CN110912108B - Bus voltage control method for grid-connected and off-grid smooth switching of direct-current micro-grid - Google Patents
Bus voltage control method for grid-connected and off-grid smooth switching of direct-current micro-grid Download PDFInfo
- Publication number
- CN110912108B CN110912108B CN201911126044.8A CN201911126044A CN110912108B CN 110912108 B CN110912108 B CN 110912108B CN 201911126044 A CN201911126044 A CN 201911126044A CN 110912108 B CN110912108 B CN 110912108B
- Authority
- CN
- China
- Prior art keywords
- grid
- current
- bus
- voltage
- direct
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
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
- H02J1/00—Circuit arrangements for dc mains or dc distribution 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
- H02J1/00—Circuit arrangements for dc mains or dc distribution networks
- H02J1/10—Parallel operation of dc sources
-
- 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
- H02J1/00—Circuit arrangements for dc mains or dc distribution networks
- H02J1/14—Balancing the load in a network
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
Abstract
The invention discloses a bus voltage control method for grid-connected and off-grid smooth switching of a direct-current micro-grid. The method combines the advantages of peer-to-peer control and centralized control, the difference value between the direct current bus voltage and the reference value is small under grid connection, the virtual admittance hardly works, the energy storage unit works in a current source mode to respond to system power scheduling, and meanwhile bus voltage disturbance can be dynamically and adaptively inhibited; under the fault of the direct-current power grid, the difference value between the direct-current bus voltage and the reference value is increased, and the energy storage unit supports the direct-current bus voltage in a self-adaptive manner through the virtual admittance; after the micro grid finishes island detection and grid-connected switch isolation, the direct-current bus voltage can be smoothly recovered to a reference value. The method can effectively realize parallel-grid and off-grid smooth switching of the direct-current micro-grid, particularly under the working condition of unplanned off-grid, has no requirement on rapidity of island detection and grid-connected switch action, is simple and reliable, has low cost, and is easy to design and realize in engineering.
Description
Technical Field
The invention belongs to the field of distributed generation direct current micro-grids in electrical engineering, and particularly relates to a bus voltage control method for smooth switching between grid connection and grid disconnection of a direct current micro-grid.
Background
The direct-current micro-grid containing the energy storage unit can be in grid-connected operation with an external direct-current power grid, participates in system power dispatching, can also be in off-grid operation when the external direct-current power grid fails, independently supplies power for a local load, has high power supply safety and reliability, and has attracted wide attention in recent years.
The peer-to-peer control and the master-slave control are two main bus voltage control methods of a direct-current micro-grid, the energy storage unit is enabled to operate in a voltage source mode no matter in grid connection or grid disconnection based on the peer-to-peer control of current-voltage droop, the switching process of grid connection and grid disconnection does not exist, but the current-voltage droop belongs to voltage difference control, the output power of the energy storage unit can only operate according to a droop curve during grid connection operation, the power dispatching instruction of the power grid cannot be effectively responded, and the direct-current bus voltage can change along with the change of a load during grid disconnection. Although various improved methods based on secondary control are provided in the research review entitled "dc microgrid droop control technology" ("chinese electro-mechanical engineering press", 2018,38 (1): 72-84.), the complexity of control is increased, and the smooth switching problem between grid connection and grid disconnection needs to be considered again.
The master-slave control method is characterized in that a direct-current power grid controls direct-current bus voltage during grid connection, the energy storage unit operates in a current source mode and flexibly participates in micro-grid power scheduling, and the energy storage unit operates in an undifferentiated voltage source mode to control the direct-current bus voltage during off-grid, so that power is supplied to a local load, the control is simple, the realization is easy, and the method is widely applied to actual demonstration projects. However, during the transition period between grid connection and grid disconnection, the energy storage unit is switched from a current source mode to a voltage source mode, and during the island detection period, the direct-current bus voltage is uncontrollable, and smooth off-grid switching is important, which becomes the key point of research. For example, the invention discloses a master-slave control-based grid-connected and off-grid smooth switching method and system for dc microgrid grid-connected and off-grid switching bus voltage control (publication No. CN 106849156A), but the dc bus voltage still changes with the change of the load under the scheme.
