CN114336737A - Bus voltage control method, control module and system of charge and discharge device - Google Patents
Bus voltage control method, control module and system of charge and discharge device Download PDFInfo
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Abstract
The invention provides a bus voltage control method, a control module and a system of a charge and discharge device, wherein the method comprises the following steps: acquiring a first bus voltage lower limit value sent by an AC side control module; if the charging and discharging device is in a charging state, calculating a lower limit value of a second bus voltage based on a charging target value of the direct current equipment; selecting a larger value from the lower limit values of the first bus voltage and the second bus voltage as a first bus voltage target value and sending the first bus voltage target value to the AC side control module so that the AC side control module performs loop control on the DC bus voltage; if the charging and discharging device is in a discharging state, calculating a lower limit value of a third bus voltage according to the actual voltage of the direct current equipment; and selecting a larger value from the lower limit values of the first bus voltage and the third bus voltage as a second bus voltage target value to perform loop control on the direct-current bus voltage. Through the scheme, the minimum modulation ratio requirement and the system efficiency index requirement can be met simultaneously.
Description
Technical Field
The invention relates to the technical field of charge and discharge control, in particular to a bus voltage control method, a bus voltage control module and a bus voltage control system of a charge and discharge device.
Background
The charging and discharging device can realize the bidirectional flow of energy at the battery side and the power grid side, has two working modes of grid-connected discharging and battery charging, and can realize the stable charging and discharging in a wide voltage range.
In order to meet the requirement of the minimum modulation ratio when the voltage of the battery side is higher or the voltage of the power grid side is higher when the charging and discharging device works normally, the bus voltage of the charging and discharging device is controlled to be higher in the full-voltage range generally in the prior art, but the system efficiency is lower, and the requirement of the system efficiency index cannot be met.
Disclosure of Invention
In view of this, the present invention provides a bus voltage control method, a control module and a system for a charge and discharge device, which can solve the problem that the minimum modulation ratio requirement and the system efficiency index requirement cannot be simultaneously satisfied when the bus voltage is controlled.
In a first aspect, an embodiment of the present invention provides a bus voltage control method for a charge and discharge device, where the charge and discharge device includes a bidirectional DCDC conversion module and a bidirectional DCAC conversion module, and a first dc side of the bidirectional DCDC conversion module is used to connect a dc device; the second direct current side of the bidirectional DCDC conversion module is connected with the direct current side of the bidirectional DCAC conversion module through a direct current bus, and the alternating current side of the bidirectional DCDC conversion module is used for connecting a power grid;
the method is applied to a DC side control module and comprises the following steps:
acquiring a first bus voltage lower limit value sent by an AC side control module, wherein the first bus voltage lower limit value is a voltage lower limit value corresponding to the direct-current bus and is obtained by calculation based on voltage data of the power grid;
if the charging and discharging device is in a discharging state, calculating a lower limit value of a second bus voltage according to the actual voltage of the direct current equipment; setting a larger value of the first bus voltage lower limit value and the second bus voltage lower limit value as a first bus voltage target value; performing loop control on the voltage of the direct current bus based on the first bus voltage target value;
if the charging and discharging device is in a charging state, calculating a third bus voltage lower limit value based on a charging target value of the direct current equipment, and taking the larger value of the first bus voltage lower limit value and the third bus voltage lower limit value as a second bus voltage target value; and sending the second bus voltage target value to the AC side control module so that the AC side control module performs loop control on the voltage of the direct current bus according to the second bus voltage target value.
In a second aspect, an embodiment of the present invention provides a bus voltage control method for a charge and discharge device, where the charge and discharge device includes a bidirectional DCDC conversion module and a bidirectional DCAC conversion module, and a first dc side of the bidirectional DCDC conversion module is used to connect a dc device; the second direct current side of the bidirectional DCDC conversion module is connected with the direct current side of the bidirectional DCAC conversion module through a direct current bus, and the alternating current side of the bidirectional DCDC conversion module is used for connecting a power grid;
the method is applied to an AC side control module and comprises the following steps:
acquiring voltage data of the power grid, wherein the voltage data of the power grid comprises a power grid line voltage effective value and a power grid line voltage instantaneous value;
calculating a first bus voltage value based on the grid line voltage effective value and the topology parameters of the bidirectional DCAC conversion circuit;
selecting the larger value of the first bus voltage value and the instantaneous value of the power grid line voltage as a first bus voltage lower limit value;
sending the first bus voltage lower limit value to a DC side control module so that the DC side control module calculates a second bus voltage target value of the charging and discharging device in a charging state according to the first bus voltage lower limit value;
and acquiring the second bus voltage target value sent by the DC side control module, and performing loop control on the voltage of the direct current bus according to the second bus voltage target value.
In a third aspect, an embodiment of the present invention provides a DC-side control module, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, where the processor implements the steps of the method according to any one of the possible implementation manners of the first aspect when executing the computer program.
In a fourth aspect, an embodiment of the present invention provides an AC-side control module, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, where the processor implements the steps of the method according to any one of the possible implementation manners of the second aspect when executing the computer program.
