CN114499232A - Six-switch single-phase current transformer control method and device - Google Patents

Six-switch single-phase current transformer control method and device Download PDF

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Publication number
CN114499232A
CN114499232A CN202210104559.3A CN202210104559A CN114499232A CN 114499232 A CN114499232 A CN 114499232A CN 202210104559 A CN202210104559 A CN 202210104559A CN 114499232 A CN114499232 A CN 114499232A
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current
sampling period
power
grid side
converter
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叶腾波
杨勇
府晓宏
刘稼唯
樊明迪
肖扬
沈刚
陈俊柱
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Suzhou University
Suzhou Dongling Vibration Test Instrument Co Ltd
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Suzhou University
Suzhou Dongling Vibration Test Instrument Co Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/21—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/217—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M7/219—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only in a bridge configuration

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Abstract

The invention provides a six-switch single-phase current transformer control method and a device, wherein the method comprises the following steps: predicting to obtain a plurality of groups of power combinations of the current sampling period by utilizing a plurality of groups of power combinations obtained by calculation of the previous sampling period, wherein each group of power combinations comprises an active power and a corresponding reactive power; calculating the output currents of the multiple groups of converters in the current sampling period; selecting an optimal solution of the power combination of the current sampling period and the current transformer output current of the current sampling period by utilizing a pre-established cost function, wherein the cost function is a linear combination of a power prediction cost function and a current prediction cost function; and determining the switch state combination of the current converter in the current sampling period by using the optimal solution, and controlling the current converter. The invention determines the switch state combination by utilizing power and current prediction, thereby not only reducing the calculated amount of the system, but also improving the stability of the system and accelerating the dynamic response capability of the system.

Description

Six-switch single-phase current transformer control method and device
Technical Field
The invention relates to the technical field of control, in particular to a six-switch single-phase current transformer control method and device.
Background
Chinese patent CN112234809A discloses a circuit and a method for eliminating secondary ripples of a single-phase back-to-back converter device. The circuit in this patent, as shown in fig. 1, its purpose is in order to utilize novel single-phase back to back converter in order to solve the problem that adopts big appearance value electrolytic capacitor to absorb secondary ripple among the traditional single-phase back to back converter device. The circuit is different from a traditional single-phase back-to-back converter and only comprises two branches, wherein a rectifier and an inverter share a middle switch in the two converter branches, and the whole circuit only comprises 6 switching devices. Compared with the traditional single-phase back-to-back converter, the number of switches is reduced, and the defect that the traditional single-phase back-to-back converter is large in the number of switching devices is overcome.
For the six-switch circuit topology structure, the classical closed-loop control is adopted to control the circuit in the prior art, and the circuit structure is different from the traditional single-phase back-to-back converter circuit structure, so when the classical closed-loop control is adopted to carry out system control on the six-switch circuit topology structure, the calculated amount, the system stability and the dynamic response capability of the six-switch circuit topology structure are all required to be improved.
Disclosure of Invention
Therefore, the invention provides a six-switch single-phase current transformer control and device, aiming at solving the technical problems that the calculation amount is large, and the system stability and the dynamic response capability are all required to be improved by adopting the classical closed-loop control to control the six-switch circuit in the prior art.
According to a first aspect, an embodiment of the present invention provides a six-switch single-phase current transformer control method, including the following steps:
predicting to obtain a plurality of groups of power combinations of the current sampling period by utilizing a plurality of groups of power combinations obtained by calculation of the previous sampling period, wherein each group of power combinations comprises an active power and a corresponding reactive power;
calculating the output currents of the multiple groups of converters in the current sampling period;
selecting an optimal solution of the power combination of the current sampling period and the current transformer output current of the current sampling period by utilizing a pre-established cost function, wherein the cost function is a linear combination of a power prediction cost function and a current prediction cost function;
and determining the switch state combination of the current converter in the current sampling period by using the optimal solution, and controlling the current converter.
