods 0.000 claims description 13
- 230000005540 biological transmission Effects 0.000 abstract description 17
- 230000010355 oscillation Effects 0.000 abstract description 7
- 238000010586 diagram Methods 0.000 description 4
- 238000002955 isolation Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Images
Classifications
-
- 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
- H02J3/04—Circuit arrangements for ac mains or ac distribution networks for connecting networks of the same frequency but supplied from different sources
- H02J3/06—Controlling transfer of power between connected networks; Controlling sharing of load between connected networks
-
- 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
- H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
-
- 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
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Feedback Control In General (AREA)
- Inverter Devices (AREA)
Abstract
A fuzzy coordination control method for an AC/DC power flow section in an AC/DC hybrid microgrid comprises the following steps: selecting more than one AC/DC bidirectional converter to control the frequency of an alternating current area in an AC/DC power flow section consisting of a plurality of AC/DC bidirectional converters, and controlling the voltage of a direct current bus by the rest AC/DC bidirectional converters; the AC/DC bidirectional converter for controlling the frequency of the AC region is controlled by adopting a frequency-active droop control method, the detected frequency of the AC region is used as an input quantity, and the frequency of the AC region is kept constant through the frequency-active droop control; an AC/DC bidirectional converter for controlling the voltage of a direct current bus adopts a voltage-active droop control method, uses the detected voltage of the direct current bus as an input quantity, and maintains the voltage of the direct current bus to be constant through the voltage-active droop control. The invention can avoid the oscillation problem caused by excessively adjusting the droop control by the self-adaptive inverse theory and improve the dynamic response speed of the transmission power.
Description
Technical Field
The invention relates to a plurality of AC/DC bidirectional converters in an alternating current and direct current mixed microgrid. In particular to a fuzzy coordination control method for an AC/DC power flow section in an AC/DC hybrid micro-grid consisting of a plurality of AC/DC bidirectional converters in the AC/DC hybrid micro-grid.
Background
The alternating current-direct current hybrid micro-grid integrates the advantages of the alternating current micro-grid and the direct current micro-grid, and provides an effective way for high-density distributed energy to be connected into a power distribution network. Under the general condition, the alternating current-direct current hybrid micro-grid has two operation modes of grid connection and grid disconnection, and due to the intermittence and the fluctuation of the output force of the distributed power supply, compared with the grid connection operation mode, the micro-grid in the grid disconnection mode lacks the power support of a large power grid, the fluctuation of the voltage and the frequency in the micro-grid is more frequent, and the fluctuation amplitude is increased. Therefore, higher requirements are put forward on a control method when the alternating current-direct current hybrid microgrid runs off the grid.
The alternating current area and the direct current area of the alternating current-direct current hybrid micro-grid are connected to the alternating current/direct current flow section, and mutual support of active power between the alternating current sub-micro-grid and the direct current sub-micro-grid can be achieved. When the alternating current-direct current hybrid micro-grid operates off-grid, the AC/DC bidirectional converters stabilize the power fluctuation of the alternating current sub-micro-grid and the direct current sub-micro-grid by dynamically adjusting the transmission power and maintain the constant voltage and frequency in the alternating current-direct current hybrid micro-grid.
Droop control is the most common control mode in the current AC/DC bidirectional converter, and has the advantages of reasonably distributing transmission power without communication, but the droop control has the inherent contradiction of power output and frequency (voltage) deviation, and the frequency (voltage) generates larger deviation when the transmission power fluctuates greatly. The droop control based on the adaptive inverse theory realizes zero error adjustment of frequency (voltage) by adjusting the droop coefficient, but the droop coefficient can fluctuate back and forth in a steady state to cause system oscillation, and when power fluctuation is large, the droop control based on the adaptive inverse theory has the problems that the droop coefficient is too slow in adjustment speed and the overshoot is large.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a fuzzy coordination control method for an AC/DC power flow section in an AC/DC hybrid micro-grid, which can enable an AC/DC bidirectional converter in the AC/DC hybrid micro-grid to overcome the inherent contradiction between power output and frequency (voltage) deviation in the traditional droop control, accelerate the dynamic response of power, reduce the overshoot of frequency (voltage), and avoid the over-regulation of a droop coefficient.
The technical scheme adopted by the invention is as follows: a fuzzy coordination control method for an AC/DC power flow section in an AC/DC hybrid microgrid comprises the following steps: selecting more than one AC/DC bidirectional converter to control the frequency of an alternating current area in an AC/DC power flow section consisting of a plurality of AC/DC bidirectional converters, and controlling the voltage of a direct current bus by the rest AC/DC bidirectional converters; the AC/DC bidirectional converter for controlling the frequency of the AC region is controlled by adopting a frequency-active droop control method, the detected frequency of the AC region is used as an input quantity, and the frequency of the AC region is kept constant through the frequency-active droop control; an AC/DC bidirectional converter for controlling the voltage of a direct current bus adopts a voltage-active droop control method, uses the detected voltage of the direct current bus as an input quantity, and maintains the voltage of the direct current bus to be constant through the voltage-active droop control.
The frequency-active droop control method comprises the following steps:
1) obtaining a frequency detection value by detecting the frequency of the alternating current area, and subtracting the frequency setting value from the frequency detection value to obtain a frequency error signal;
2) respectively inputting the frequency error signals into a fuzzy controller, a self-adaptive inverse controller and a secondary controller, and inputting a frequency set value and a frequency detection value into the self-adaptive inverse controller;
3) the fuzzy controller respectively outputs a frequency iteration step signal and a frequency secondary control signal according to the obtained error signal, inputs the frequency iteration step signal into the self-adaptive inverse controller, and inputs the frequency secondary control signal into the secondary controller;
4) the self-adaptive inverse controller obtains a frequency-active droop coefficient according to the frequency error signal and the frequency iteration step length signal, and then multiplies the frequency-active droop coefficient by the frequency error signal to obtain a frequency power deviation signal; the secondary controller obtains a frequency secondary power deviation according to a frequency secondary control signal and a frequency error signal output by the fuzzy controller;
5) adding the set frequency power signal, the frequency power deviation signal and the frequency secondary power deviation signal to obtain a reference signal of the frequency active power;
6) and the reference signal of the frequency active power is output through proportional-integral control and current inner loop control in sequence, so that the control target that the frequency detection value of the AC/DC bidirectional converter is equal to the frequency set value is achieved.