In a fifth aspect, an embodiment of the present invention provides a charging and discharging system, including a charging and discharging device, a DC side control module as described in the third aspect above, and an AC side control module as described in the fourth aspect above;
the charging and discharging device comprises a bidirectional DCDC conversion module and a bidirectional DCAC conversion module, wherein the first direct current side of the bidirectional DCDC conversion module is used for connecting direct current equipment; the second direct current side of the bidirectional DCDC conversion module is connected with the direct current side of the bidirectional DCAC conversion module through a direct current bus, and the alternating current side of the bidirectional DCDC conversion module is used for connecting a power grid;
the DC side control module is used for controlling the bidirectional DCDC conversion module to work;
and the AC side control module is used for controlling the bidirectional DCAC conversion module to work.
Compared with the prior art, the embodiment of the invention has the following beneficial effects:
according to the embodiment of the invention, a first bus voltage lower limit value sent by an AC side control module is firstly obtained, and the first bus voltage lower limit value is calculated based on voltage data of a power grid; if the charging and discharging device is in a discharging state, calculating a lower limit value of a second bus voltage according to the actual voltage of the direct current equipment; setting a larger value of the first bus voltage lower limit value and the second bus voltage lower limit value as a first bus voltage target value; performing loop control on the voltage of the direct current bus based on the first bus voltage target value; if the charging and discharging device is in a charging state, calculating a third bus voltage lower limit value based on a charging target value of the direct current equipment, and taking the larger value of the first bus voltage lower limit value and the third bus voltage lower limit value as a second bus voltage target value; and sending the second bus voltage target value to the AC side control module so that the AC side control module performs loop control on the voltage of the direct current bus according to the second bus voltage target value. By the scheme, the wide voltage range conditions of the power grid side and the direct current side can be comprehensively considered, and the bus voltage target value in the charging process and the discharging process can be obtained in a coordinated mode, so that the normal work of the system topology in the wide voltage range can be met, and the high-efficiency control requirement of the system can be met.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.
Fig. 1 is an application scenario diagram of a bus voltage control method of a charge and discharge device according to an embodiment of the present invention;
fig. 2 is a flowchart illustrating an implementation of a bus voltage control method of a charge/discharge device according to an embodiment of the present invention;
fig. 3 is an interactive flowchart of a bus voltage control method of a charge and discharge device according to an embodiment of the present invention;
fig. 4 is a schematic diagram of an AC-side control module/a DC-side control module according to an embodiment of the present invention.
Detailed Description
In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.
In order to make the objects, technical solutions and advantages of the present invention more apparent, the following description is made by way of specific embodiments with reference to the accompanying drawings.
Fig. 1 is an application scene diagram of a bus voltage control method of a charge and discharge device according to an embodiment of the present invention. As shown in fig. 1, the charge and discharge system includes a charge and discharge device, a DC side control module 30, and an AC side control module 40;
the charging and discharging device comprises a bidirectional DCDC conversion module 10 and a bidirectional DCAC conversion module 20, wherein a first direct current side of the bidirectional DCDC conversion module 10 is used for connecting direct current equipment; a second direct current side of the bidirectional DCDC conversion module 10 is connected to a direct current side of the bidirectional DCAC conversion module 20 through a direct current bus, and an alternating current side of the bidirectional DCDC conversion module 10 is used for connecting to a power grid;
the DC side control module 30 is configured to control the bidirectional DCDC conversion module 10 to operate;
the AC side control module 40 is configured to control the bidirectional DCAC conversion module 20 to operate.
Referring to fig. 2, it shows an implementation flowchart of a bus voltage control method of a charge and discharge device provided in an embodiment of the present invention, an execution main body of the method is a DC side control module, and a process thereof is detailed as follows:
s101: and acquiring a first bus voltage lower limit value sent by an AC side control module, wherein the first bus voltage lower limit value is a voltage lower limit value corresponding to the direct-current bus, and the first bus voltage lower limit value is calculated based on voltage data of the power grid.
In this embodiment, based on the above circuit topology, in the charging and discharging device, the AC side control module controls the voltage of the DC bus based on the grid voltage data in the charging state, and the DC side control module controls the voltage of the DC bus based on the voltage data of the DC device in the discharging state. Therefore, in order for the DC-side control module to refer to the grid voltage data when controlling the DC bus, the DC-side control module needs to receive a first bus voltage lower limit value calculated from the grid voltage data transmitted by the AC-side control module.
Specifically, the DC side control module obtains a first bus voltage lower limit value calculated by the AC side control module based on the grid voltage data and the topology characteristics of the bidirectional DCAC conversion module, and the first bus voltage lower limit value can satisfy the minimum modulation ratio of the topology.
S102: if the charging and discharging device is in a discharging state, calculating a lower limit value of a second bus voltage according to the actual voltage of the direct current equipment; setting a larger value of the first bus voltage lower limit value and the second bus voltage lower limit value as a first bus voltage target value; and performing loop control on the voltage of the direct current bus based on the first bus voltage target value.