Optionally, the predicting the multiple groups of power combinations of the current sampling period by using the multiple groups of power combinations calculated in the last sampling period includes:
acquiring the actual input voltage of the power grid side, the actual input current of the power grid side, the actual active power of the power grid side, the actual reactive power of the power grid side and the input voltage of a converter in the last sampling period;
performing orthogonal transformation on the power grid side actual input voltage, the power grid side actual input current and the converter input voltage respectively to obtain a transformed power grid side actual input voltage vector, a transformed power grid side actual input current vector and a transformed converter input voltage vector;
and calculating to obtain a group of power combinations of the current sampling period according to the actual input voltage vector of the power grid side, the input voltage vector of the converter, the actual active power of the power grid side in the last sampling period and the actual reactive power of the power grid side.
Optionally, the power combination of the current sampling period is predicted by the following formula:
Figure BDA0003493517670000031
Figure BDA0003493517670000032
wherein P (k +1) is the predicted active power of the grid side in the current sampling period, Q (k +1) is the predicted reactive power of the grid side in the current sampling period, P (k) is the actual active power of the grid side in the last sampling period, Q (k) is the actual reactive power of the grid side in the last sampling period, v (k)gα(k)，vgβ(k) All are the actual input voltage vector u of the power grid side in the last sampling periodgα(k)，ugβ(k) Are all the current transformer input voltage vector, L, of the previous sampling periodgFor the grid side inductance, RgIs the grid side resistance, ωgIs constant and Ts is the sampling period.
Optionally, the multiple sets of converter output currents of the current sampling period are calculated by the following formula:
Figure BDA0003493517670000033
wherein ioαβ(k +1) is the current output current of the current transformer in the current sampling period, uoαβ(k +1) is the converter output voltage in the current sampling period, ioαβ(k) For the last sampling period the actual output current of the converter, LoIs a load side inductance, RoIs the load side resistance.
Optionally, the converter actual output voltage satisfies the following relation function:
Figure BDA0003493517670000034
wherein u isoαβFor the actual output voltage, i, of the converter for the previous sampling periodoαβIs a stand forAnd the current transformer actually outputs current in the last sampling period.
Optionally, the pre-established cost function is:
Figure BDA0003493517670000041
wherein, P*For reference to active power, Q*With reference to the reactive power,
Figure BDA0003493517670000042
are all the converter target output current ioα(k+1)，ioβAnd (k +1) is the current output current of the current transformer in the current sampling period, and J is a variable.
According to a second aspect, an embodiment of the present invention provides a six-switch single-phase current transformer control device, including:
the prediction module is used for predicting and obtaining a plurality of groups of power combinations of the current sampling period by utilizing a plurality of groups of power combinations obtained by calculation of the previous sampling period, wherein each group of power combinations comprises an active power and a corresponding reactive power;
the calculation module is used for calculating the output currents of the multiple groups of converters in the current sampling period;
the solving module is used for selecting the optimal solution of the power combination of the current sampling period and the current transformer output current of the current sampling period by utilizing a pre-established cost function, wherein the cost function is a linear combination of a power prediction cost function and a current prediction cost function;
and the determining module is used for determining the switching state combination of the current converter in the current sampling period by using the optimal solution and controlling the current converter.
Optionally, the prediction module further comprises:
the acquisition module is used for acquiring the actual input voltage of the power grid side, the actual input current of the power grid side, the actual active power of the power grid side, the actual reactive power of the power grid side and the input voltage of the converter in the last sampling period;
the transformation module is used for respectively carrying out orthogonal transformation on the actual input voltage of the power grid side, the actual input current of the power grid side and the input voltage of the converter to obtain a transformed actual input voltage vector of the power grid side, an actual input current vector of the power grid side and an input voltage vector of the converter;
and the combination module is used for calculating a group of power combinations of the current sampling period according to the actual input voltage vector of the power grid side, the input voltage vector of the converter, the actual active power of the power grid side in the last sampling period and the actual reactive power of the power grid side.
According to a third aspect, an embodiment of the present invention provides an electronic device, including: the six-switch single-phase current transformer control method comprises a memory and a processor, wherein the memory and the processor are mutually connected in a communication mode, computer instructions are stored in the memory, and the processor executes the computer instructions so as to execute the six-switch single-phase current transformer control method.
According to a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, which stores computer instructions for causing a computer to execute the six-switch single-phase current transformer control method described above.