And 3) the fuzzy controller sequentially performs analog-to-digital conversion and fuzzification on the frequency error signal, performs fuzzy reasoning, defuzzification and digital-to-analog conversion according to a fuzzy rule base, and then respectively obtains a frequency iteration step signal and a frequency secondary control signal.
The self-adaptive inverse controller in the step 4) carries out the following processes:
(1) the self-adaptive inverse controller inputs the frequency set value into a replica self-adaptive inverse filter, and the replica self-adaptive inverse filter multiplies the frequency set value by a weight coefficient in the replica self-adaptive inverse filter through signal delay and then adds the frequency set value and the weight coefficient to obtain a first frequency-active droop coefficient kf 1;
(2) the adaptive inverse controller takes the first frequency-active droop coefficient kf1 as a frequency-active droop coefficient to carry out droop control on the AC/DC bidirectional converter;
(3) the adaptive inverse controller takes the frequency detection value as the input of the adaptive inverse filter, multiplies the frequency detection value by the weight coefficient in the adaptive inverse filter through signal delay, and then adds the frequency detection value and the weight coefficient to obtain a second frequency-active droop coefficient kf 2;
(4) the adaptive inverse controller subtracts the first frequency-active droop coefficient kf1 from the second frequency-active droop coefficient kf2, and the difference value is subjected to an adaptive algorithm, and meanwhile, the obtained frequency iteration step signal is input into the adaptive algorithm, and the weight coefficients of the adaptive inverse filter and the replica adaptive inverse filter are dynamically adjusted through the adaptive algorithm, so that the first frequency-active droop coefficient kf1 and the second frequency-active droop coefficient kf2 are adjusted.
In the step 4), the secondary controller obtains the frequency secondary power deviation through the following judgment:
(1) when the frequency secondary control signal is 0, the frequency secondary power deviation output by the secondary controller is always a constant value;
(2) when the frequency secondary control signal is 1, the secondary controller adjusts the constant value of the frequency secondary power deviation according to the frequency error signal, and the constant value of the frequency secondary power deviation is adjusted once every time the frequency error signal exceeds a set frequency limit value, and the frequency secondary power deviation obtained by the adjustment is used as a new constant value of the frequency secondary power deviation.
The voltage-active droop control method comprises the following steps:
1) obtaining a voltage detection value by detecting the voltage of the direct current bus, and subtracting the voltage set value from the voltage detection value to obtain a voltage error signal;
2) respectively inputting the voltage error signals into a fuzzy controller, a self-adaptive inverse controller and a secondary controller, and inputting a voltage set value and a voltage detection value into the self-adaptive inverse controller;
3) the fuzzy controller respectively outputs a voltage iteration step signal and a voltage secondary control signal according to the obtained voltage error signal, inputs the voltage iteration step signal into the self-adaptive inverse controller, and inputs the voltage secondary control signal into the secondary controller;
4) the self-adaptive inverse controller obtains a voltage-active droop coefficient according to the voltage error signal and the voltage iteration step length signal, and then multiplies the voltage-active droop coefficient by the voltage error signal to obtain a voltage power deviation signal; the secondary controller obtains a voltage secondary power deviation according to a voltage secondary control signal and a voltage error signal output by the fuzzy controller;
5) adding the set voltage power signal, the voltage power deviation signal and the voltage secondary power deviation signal to obtain a reference signal of voltage active power;
6) and the reference signal of the voltage active power is output through proportional-integral control and current inner loop control in sequence, so that the control target that the voltage detection value of the AC/DC bidirectional converter is equal to the voltage set value is achieved.
And 3) the fuzzy controller sequentially performs analog-to-digital conversion, fuzzification, fuzzy reasoning according to a fuzzy rule base, defuzzification and digital-to-analog conversion on the voltage error signal to respectively obtain a voltage iteration step signal and a voltage secondary control signal.
The self-adaptive inverse controller in the step 4) carries out the following processes:
(1) the self-adaptive inverse controller inputs the voltage set value into a replica self-adaptive inverse filter, and the replica self-adaptive inverse filter multiplies the voltage set value by a weight coefficient in the replica self-adaptive inverse filter through signal delay and then adds the product to obtain a first voltage-active droop coefficient kv 1;
(2) the adaptive inverse controller takes the first voltage-active droop coefficient kv1 as a voltage-active droop coefficient to carry out droop control on the AC/DC bidirectional converter;
(3) the adaptive inverse controller takes the voltage detection value as the input of the adaptive inverse filter, multiplies the voltage detection value by a weight coefficient in the adaptive inverse filter through signal delay, and then adds the product to obtain a second voltage-active droop coefficient kv 2;
(4) the adaptive inverse controller subtracts the first voltage-active droop coefficient kv1 from the second voltage-active droop coefficient kv2, and the difference value is subjected to an adaptive algorithm, and simultaneously, the obtained voltage iteration step signal is input into the adaptive algorithm, and the weight coefficients of the adaptive inverse filter and the replica adaptive inverse filter are dynamically adjusted through the adaptive algorithm, so that the first voltage-active droop coefficient kv1 and the second voltage-active droop coefficient kv2 are adjusted.
In the step 4), the secondary controller obtains the voltage secondary power deviation through the following judgment:
(1) when the voltage secondary control signal is 0, the voltage secondary power deviation output by the secondary controller is always a constant value;
(2) when the voltage secondary control signal is 1, the secondary controller adjusts the constant value of the voltage secondary power deviation according to the voltage error signal, and the voltage error signal is adjusted once for the constant value of the voltage secondary power deviation every time the voltage error signal exceeds a set voltage limit value, and the adjusted voltage secondary power deviation is used as a new constant value of the voltage secondary power deviation.
The fuzzy coordination control method for the alternating current-direct current section in the alternating current-direct current hybrid microgrid can effectively overcome the inherent contradiction between power output and frequency (voltage) deviation in the traditional droop control, avoid the oscillation problem caused by the over-regulation of the droop control by the self-adaptive inverse theory, effectively reduce the overshoot of the frequency (voltage) during power fluctuation, and improve the dynamic response speed of transmission power. The method has important value in maintaining the constant frequency of the alternating current area and the constant voltage of the direct current bus of the alternating current and direct current hybrid micro-grid.