In this embodiment, the bus voltage of the dc bus, which is an intermediate connection portion between the bidirectional DCDC conversion module and the bidirectional DCAC conversion module, needs to satisfy the modulation ratio requirements of the two topologies, so after determining the actual voltage value of the dc device, the actual voltage value needs to be converted into the second bus voltage lower limit value on the dc bus side through the topology parameters of the bidirectional DCDC conversion circuit. The DC bus voltage in the charging state is the larger value of the first bus voltage lower limit value calculated by the AC side and the second bus voltage lower limit value calculated by the DC side. And then performing loop control on the voltage of the direct current bus by using the obtained first bus voltage target value.
S103: if the charging and discharging device is in a charging state, calculating a third bus voltage lower limit value based on a charging target value of the direct current equipment, and taking the larger value of the first bus voltage lower limit value and the third bus voltage lower limit value as a second bus voltage target value; and sending the second bus voltage target value to the AC side control module so that the AC side control module performs loop control on the voltage of the direct current bus according to the second bus voltage target value.
In this embodiment, after determining the charging target value of the direct current device, the charging target value needs to be converted into a third bus voltage lower limit value on the direct current bus side through the topology parameter of the bidirectional DCDC conversion circuit. The direct current bus voltage in the discharging state is the larger value of the first bus voltage lower limit value calculated by the alternating current side and the third bus voltage lower limit value calculated by the direct current side. After the second bus voltage target value is obtained through calculation, the DC side control module finishes the control process in the charging state and sends the second bus voltage target value to the AC side control module, and the AC side control module controls the bidirectional DCAC conversion module to work according to the second bus voltage target value.
It can be known from the foregoing embodiments that the bus voltage control method provided in this embodiment can implement real-time and intelligent control of the system bus voltage, and perform linear real-time control on the bus voltage according to different charging voltages (dc device voltages), different grid voltages, and different loading amounts, thereby achieving the purpose of ensuring normal operation of the topology and achieving the highest system efficiency.
In one embodiment, the specific implementation flow of S102 in fig. 2 includes:
taking a larger value of the first bus voltage lower limit value and the second bus voltage lower limit value as a first bus voltage target minimum value.
And acquiring the actual power of the power grid.
And calculating a first voltage margin based on the actual power of the power grid and the full-load power of the charge and discharge device.
And adding the first bus voltage target minimum value and the first voltage margin to obtain a first bus voltage target value.
In this embodiment, after the first bus voltage target minimum value is calculated, the influence of the load factor on the bus voltage needs to be considered, and a certain margin needs to be left. Specifically, when the charging and discharging device is in a discharging state, the load is the power grid, so the load rate can be the actual power of the power grid, and then based on the formula Δ U3＝PPmw x k to obtain a first voltage margin, wherein Δ U3Representing a first electricityResidual pressure, PwRepresenting the actual power of the grid, PmAnd k represents the full load power of the charging and discharging device, and k represents a preset adjustment coefficient, wherein the preset adjustment coefficient is obtained by actual calculation, and exemplarily, k may be 22.
In this embodiment, after the first bus voltage target value is calculated, it is necessary to perform a clipping process on the first bus voltage target value in order to prevent the bus voltage from being excessively high.
In one embodiment, the specific implementation flow of S103 in fig. 2 includes:
taking a larger value of the first bus voltage lower limit value and the third bus voltage lower limit value as a second bus voltage target minimum value;
acquiring the actual power of the direct current equipment;
calculating a second voltage margin based on the actual power of the direct current device and the full-load power of the charge and discharge device;
and adding the minimum bus voltage target value and the second voltage margin to obtain a second bus voltage target value.
In this embodiment, after the second bus voltage target minimum value is calculated, the influence of the load factor on the bus voltage needs to be considered, and a certain margin needs to be left. Specifically, when the charging and discharging device is in a charging state, the load is a direct current device, so the load rate can be the actual power of the direct current device, and then based on a formula
Obtaining a second voltage margin, wherein Δ U4Representing a second voltage margin, PzRepresenting the actual power, P, of the DC plantmAnd k represents the full load power of the charging and discharging device, and k represents a preset adjustment coefficient, wherein the preset adjustment coefficient is obtained by actual calculation, and exemplarily, k may be 22.
In one embodiment, the bidirectional DCDC conversion module comprises a bidirectional BUCK-BOOST circuit and a CLLC resonant conversion circuit; the bidirectional BUCK-BOOST circuit is connected with the CLLC resonance conversion circuit through a midpoint bus, and the CLLC resonance conversion circuit is connected with the bidirectional DCAC conversion module through a direct current bus; the specific implementation flow of S102 in fig. 2 further includes:
adding the actual voltage of the direct current equipment to the minimum boost value to obtain a first midpoint bus voltage;
converting the first midpoint bus voltage to a second bus voltage lower limit value based on a topology parameter of the CLLC resonant conversion circuit.