The technical scheme of the invention has the following advantages:
according to the embodiment of the invention, the input voltage, the input current and the like in the last sampling period are obtained through detection, the multiple groups of power combinations in the last sampling period are calculated, then the multiple groups of power combinations in the current sampling period are obtained through further prediction, and the multiple groups of converter output currents in the current sampling period are calculated. And selecting the optimal solution of the power combination of the current sampling period and the converter output current of the current sampling period by using a pre-established cost function, determining the switch state combination of the converter of the current sampling period by using the optimal solution, and controlling the converter. In the embodiment of the invention, a traditional double closed-loop control system is not adopted, but power and current are predicted, the power combination of the current acquisition period and the converter output current of the current sampling period are predicted, a cost function is established according to the prediction result, the optimal voltage vector is solved, and the switching state combination of the six-switch single-phase converter is controlled. The switching state combination is determined by utilizing power and current prediction, so that the calculated amount of a system is reduced, the stability of the system is improved, and the dynamic response capability of the system is accelerated.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a block diagram of a specific example of a six-switch single-phase current transformer in the prior art;
fig. 2 is a flowchart of a specific example of a six-switch single-phase current transformer control method according to embodiment 1 of the present invention;
fig. 3 is a schematic diagram illustrating control of a six-switch single-phase current transformer in embodiment 1 of the present invention;
fig. 4 is a schematic block diagram of a specific example of a six-switch single-phase current transformer control device according to embodiment 2 of the present invention;
fig. 5 is a schematic structural diagram of a specific example of an electronic device in embodiment 3 of the present invention.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; the two elements may be directly connected or indirectly connected through an intermediate medium, or may be communicated with each other inside the two elements, or may be wirelessly connected or wired connected. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
Example 1
The embodiment provides a control method of a six-switch single-phase current transformer, which can be executed by electronic devices such as a processor, a controller and the like, wherein the electronic devices can detect and acquire current and voltage information of each part of the six-switch single-phase current transformer, predict and calculate the current and voltage information, and acquire an optimal solution; the electronic device is further configured to control a switching state combination of the switching devices of the six-switch single-phase current transformer according to an obtained optimal solution, that is, an optimal voltage vector, so as to control the six-switch single-phase current transformer, as shown in fig. 2, including the following steps:
and S101, predicting to obtain multiple groups of power combinations of the current sampling period by utilizing multiple groups of power combinations obtained by calculation of the previous sampling period, wherein each group of power combinations comprises an active power and a corresponding reactive power.
As shown in fig. 1 or 3, the grid side and grid side inductances LgGrid side resistor RgAnd the six-switch single-phase current transformer is connected in series and then is connected. Output load side and load side inductance L of six-switch single-phase current transformeroLoad side voltage RoAre connected in series. The voltage and the current at any position in the six-switch single-phase converter topological circuit can be detected through electronic equipment, and the voltage and the current comprise power grid side actual input voltage, power grid side actual input current, converter input voltage, converter input current and the like.
In the embodiment of the present invention, if it is desired to predict a plurality of groups of power combinations of a certain sampling period, it is necessary to first obtain a previous sampling period of the certain sampling period through electronic device detection, where the previous sampling period is used as a known grid-side actual input voltage and a known grid-side actual input current, and a known converter actual output voltage and a known converter actual output current, and the like.
Calculating multiple groups of power combinations by using the last sampling period, specifically, detecting the actual input voltage v of the power grid side of the last sampling periodgActual input current i on the network sidegThe actual input voltage v of the power grid side is converted into the actual input voltage vgThe actual input current i of the grid sidegRespectively carrying out orthogonal transformation, and the transformed actual input voltage v at the power grid sidegFor the actual input voltage vector v of the network sidegαAnd vgβ. That is, vgα，vgβAnd all the actual input voltage vectors of the power grid side in the last sampling period are obtained. Further, vgα，vgβVector sum is vgαβIn this embodiment, vgαβAnd the actual input voltage vector of the power grid side is also the last sampling period. Likewise, the converted actual input current i on the network sidegFor the actual input current vector i of the network sidegαAnd igβ. That is, igα，igβAnd all the actual input voltage vectors of the power grid side in the last sampling period are obtained. Further, igα，igβThe vector sum is igαβThis implementationIn example igαβAnd the actual input current vector of the power grid side is also the last sampling period. According to the actual input voltage vector v of the power grid side obtained by conversion after detectiongαAnd vgβAnd the actual input current vector i of the power grid side obtained by conversion after detectiongαAnd igβCalculating a last sampling period power combination, wherein the power combination comprises the grid-side actual active power P and the grid-side actual reactive power Q, and is:
P＝vgαigα+vgβigβ (1)
Q＝vgαigα+vgβigβ (2)
in this embodiment, a group of power combinations is first taken as an example to predict a group of power combinations of the current sampling period. And P is the actual active power of the power grid side in the last sampling period, and Q is the actual reactive power of the power grid side in the last sampling period.