The above analysis shows that although the existing methods can realize the grid-connected and off-grid smooth switching of the direct current microgrid, the existing methods have respective defects, so that further research needs to be carried out on a bus voltage control method for the grid-connected and off-grid smooth switching of the direct current microgrid.
Disclosure of Invention
The invention provides a bus voltage control method for parallel and off-grid smooth switching of a direct-current micro-grid based on virtual admittance, aiming at the bus voltage control problem of parallel and off-grid smooth switching of the direct-current micro-grid, and combining the advantages of master-slave control and peer-to-peer control. The method combines the advantages of peer-to-peer control and centralized control, the difference value between the direct current bus voltage and the reference value is small under grid connection, the virtual admittance hardly works, the energy storage unit works in a current source mode to respond to system power scheduling, and meanwhile bus voltage disturbance can be dynamically and adaptively inhibited; under the fault of the direct-current power grid, the difference value between the direct-current bus voltage and the reference value is increased, and the energy storage unit supports the direct-current bus voltage in a self-adaptive mode through the virtual admittance; after the micro grid finishes island detection and grid-connected switch isolation, the voltage of the direct-current bus can be smoothly recovered to a reference value. The method can effectively realize parallel-grid and off-grid smooth switching of the direct-current micro-grid, particularly under the working condition of unplanned off-grid, has no requirement on rapidity of island detection and grid-connected switch action, is simple and reliable, has low cost, and is easy to design and realize in engineering.
The object of the invention is thus achieved. The invention provides a bus voltage control method for grid-connected and off-grid smooth switching of a direct-current micro-grid, wherein the direct-current micro-grid related to the control method comprises a direct-current grid V G The system comprises a grid-connected switch KB, a direct-current bus, an energy storage unit, a Buck/Boost energy storage DC/DC converter and a load R; DC network V G The energy storage unit is connected to the direct-current bus in parallel through a grid-connected switch KB, the energy storage unit is connected to the direct-current bus in parallel through a Buck/Boost energy storage DC/DC converter, and a load R is connected to the direct-current bus in parallel; the Buck/Boost energy storage DC/DC converter comprises an input capacitor C Bat An inductor L and a switch tube S 1 A switch tube S 2 And an output capacitor C Bus (ii) a Will input into the capacitor C Bat Positive pole of (2) is marked as node A 1 Input capacitance C Bat Is noted as node A 2 Node A 1 A 2 One end of an inductor L is connected to a node A as an input port of the Buck/Boost energy storage DC/DC converter 1 In the above, the other end of the inductor L is denoted as node A 3 Switching tube S 2 Is connected to node A 3 Upper, switch tube S 2 Is connected to node A 2 Upper, switch tube S 1 Is marked as node A 4 Switching tube S 1 Is connected to the nodePoint A 3 Upper and output capacitor C Bus Is connected to node A 4 Upper and output capacitors C Bus Is connected to node A 2 Upper, node A 4 A 2 The output port of the Buck/Boost energy storage DC/DC converter is used;
the control method is characterized by comprising the following steps:
step 1: sampling DC bus Voltage, noted V Bus Sampling the energy storage cell voltage, denoted V Bat Sampling the current of inductor L, denoted as I L ；
Step 2: given bus voltage reference value V ref Given a current command value I ref Define the voltage controller G VPI Define the voltage controller G VPI The output of (A) is an off-grid current loop reference value I OLref Said voltage controller G VPI Is a proportional-integral regulator, the transfer function G of which VPI (s) is:
wherein k is vp Is a voltage controller G VPI Coefficient of proportionality, k vi Is a voltage controller G VPI The integral coefficient of (d);
and step 3: judging whether a grid-connected switch KB is closed or not, if the grid-connected switch KB is closed, executing the step 3.1 and the step 3.2, and if the grid-connected switch KB is disconnected, executing the step 3.3, the step 3.4 and the step 3.5;