Drawings
FIG. 1 is a fuzzy coordination control method for AC/DC power flow section according to the present invention;
FIG. 2 is a method of section droop control for a single AC/DC bi-directional converter according to the present invention;
FIG. 3 is a schematic view of the segment control of the present invention;
FIG. 4 is a block diagram of a fuzzy controller of the present invention;
FIG. 5 is a block diagram of an adaptive inverse controller based on an adjustable iteration step size according to the present invention;
FIG. 6 is a graph of secondary power deviation as a function of frequency (voltage) deviation in the secondary control of the present invention;
FIG. 7 is a graph of AC zone frequencies during a first operating condition of the present invention;
FIG. 8 is a graph of droop coefficients for 1# and 2# AC/DC bi-directional converters in a first operating mode in accordance with an example of the present invention;
FIG. 9 is a transmission power diagram of 1# and 2# AC/DC bidirectional converters in condition one according to an example of the present invention;
FIG. 10 is a graph of DC bus voltage waveforms in condition two according to an example of the present invention;
FIG. 11 is a graph of droop coefficients for an operating mode two # 3 AC/DC bi-directional converter in accordance with an example of the present invention;
fig. 12 is a transmission power diagram of an operating mode two 3# AC/DC bidirectional converter in an example of the invention.
Detailed Description
The following describes in detail a fuzzy coordination control method for ac/dc power flow sections in an ac/dc hybrid microgrid according to the present invention with reference to embodiments and accompanying drawings.
The invention relates to a fuzzy coordination control method for an AC/DC power flow section in an AC/DC hybrid micro-grid, which is characterized in that one or more AC/DC bidirectional converters are selected from the AC/DC power flow section consisting of a plurality of AC/DC bidirectional converters to control the frequency of an AC region, the detected frequency of the AC region is used as an input quantity, and a frequency-active droop control method is adopted to maintain the frequency of the AC region to be constant. And the rest AC/DC bidirectional converters control the voltage of the direct current bus, the detected voltage of the direct current bus is used as an input quantity, and a voltage-active droop control method is adopted to maintain the voltage of the direct current bus to be constant.
The invention discloses a fuzzy coordination control method for an alternating current-direct current section in an alternating current-direct current hybrid micro-grid, which comprises the following steps: selecting more than one AC/DC bidirectional converter to control the frequency of an alternating current area in an AC/DC power flow section consisting of a plurality of AC/DC bidirectional converters, and controlling the voltage of a direct current bus by the rest AC/DC bidirectional converters; the AC/DC bidirectional converter for controlling the frequency of the AC region is controlled by adopting a frequency-active droop control method, the detected frequency of the AC region is used as an input quantity, and the frequency of the AC region is kept constant through the frequency-active droop control; an AC/DC bidirectional converter for controlling the voltage of a direct current bus adopts a voltage-active droop control method, uses the detected voltage of the direct current bus as an input quantity, and maintains the voltage of the direct current bus to be constant through the voltage-active droop control. Wherein,
as shown in fig. 2, the frequency-active droop control method includes the following steps:
1) obtaining a frequency detection value by detecting the frequency of the alternating current area, and subtracting the frequency setting value from the frequency detection value to obtain a frequency error signal;
2) respectively inputting the frequency error signals into a fuzzy controller, a self-adaptive inverse controller and a secondary controller, and inputting a frequency set value and a frequency detection value into the self-adaptive inverse controller;
3) the fuzzy controller respectively outputs a frequency iteration step signal and a frequency secondary control signal according to the obtained error signal, inputs the frequency iteration step signal into the self-adaptive inverse controller, and inputs the frequency secondary control signal into the secondary controller;
as shown in fig. 3, the fuzzy controller determines the magnitude of the frequency error value, and selects different control modes to adjust the transmission power. When the frequency error value is small, the frequency-active droop control is selected, when the frequency error value is medium, the self-adaptive inverse control mode is selected, and when the frequency error value is large, the control mode combining the self-adaptive inverse control and the secondary control is selected. Different control modes are selected under different frequency error values, so that the dynamic response of the frequency can be accelerated, the overshoot can be reduced, and the oscillation problem caused by the excessive adjustment of the frequency-active droop coefficient in a steady state can be avoided.
As shown in fig. 4, the fuzzy controller is specifically configured to perform analog-to-digital conversion, fuzzification, fuzzy inference, defuzzification, and digital-to-analog conversion on the frequency error signal in sequence according to a fuzzy rule base, and then obtain a frequency iteration step signal and a frequency secondary control signal, respectively.
4) The self-adaptive inverse controller obtains a frequency-active droop coefficient according to the frequency error signal and the frequency iteration step length signal, and then multiplies the frequency-active droop coefficient by the frequency error signal to obtain a frequency power deviation signal; the secondary controller obtains a frequency secondary power deviation according to a frequency secondary control signal and a frequency error signal output by the fuzzy controller; wherein,
as shown in fig. 5, the adaptive inverse controller performs the following process:
(1) the self-adaptive inverse controller inputs the frequency set value into a replica self-adaptive inverse filter, and the replica self-adaptive inverse filter multiplies the frequency set value by a weight coefficient in the replica self-adaptive inverse filter through signal delay and then adds the frequency set value and the weight coefficient to obtain a first frequency-active droop coefficient kf 1;
(2) the adaptive inverse controller takes the first frequency-active droop coefficient kf1 as a frequency-active droop coefficient to carry out droop control on the AC/DC bidirectional converter;
(3) the adaptive inverse controller takes the frequency detection value as the input of the adaptive inverse filter, multiplies the frequency detection value by the weight coefficient in the adaptive inverse filter through signal delay, and then adds the frequency detection value and the weight coefficient to obtain a second frequency-active droop coefficient kf 2;
(4) the adaptive inverse controller subtracts the first frequency-active droop coefficient kf1 from the second frequency-active droop coefficient kf2, and the difference value is subjected to an adaptive algorithm, and meanwhile, the obtained frequency iteration step signal is input into the adaptive algorithm, and the weight coefficients of the adaptive inverse filter and the replica adaptive inverse filter are dynamically adjusted through the adaptive algorithm, so that the first frequency-active droop coefficient kf1 and the second frequency-active droop coefficient kf2 are adjusted. When the first frequency-active droop coefficient kf1 is equal to the second frequency-active droop coefficient kf2, the ac zone frequency detection value is equal to the frequency set point.