Step S102, calculating a plurality of groups of converter output currents in the current sampling period;
the actual output voltage v of the current transformer on the load side in the last sampling period can be detected through electronic equipmentoAnd the actual output current i of the load side of the converteroAnd the like. As described above, the grid-side actual input voltage v of the last sampling period is detectedgActual input current i on the network sidegThe actual input voltage v of the power grid side is converted into the actual input voltage vgThe actual input current i of the grid sidegOrthogonal transformation is performed separately. According to the conversion result, the actual output voltage of the load side of the six-switch single-phase converter can be simplified into the following steps under the condition of orthotropic conversion:
Figure BDA0003493517670000091
wherein u isoαβThe actual output voltage of the converter on the load side in the last sampling period, i.e. the actual output voltage of the converter in the last sampling period, isoαβThe actual output current on the load side of the converter for the last sampling period,i.e. the actual output current, L, of the converter in the previous sampling periodoIs a load side inductor, RoIs the load side voltage.
After a lagging euler transformation, equation (3) can further calculate the converter output current for the current sampling period:
Figure BDA0003493517670000092
wherein ioαβ(k +1) is the current output current of the current transformer in the current sampling period, uoαβ(k +1) is the converter output voltage in the current sampling period, ioαβ(k) And the actual output current of the current transformer in the last sampling period is Ts.
Step S103, selecting an optimal solution of the power combination of the current sampling period and the converter output current of the current sampling period by utilizing a pre-established cost function, wherein the cost function is a linear combination of a power prediction cost function and a current prediction cost function;
the pre-established cost function is a linear combination of a power prediction cost function and a current prediction cost function, and comprises the following steps:
Figure BDA0003493517670000101
and (3) calculating the minimum value of J of the current formula under multiple groups of parameters through the formula (5), wherein the minimum value is the optimal solution of the active power and the reactive power of the current sampling period and the converter output current of the current sampling period. The meaning of said formula (5) and sets of power combinations etc. are presented below.
And S104, determining the switch state combination of the current converter in the current sampling period by using the optimal solution, and controlling the current converter.
And selecting the switching state combination of the current converter in the current sampling period according to the solved optimal solution, namely the optimal voltage vector, and determining the switching state combination of the current converter in the current sampling period as the working state of the current period so as to achieve the target power, the target current and the like.
In this embodiment, the input voltage, the input current, and the like in the previous sampling period are obtained through detection, multiple groups of power combinations in the previous sampling period are calculated, and then, multiple groups of power combinations in the current sampling period are obtained through further prediction, and multiple groups of converter output currents in the current sampling period are calculated. And selecting the optimal solution of the power combination of the current sampling period and the converter output current of the current sampling period by using a pre-established cost function, determining the switch state combination of the converter of the current sampling period by using the optimal solution, and controlling the converter. In the embodiment of the invention, a traditional double closed-loop control system is not adopted, but power and current prediction is adopted, the power combination of the current acquisition period and the converter output current of the current sampling period are predicted, a cost function is established according to the prediction result, so that the optimal voltage vector is solved, and the switching state combination of the six-switch single-phase converter is controlled. The switching state combination is determined by utilizing power and current prediction, so that the calculated amount of a system is reduced, the stability of the system is improved, and the dynamic response capability of the system is accelerated.
As an optional implementation manner, in an embodiment of the present invention, the predicting, by using multiple sets of power combinations calculated in a previous sampling period, multiple sets of power combinations of a current sampling period includes:
step S201, obtaining the actual input voltage of the power grid side, the actual input current of the power grid side, the actual active power of the power grid side, the actual reactive power of the power grid side and the input voltage of a converter in the last sampling period;
step S202, orthogonal transformation is respectively carried out on the actual input voltage of the power grid side, the actual input current of the power grid side and the input voltage of the converter, and a transformed actual input voltage vector of the power grid side, an actual input current vector of the power grid side and an input voltage vector of the converter are obtained.