step 3.1: giving a virtual admittance Y, and obtaining a direct current bus voltage V according to the step 1 Bus And 2, setting a direct current bus voltage reference value V in the step ref And the current command value I given in step 2 ref And calculating to obtain a grid-connected current loop reference value I GLref The calculation formula is as follows:
I GLref ＝I ref +(V ref -V Bus )×Y
step 3.2: the grid-connected current loop reference value I obtained in the step 3.1 GLref And off-grid current loop reference value I OLref The difference is made to obtain a current error signal delta I, delta I = I GLref -I OLref Executing the step 4;
step 3.3: starting voltage command slow start control in the Nth control period with N = N, wherein N is the cycle number of the voltage command slow start control period, N =1,2, \8230n \8230 + ∞, N is an intermediate variable of the cycle number of the control period, and obtaining a voltage command slow start initial value V in the following mode Bus0 ：
When N =1, V Bus0 ＝V Bus
When N is not equal to 1, V Bus0 Is not changed
Step 3.4: giving expected voltage command slow start times M, and obtaining a voltage command slow start output V according to the following mode Ramp ：
When N is less than or equal to M, V Ramp ＝V Bus0 +(V ref -V Bus0 )×N÷M
When N > M, V Ramp ＝V ref
Step 3.5: let N = N +1, output V for slow start of voltage instruction Ramp And the DC bus voltage V obtained in the step 1 Bus Differencing to obtain a voltage error signal Δ V, Δ V = V Ramp -V Bus Executing the step 4;
and 4, step 4: the voltage controller G is obtained as follows VPI Input Δ E of rror ：
When the grid-connected switch KB is closed, Δ E rror ＝ΔI
When the grid-connected switch KB is off, delta E rror ＝ΔV
And 5: the current loop reference value I is obtained as follows Lref ：
When the grid-connected switch KB is closed, I Lref ＝I GLref
When the grid-connected switch KB is off, I Lref ＝I OLref
Step 6: the reference value I of the current loop obtained in the step 5 is compared with the reference value I of the current loop Lref With the current I of the inductor L obtained in step 1 L Obtaining an inductive current error signal delta I by differencing L ,ΔI L ＝I Lref -I L Define current loop controller G IPI Define current loop controller G IPI The output of (a) is an inductance control voltage, denoted as V L Obtaining an inductive current error signal Delta I L Is a current loop controller G IPI Of a current loop controller G IPI Is a proportional-integral regulator with a transfer function G IPI (s) is:
wherein k is ip Is a current loop controller G IPI Of the proportionality coefficient k ii Is a current loop controller G IPI The integral coefficient of (a);
and 7: the DC bus voltage V obtained according to the step 1 Bus Voltage V of energy storage unit Bat And the inductance control voltage V obtained in the step 6 L The switching tube S is calculated as follows 1 Duty cycle of (d) 1 ：
d 1 ＝(V Bat -V L )÷V Bus
The switching tube S is obtained by calculation in the following way 2 Duty cycle of (d) 2 ：
d 2 ＝1-d 1
Switch tube S 1 Duty cycle d of 1 And a switching tube S 2 Duty ratio d of 2 Switching tube S for controlling Buck/Boost energy storage DC/DC converter through driving and protecting circuit 1 And a switching tube S 2 Make-and-break;
and step 8: and (5) repeating the steps 1-8 to realize the bus voltage control of the grid-connected and off-grid smooth switching of the direct-current micro-grid.
Compared with the prior art, the invention has the advantages that:
1. the parallel-grid and off-grid smooth switching of the direct-current micro-grid is effectively realized, particularly under the unplanned off-grid working condition, extra cost is not required to be added, the requirement on rapidity of island detection is avoided, and the method is flexible and simple and is easy to design and engineer realize;
2. when the grid-connected operation is carried out, although the energy storage unit works in a current source mode, the dynamic disturbance of the direct-current bus voltage can be effectively and adaptively inhibited.
Drawings
Fig. 1 is a schematic diagram of a dc microgrid structure in a bus voltage control method for smooth grid-on and off-grid switching of a dc microgrid according to an embodiment of the present invention.