The secondary controller obtains the frequency secondary power deviation through the following judgment:
(1) when the frequency secondary control signal is 0, the frequency secondary power deviation output by the secondary controller is always a constant value;
(2) when the frequency secondary control signal is 1, the secondary controller adjusts the constant value of the frequency secondary power deviation according to the frequency error signal, and the constant value of the frequency secondary power deviation is adjusted once every time the frequency error signal exceeds a set frequency limit value, and the frequency secondary power deviation obtained by the adjustment is used as a new constant value of the frequency secondary power deviation.
As shown in fig. 6, when the abscissa in fig. 6 represents the frequency error signal, the ordinate represents the frequency secondary power deviation signal, and the secondary controller adjusts the frequency secondary power deviation value according to the relationship shown in fig. 6, which can not only increase the response speed of the frequency and reduce the overshoot, but also avoid the jitter problem caused by the fuzzy controller.
5) Adding the set frequency power signal, the frequency power deviation signal and the frequency secondary power deviation signal to obtain a reference signal of the frequency active power;
6) and the reference signal of the frequency active power is output through proportional-integral control and current inner loop control in sequence, so that the control target that the frequency detection value of the AC/DC bidirectional converter is equal to the frequency set value is achieved.
The voltage-active droop control method comprises the following steps:
1) obtaining a voltage detection value by detecting the voltage of the direct current bus, and subtracting the voltage set value from the voltage detection value to obtain a voltage error signal;
2) respectively inputting the voltage error signals into a fuzzy controller, a self-adaptive inverse controller and a secondary controller, and inputting a voltage set value and a voltage detection value into the self-adaptive inverse controller;
3) the fuzzy controller respectively outputs a voltage iteration step signal and a voltage secondary control signal according to the obtained voltage error signal, inputs the voltage iteration step signal into the self-adaptive inverse controller, and inputs the voltage secondary control signal into the secondary controller;
similarly, as shown in fig. 3, the fuzzy controller determines according to the magnitude of the voltage error value, and selects different control modes to adjust the transmission power. Different control modes are selected under different voltage error values, so that the dynamic response of the voltage can be accelerated, the overshoot is reduced, and the oscillation problem caused by the excessive adjustment of the voltage-active droop coefficient in a steady state can be avoided.
Specifically, the fuzzy controller sequentially performs analog-to-digital conversion, fuzzification, fuzzy inference, defuzzification and digital-to-analog conversion on the voltage error signal according to a fuzzy rule base to respectively obtain a voltage iteration step signal and a voltage secondary control signal.
4) The self-adaptive inverse controller obtains a voltage-active droop coefficient according to the voltage error signal and the voltage iteration step length signal, and then multiplies the voltage-active droop coefficient by the voltage error signal to obtain a power deviation signal; the secondary controller obtains a voltage secondary power deviation according to a voltage secondary control signal and a voltage error signal output by the fuzzy controller; wherein,
the adaptive inverse controller performs the following process:
(1) the self-adaptive inverse controller inputs the voltage set value into a replica self-adaptive inverse filter, and the replica self-adaptive inverse filter multiplies the voltage set value by a weight coefficient in the replica self-adaptive inverse filter through signal delay and then adds the product to obtain a first voltage-active droop coefficient kv 1;
(2) the adaptive inverse controller takes the first voltage-active droop coefficient kv1 as a voltage-active droop coefficient to carry out droop control on the AC/DC bidirectional converter;
(3) the adaptive inverse controller takes the voltage detection value as the input of the adaptive inverse filter, multiplies the voltage detection value by a weight coefficient in the adaptive inverse filter through signal delay, and then adds the product to obtain a second voltage-active droop coefficient kv 2;
(4) the adaptive inverse controller subtracts the first voltage-active droop coefficient kv1 from the second voltage-active droop coefficient kv2, and the difference value is subjected to an adaptive algorithm, and simultaneously, the obtained voltage iteration step signal is input into the adaptive algorithm, and the weight coefficients of the adaptive inverse filter and the replica adaptive inverse filter are dynamically adjusted through the adaptive algorithm, so that the first voltage-active droop coefficient kv1 and the second voltage-active droop coefficient kv2 are adjusted. When the first voltage-active droop coefficient kf1 is equal to the second voltage-active droop coefficient kv2, the voltage detection value of the direct current bus voltage is equal to the voltage set value.
The secondary controller obtains the voltage secondary power deviation through the following judgment:
(1) when the voltage secondary control signal is 0, the voltage secondary power deviation output by the secondary controller is always a constant value;
(2) when the voltage secondary control signal is 1, the secondary controller adjusts the constant value of the voltage secondary power deviation according to the voltage error signal, and the voltage error signal is adjusted once for the constant value of the voltage secondary power deviation every time the voltage error signal exceeds a set voltage limit value, and the adjusted voltage secondary power deviation is used as a new constant value of the voltage secondary power deviation.
As shown in fig. 6, when the abscissa in fig. 6 represents the voltage error signal, the ordinate represents the voltage secondary power deviation signal, and the secondary controller adjusts the voltage secondary power deviation value according to the relationship shown in fig. 6, which not only can increase the response speed of the voltage and reduce the overshoot, but also can avoid the jitter problem caused by the fuzzy controller.
5) Adding the set voltage power signal, the voltage power deviation signal and the voltage secondary power deviation signal to obtain a reference signal of voltage active power;
6) and the reference signal of the voltage active power is output through proportional-integral control and current inner loop control in sequence, so that the control target that the voltage detection value of the AC/DC bidirectional converter is equal to the voltage set value is achieved.