Specifically, the detection acquires the last sampling periodGrid-side actual input voltage vgActual input current i on the network sidegInput voltage u of converterg，
The actual input voltage v of the power grid side is measuredgThe actual input current i of the grid sidegConverter input voltage ugOrthogonal transformation is performed separately. The converted actual input voltage v of the network sidegFor the actual input voltage vector v of the network sidegαAnd vgβ. That is, vgα，vgβAnd all the actual input voltage vectors of the power grid side in the last sampling period are obtained. Further, vgα，vgβVector sum is vgαβIn this embodiment, vgαβAnd the actual input voltage vector of the power grid side is also the last sampling period. Likewise, the converted actual input current i on the network sidegFor the actual input current vector i of the network sidegαAnd igβ. That is, igα，igβAnd all the actual input voltage vectors of the power grid side in the last sampling period are obtained. Further, igα，igβThe vector sum is igαβIn this embodiment igαβAnd the actual input current vector of the power grid side is also the last sampling period. Likewise, the converted converter input voltage ugThe converter input voltage vector u is the last sampling periodgαAnd ugβ. That is, ugα，ugβAll the current transformer input voltage vectors in the last sampling period. Further, igα，igβThe vector sum is igαβIn this embodiment, igαβAnd the actual input current vector of the power grid side is also the last sampling period.
The active power and the reactive power which are directly obtained through detection are called the actual active power of the power grid side and the actual reactive power of the power grid side, and the actual input voltage of the power grid side in the last sampling period and the active power and the reactive power which are obtained through calculation after the actual input current of the power grid side is subjected to orthogonal transformation are also called the actual active power of the power grid side and the actual reactive power of the power grid side.
Step S203, calculating according to the grid side actual input voltage vector, the converter input voltage vector, the grid side actual active power and the grid side actual reactive power of the previous sampling period to obtain a group of power combinations of the current sampling period.
According to the actual input voltage vector v of the power grid sidegα，vgβAnd said converter input voltage vector ugα，ugβAnd calculating the actual active power P and the actual reactive power Q of the power grid side in the last sampling period, namely predicting to obtain a group of power combinations of the current sampling period.
In this embodiment, orthogonal transformation is performed on detected power grid-side actual input voltage, power grid-side actual input current, converter input voltage, and the like in an α β coordinate system through orthogonal transformation, voltage and current are vectorized, and a power combination of a current sampling period is calculated according to a transformation result.
As an alternative implementation manner, in the embodiment of the present invention, the power combination of the current sampling period is obtained through prediction by the following formula:
Figure BDA0003493517670000121
Figure BDA0003493517670000131
wherein P (k +1) is the predicted active power of the grid side in the current sampling period, Q (k +1) is the predicted reactive power of the grid side in the current sampling period, P (k) is the actual active power of the grid side in the last sampling period, Q (k) is the actual reactive power of the grid side in the last sampling period, v (k)gα(k)，vgβ(k) Are all the actual input voltage vectors i of the power grid side in the last sampling periodgα(k)，igβ(k) All the actual input current vectors u of the power grid side in the last sampling periodgα(k)，ugβ(k) Are all as described aboveA sampling period of the converter input voltage vector, LgFor the grid side inductance, RgIs the grid side resistance, ωgIs constant and Ts is the sampling period.
Further, the current transformer input voltage vector u of the last sampling periodgα(k)，ugβ(k) The method has important influence on the switching state of the six-switch single-phase converter, and the converter input voltage vector u is used in the last sampling periodgα(k)，ugβ(k) And when the current sampling period changes, the power grid side predicts active power P (k +1), and the power grid side predicts reactive power Q (k +1) in the current sampling period also changes correspondingly, so that multiple groups of power combinations and multiple groups of converter output currents are generated.
In the embodiment of the present invention, (k) represents a previous sampling period, and (k +1) represents a current sampling period.
In this embodiment, the MPC control model may replace a conventional dual closed-loop control system, and multiple sets of power combinations and multiple sets of output currents of the converter in the current sampling period may be obtained by changing an input voltage vector of the converter.