Fig. 2 is a control block diagram of a bus voltage control method for grid-on and off-grid smooth switching of a dc microgrid in an embodiment of the present invention.
FIG. 3 is a DC bus voltage V obtained from experiments performed on practical experimental platforms according to specific parameters of the present invention and embodiments of the present invention Bus Current I of inductor L L And a load current I O Experimental waveforms of (4).
Detailed Description
Preferred embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.
Fig. 1 is a schematic diagram of a dc microgrid structure in a bus voltage control method for smooth grid-on and off-grid switching of a dc microgrid according to an embodiment of the present invention, and it can be understood from fig. 1 that the dc microgrid related to the control method includes a dc power grid V G The system comprises a grid-connected switch KB, a direct-current bus, an energy storage unit, a Buck/Boost energy storage DC/DC converter and a load R; DC network V G The energy storage unit is connected to the direct current bus in parallel through a grid-connected switch KB, the energy storage unit is connected to the direct current bus in parallel through a Buck/Boost energy storage DC/DC converter, a load R is connected to the direct current bus in parallel, and the current flowing through the load is defined as load current I O The direction of flow into the load is positive; the Buck/Boost energy storage DC/DC converter comprises an input capacitor C Bat An inductor L and a switch tube S 1 A switch tube S 2 And an output capacitor C Bus (ii) a Will input capacitance C Bat Is marked as node A 1 Input capacitance C Bat Is noted as node A 2 Node A 1 A 2 One end of an inductor L is connected to a node A as an input port of the Buck/Boost energy storage DC/DC converter 1 In the above, the other end of the inductor L is denoted as node A 3 Switching tube S 2 Is connected to node A 3 Upper, switch tube S 2 Is connected to node A 2 Upper, switch tube S 1 Is marked as node A 4 Switching tube S 1 Is connected to node A 3 Upper and output capacitor C Bus Is connected to node A 4 Upper and output capacitor C Bus Is connected to node A 2 Upper, node A 4 A 2 The output port of the Buck/Boost energy storage DC/DC converter is used.
The specific parameters of the embodiment of the invention are as follows: DC network V G Voltage of 400V, voltage V of the energy storage unit Bat 150V, input capacitance C Bat Has a capacitance value of 110uF, an inductance value of 1mH, and an output capacitor C Bus The capacity value is 110uF, the resistance value of the load R is 94 omega, the virtual admittance Y is 0.57, and the current instruction value I ref Is 0A, voltage controller G VPI Proportional coefficient k of vp Is 1.25, voltage controller G VPI Integral coefficient k of vi 1699 Current Loop controller G IPI Proportional coefficient k of ip Is 0.6, current loop controller G IPI Integral coefficient k of ii 20, a DC bus voltage reference value V ref At 400V, the expected number of voltage command slow starts M is 3000.
Fig. 2 is a control block diagram of a bus voltage control method for grid-on and off-grid smooth switching of a dc microgrid in an embodiment of the present invention, and details steps of the control method are as follows, taking a grid-connected state in which an initial grid-connected switch KB is closed as an example:
step 1: sampling the DC bus voltage, denoted as V Bus Sampling the energy storage cell voltage, denoted V Bat Sampling the current of the inductor L, denoted as I L 。
Step 2: given bus voltage reference value V ref Given a current command value I ref Define the voltage controller G VPI Define the voltage controller G VPI The output of (A) is an off-grid current loop reference value I OLref Said voltage controller G VPI Is a proportional-integral regulator, the transfer function G of which VPI (s) is:
wherein k is vp Is a voltage controller G VPI Coefficient of proportionality, k vi Is a voltage controller G VPI The integral coefficient of (2).
In this embodiment: v ref ＝400V，I ref ＝0A，k vp ＝1.25，k vi ＝1699。
And 3, step 3: and (3) judging whether a grid-connected switch KB is closed or not, if the grid-connected switch KB is closed, executing the step 3.1 and the step 3.2, and if the grid-connected switch KB is disconnected, executing the step 3.3, the step 3.4 and the step 3.5.