The implementation mode of the fuzzy controller is that a frequency error value or a voltage error value is used as the input of the fuzzy controller, and the output of the fuzzy controller is obtained through a preset fuzzy rule, and the implementation mode is as follows:
(1) determining input and output variables of a fuzzy controller
(2) Fuzzification and defuzzification are carried out: and converting the detected frequency error value or voltage error value from an accurate value to a fuzzy value, and designing membership functions of the input variable and the output variable to be trapezoidal functions. And (3) a centroid method is selected for defuzzification, wherein the formula of the centroid method is as follows:
(3) designing a fuzzy control rule: the design of the fuzzy control rule is the core of the fuzzy controller, and mainly comprises three main contents of description input and output variable word set selection, definition of fuzzy variable fuzzy subsets, establishment of the fuzzy control rule and the like.
Fuzzy subsets S, M, B are used to describe the input variables, with the corresponding linguistic variables S being small, M being medium and B being large. And describing the output variable by using the fuzzy subset { Y, N }, wherein the corresponding linguistic variable Y represents yes and N represents no. The established fuzzy rules are shown in table 1.
TABLE 1 fuzzy rules
(4) After the fuzzy controller is integrally designed, the performance of the system is tested and evaluated, and various parameters of the fuzzy controller are adjusted and optimized according to the performance of the system.
The adaptive algorithm has various choices, the invention selects a least mean square error algorithm (LMS algorithm) as the adaptive algorithm, and the LMS algorithm generally comprises the following three steps:
1) the output response of the adaptive inverse controller.
y(n)＝wT(n)x(n)
2) The error between the set value and the actual output value.
e(n)＝d(n)-y(n)
3) And (5) iterating the relational expression.
w(n+1)＝w(n)+▽J(n)x(n)
Where x (n) y (n) respectively represent input and output signals of the adaptive inverse controller, w (n) represents weight coefficients of the adaptive inverse controller, d (n) represents a set value of the output signal, e (n) represents an error signal, and ∑ j (n) represents a gradient of the error function.
The error function is defined as:
J(n)＝0.5|e(n)|2＝0.5|d(n)-y(n)|·|d(n)-y(n)|*
the gradient of the error function is found:
thus, the iterative formula of the LMS algorithm is:
w(n+1)＝w(n)-u(n)x(n)e(n)*
mu (n) is a frequency iteration step signal or a voltage iteration step signal and is output by the fuzzy controller.
Examples are given below:
the invention discloses a fuzzy coordination control method for an alternating current/direct current section in an alternating current/direct current hybrid micro-grid, which is applied to the alternating current/direct current hybrid micro-grid. The rest AC/DC bidirectional converter controls the voltage of the direct current bus, the detected voltage of the direct current bus is used as an input quantity, a voltage-active droop control method is adopted to maintain the constant of the voltage of the direct current bus, the inherent contradiction between power output and frequency (voltage) deviation in the traditional droop control can be effectively overcome, the dynamic response of power is accelerated, the overshoot of frequency (voltage) is reduced, and the oscillation caused by the over-regulation of a droop coefficient can be avoided.
An alternating current-direct current hybrid micro grid is designed, and three AC/DC bidirectional converters are designed between an alternating current sub-micro grid and a direct current sub-micro grid of the alternating current-direct current hybrid micro grid and are respectively numbered as a 1# AC/DC bidirectional converter, a 2# AC/DC bidirectional converter and a 3# AC/DC bidirectional converter. The rated capacities of the three AC/DC bidirectional converters are set to be the same, and the direct current sub-microgrid and the alternating current sub-microgrid generate power fluctuation in the alternating current and direct current mixed microgrid off-grid operation mode.
And selecting 1# and 2# AC/DC bidirectional converters to control the frequency of the alternating current region, and adopting a frequency-active droop control method. And taking the frequency of the AC area as a detection value, setting a reference value of the frequency of the AC area, subtracting the detection value of the frequency of the AC area from the set value, and taking the difference value as a frequency error signal. The frequency error signals are input to a fuzzy controller, an adaptive inverse controller and a quadratic controller respectively. The fuzzy controller carries out fuzzy discrimination according to the input frequency error signal and outputs a frequency iteration step length signal and a frequency secondary control signal according to a preset fuzzy rule. And inputting the frequency iteration step signal output by the fuzzy controller into the adaptive inverse controller, and inputting the frequency secondary control signal into the secondary controller. And the self-adaptive inverse controller adjusts the frequency-active droop coefficient according to the frequency error signal and the frequency iteration step length signal, the obtained frequency-active droop coefficient is multiplied by the frequency error signal, and the product is the frequency active power deviation. And the secondary controller calculates a frequency secondary power deviation value according to the frequency secondary control signal and the frequency error signal output by the fuzzy controller. The set frequency power signal, the frequency power deviation signal and the frequency secondary power deviation signal are added to obtain a reference signal of frequency active power, and the reference signal are sequentially subjected to proportional-integral control and current inner loop control to form output, so that the aim of enabling the frequency detection value of the bidirectional converter to be equal to the frequency set value is fulfilled.
Selecting a 3# AC/DC bidirectional converter to control the voltage of the direct current bus, setting a reference value of the voltage of the direct current bus by adopting a voltage-active droop control method, subtracting a detection value of the voltage of the direct current bus from a set value, and taking a difference value as a voltage error signal. The voltage error signals are input into a fuzzy controller, an adaptive inverse controller and a secondary controller respectively. The fuzzy controller carries out fuzzy discrimination according to the input voltage error signal and outputs a voltage iteration step signal and a voltage secondary control signal according to a preset fuzzy rule. And inputting a voltage iteration step signal output by the fuzzy controller into the self-adaptive inverse controller, and inputting a voltage secondary control signal output by the fuzzy controller into the secondary controller. And the self-adaptive inverse controller adjusts the voltage-active droop coefficient according to the voltage error signal and the voltage iteration step length signal, the obtained voltage-active droop coefficient is multiplied by the voltage error signal, and the product is the voltage active power deviation. And the secondary controller calculates a voltage secondary power deviation value according to the voltage secondary control signal and the voltage error signal output by the fuzzy controller. The set voltage power signal, the voltage power deviation signal and the voltage secondary power deviation signal are added to obtain a reference signal of voltage active power, and then the reference signal and the reference signal are subjected to proportional-integral control and current inner loop control in sequence to form output, so that the purpose that the voltage detection value of the direct current bus detected by the 3# AC/DC bidirectional converter is equal to the voltage set value is achieved.