As an optional implementation manner, in the embodiment of the present invention, the multiple sets of converter output currents in the current sampling period are calculated by the following formula:
Figure BDA0003493517670000132
wherein ioαβ(k +1) is the current output current of the current transformer in the current sampling period, uoαβ(k +1) is the current sampling period output voltage of the converter, ioαβ(k) The actual output current L of the converter for the last sampling periodoIs a load side inductance, RoIs the load side resistance.
，
As an optional implementation manner, in an embodiment of the present invention, the actual output voltage of the converter satisfies the following relationship function:
Figure BDA0003493517670000141
wherein u isoαβFor the actual output voltage, i, of the converter for the previous sampling periodoαβAnd actually outputting the current by the current transformer for the last sampling period.
As an optional implementation manner, in the embodiment of the present invention, the pre-established cost function is:
Figure BDA0003493517670000142
wherein, P*For reference to active power, Q*With reference to the reactive power,
Figure BDA0003493517670000143
are all the converter target output current ioα(k+1)，ioβAnd (k +1) is the current output current of the current transformer in the current sampling period, and J is a variable.
In particular, reference active power P*For the actual active power P and the reference reactive power Q of the power grid side in the embodiment*For the actual reactive power Q on the grid side in this embodiment, P (k +1) is the predicted active power on the grid side in the current sampling period, and Q (k +1) is the predicted reactive power on the grid side in the current sampling period.
Figure BDA0003493517670000144
The converter target output current is the converter target output current, namely, the converter load side output current to be obtained. i.e. ioα(k+1)，ioβ(k +1) is the current outputted by the current transformer in the current sampling period. In this example, ioα(k+1)，ioβThe vector sum of (k +1) is ioαβ(k +1), hence ioα(k+1)，ioβ(k+1)，ioαβ(k +1) are both referred to as the converter output current for the current sampling period.
The actual active power P of the power grid side, the actual reactive power Q of the power grid side and the target output current of the converter are measured
Figure BDA0003493517670000151
Four groups of actual known values, the predicted active power P (k +1) of the power grid side, the predicted reactive power Q (k +1) of the power grid side and the output current i of the converter in the current sampling periodoα(k+1)，ioβAnd (k +1) superposing the difference values of the four groups of predicted values, namely forming a cost function by linear combination of the power prediction cost function and the current prediction cost function. And solving the minimum value J, namely solving a voltage vector of the minimum cost function, wherein the voltage vector is an optimal solution. And determining the switch state combination of the current converter in the current sampling period by using the optimal solution, and controlling the current converter.
Example 2
This embodiment provides a six-switch single-phase current transformer control apparatus, which may be used to execute the six-switch single-phase current transformer control method in embodiment 1, and the apparatus may be disposed inside a server or other devices, and modules of the apparatus cooperate with each other to realize control of the six-switch single-phase current transformer, as shown in fig. 4, the apparatus includes:
the prediction module 201 is configured to predict, by using multiple groups of power combinations obtained by calculation in a previous sampling period, multiple groups of power combinations in a current sampling period, where each group of power combinations includes an active power and a corresponding reactive power;
a calculating module 202, configured to calculate multiple sets of converter output currents in the current sampling period;
a solving module 203, configured to select an optimal solution of the current sampling period and the current transformer output current according to a pre-established cost function, where the cost function is a linear combination of a power prediction cost function and a current prediction cost function;
a determining module 204, configured to determine, by using the optimal solution, a switching state combination of the converter in the current sampling period, so as to control the converter.
As an optional implementation manner, in an embodiment of the present invention, the prediction module further includes:
the acquisition module is used for acquiring the actual input voltage of the power grid side, the actual input current of the power grid side, the actual active power of the power grid side, the actual reactive power of the power grid side and the input voltage of the converter in the last sampling period;
the transformation module is used for respectively carrying out orthogonal transformation on the actual input voltage of the power grid side, the actual input current of the power grid side and the input voltage of the converter to obtain a transformed actual input voltage vector of the power grid side, an actual input current vector of the power grid side and an input voltage vector of the converter;
and the combination module is used for calculating to obtain a group of power combinations of the current sampling period according to the actual input voltage vector of the power grid side, the input voltage vector of the converter, the actual active power of the power grid side in the last sampling period and the actual reactive power of the power grid side.