Step 3.1: giving a virtual admittance Y, and obtaining a direct current bus voltage V according to the step 1 Bus And 2, setting a direct current bus voltage reference value V in the step ref And the current command value I given in step 2 ref And calculating to obtain a grid-connected current loop reference value I GLref The calculation formula is as follows:
I GLref ＝I ref +(V ref -V Bus )×Y
in this embodiment: y =0.57.
Step 3.2: the grid-connected current loop reference value I obtained in the step 3.1 GLref And off-grid current loop reference value I OLref The difference is made to obtain a current error signal delta I, delta I = I GLref -I OLref And step 4 is executed.
Step 3.3: starting voltage command slow start control in the Nth control period with N = N, wherein N is the cycle number of the voltage command slow start control period, N =1,2, \8230n \8230 + ∞, N is an intermediate variable of the cycle number of the control period, and obtaining a voltage command slow start initial value V in the following mode Bus0 ：
When N =1, V Bus0 ＝V Bus
When N is not equal to 1, V Bus0 And is not changed.
Step 3.4: given the expected voltage command slow start times M, the expected voltage command slow start times M are obtained in the following mannerVoltage command slow start output V Ramp ：
When N is less than or equal to M, V Ramp ＝V Bus0 +(V ref -V Bus0 )×N÷M
When N > M, V Ramp ＝V ref
In this embodiment: m =3000.
Step 3.5: let N = N +1, slowly start the voltage command to output V Ramp And the DC bus voltage V obtained in the step 1 Bus Differencing to obtain a voltage error signal Δ V, Δ V = V Ramp -V Bus And executing the step 4.
And 4, step 4: the voltage controller G is obtained as follows VPI Input Δ E of rror ：
When the grid-connected switch KB is closed, Δ E rror ＝ΔI
When the grid-connected switch KB is turned off, Δ E rror ＝ΔV。
And 5: the current loop reference value I is obtained as follows Lref ：
When the grid-connected switch KB is closed, I Lref ＝I GLref
When the grid-connected switch KB is turned off, I Lref ＝I OLref 。
Step 6: the current loop reference value I obtained in the step 5 is compared with Lref With the current I of the inductor L obtained in step 1 L Obtaining an inductive current error signal delta I by difference L ,ΔI L ＝I Lref -I L Define current loop controller G IPI Define current loop controller G IPI The output of (a) is an inductance control voltage, denoted as V L Obtaining an inductor current error signal delta I L Is a current loop controller G IPI The input of, the current loop controller G IPI Is a proportional-integral regulator, the transfer function G of which IPI (s) is:
wherein k is ip For current loop controlDevice G IPI Coefficient of proportionality, k ii Is a current loop controller G IPI The integral coefficient of (2).
In this embodiment: k is a radical of formula ip ＝0.6，k ii ＝20。
And 7: the DC bus voltage V obtained according to the step 1 Bus Voltage V of energy storage unit Bat And the inductance control voltage V obtained in the step 6 L The switching tube S is calculated as follows 1 Duty cycle of (d) 1 ：
d 1 ＝(V Bat -V L )÷V Bus
The switching tube S is obtained by calculation in the following way 2 Duty cycle of (d) 2 ：
d 2 ＝1-d 1
Switch tube S 1 Duty ratio d of 1 And a switching tube S 2 Duty ratio d of 2 Switching tube S for controlling Buck/Boost energy storage DC/DC converter through driving and protecting circuit 1 And a switching tube S 2 Make and break of (2).
And 8: and (5) repeating the steps 1-8 to realize the bus voltage control of the parallel and off-grid smooth switching of the direct-current micro-grid.