In this embodiment, when the charging and discharging device is in a discharging state, that is, the DC device charges the power grid, the DC-side voltage is an actual voltage of the DC device, and according to the characteristic of the bidirectional Buck-Boost circuit, the bus voltage needs to satisfy the minimum Boost value of the topology, so that the DC-side control module needs to calculate the minimum value of the midpoint bus voltage, that is, the first midpoint bus voltage U, according to the actual voltage of the DC device21＝Udz+ΔU2. Wherein, U21Representing the first midpoint bus voltage, UdzRepresenting the actual voltage, Δ U, of the DC plant2Representing the minimum boost value.
Specifically, the minimum boost value can be set by user according to actual circuit requirements. Exemplary, Δ U2＝20V。
After the first midpoint bus voltage is obtained through calculation, the first midpoint bus voltage is also required to be multiplied by a topology parameter of the CLLC resonant conversion circuit to obtain a second bus voltage lower limit value corresponding to the dc bus. The topological parameter of the CLLC resonant conversion circuit may be 13/11.
In one embodiment, the bidirectional DCDC conversion module comprises a bidirectional BUCK-BOOST circuit and a CLLC resonant conversion circuit; the bidirectional BUCK-BOOST circuit is connected with the CLLC resonance conversion circuit through a midpoint bus, and the CLLC resonance conversion circuit is connected with the bidirectional DCAC conversion module through a direct current bus; the specific implementation flow of S102 in fig. 2 further includes:
converting the first bus voltage target value into a midpoint bus voltage target value based on the topological parameters of the CLLC resonant conversion circuit;
and performing loop control on the voltage of the midpoint bus based on the midpoint bus voltage target value.
In this embodiment, since the CLLC resonant converting circuit is controlled by an open loop in this embodiment, the DC-side voltage loop actually controls the voltage of the midpoint bus, and the circuit forms the corresponding bus voltage according to the transformer transformation ratio.
In this embodiment, after the midpoint bus voltage target value is obtained, in order to prevent the bus voltage from being excessively high, it is necessary to perform a clipping process on the midpoint bus voltage target value. Illustratively, the midpoint bus voltage target value may be limited to between 850V-980V. Correspondingly, the DC side control module takes the midpoint bus voltage target value after amplitude limiting processing as the given value of the midpoint bus to carry out loop control on the bidirectional DCDC conversion circuit.
In one embodiment, the bidirectional DCDC conversion module comprises a bidirectional BUCK-BOOST circuit and a CLLC resonant conversion circuit; the bidirectional BUCK-BOOST circuit is connected with the CLLC resonance conversion circuit through a midpoint bus, and the CLLC resonance conversion circuit is connected with the bidirectional DCAC conversion module through a direct current bus; the specific implementation flow of S103 in fig. 2 further includes:
adding the charging target value of the direct current equipment and the minimum boosting value to obtain a second midpoint bus voltage;
converting the second midpoint bus voltage to a third bus voltage lower limit value based on a topology parameter of the CLLC resonant conversion circuit.
Specifically, when the charging and discharging device is in a charging state, that is, the power grid charges the DC device, the DC-side voltage at this time is a charging target value of the DC device, the charging target value may be a voltage value, and according to the bidirectional Buck-Boost circuit characteristic, the bus voltage needs to satisfy the minimum Boost value of the topology, so that the DC-side control module needs to calculate the minimum value of the midpoint bus voltage, that is, the second midpoint bus voltage U, according to the charging target value of the DC device22＝Udl+ΔU2. Wherein, U22Representing the second midpoint bus voltage, UdlIndicating the charging target value, Δ U, of the DC device2Representing the minimum boost value.
After the second midpoint bus voltage is obtained through calculation, the third bus voltage lower limit value corresponding to the dc bus is obtained by multiplying the second midpoint bus voltage by the topology parameter of the CLLC resonant conversion circuit in this embodiment.
In an embodiment, the embodiment provides an implementation process of a bus voltage control method of a charge and discharge device, where an execution main body of the method is an AC side control module, and a process of the method is detailed as follows:
s201: and acquiring voltage data of the power grid, wherein the voltage data of the power grid comprises a power grid line voltage effective value and a power grid line voltage instantaneous value.
S202: and calculating a first bus voltage value based on the power grid line voltage effective value and the topological parameter of the bidirectional DCAC conversion circuit.
Specifically, according to the bidirectional DCAC topology characteristic, the bus voltage needs a lower limit value to satisfy the minimum modulation ratio of the topology, so the AC side control module in this embodiment converts the real-time voltage effective value of the power grid into a corresponding bus voltage lower limit value, that is, a first bus voltage value, and the formula may be:
s203: and selecting the larger value of the first bus voltage value and the instantaneous value of the power grid line voltage as a first bus voltage lower limit value.
In this embodiment, the dynamic grid voltage fluctuation condition is considered, and because the instantaneous fluctuation time of the grid voltage is short and the effective value of the grid voltage cannot be calculated in time, the effective value of the grid voltage is not calculated in time, the method and the system for calculating the grid voltage fluctuation condition are applicable to the power grid
Wherein, U1Represents a first bus voltage lower limit value, UnRepresenting the effective value of the grid voltage, UsRepresenting the grid voltage transient.