In this embodiment, in the embodiment of the present invention, the input voltage, the input current, and the like in the previous sampling period are obtained through detection, a plurality of groups of power combinations in the previous sampling period are calculated, and then the plurality of groups of power combinations in the current sampling period are obtained through further prediction, and a plurality of groups of converter output currents in the current sampling period are calculated. And selecting the optimal solution of the power combination of the current sampling period and the converter output current of the current sampling period by using a pre-established cost function, determining the switch state combination of the converter of the current sampling period by using the optimal solution, and controlling the converter. In the embodiment of the invention, a traditional double closed-loop control system is not adopted, but an MPC model prediction control method is adopted, namely, power and current prediction, prediction is carried out on the power combination of the current acquisition period and the current output current of the current sampling period, and a cost function is established according to the prediction result to solve the optimal voltage vector to control the switching state combination of the six-switch single-phase converter. The switching state combination is determined by utilizing power and current prediction, so that the calculated amount of a system is reduced, the stability of the system is improved, and the dynamic response capability of the system is accelerated.
For the detailed description of the above device part, reference may be made to the above method embodiments, which are not described herein again.
Example 3
The present embodiment provides an electronic device, as shown in fig. 5, the electronic device includes a processor 301 and a memory 302, where the processor 301 and the memory 302 may be connected by a bus or by other means, and fig. 5 takes the example of connection by a bus as an example.
Processor 301 may be a Central Processing Unit (CPU). The Processor 301 may also be other general purpose processors, Digital Signal Processors (DSPs), Graphics Processing Units (GPUs), embedded Neural Network Processors (NPUs), or other dedicated deep learning coprocessors, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), or other Programmable logic devices, discrete Gate or transistor logic devices, discrete hardware components, or any combination thereof.
The memory 302 is a non-transitory computer readable storage medium, and can be used to store non-transitory software programs, non-transitory computer executable programs, and modules, such as program instructions/modules corresponding to the control method of the six-switch single phase inverter in the embodiment of the present invention. The processor 301 executes various functional applications and data processing of the processor by running non-transitory software programs, instructions and modules stored in the memory 302, that is, the six-switch single-phase current transformer control method in the above method embodiment is implemented.
The memory 302 may further include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required for at least one function; the storage data area may store data created by the processor 301, and the like. Further, the memory 302 may include high speed random access memory, and may also include non-transitory memory, such as at least one magnetic disk storage device, flash memory device, or other non-transitory solid state storage device. In some embodiments, the memory 302 may optionally include memory located remotely from the processor 301, which may be connected to the processor 301 via a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.
The memory 302 stores one or more modules that, when executed by the processor 301, perform the six-switch single-phase inverter control method of the embodiment shown in fig. 2.
The details of the electronic device may be understood with reference to the corresponding related description and effects in the embodiment shown in fig. 2, and are not described herein again.
The embodiment of the present invention further provides a computer-readable storage medium, where computer-executable instructions are stored, and the computer-executable instructions may execute the six-switch single-phase current transformer control method in any of the above embodiments. The storage medium may be a magnetic Disk, an optical Disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a Flash Memory (Flash Memory), a Hard Disk (Hard Disk Drive, abbreviated as HDD), a Solid State Drive (SSD), or the like; the storage medium may also comprise a combination of memories of the kind described above.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.

Claims (10)

1. A six-switch single-phase current converter control method is characterized by comprising the following steps:
predicting to obtain a plurality of groups of power combinations of the current sampling period by utilizing a plurality of groups of power combinations obtained by calculation of the previous sampling period, wherein each group of power combinations comprises an active power and a corresponding reactive power;
calculating the output currents of the multiple groups of converters in the current sampling period;
selecting an optimal solution of the power combination of the current sampling period and the current converter output current of the current sampling period by utilizing a pre-established cost function, wherein the cost function is a linear combination of a power prediction cost function and a current prediction cost function;
and determining the switch state combination of the current converter in the current sampling period by using the optimal solution, and controlling the current converter.
2. The six-switch single-phase current transformer control method of claim 1, wherein the predicting the multiple power combinations of the current sampling period by using the multiple power combinations calculated in the last sampling period comprises:
acquiring the actual input voltage of the power grid side, the actual input current of the power grid side, the actual active power of the power grid side, the actual reactive power of the power grid side and the input voltage of a converter in the last sampling period;
performing orthogonal transformation on the power grid side actual input voltage, the power grid side actual input current and the converter input voltage respectively to obtain a transformed power grid side actual input voltage vector, a transformed power grid side actual input current vector and a transformed converter input voltage vector;
and calculating to obtain a group of power combinations of the current sampling period according to the actual input voltage vector of the power grid side, the input voltage vector of the converter, the actual active power of the power grid side in the last sampling period and the actual reactive power of the power grid side.
3. The six-switch single-phase current transformer control method of claim 2, wherein the power combination of the current sampling period is predicted by the following formula:
Figure FDA0003493517660000021
Figure FDA0003493517660000022
wherein P (k +1) is the predicted active power of the grid side in the current sampling period, Q (k +1) is the predicted reactive power of the grid side in the current sampling period, P (k) is the actual active power of the grid side in the last sampling period, Q (k) is the actual reactive power of the grid side in the last sampling period, v (k)gα(k)，vgβ(k) All are the actual input voltage vector u of the power grid side in the last sampling periodgα(k)，ugβ(k) Are all the converter input voltage vector, L, of the last sampling periodgFor the grid side inductance, RgIs the grid side resistance, ωgIs constant and Ts is the sampling period.
4. The six-switch single-phase current transformer control method according to claim 3, wherein the current sampling period of the multiple sets of current transformer output currents is calculated by the following formula:
Figure FDA0003493517660000023
wherein ioαβ(k +1) is the current output current of the current transformer in the current sampling period, uoαβ(k +1) is the converter output voltage in the current sampling period, ioαβ(k) For the current actually output by the converter in the last sampling period, LoIs a load side inductance, RoIs the load side resistance.
5. The six-switch single-phase converter control method according to claim 4, wherein the converter actual output voltage satisfies the following relation function:
Figure FDA0003493517660000024
wherein u isoαβFor the actual output voltage, i, of the converter for the previous sampling periodoαβAnd actually outputting the current by the current transformer for the last sampling period.
6. The six-switch single-phase current transformer control method of claim 5, wherein the pre-established cost function is:
Figure FDA0003493517660000031
wherein, P*For reference of active power, Q*With reference to the reactive power,
Figure FDA0003493517660000032
are all the converter target output current ioα(k+1)，ioβAnd (k +1) is the current output current of the current converter in the current sampling period, and J is a variable.
7. A six-switch single-phase current transformer control device is characterized by comprising:
the prediction module is used for predicting to obtain a plurality of groups of power combinations of the current sampling period by utilizing a plurality of groups of power combinations obtained by calculation of the last sampling period, wherein each group of power combinations comprises an active power and a corresponding reactive power;
the calculation module is used for calculating the output currents of the multiple groups of converters in the current sampling period;
the solving module is used for selecting an optimal solution of the power combination of the current sampling period and the converter output current of the current sampling period by utilizing a pre-established cost function, wherein the cost function is a linear combination of a power prediction cost function and a current prediction cost function;
and the determining module is used for determining the switching state combination of the current converter in the current sampling period by using the optimal solution and controlling the current converter.
8. The apparatus of claim 7, wherein the prediction module further comprises:
the acquisition module is used for acquiring the actual input voltage of the power grid side, the actual input current of the power grid side, the actual active power of the power grid side, the actual reactive power of the power grid side and the input voltage of the converter in the last sampling period;
the transformation module is used for respectively carrying out orthogonal transformation on the actual input voltage of the power grid side, the actual input current of the power grid side and the input voltage of the converter to obtain a transformed actual input voltage vector of the power grid side, an actual input current vector of the power grid side and an input voltage vector of the converter;
and the combination module is used for calculating to obtain a group of power combinations of the current sampling period according to the actual input voltage vector of the power grid side, the input voltage vector of the converter, the actual active power of the power grid side in the last sampling period and the actual reactive power of the power grid side.
9. An electronic device, comprising:
a memory and a processor, the memory and the processor being communicatively connected to each other, the memory having stored therein computer instructions, the processor executing the computer instructions to perform the six-switch single-phase inverter control method according to any one of claims 1 to 6.
10. A computer-readable storage medium storing computer instructions for causing a computer to perform the six-switch single-phase current transformer control method of any one of claims 1-6.
CN202210104559.3A 2022-01-28 2022-01-28 Six-switch single-phase current transformer control method and device Pending CN114499232A (en)

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