FIG. 3 shows DC bus voltage V obtained by experiment on practical experimental platform according to specific parameters of the present invention and embodiments of the present invention Bus Current I of inductor L L And a load current I O Experimental waveforms of (4). In the figure T 3 Before the moment, a grid-connected switch KB is closed, an energy storage unit works in a current source mode, and a current instruction value I is tracked ref (given current command value I ref Is 0), T 1 At the moment, the load R suddenly changes from no load to 94 omega, and the current I of the inductor L can be seen L Self-adaptive output increase in dynamic process to inhibit direct-current bus voltage V Bus Is dropped; t is 2 Time direct current power grid V G Failure to lose the DC bus voltage V Bus Since the island detection and the operation of the grid-connected switch KB take a certain time, the support function of (1) is up to T 3 The island detection is completed and the grid-connected switch KB is disconnected at the moment, which can be seen from FIG. 3See T 2 ～T 3 Current I of inductor L L Self-adaptive increasing and removing support direct current bus voltage V Bus When the energy storage unit works in a voltage source mode with a voltage difference, although the direct current bus voltage V Bus Slightly dropping, the amplitude of the drop is determined by the preset virtual admittance Y, but the DC bus voltage V Bus Is stable; t is a unit of 3 ～T 4 Recovery of DC bus voltage V with smooth duration Bus To the reference value V of the DC bus voltage ref And at the moment, the energy storage unit works in a voltage source mode with no voltage difference to support the direct current bus voltage V Bus And finishing the bus voltage control of the parallel and off-grid smooth switching of the direct-current micro-grid. The direct-current bus voltage V in the whole grid-connected and off-grid switching process can be seen Bus The transition is smooth, and the experimental result proves the feasibility and the effectiveness of the invention.
Claims (1)
1. A bus voltage control method for parallel and off-grid smooth switching of a direct current micro-grid is provided, wherein the direct current micro-grid related to the control method comprises a direct current grid V G The grid-connected switch KB, the direct-current bus, the energy storage unit, the Buck/Boost energy storage DC/DC converter and the load R; DC network V G The energy storage unit is connected to the direct-current bus in parallel through a grid-connected switch KB, the energy storage unit is connected to the direct-current bus in parallel through a Buck/Boost energy storage DC/DC converter, and a load R is connected to the direct-current bus in parallel; the Buck/Boost energy storage DC/DC converter comprises an input capacitor C Bat An inductor L and a switch tube S 1 A switch tube S 2 And an output capacitor C Bus (ii) a Will input capacitance C Bat Positive pole of (2) is marked as node A 1 Input capacitance C Bat Is denoted as node A 2 Node A 1 A 2 One end of an inductor L is connected to a node A as an input port of the Buck/Boost energy storage DC/DC converter 1 In the above, the other end of the inductor L is denoted as node A 3 Switching tube S 2 Is connected to node A 3 Upper, switch tube S 2 Is connected to node A 2 Upper, switch tube S 1 Is marked as node A 4 Switching tube S 1 Is connected to node A 3 Upper and output capacitor C Bus Is connected to node A 4 Upper and output capacitor C Bus Is connected to node A 2 Upper, node A 4 A 2 The output port of the Buck/Boost energy storage DC/DC converter is used;
the control method is characterized by comprising the following steps:
step 1: sampling DC bus Voltage, noted V Bus Sampling the energy storage cell voltage, denoted V Bat Sampling the current of inductor L, denoted as I L ；
Step 2: given bus voltage reference value V ref Given a current command value I ref Define the voltage controller G VPI Define the voltage controller G VPI Is an off-grid current loop reference value I OLref Said voltage controller G VPI Is a proportional-integral regulator with a transfer function G VPI (s) is:
wherein k is vp Is a voltage controller G VPI Coefficient of proportionality, k vi Is a voltage controller G VPI The integral coefficient of (a);
and step 3: judging whether a grid-connected switch KB is closed or not, if the grid-connected switch KB is closed, executing the step 3.1 and the step 3.2, and if the grid-connected switch KB is disconnected, executing the step 3.3, the step 3.4 and the step 3.5;