In an embodiment, after S203, the method provided in this embodiment further includes:
adding the first bus voltage lower limit value and a preset modulation ratio allowance to obtain a compensated first bus voltage lower limit value;
correspondingly, the specific implementation flow of S204 includes:
and sending the compensated lower limit value of the first bus voltage to the DC side control module.
Specifically, in order to meet the actual requirement, the bidirectional DCAC conversion module needs to leave a certain modulation ratio margin. Modulation ratio margin Δ U1The self-defined setting can be carried out according to the actual circuit requirement. Exemplary, Δ U1＝50V。
S204: and sending the first bus voltage lower limit value to a DC side control module so that the DC side control module calculates a second bus voltage target value of the charging and discharging device in a charging state according to the first bus voltage lower limit value.
S205: and acquiring the second bus voltage target value sent by the DC side control module, and performing loop control on the voltage of the direct current bus according to the second bus voltage target value.
In this embodiment, after the second bus voltage target value sent by the DC-side control module is obtained, the AC-side control module needs to perform a clipping process on the second bus voltage target value in order to avoid the bus voltage from being too high. For example, the clipping range of the second bus voltage target value may be 720V-830V.
After the second bus voltage target value after amplitude limiting processing is obtained, the AC side control module performs loop control on the bidirectional DCAC conversion circuit by taking the second bus voltage target value after amplitude limiting processing as a bus voltage given value of the direct current bus.
As another specific embodiment, when the bidirectional DCDC conversion module includes a bidirectional BUCK-BOOST circuit and a CLLC resonant conversion circuit, another implementation method of the bus voltage control method of the charge and discharge device provided in this embodiment directly calculates the required data on the midpoint bus side through the DC side control module; the interaction flow is detailed as follows (wherein, the execution subjects of SA 1-SA 5 are DC side control modules, and the execution subjects of SB 1-SB 5 are AC side control modules):
SB 1: and acquiring voltage data of the power grid, wherein the voltage data of the power grid comprises a power grid line voltage effective value and a power grid line voltage instantaneous value.
SB 2: and calculating a first bus voltage value based on the power grid line voltage effective value and the topological parameter of the bidirectional DCAC conversion circuit.
SB 3: and selecting the larger value of the first bus voltage value and the instantaneous value of the power grid line voltage as a first bus voltage lower limit value.
SB 4: and sending the first bus voltage lower limit value to a DC side control module.
SA 1: and acquiring a first bus voltage lower limit value sent by the AC side control module.
SA 2: and converting the first bus voltage lower limit value into a third midpoint bus voltage based on the topological parameters of the CLLC resonant conversion circuit.
SA 3: if the charging and discharging device is in a charging state, calculating a second midpoint bus voltage based on the charging target value of the direct current equipment; selecting the larger value of the second midpoint bus voltage and the third midpoint bus voltage as a first midpoint bus voltage target value; and converting the first midpoint bus voltage target value into a second bus voltage target value based on the topological parameters of the CLLC resonant conversion circuit, and sending the second bus voltage target value to the AC side control module.
SA 4: if the charging and discharging device is in a discharging state, calculating a first midpoint bus voltage according to the actual voltage of the direct current equipment; selecting the larger value of the first midpoint bus voltage and the third midpoint bus voltage as a midpoint bus voltage target value; and performing loop control on the voltage of the midpoint bus based on the midpoint bus voltage target value.
SB 5: and acquiring a second bus voltage target value sent by the DC side control module, and performing loop control on the voltage of the direct current bus according to the second bus voltage target value.
The embodiment can meet the normal work of the system topology in a wide voltage range, can meet the requirement that the system can realize real-time and intelligent control of the system bus voltage through the process, performs linear real-time control on the bus voltage according to different charging voltages (direct current source voltages), different grid voltages and different carrying capacities, and achieves the efficient control requirement of the purpose of the highest system efficiency while ensuring the normal work of the topology.
It should be understood that, the sequence numbers of the steps in the foregoing embodiments do not imply an execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.
The following are embodiments of the apparatus of the invention, reference being made to the corresponding method embodiments described above for details which are not described in detail therein.
The embodiment of the invention provides a bus voltage control device of a charge and discharge device, which is applied to a DC side control module and comprises the following components:
the first bus voltage lower limit value acquisition module is used for acquiring a first bus voltage lower limit value sent by the AC side control module, wherein the first bus voltage lower limit value is a voltage lower limit value corresponding to the direct-current bus and is obtained by calculation based on voltage data of the power grid;
the first bus voltage control module is used for calculating a second bus voltage lower limit value according to the actual voltage of the direct current equipment if the charging and discharging device is in a discharging state; setting a larger value of the first bus voltage lower limit value and the second bus voltage lower limit value as a first bus voltage target value; performing loop control on the voltage of the direct current bus based on the first bus voltage target value;
a second bus voltage control module, configured to calculate a third bus voltage lower limit based on a charging target value of the dc device if the charging and discharging apparatus is in a charging state, and use a larger value of the first bus voltage lower limit and the third bus voltage lower limit as a second bus voltage target value; and sending the second bus voltage target value to the AC side control module so that the AC side control module performs loop control on the voltage of the direct current bus according to the second bus voltage target value.
In one embodiment, the first bus voltage control module includes:
taking a larger value of the first bus voltage lower limit value and the second bus voltage lower limit value as a first bus voltage target minimum value;
acquiring the actual power of the power grid;
calculating a first voltage margin based on the actual power of the power grid and the full-load power of the charge and discharge device;
and adding the first bus voltage target minimum value and the first voltage margin to obtain a first bus voltage target value.
In one embodiment, the second bus voltage control module comprises:
taking a larger value of the first bus voltage lower limit value and the third bus voltage lower limit value as a second bus voltage target minimum value;
acquiring the actual power of the direct current equipment;
calculating a second voltage margin based on the actual power of the direct current device and the full-load power of the charge and discharge device;
and adding the minimum bus voltage target value and the second voltage margin to obtain a second bus voltage target value.
In one embodiment, the bidirectional DCDC conversion module comprises a bidirectional BUCK-BOOST circuit and a CLLC resonant conversion circuit; the bidirectional BUCK-BOOST circuit is connected with the CLLC resonance conversion circuit through a midpoint bus, and the CLLC resonance conversion circuit is connected with the bidirectional DCAC conversion module through a direct current bus; the first bus voltage control module further comprises:
adding the actual voltage of the direct current equipment to the minimum boost value to obtain a first midpoint bus voltage;
converting the first midpoint bus voltage to a second bus voltage lower limit value based on a topology parameter of the CLLC resonant conversion circuit.
In one embodiment, the bidirectional DCDC conversion module comprises a bidirectional BUCK-BOOST circuit and a CLLC resonant conversion circuit; the bidirectional BUCK-BOOST circuit is connected with the CLLC resonance conversion circuit through a midpoint bus, and the CLLC resonance conversion circuit is connected with the bidirectional DCAC conversion module through a direct current bus; the second bus voltage control module further comprises:
adding the charging target value of the direct current equipment and the minimum boosting value to obtain a second midpoint bus voltage;
converting the second midpoint bus voltage to a third bus voltage lower limit value based on a topology parameter of the CLLC resonant conversion circuit.
In one embodiment, the bidirectional DCDC conversion module comprises a bidirectional BUCK-BOOST circuit and a CLLC resonant conversion circuit; the bidirectional BUCK-BOOST circuit is connected with the CLLC resonance conversion circuit through a midpoint bus, and the CLLC resonance conversion circuit is connected with the bidirectional DCAC conversion module through a direct current bus; the first bus voltage control module includes:
converting the first bus voltage target value into a midpoint bus voltage target value based on the topological parameters of the CLLC resonant conversion circuit;
and performing loop control on the voltage of the midpoint bus based on the midpoint bus voltage target value.
The embodiment of the invention also discloses a structure of the bus voltage control device of the charging and discharging device, which is applied to the AC side control module and comprises the following components:
the voltage data acquisition module is used for acquiring voltage data of the power grid, wherein the voltage data of the power grid comprises a power grid line voltage effective value and a power grid line voltage instantaneous value;
the first bus voltage calculation module is used for calculating a first bus voltage value based on the power grid line voltage effective value and the topology parameters of the bidirectional DCAC conversion circuit;
the first bus voltage lower limit value calculation module is used for selecting the larger value of the first bus voltage value and the electric network line voltage instantaneous value as a first bus voltage lower limit value;
the first bus voltage lower limit value sending module is used for sending the first bus voltage lower limit value to the DC side control module so that the DC side control module can calculate a second bus voltage target value of the charging and discharging device in a charging state according to the first bus voltage lower limit value;
and the third bus voltage control module is used for acquiring the second bus voltage target value sent by the DC side control module and performing loop control on the voltage of the direct current bus according to the second bus voltage target value.
It can be known from the foregoing embodiments that the bus voltage control method provided in this embodiment can implement real-time and intelligent control of the system bus voltage, and perform linear real-time control on the bus voltage according to different charging voltages (dc device voltages), different grid voltages, and different loading amounts, thereby achieving the purpose of ensuring normal operation of the topology and achieving the highest system efficiency.
Fig. 4 is a schematic diagram of an AC-side control module/a DC-side control module according to an embodiment of the invention. As shown in fig. 4, the AC side control module/DC side control module 4 of this embodiment includes: a processor 40, a memory 41 and a computer program 42 stored in said memory 41 and executable on said processor 40. The processor 40 executes the computer program 42 to implement the steps in the above-described embodiments of the bus voltage control method for each charging and discharging device, for example, steps 101 to 103 shown in fig. 2 in the case of a DC side control module.
Illustratively, the computer program 42 may be partitioned into one or more modules/units that are stored in the memory 41 and executed by the processor 40 to implement the present invention. The one or more modules/units may be a series of computer program instruction segments capable of performing specific functions, which are used to describe the execution of the computer program 42 in the AC-side control module/DC-side control module 4.
The AC side control module/DC side control module 4 may include, but is not limited to, a processor 40 and a memory 41. Those skilled in the art will appreciate that fig. 4 is merely an example of the AC side control module/DC side control module 4, and does not constitute a limitation of the AC side control module/DC side control module 4, and may include more or less components than those shown, or combine certain components, or different components, for example, the terminal may further include an input-output device, a network access device, a bus, etc.
The Processor 40 may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic, discrete hardware components, etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
The memory 41 may be an internal storage unit of the AC side control module/DC side control module 4, such as a hard disk or a memory of the AC side control module/DC side control module 4. The memory 41 may also be an external storage device of the AC-side control module/DC-side control module 4, such as a plug-in hard disk provided on the AC-side control module/DC-side control module 4, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash Card (Flash Card), and the like. Further, the memory 41 may also include both an internal storage unit and an external storage device of the AC side control module/DC side control module 4. The memory 41 is used for storing the computer program and other programs and data required by the terminal. The memory 41 may also be used to temporarily store data that has been output or is to be output.
It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-mentioned division of the functional units and modules is illustrated, and in practical applications, the above-mentioned function distribution may be performed by different functional units and modules according to needs, that is, the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-mentioned functions. Each functional unit and module in the embodiments may be integrated in one processing unit, or each unit may exist alone physically, or two or more units are integrated in one unit, and the integrated unit may be implemented in a form of hardware, or in a form of software functional unit. In addition, specific names of the functional units and modules are only for convenience of distinguishing from each other, and are not used for limiting the protection scope of the present application. The specific working processes of the units and modules in the system may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and reference may be made to the related descriptions of other embodiments for parts that are not described or illustrated in a certain embodiment.
Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
In the embodiments provided in the present invention, it should be understood that the disclosed apparatus/terminal and method may be implemented in other ways. For example, the above-described apparatus/terminal embodiments are merely illustrative, and for example, the division of the modules or units is only one logical division, and there may be other divisions when actually implemented, for example, a plurality of units or components may be combined or may be integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated modules/units, if implemented in the form of software functional units and sold or used as separate products, may be stored in a computer readable storage medium. Based on such understanding, all or part of the flow in the method according to the above embodiments may be implemented by a computer program, which may be stored in a computer readable storage medium, and when the computer program is executed by a processor, the steps of the embodiments of the bus voltage control method of each charging and discharging device may be implemented. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, usb disk, removable hard disk, magnetic disk, optical disk, computer Memory, Read-Only Memory (ROM), Random Access Memory (RAM), electrical carrier wave signals, telecommunications signals, software distribution medium, and the like. It should be noted that the computer readable medium may contain other components which may be suitably increased or decreased as required by legislation and patent practice in jurisdictions, for example, in some jurisdictions, computer readable media which may not include electrical carrier signals and telecommunications signals in accordance with legislation and patent practice.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present invention, and are intended to be included within the scope of the present invention.
Claims (10)
1. A bus voltage control method of a charge and discharge device is characterized in that the charge and discharge device comprises a bidirectional DCDC conversion module and a bidirectional DCAC conversion module, wherein a first direct current side of the bidirectional DCDC conversion module is used for connecting direct current equipment; the second direct current side of the bidirectional DCDC conversion module is connected with the direct current side of the bidirectional DCAC conversion module through a direct current bus, and the alternating current side of the bidirectional DCDC conversion module is used for connecting a power grid;
the method is applied to a DC side control module and comprises the following steps:
acquiring a first bus voltage lower limit value sent by an AC side control module, wherein the first bus voltage lower limit value is a voltage lower limit value corresponding to the direct-current bus and is obtained by calculation based on voltage data of the power grid;
if the charging and discharging device is in a discharging state, calculating a lower limit value of a second bus voltage according to the actual voltage of the direct current equipment; setting a larger value of the first bus voltage lower limit value and the second bus voltage lower limit value as a first bus voltage target value; performing loop control on the voltage of the direct current bus based on the first bus voltage target value;
if the charging and discharging device is in a charging state, calculating a third bus voltage lower limit value based on a charging target value of the direct current equipment, and taking the larger value of the first bus voltage lower limit value and the third bus voltage lower limit value as a second bus voltage target value; and sending the second bus voltage target value to the AC side control module so that the AC side control module performs loop control on the voltage of the direct current bus according to the second bus voltage target value.
2. The bus voltage control method of a charge and discharge device according to claim 1, wherein the setting, as the first bus voltage target value, the larger of the first bus voltage lower limit value and the second bus voltage lower limit value includes:
taking a larger value of the first bus voltage lower limit value and the second bus voltage lower limit value as a first bus voltage target minimum value;
acquiring the actual power of the power grid;
calculating a first voltage margin based on the actual power of the power grid and the full-load power of the charge and discharge device;
and adding the first bus voltage target minimum value and the first voltage margin to obtain a first bus voltage target value.
3. The bus voltage control method of a charge and discharge device according to claim 1, wherein the setting the larger of the first bus voltage lower limit value and the third bus voltage lower limit value as a second bus voltage target value includes:
taking a larger value of the first bus voltage lower limit value and the third bus voltage lower limit value as a second bus voltage target minimum value;
acquiring the actual power of the direct current equipment;
calculating a second voltage margin based on the actual power of the direct current device and the full-load power of the charge and discharge device;
and adding the minimum bus voltage target value and the second voltage margin to obtain a second bus voltage target value.
4. The bus voltage control method of the charge and discharge device according to claim 1, wherein the bidirectional DCDC conversion module includes a bidirectional BUCK-BOOST circuit and a CLLC resonant conversion circuit; the bidirectional BUCK-BOOST circuit is connected with the CLLC resonance conversion circuit through a midpoint bus, and the CLLC resonance conversion circuit is connected with the bidirectional DCAC conversion module through a direct current bus;
the calculating a second bus voltage lower limit value according to the actual voltage of the direct current device includes:
adding the actual voltage of the direct current equipment to the minimum boost value to obtain a first midpoint bus voltage;
converting the first midpoint bus voltage to a second bus voltage lower limit value based on a topology parameter of the CLLC resonant conversion circuit.
5. The bus voltage control method of the charge and discharge device according to claim 1, wherein the bidirectional DCDC conversion module includes a bidirectional BUCK-BOOST circuit and a CLLC resonant conversion circuit; the bidirectional BUCK-BOOST circuit is connected with the CLLC resonance conversion circuit through a midpoint bus, and the CLLC resonance conversion circuit is connected with the bidirectional DCAC conversion module through a direct current bus;
the calculating a third bus voltage lower limit value based on the charging target value of the direct current device includes:
adding the charging target value of the direct current equipment and the minimum boosting value to obtain a second midpoint bus voltage;
converting the second midpoint bus voltage to a third bus voltage lower limit value based on a topology parameter of the CLLC resonant conversion circuit.
6. The bus voltage control method of the charge and discharge device according to claim 1, wherein the bidirectional DCDC conversion module includes a bidirectional BUCK-BOOST circuit and a CLLC resonant conversion circuit; the bidirectional BUCK-BOOST circuit is connected with the CLLC resonance conversion circuit through a midpoint bus, and the CLLC resonance conversion circuit is connected with the bidirectional DCAC conversion module through a direct current bus;
the loop control of the voltage of the direct current bus based on the first bus voltage target value comprises the following steps:
converting the first bus voltage target value into a midpoint bus voltage target value based on the topological parameters of the CLLC resonant conversion circuit;
and performing loop control on the voltage of the midpoint bus based on the midpoint bus voltage target value.
7. A bus voltage control method of a charge and discharge device is characterized in that the charge and discharge device comprises a bidirectional DCDC conversion module and a bidirectional DCAC conversion module, wherein a first direct current side of the bidirectional DCDC conversion module is used for connecting direct current equipment; the second direct current side of the bidirectional DCDC conversion module is connected with the direct current side of the bidirectional DCAC conversion module through a direct current bus, and the alternating current side of the bidirectional DCDC conversion module is used for connecting a power grid;
the method is applied to an AC side control module and comprises the following steps:
acquiring voltage data of the power grid, wherein the voltage data of the power grid comprises a power grid line voltage effective value and a power grid line voltage instantaneous value;
calculating a first bus voltage value based on the grid line voltage effective value and the topology parameters of the bidirectional DCAC conversion circuit;
selecting the larger value of the first bus voltage value and the instantaneous value of the power grid line voltage as a first bus voltage lower limit value;
sending the first bus voltage lower limit value to a DC side control module so that the DC side control module calculates a second bus voltage target value of the charging and discharging device in a charging state according to the first bus voltage lower limit value;
and acquiring the second bus voltage target value sent by the DC side control module, and performing loop control on the voltage of the direct current bus according to the second bus voltage target value.
8. A DC-side control module comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that the processor implements the steps of the method according to any of the preceding claims 1 to 6 when executing the computer program.
9. An AC side control module comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method as recited in claim 7 above when executing the computer program.
10. A charge and discharge system comprising a charge and discharge device, a DC-side control module according to any one of claims 1 to 6, and an AC-side control module according to claim 7;
the charging and discharging device comprises a bidirectional DCDC conversion module and a bidirectional DCAC conversion module, wherein the first direct current side of the bidirectional DCDC conversion module is used for connecting direct current equipment; the second direct current side of the bidirectional DCDC conversion module is connected with the direct current side of the bidirectional DCAC conversion module through a direct current bus, and the alternating current side of the bidirectional DCDC conversion module is used for connecting a power grid;
the DC side control module is used for controlling the bidirectional DCDC conversion module to work;
and the AC side control module is used for controlling the bidirectional DCAC conversion module to work.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115241926A (en) * | 2022-09-16 | 2022-10-25 | 深圳市首航新能源股份有限公司 | Bus voltage control method, bus balance control method and system |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115241926A (en) * | 2022-09-16 | 2022-10-25 | 深圳市首航新能源股份有限公司 | Bus voltage control method, bus balance control method and system |
| CN115241926B (en) * | 2022-09-16 | 2023-02-28 | 深圳市首航新能源股份有限公司 | Bus voltage control method, bus balance control method and system |
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