In order to verify the correctness and feasibility of the fuzzy coordination control method for the alternating current and direct current power flow sections in the alternating current and direct current hybrid micro-grid, the alternating current and direct current hybrid micro-grid is established, the voltage level of an alternating current area is set to be 10kV, the frequency is set to be 50Hz, and the voltage of a direct current bus is set to be 560V. Three AC/DC bidirectional converters are designed between an AC sub-microgrid and a DC sub-microgrid, the three bidirectional converters have the same rated capacity and are 300KVA, each AC/DC bidirectional converter is filtered by an L-shaped filter, the parameter of the L-shaped filter is designed to be L ═ 15.6mH, an isolation transformer with the capacity of 300KVA is arranged between the L-shaped filter and an AC bus, and the isolation transformer plays an important role in voltage level conversion, prevention of circulation of zero-sequence components in the AC sub-microgrid and the DC sub-microgrid, filtering and the like. In order to fully verify the effectiveness of the control method provided by the invention, two working conditions are designed, wherein the working condition is as follows: the load in the AC area is increased by 20KW at 1.0s, increased by 70KW again at 2.0s, and decreased by 10KW at 3.5 s. The frequency-active droop coefficient and transmission power of the 1# AC/DC bidirectional converter and the 2# AC/DC bidirectional converter were observed and analyzed, and the AC zone frequency was detected. Working conditions are as follows: the load in the direct current region is increased by 20KW at 1.0s, the power is suddenly increased by 30KW at 2.0s, and the power is increased by 2KW at 3.5 s. And observing and analyzing the voltage-active droop coefficient and transmission power of the 3# AC/DC bidirectional converter, and detecting the voltage of the direct current bus.
Fig. 7, 8, and 9 are experimental results for condition one. Fig. 7 shows the frequency of the ac region, when power fluctuation occurs in the ac sub-microgrid, the frequency of the ac region is also fluctuating, and under the condition that a power fluctuation value is not changed under a working condition, a dotted line shows the frequency fluctuation under the conventional adaptive inverse control, and a solid line shows the frequency fluctuation under the control of the present invention, as can be seen from fig. 7, compared with the adaptive inverse control, the method of the present invention has a small overshoot and a small steady-state fluctuation value. Fig. 8 shows the droop coefficients of the 1# AC/DC bidirectional converter and the 2# AC/DC bidirectional converter, where the droop coefficient of the bidirectional converter is adjusted when the power fluctuation value is large, and the droop coefficient is kept constant when the power fluctuation value is small; fig. 9 shows transmission power of the 1# AC/DC bidirectional converter and the 2# AC/DC bidirectional converter, and when power fluctuation occurs in the AC region, the bidirectional converters adjust the transmission power in time to suppress the power fluctuation in the AC region.
From the experimental results of fig. 7, 8, and 9, it was analyzed that the 1# AC/DC bidirectional converter and the 2# AC/DC bidirectional converter can adjust the transmission power according to the detected AC zone frequency, and maintain the stability of the AC zone frequency. And different control modes are selected according to the power fluctuation. When the power fluctuation is small, the droop coefficient is not adjusted, and a traditional droop control mode is adopted; and when the power fluctuation is large, the adjustment of the transmission power is accelerated through the adaptive inverse controller and the secondary controller, the power fluctuation of the AC area is stabilized, and the frequency of the AC area is kept constant.
Fig. 10, 11, and 12 are experimental results for condition two. Fig. 10 shows the dc bus voltage, when power fluctuation occurs in the dc sub-microgrid, the dc bus voltage is also fluctuating, and under the condition that the fluctuation value of the second working condition is not changed, the dotted line shows the voltage fluctuation under the conventional adaptive inverse control, and the solid line shows the voltage fluctuation under the control of the present invention. As can be seen from fig. 10, the method of the present invention has a small overshoot and a small steady-state fluctuation value compared to the adaptive inverse control. Fig. 11 shows the droop coefficient of the # 3 AC/DC bidirectional converter, which is adjusted when the power fluctuation value is large, and is kept constant when the power fluctuation value is small. Fig. 12 shows transmission power of the # 3 AC/DC bidirectional converter, and when power fluctuation occurs in the DC sub-microgrid, the bidirectional converter adjusts the transmission power in time, stabilizes power fluctuation in the DC region, and maintains the DC bus voltage within a small deviation range.
In summary, when power fluctuates in the ac microgrid and the dc microgrid, the method of the present invention can maintain the stability of the ac region frequency and the dc bus voltage, effectively overcome the inherent contradiction between the power output and the frequency (voltage) deviation in the conventional droop control, accelerate the dynamic response of the power, reduce the overshoot of the frequency (voltage), and avoid the oscillation problem caused by the over-adjustment of the droop coefficient.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are also included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (8)
1. A fuzzy coordination control method for an AC/DC power flow section in an AC/DC hybrid microgrid is characterized by comprising the following steps: selecting more than one AC/DC bidirectional converter to control the frequency of an alternating current area in an AC/DC power flow section consisting of a plurality of AC/DC bidirectional converters, and controlling the voltage of a direct current bus by the rest AC/DC bidirectional converters; the AC/DC bidirectional converter for controlling the frequency of the AC region is controlled by adopting a frequency-active droop control method, the detected frequency of the AC region is used as an input quantity, and the frequency of the AC region is kept constant through the frequency-active droop control; the AC/DC bidirectional converter for controlling the voltage of the direct current bus adopts a voltage-active droop control method, uses the detected voltage of the direct current bus as an input quantity, and maintains the voltage of the direct current bus to be constant through the voltage-active droop control; the frequency-active droop control method comprises the following steps:
1) obtaining a frequency detection value by detecting the frequency of the alternating current area, and subtracting the frequency setting value from the frequency detection value to obtain a frequency error signal;
2) respectively inputting the frequency error signals into a fuzzy controller, a self-adaptive inverse controller and a secondary controller, and inputting a frequency set value and a frequency detection value into the self-adaptive inverse controller;
3) the fuzzy controller respectively outputs a frequency iteration step signal and a frequency secondary control signal according to the obtained frequency error signal, inputs the frequency iteration step signal into the self-adaptive inverse controller, and inputs the frequency secondary control signal into the secondary controller;
4) the self-adaptive inverse controller obtains a frequency-active droop coefficient according to the frequency error signal and the frequency iteration step length signal, and then multiplies the frequency-active droop coefficient by the frequency error signal to obtain a frequency power deviation signal; the secondary controller obtains a frequency secondary power deviation according to a frequency secondary control signal and a frequency error signal output by the fuzzy controller;
5) adding the set frequency power signal, the frequency power deviation signal and the frequency secondary power deviation signal to obtain a reference signal of the frequency active power;
6) and the reference signal of the frequency active power is output through proportional-integral control and current inner loop control in sequence, so that the control target that the frequency detection value of the AC/DC bidirectional converter is equal to the frequency set value is achieved.