step 3.1: giving a virtual admittance Y, and obtaining the direct current bus voltage V according to the step 1 Bus And 2, setting a direct current bus voltage reference value V in the step ref And the current command value I given in step 2 ref And calculating to obtain a grid-connected current loop reference value I GLref The calculation formula is as follows:
I GLref ＝I ref +(V ref -V Bus )×Y
step 3.2: the grid-connected current loop reference value I obtained in the step 3.1 GLref And off-grid current loopReference value I OLref Differencing to obtain a current error signal Δ I, Δ I = I GLref -I OLref Executing the step 4;
step 3.3: starting voltage command slow start control in the Nth control period with N = N, wherein N is the cycle number of the voltage command slow start control period, N =1,2, \8230n \8230 + ∞, N is an intermediate variable of the cycle number of the control period, and obtaining a voltage command slow start initial value V in the following mode Bus0 ：
When N =1, V Bus0 ＝V Bus
When N ≠ 1, V Bus0 Is not changed
Step 3.4: giving expected voltage command slow start times M, and obtaining a voltage command slow start output V according to the following mode Ramp ：
When N is less than or equal to M, V Ramp ＝V Bus0 +(V ref -V Bus0 )×N÷M
When N > M, V Ramp ＝V ref
Step 3.5: let N = N +1, output V for slow start of voltage instruction Ramp And the DC bus voltage V obtained in the step 1 Bus Differencing to obtain a voltage error signal Δ V, Δ V = V Ramp -V Bus Executing the step 4;
and 4, step 4: the voltage controller G is obtained as follows VPI Input Δ E of rror ：
When the grid-connected switch KB is closed, Δ E rror ＝ΔI
When the grid-connected switch KB is turned off, Δ E rror ＝ΔV
And 5: the current loop reference value I is obtained as follows Lref ：
When the grid-connected switch KB is closed, I Lref ＝I GLref
When the grid-connected switch KB is off, I Lref ＝I OLref
Step 6: the current loop reference value I obtained in the step 5 is compared with Lref With the current I of the inductor L obtained in step 1 L Obtaining an inductive current error signal delta I by difference L ,ΔI L ＝I Lref -I L Define current loop controller G IPI Define current loop controller G IPI The output of (a) is an inductance control voltage, denoted as V L Obtaining an inductor current error signal delta I L Is a current loop controller G IPI Of a current loop controller G IPI Is a proportional-integral regulator with a transfer function G IPI (s) is:
wherein k is ip Is a current loop controller G IPI Of the proportionality coefficient k ii Is a current loop controller G IPI The integral coefficient of (a);
and 7: the DC bus voltage V obtained according to the step 1 Bus Voltage V of energy storage unit Bat And the inductance control voltage V obtained in the step 6 L The switching tube S is calculated as follows 1 Duty cycle of (d) 1 ：
d 1 ＝(V Bat -V L )÷V Bus
The switching tube S is obtained by calculation in the following way 2 Duty cycle of (d) 2 ：
d 2 ＝1-d 1
Switch tube S 1 Duty cycle d of 1 And a switching tube S 2 Duty ratio d of 2 Switching tube S for controlling Buck/Boost energy storage DC/DC converter through driving and protecting circuit 1 And a switching tube S 2 Make-and-break;
and step 8: and (5) repeating the steps 1 to 7 to realize the bus voltage control of the grid-connected and off-grid smooth switching of the direct-current micro-grid.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911126044.8A CN110912108B (en) | 2019-11-18 | 2019-11-18 | Bus voltage control method for grid-connected and off-grid smooth switching of direct-current micro-grid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911126044.8A CN110912108B (en) | 2019-11-18 | 2019-11-18 | Bus voltage control method for grid-connected and off-grid smooth switching of direct-current micro-grid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110912108A CN110912108A (en) | 2020-03-24 |
| CN110912108B true CN110912108B (en) | 2022-10-04 |
Family
ID=69817630
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911126044.8A Active CN110912108B (en) | 2019-11-18 | 2019-11-18 | Bus voltage control method for grid-connected and off-grid smooth switching of direct-current micro-grid |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110912108B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111463772B (en) * | 2020-04-22 | 2024-05-31 | 中国船舶重工集团公司第七0四研究所 | Energy storage interface converter control method capable of inhibiting voltage fluctuation of micro-grid bus |
| CN112134270B (en) * | 2020-09-16 | 2022-05-06 | 水发兴业能源(珠海)有限公司 | Direct current power supply system and control method thereof |
| CN114189007B (en) * | 2021-11-15 | 2024-04-12 | 阳光电源股份有限公司 | Vehicle-mounted charger working mode switching control method and device and vehicle-mounted charger |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010239736A (en) * | 2009-03-31 | 2010-10-21 | Mitsubishi Electric Corp | Power conversion apparatus |
| CN106849156A (en) * | 2017-01-06 | 2017-06-13 | 许继集团有限公司 | A kind of direct-current grid and off-network transfer bus voltage control smoothing method and system |
| CN107863785A (en) * | 2017-12-13 | 2018-03-30 | 山东大学 | The micro-capacitance sensor seamless switching control system and method for voltage x current Collaborative Control |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9680397B2 (en) * | 2015-10-13 | 2017-06-13 | National Tsing Hua University | Three-phase inverting apparatus and control method and paralleled power conversion system thereof |
-
2019
- 2019-11-18 CN CN201911126044.8A patent/CN110912108B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010239736A (en) * | 2009-03-31 | 2010-10-21 | Mitsubishi Electric Corp | Power conversion apparatus |
| CN106849156A (en) * | 2017-01-06 | 2017-06-13 | 许继集团有限公司 | A kind of direct-current grid and off-network transfer bus voltage control smoothing method and system |
| CN107863785A (en) * | 2017-12-13 | 2018-03-30 | 山东大学 | The micro-capacitance sensor seamless switching control system and method for voltage x current Collaborative Control |
Non-Patent Citations (2)
| Title |
|---|
| Bi-directional hybrid DC-DC converter with large conversion ratio for microgrid DC busses interface;O. Cornea, E. Guran, N. Muntean and D. Hulea;《2014 International Symposium on Power Electronics, Electrical Drives, Automation and Motion》;20140807;第695-700页 * |
| 直流微电网并离网切换母线电压平滑控制技术研究;毋炳鑫等;《电气应用》;20171220(第24期);第36-41页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110912108A (en) | 2020-03-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110912108B (en) | Bus voltage control method for grid-connected and off-grid smooth switching of direct-current micro-grid | |
| CN104242651B (en) | The advanced number of phases for multiphase converter controls | |
| JP5940946B2 (en) | Power conditioner and control method thereof | |
| CN103715886A (en) | Four-switch buck/boost mode converter control method and control circuit | |
| WO2013151949A1 (en) | Transformer coupled current capping power supply topology | |
| Saadatmand et al. | The heuristic dynamic programming approach in boost converters | |
| Modi et al. | A maximum correntropy criteria based adaptive algorithm for an improved power quality SPV system | |
| Choubey et al. | A tri-state 4-switch bi-directional converter for interfacing supercapacitors to DC micro-grids | |
| KR20070001031A (en) | Uninterrupted power supply apparatus with a solar generating apparatus | |
| CN112928907A (en) | Starting control method and system for multi-level bidirectional DC-DC converter | |
| CN108711875B (en) | Distributed energy storage unit coordination control system and control method | |
| CN111313724A (en) | Power module series-parallel connection management system | |
| CN111327040A (en) | Data-driven direct-current micro-grid power and voltage control method and device | |
| CN113852067B (en) | Method, system, storage medium and equipment for controlling seamless switching between off-grid and on-grid | |
| Chakraborty et al. | Current-programmed control for integrated dual input single output converter for solar-battery integration | |
| CN112583279B (en) | Control method and system suitable for bidirectional isolation type DCDC converter | |
| CN114785157A (en) | AC-DC-AC converter for online UPS and control method thereof | |
| Zammit et al. | Alternative droop control method using a modified lag compensator for paralleled converters in DC microgrids | |
| Abraham | Sine Wave Inverter with Three Stage Battery Charger for Solar Photovoltaic Application | |
| JP5813028B2 (en) | Distributed power supply | |
| CN108767841B (en) | Energy storage unit separated type converter and control method | |
| JP2007193739A (en) | Power conversion device | |
| JP6271638B2 (en) | Power conditioner and control method thereof | |
| CN111628525A (en) | Switching system-based micro-grid dual-mode stable control method | |
| CN220210260U (en) | Power 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 |