2. The fuzzy coordination control method for the AC/DC power flow section in the AC/DC hybrid microgrid according to claim 1, characterized in that the fuzzy controller in step 3) sequentially performs analog-to-digital conversion, fuzzification, fuzzy inference, defuzzification and digital-to-analog conversion on the frequency error signal according to a fuzzy rule base to respectively obtain a frequency iteration step size signal and a frequency secondary control signal.
3. The fuzzy coordination control method for the alternating current-direct current power flow section in the alternating current-direct current hybrid microgrid according to claim 1, characterized in that the adaptive inverse controller in the step 4) performs the following processes:
(1) the self-adaptive inverse controller inputs the frequency set value into a replica self-adaptive inverse filter, and the replica self-adaptive inverse filter multiplies the frequency set value by a weight coefficient in the replica self-adaptive inverse filter through signal delay and then adds the frequency set value and the weight coefficient to obtain a first frequency-active droop coefficient kf 1;
(2) the adaptive inverse controller takes the first frequency-active droop coefficient kf1 as a frequency-active droop coefficient to carry out droop control on the AC/DC bidirectional converter;
(3) the adaptive inverse controller takes the frequency detection value as the input of the adaptive inverse filter, multiplies the frequency detection value by the weight coefficient in the adaptive inverse filter through signal delay, and then adds the frequency detection value and the weight coefficient to obtain a second frequency-active droop coefficient kf 2;
(4) the adaptive inverse controller subtracts the first frequency-active droop coefficient kf1 from the second frequency-active droop coefficient kf2, and the difference value is subjected to an adaptive algorithm, and meanwhile, the obtained frequency iteration step signal is input into the adaptive algorithm, and the weight coefficients of the adaptive inverse filter and the replica adaptive inverse filter are dynamically adjusted through the adaptive algorithm, so that the first frequency-active droop coefficient kf1 and the second frequency-active droop coefficient kf2 are adjusted.
4. The fuzzy coordination control method for the alternating current-direct current power flow section in the alternating current-direct current hybrid microgrid according to claim 1, characterized in that in the step 4), the secondary controller obtains the frequency secondary power deviation through the following judgment:
(1) when the frequency secondary control signal is 0, the frequency secondary power deviation output by the secondary controller is always a constant value;
(2) when the frequency secondary control signal is 1, the secondary controller adjusts the constant value of the frequency secondary power deviation according to the frequency error signal, and the constant value of the frequency secondary power deviation is adjusted once every time the frequency error signal exceeds a set frequency limit value, and the frequency secondary power deviation obtained by the adjustment is used as a new constant value of the frequency secondary power deviation.
5. The fuzzy coordination control method for the AC/DC power flow section in the AC/DC hybrid microgrid according to claim 1, wherein the voltage-active droop control method comprises the following steps:
1) obtaining a voltage detection value by detecting the voltage of the direct current bus, and subtracting the voltage set value from the voltage detection value to obtain a voltage error signal;
2) respectively inputting the voltage error signals into a fuzzy controller, a self-adaptive inverse controller and a secondary controller, and inputting a voltage set value and a voltage detection value into the self-adaptive inverse controller;
3) the fuzzy controller respectively outputs a voltage iteration step signal and a voltage secondary control signal according to the obtained voltage error signal, inputs the voltage iteration step signal into the self-adaptive inverse controller, and inputs the voltage secondary control signal into the secondary controller;
4) the self-adaptive inverse controller obtains a voltage-active droop coefficient according to the voltage error signal and the voltage iteration step length signal, and then multiplies the voltage-active droop coefficient by the voltage error signal to obtain a voltage power deviation signal; the secondary controller obtains a voltage secondary power deviation according to a voltage secondary control signal and a voltage error signal output by the fuzzy controller;
5) adding the set voltage power signal, the voltage power deviation signal and the voltage secondary power deviation signal to obtain a reference signal of voltage active power;
6) and the reference signal of the voltage active power is output through proportional-integral control and current inner loop control in sequence, so that the control target that the voltage detection value of the AC/DC bidirectional converter is equal to the voltage set value is achieved.
6. The fuzzy coordination control method for the AC/DC power flow section in the AC/DC hybrid microgrid according to claim 5, characterized in that the fuzzy controller in step 3) sequentially performs analog-to-digital conversion, fuzzification, fuzzy inference, defuzzification and digital-to-analog conversion on the voltage error signal according to a fuzzy rule base to respectively obtain a voltage iteration step signal and a voltage secondary control signal.
7. The fuzzy coordination control method for the AC/DC power flow section in the AC/DC hybrid microgrid according to claim 5, characterized in that the adaptive inverse controller in the step 4) performs the following processes:
(1) the self-adaptive inverse controller inputs the voltage set value into a replica self-adaptive inverse filter, and the replica self-adaptive inverse filter multiplies the voltage set value by a weight coefficient in the replica self-adaptive inverse filter through signal delay and then adds the product to obtain a first voltage-active droop coefficient kv 1;
(2) the adaptive inverse controller takes the first voltage-active droop coefficient kv1 as a voltage-active droop coefficient to carry out droop control on the AC/DC bidirectional converter;
(3) the adaptive inverse controller takes the voltage detection value as the input of the adaptive inverse filter, multiplies the voltage detection value by a weight coefficient in the adaptive inverse filter through signal delay, and then adds the product to obtain a second voltage-active droop coefficient kv 2;
(4) the adaptive inverse controller subtracts the first voltage-active droop coefficient kv1 from the second voltage-active droop coefficient kv2, and the difference value is subjected to an adaptive algorithm, and simultaneously, the obtained voltage iteration step signal is input into the adaptive algorithm, and the weight coefficients of the adaptive inverse filter and the replica adaptive inverse filter are dynamically adjusted through the adaptive algorithm, so that the first voltage-active droop coefficient kv1 and the second voltage-active droop coefficient kv2 are adjusted.
8. The fuzzy coordination control method for the alternating current-direct current power flow section in the alternating current-direct current hybrid microgrid according to claim 5, characterized in that in the step 4), the secondary controller obtains the voltage secondary power deviation through the following judgment:
(1) when the voltage secondary control signal is 0, the voltage secondary power deviation output by the secondary controller is always a constant value;
(2) when the voltage secondary control signal is 1, the secondary controller adjusts the constant value of the voltage secondary power deviation according to the voltage error signal, and the voltage error signal is adjusted once for the constant value of the voltage secondary power deviation every time the voltage error signal exceeds a set voltage limit value, and the adjusted voltage secondary power deviation is used as a new constant value of the voltage secondary power deviation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810373603.4A CN108512229B (en) | 2018-04-24 | 2018-04-24 | Fuzzy coordination control method for alternating current-direct current section in alternating current-direct current hybrid micro-grid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810373603.4A CN108512229B (en) | 2018-04-24 | 2018-04-24 | Fuzzy coordination control method for alternating current-direct current section in alternating current-direct current hybrid micro-grid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108512229A CN108512229A (en) | 2018-09-07 |
| CN108512229B true CN108512229B (en) | 2021-03-02 |
Family
ID=63399043
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810373603.4A Expired - Fee Related CN108512229B (en) | 2018-04-24 | 2018-04-24 | Fuzzy coordination control method for alternating current-direct current section in alternating current-direct current hybrid micro-grid |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108512229B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109672182B (en) * | 2019-01-23 | 2021-04-06 | 华北电力大学（保定） | Coordination control method among multiple power converters |
| CN111884248B (en) * | 2019-11-12 | 2021-10-15 | 株洲中车时代电气股份有限公司 | Voltage control method and system |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102709956A (en) * | 2012-05-29 | 2012-10-03 | 华北电力大学（保定） | Active frequency adjusting method of microgrid |
| CN104242330A (en) * | 2014-10-13 | 2014-12-24 | 北京四方继保自动化股份有限公司 | Energy accumulation converter-based active micro power grid seamless switching method under peer-to-peer control |
-
2018
- 2018-04-24 CN CN201810373603.4A patent/CN108512229B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102709956A (en) * | 2012-05-29 | 2012-10-03 | 华北电力大学（保定） | Active frequency adjusting method of microgrid |
| CN104242330A (en) * | 2014-10-13 | 2014-12-24 | 北京四方继保自动化股份有限公司 | Energy accumulation converter-based active micro power grid seamless switching method under peer-to-peer control |
Non-Patent Citations (2)
| Title |
|---|
| 刘佳易等.交直流双向功率变换器的改进下垂控制策略.《电网技术》.2014,第38卷(第2期),304-310页. * |
| 苏玲等.微电网控制策略综述.《华东电力》.2014,第42卷(第11期),2249-2253页. * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108512229A (en) | 2018-09-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Sedighizadeh et al. | Voltage and frequency regulation in autonomous microgrids using Hybrid Big Bang-Big Crunch algorithm | |
| JP2001506385A (en) | Flicker controller using voltage source converter | |
| CN108512229B (en) | Fuzzy coordination control method for alternating current-direct current section in alternating current-direct current hybrid micro-grid | |
| Mekri et al. | A comparative study of voltage controllers for series active power filter | |
| Heydari et al. | A decentralized adaptive control method for frequency regulation and power sharing in autonomous microgrids | |
| Moarref et al. | Multi-objective voltage and frequency regulation in autonomous microgrids using Pareto-based Big Bang-Big Crunch algorithm | |
| Patjoshi et al. | Resistive optimization with enhanced PLL based nonlinear variable gain fuzzy hysteresis control strategy for unified power quality conditioner | |
| Roselyn et al. | Intelligent coordinated control for improved voltage and frequency regulation with smooth switchover operation in LV microgrid | |
| Hajiaghasi et al. | Hybrid energy storage for microgrid performance improvement under unbalanced load conditions | |
| CN107317337B (en) | The decentralized coordinated control method of alternating current-direct current mixing microgrid flow controller | |
| Bouaziz et al. | High performance of fuzzy direct power control for PWM converters | |
| Tan et al. | Droop controlled microgrid with DSTATCOM for reactive power compensation and power quality improvement | |
| US4888674A (en) | Method and apparatus for decoupling the active and reactive power control for a high voltage DC transmission line coupling two networks | |
| Ma et al. | Event triggering power sharing control for AC/DC microgrids based on P-F droop curve method | |
| CN108521143B (en) | Alternating current-direct current hybrid micro-grid-connected robust control method considering uncertainty | |
| CN107910885B (en) | Slave station outer ring current control method of multi-terminal flexible direct current transmission system | |
| Kubragyi et al. | Sugeno—PI fuzzy controller for battery bidirectional charging in the electric vehicle to support voltage stability in V2G distribution grids | |
| Chaithanya | A Comparative Study on Adaptive Control Algorithms for Grid-tie Inverter | |
| Gholami-Khesht et al. | Robust H∞ Current Control of Three-Phase Grid-Connected Voltage Source Converters Using Linear Matrix Inequalities | |
| Palandöken et al. | A fuzzy-controlled single-phase active power filter operating with fixed switching frequency for reactive power and current harmonics compensation | |
| Biju et al. | A new control strategy for single phase cascaded H bridge multilevel inverter in stationary reference frame with nonlinear loads | |
| Nguyen et al. | Efficient Power Allocation Scheme for Hybrid Energy Storage Systems in Autonomous DC Microgrids | |
| CN113964886B (en) | Inverter voltage control method and system under distributed photovoltaic grid connection based on sequencing | |
| Carballo et al. | Stability analysis of multiple grid-connected inverters using different feedback currents | |
| CN116454986A (en) | Virtual inertia control method, medium and system for bidirectional grid-connected converter |
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 | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20210302 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |