Wide-range high-efficiency cooperative control method, device, equipment and medium

Abstract

The invention provides a large-range high-efficiency cooperative control and operation method. The method comprises the following steps: determining that one or more converter units in equipment or a system operate in a first operation state; obtaining harmonic information when the converter unit operates according to the operating condition of the converter unit operating in the first operating state, and injecting the harmonic information in a control link; determining that the remaining converter units in the equipment or the system operate in a second operation state; and according to the harmonic information of the first operation state, calculating the harmonic information corresponding to the converter unit in the second operation state, and controlling the converter unit in the second operation state to carry out harmonic compensation on the converter unit in the first operation state, so that the harmonic only flows between the converter units in the first operation state and the second operation state. According to the technical scheme of the embodiment, large-range high-efficiency operation of the hybrid transformer is realized, and the voltage and transmission power range and efficiency are improved.

Description

Technical Field

[0001] This invention relates to the field of energy and power system technology, and in particular to a method, apparatus, equipment and medium for large-scale and high-efficiency coordinated control. Background Technology

[0002] Currently, the integration of new energy sources such as photovoltaics into the power distribution network is becoming increasingly common. Most of these new energy sources are equipped with energy storage to achieve power flow stability and thus reduce the impact of new energy integration on the power grid. However, the converter units that connect new energy sources, energy storage, and the power grid in existing technologies are limited by AC voltage and maximum modulation ratio. In addition, voltage fluctuations caused by energy storage result in a small operating range for the converter units. Summary of the Invention

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a wide-range, high-efficiency collaborative control and operation method, apparatus, and equipment, which can be applied to equipment or systems with two or more AC / DC converter units connected in parallel on the AC side or coupled through a transformer, thereby improving the operating range and power transmission efficiency.

[0004] In a first aspect, a wide-range, high-efficiency collaborative control method is characterized by its application to a device or system having two or more converter units operating in parallel on the AC side or coupled via a transformer, wherein the operating states of the converter units in the device or system include a first operating state and a second operating state, and the method includes:

[0005] It is determined that one or more converter units in the device or system are operating in a first operating state, wherein the first operating state characterizes the harmonic injection state;

[0006] Harmonic information of the converter unit during operation is obtained according to the operating conditions of the converter unit operating in the first operating state. The harmonic information is injected in the control loop to realize the harmonic injection function of the converter unit in the first operating state. The harmonic information includes harmonic voltage value and harmonic current value.

[0007] The remaining converter units in the device or system are determined to be operating in a second operating state, wherein the second operating state characterizes the harmonic compensation state;

[0008] The harmonic information corresponding to the converter unit when operating in the second operating state is calculated based on the harmonic information of the first operating state, wherein the harmonic information of the second operating state includes harmonic voltage value and harmonic current value.

[0009] Based on the harmonic information in the second operating state, the converter unit in the second operating state is controlled to perform harmonic compensation on the converter unit in the first operating state, so that the harmonics only flow between the converter units in the first operating state and the second operating state, thereby achieving coordinated control and operation.

[0010] In some embodiments of the present invention, determining that one or more converter units in the device or system are operating in a first operating state includes:

[0011] Obtain the operating conditions of the converter unit when it is in the first operating state;

[0012] The modulation ratio is determined based on the operating conditions, the fundamental modulation coefficient and harmonic modulation coefficient are calculated based on the modulation ratio, a modulation wave function is established based on the fundamental modulation coefficient and the harmonic modulation coefficient, and the converter unit is modulated based on the modulation wave function.

[0013] In some embodiments of the present invention, determining that the remaining converter units in the device or system are operating in a second operating state includes:

[0014] The harmonic information for operating in the second operating state is determined based on the harmonic information in the first operating state.

[0015] The harmonic information in the second operating state is used as the control reference information for the converter unit;

[0016] Based on the control reference information, multi-frequency harmonic comprehensive control is performed on the harmonic information in the second operating state to achieve harmonic compensation of the converter unit.

[0017] In some embodiments of the present invention, the device or system has two or more converter units, which operate in parallel on the AC side or are coupled via transformers. Determining the equivalent model of the device includes:

[0018] The AC side of the converter unit is equivalent to an inductor and a resistor connected in series. The transformer winding connected to the converter unit is equivalent to a leakage inductance and a leakage resistance connected in series. The inductance and resistance of the converter unit operating in the first operating state and the leakage inductance and leakage resistance of the transformer winding connected to the converter unit are equivalently calculated as a first inductance and a first resistance. The inductance and resistance of the converter unit operating in the second operating state and the leakage inductance and leakage resistance of the transformer winding connected to the converter unit are equivalently calculated as a second inductance and a second resistance.

[0019] The number of converter units operating in the first operating state is determined. When the number is greater than 1, the first inductance and first resistance of the multiple converter units are equivalently calculated as a first integrated inductor and a first integrated resistor. The number of converter units operating in the second operating state is determined. When the number is greater than 1, the second inductance and second resistance of the multiple converter units are equivalently calculated as a second integrated inductor and a second integrated resistor. The device or system is connected to an external grid-side unit, which can be equivalently calculated as a third integrated inductor and a third integrated resistor.

[0020] In some embodiments of the present invention, the control of the converter unit in the second operating state to perform harmonic compensation on the converter unit in the first operating state includes:

[0021] Determine the AC voltage and DC voltage of the converter unit when it is in the first operating state, and calculate the voltage range of the converter unit based on the AC voltage and DC voltage;

[0022] The transmission power range between the converter unit operating in the first operating state and the converter unit operating in the second operating state is calculated based on the harmonic information in the first operating state and the harmonic information in the second operating state.

[0023] The harmonic information in the first operating state is injected into the converter unit operating in the first operating state to obtain the first operating loss;

[0024] The harmonic information in the second operating state is injected into the converter unit operating in the second operating state to obtain the second operating loss. The improved efficiency of the device or system is calculated based on the first operating loss and the second operating loss.

[0025] In some embodiments of the present invention, the control of the converter unit in the first operating state is provided with a voltage compensator and a current compensator. The step of injecting harmonic information in the control loop to achieve the harmonic injection function of the converter unit in the first operating state includes:

[0026] Obtain the power reference value, AC voltage value, DC voltage reference value, and DC voltage feedback value of the converter unit in the first operating state;

[0027] The current reference value of the converter unit in the first operating state is calculated based on the AC voltage value and the power reference value, or the current reference value of the converter unit in the first operating state is obtained by inputting the DC voltage reference value and the DC voltage feedback value into the voltage compensator.

[0028] Obtain the current feedback value of the converter unit in the first operating state, input the current feedback value and the current reference value into the current compensator to calculate the modulation wave reference value of the converter unit, and input the modulation wave reference value into the harmonic injection module to perform harmonic injection on the converter unit operating in the first operating state;

[0029] After a harmonic is injected into the converter unit operating in the first operating state, the harmonic voltage value of the converter unit in the first operating state is obtained. The harmonic voltage value is then input into the first formula to obtain the harmonic current value of the converter unit in the first operating state.

[0030] In some embodiments of the present invention, the converter unit in the second operating state is provided with a comprehensive current compensator for multi-frequency harmonics, and controlling the converter unit in the second operating state to perform harmonic compensation on the converter unit in the first operating state includes:

[0031] The AC voltage and harmonic current values ​​of the converter unit operating in the first operating state and the AC voltage value of the converter unit operating in the second operating state are obtained. The AC voltage and harmonic current values ​​and the AC voltage value are input into the first formula and the second formula to obtain the reference value of the harmonic current value of the converter unit operating in the second operating state.

[0032] Obtain the harmonic current feedback value of the converter unit operating in the second operating state, and input the harmonic current reference value and the harmonic current feedback value to the multi-frequency harmonic integrated current compensator to perform harmonic compensation on the converter unit operating in the first operating state.

[0033] In a second aspect, embodiments of the present invention provide a control device for a wide-range, high-efficiency cooperative control method, comprising at least one control processor and a memory for communicatively connecting to the at least one control processor; the memory stores instructions executable by the at least one control processor, which are executed by the at least one control processor to enable the at least one control processor to perform the control method as described in the first aspect above.

[0034] Thirdly, embodiments of the present invention provide an electronic device including a control device having the wide-range, high-efficiency cooperative control method as described in the second aspect above.

[0035] Fourthly, embodiments of the present invention provide a computer-readable storage medium storing computer-executable instructions for executing a control method of the large-scale, high-efficiency cooperative control method as described in the first aspect above.

[0036] The control method according to embodiments of the present invention has at least the following beneficial effects:

[0037] The system determines that one or more converter units in a device or system are operating in a first operating state, where the first operating state represents a harmonic injection state. Based on the operating conditions of the converter units operating in the first operating state, the system obtains the harmonic information of the converter units during operation and injects this information into the control loop to achieve the harmonic injection function of the converter units in the first operating state. The harmonic information includes harmonic voltage and harmonic current values. The system then determines that the remaining converter units in the device or system are operating in a second operating state, where the second operating state represents a harmonic compensation state. Based on the harmonic information of the first operating state, the system calculates the corresponding harmonic information for the converter units operating in the second operating state, where the harmonic information of the second operating state includes harmonic voltage and harmonic current values. Based on the harmonic information of the second operating state, the system controls the converter units in the second operating state to perform harmonic compensation on the converter units in the first operating state, so that harmonics only flow between the converter units in the first and second operating states, achieving coordinated control and operation. According to the technical solution of this embodiment, based on the synergistic application of harmonic injection and harmonic compensation, the new hybrid transformer can achieve wide-range and high-efficiency operation, and improve the voltage and transmission power range of the DC port of the new hybrid transformer, thereby realizing the flexible operation of the new hybrid transformer. Attached Figure Description

[0038] Figure 1 This is a flowchart of a large-scale, high-efficiency collaborative control method provided in one embodiment of the present invention;

[0039] Figure 2 This is a flowchart provided in the embodiment for determining that one or more converter units in a device or system are operating in a first operating state;

[0040] Figure 3 This is a flowchart provided in the embodiment for determining the operation of the remaining converter units in the second operating state in the device or system;

[0041] Figure 4 This is a flowchart illustrating how the equivalent model of the equipment is determined when the converter unit provided in the embodiment operates in parallel on the AC side or is coupled through a transformer.

[0042] Figure 5 This is a flowchart illustrating the improved computational range and efficiency provided in the embodiment;

[0043] Figure 6 This is a flowchart provided in the embodiment for implementing the harmonic injection function of the converter unit in the first operating state;

[0044] Figure 7This is a flowchart provided in the embodiment for controlling the converter unit in the second operating state to perform harmonic compensation on the converter unit in the first operating state;

[0045] Figure 8 This is a structural diagram of the control device provided in the embodiment;

[0046] Figure 9 This is a circuit diagram of a novel single-phase and three-phase hybrid transformer provided in the embodiment;

[0047] Figure 10 This is a circuit diagram of the single-phase and three-phase two-converter units operating on the AC side via transformer coupling, provided in the embodiment.

[0048] Figure 11 This is a circuit diagram showing the parallel operation of single-phase and three-phase two-converter units on the AC side, provided in the embodiment.

[0049] Figure 12 This is a schematic diagram of an equivalent model of the converter unit operating in parallel on the AC side or coupled through a transformer, provided in the embodiment.

[0050] Figure 13 This is a control block diagram for wide-range, high-efficiency operation provided in the embodiment;

[0051] Figure 14 This is a graph showing the harmonic and fundamental frequency information provided in the embodiment. Detailed Implementation

[0052] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0053] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0054] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0055] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0056] Reference Figure 9 , Figure 10 and Figure 11 The present invention provides a wide-range and high-efficiency collaborative control and operation method, which is applied to a device or system having two or more converter units operating in parallel on the AC side or coupled through a transformer. The device or system includes a converter unit in a first operating state, a converter unit in a second operating state, and a grid-side unit. In this embodiment, the converter unit in the first operating state operates in a harmonic injection state, while the converter unit in the second operating state operates in a harmonic compensation state. The modulation ratio of the converter unit in the first operating state is increased from the traditional 1.15 to 1.27, improving the operating efficiency of the equipment or system. To meet the grid harmonic requirements, coordinated control of the converter units in the first and second operating states is achieved, ensuring that harmonic information flows only between the converter units in the first and second operating states. This reduces the use of passive filtering devices and lowers system costs. By adjusting the fundamental and harmonic content of the converter units in the first and second operating states, the port voltage and power transmission range of the equipment or system are improved, enhancing the flexibility of the equipment or system in new energy and energy storage integrated systems. Furthermore, this embodiment also features diverse operating modes, such as the highest efficiency operating mode, the maximum power transmission operating mode, the optimal power quality operating mode, and the optimal dynamic operating mode, to meet the operational needs of different scenarios.

[0057] It should be noted that, referring to Figure 9 , Figure 10 and Figure 11 This technology can be further expanded to include multiple converter units, such as multiple units connected in parallel or an increase in the number of transformer windings. (See reference...) Figure 9 The new hybrid transformer can be further extended into a multi-port hybrid transformer, such as increasing the number of DC side series windings to form a multi-port transformer with more than three DC ports; or increasing the number of AC side windings to form a multi-port transformer with more than two external AC connection ports, etc. Through the comprehensive application of converter units in two operating states, multiple AC and DC power conversions can be realized.

[0058] The control method of the present invention will be further described below with reference to the accompanying drawings.

[0059] Reference Figure 1 , Figure 1A flowchart of a large-scale, high-efficiency cooperative control method provided in an embodiment of the present invention, the control method including but not limited to the following steps:

[0060] Step S11: Determine that one or more converter units in the equipment or system are operating in a first operating state, wherein the first operating state represents the harmonic injection state;

[0061] Step S12: Obtain harmonic information of the converter unit during operation according to the operating conditions of the converter unit in the first operating state, and inject the harmonic information in the control loop to realize the harmonic injection function of the converter unit in the first operating state. The harmonic information includes harmonic voltage value and harmonic current value.

[0062] It should be noted that the converter unit operating in the first operating state will generate harmonics. The harmonic voltage and harmonic current reference of the converter unit operating in the second operating state are calculated according to the first formula and the second formula, thereby realizing harmonic compensation and preventing harmonic information from flowing to the grid-side unit.

[0063] The first formula is as follows:

[0064]

[0065] Among them, V 1h R is the harmonic voltage under the first operating state. 1h L is the first equivalent resistance. 1h I is the first equivalent inductance. 1h The harmonic current in the first operating state; V 2h For the preferred harmonic voltage in the second operating state, R 2h L is the second equivalent resistance. 2h For the second equivalent inductance, I 2h This refers to the harmonic current in the second operating state.

[0066] The second formula is as follows:

[0067]

[0068] Among them, V ac1 V is the AC voltage in the first operating state. ac2 I is the AC voltage in the second operating state. ac1 I is the alternating current in the first operating state. ac2 This refers to the alternating current in the second operating state.

[0069] Step S13: Determine that the remaining converter units in the equipment or system are operating in the second operating state, wherein the second operating state represents the harmonic compensation state;

[0070] It should be noted that in the new hybrid transformer, the converter unit in the first operating state operates in the harmonic injection state, and the converter unit in the second operating state operates in the harmonic compensation state. The converter unit in the first operating state and the converter unit in the second operating state can be one or more converter units. The number of converter units in the first operating state and the number of converter units in the second operating state are determined by the number of ports and the operating mode of the new hybrid transformer.

[0071] Step S14: Calculate the harmonic information corresponding to the converter unit operating in the second operating state based on the harmonic information of the first operating state. The harmonic information of the second operating state includes harmonic voltage value and harmonic current value.

[0072] Step S15: Based on the harmonic information in the second operating state, control the converter unit in the second operating state to perform harmonic compensation on the converter unit in the first operating state, so that the harmonics only flow between the converter units in the first and second operating states, thereby achieving coordinated control and operation.

[0073] It should be noted that this embodiment improves the port voltage and power transmission range of the hybrid transformer by adjusting the fundamental and harmonic content of the converter unit in the first or second operating state, thereby enhancing the flexibility of the new hybrid transformer in new energy and energy storage integrated systems. Furthermore, the new hybrid transformer proposed in this embodiment also possesses diverse operating modes, such as highest efficiency operation, maximum power transmission operation, optimal power quality operation, and optimal dynamic operation, to meet the operational needs of different scenarios.

[0074] Additionally, in one embodiment, reference is made to Figure 2 ,exist Figure 1 Step S11 in the illustrated embodiment also includes, but is not limited to, the following steps:

[0075] Step S21: Obtain the operating conditions of the converter unit in the first operating state;

[0076] Step S22: Determine the modulation ratio based on the operating conditions, calculate the fundamental modulation coefficient and harmonic modulation coefficient based on the modulation ratio, establish the modulation wave function based on the fundamental modulation coefficient and harmonic modulation coefficient, and modulate the converter unit based on the modulation wave function.

[0077] It should be noted that for the converter unit, there are various methods for implementing harmonic injection, including but not limited to, such as analyzing the harmonic content under different modulation ratios, calculating the fundamental modulation coefficient and harmonic modulation coefficient, and establishing a modulation wave function based on PWM modulation to modulate the converter unit in the first operating state, thereby realizing the continuous operation of the converter unit in the harmonic injection state; for the converter unit, there are various methods for implementing harmonic compensation, including but not limited to, such as implementing the harmonic compensation function of the converter unit based on multi-frequency harmonic comprehensive control, thereby compensating for the harmonics of the converter unit in the first operating state.

[0078] Furthermore, the coordinated operation of the first and second operating states in the converter unit enables the equipment or system to have multiple optimized operating modes, such as: the highest efficiency operation mode, which integrates the efficiency of the converter unit, harmonic injection and harmonic compensation methods, and the partial power processing effect of the new hybrid transformer to achieve comprehensive optimization of operating efficiency; the maximum power transmission operation mode, which realizes the operation of the converter unit at the highest modulation ratio, so that its fundamental frequency content and harmonic content reach the highest level, using the fundamental frequency to achieve maximum power transmission between ports, and using harmonics to achieve maximum power transmission between DC ports; the optimal power quality operation mode, which optimizes the control method of harmonic compensation of the converter unit to minimize the harmonic content on the grid side and improve the power quality on the grid side; in addition, the optimal dynamic operation mode takes into account the randomness of the output of the new energy port and the voltage fluctuation of the energy storage port, and achieves the optimal dynamic operation of the hybrid transformer by optimizing the control of the converter unit and the control mode of the ports.

[0079] Additionally, in one embodiment, reference is made to Figure 3 ,exist Figure 2 Step S21 in the illustrated embodiment also includes, but is not limited to, the following steps:

[0080] Step S31: Determine the harmonic information for the second operating state based on the harmonic information in the first operating state;

[0081] Step S32: Use the harmonic information in the second operating state as the control reference information for the converter unit;

[0082] Step S33: Perform multi-frequency harmonic comprehensive control on the harmonic information in the second operating state according to the control reference information to realize harmonic compensation of the converter unit.

[0083] It should be noted that in this embodiment, when the multi-port novel hybrid transformer has a total of k converter units, of which m converter units are operating in the first operating state, then km converter units are operating in the second operating state accordingly.

[0084] Reference Figure 4 ,exist Figure 1Step S14 of the illustrated embodiment also includes, but is not limited to, the following steps:

[0085] Step S41: The AC side of the converter unit is equivalent to an inductor and a resistor connected in series. The transformer winding connected to the converter unit is equivalent to a leakage inductance and a leakage resistance connected in series. The inductance and resistance of the converter unit operating in the first operating state and the leakage inductance and leakage resistance of the transformer winding connected to the converter unit are equivalently calculated as the first inductance and the first resistance. The inductance and resistance of the converter unit operating in the second operating state and the leakage inductance and leakage resistance of the transformer winding connected to the converter unit are equivalently calculated as the second inductance and the second resistance.

[0086] Step S42: Determine the number of converter units operating in the first operating state. When the number is greater than 1, the first inductance and first resistance of the multiple converter units are equivalently calculated as the first integrated inductance and first integrated resistance. Determine the number of converter units operating in the second operating state. When the number is greater than 1, the second inductance and second resistance of the multiple converter units are equivalently calculated as the second integrated inductance and second integrated resistance. For the external grid-side unit of the device or system, the grid-side unit is equivalently calculated as the third integrated inductance and third integrated resistance.

[0087] It should be noted that the harmonic information of the first operating state, the second operating state, and the grid-side unit can be expressed by the following third formula:

[0088]

[0089] Among them, V 1h R is the harmonic voltage under the first operating state. 1h L is the first integrated resistor. 1h As the first integrated inductor, I 1h The harmonic current in the first operating state; V 2h R is the harmonic voltage in the second operating state. 2h L is the second integrated resistor. 2h For the second integrated inductor, I 2h The harmonic current in the second operating state; V mh R represents the harmonic voltage of the grid-side unit. 3h For the third integrated resistor, I 3h This refers to the harmonic current of the grid-side unit.

[0090] When the harmonic voltage and harmonic current of the grid-side unit are 0, the above first formula is obtained;

[0091] Since the impedance of the leakage inductance of a reactor is usually much greater than the loss resistance, the fourth formula can be derived from the first formula above:

[0092]

[0093] Furthermore, the leakage inductance L of unit k k1 The design is as shown in Formula 5:

[0094]

[0095] Among them, L kpu Here are the weighting coefficients, f1 is the fundamental frequency, and V... ack For AC voltage, P uk The rated power is given, and k = 1 or 2 represents the kth operating state.

[0096] When assuming L 1pu ≈L 2pu From the fifth formula, we can obtain the following sixth formula:

[0097]

[0098] Reference Figure 12 L s1 With R s1 For the equivalent inductance and equivalent resistance of the converter unit operating in the first operating state, L s2 With R s2 These are the inductor and resistor of the converter unit operating in the second operating state, respectively. g1 With R g1 These are the equivalent leakage inductance and leakage resistance of the transformer winding connected to the converter unit in the first operating state, respectively. g2 With R g2 These are the equivalent leakage inductance and leakage resistance of the transformer winding connected to the converter unit in the second operating state, respectively. g3 With R g3 These are the equivalent leakage inductance and leakage group of the network-side unit, respectively.

[0099]

[0100] When the number of converter units operating in both the first and second operating states is 1, L1 and R1 are the first inductor and the first resistor, and L2 and R2 are the second inductor and the second resistor. When the number of converter units operating in both the first and second operating states is greater than 1, L1 and R1 are the first integrated inductor and the first integrated resistor, L2 and R2 are the second integrated inductor and the second integrated resistor, and L3 and R3 are the third integrated inductor and the third integrated resistor.

[0101] Additionally, in one embodiment, reference is made to Figure 5 ,exist Figure 1 Step S13 of the illustrated embodiment also includes, but is not limited to, the following steps:

[0102] Step S51: Determine the AC voltage and DC voltage of the converter unit in the first operating state, and calculate the voltage range of the converter unit based on the AC voltage and DC voltage.

[0103] Step S52: Calculate the transmission power range between the converter unit operating in the first operating state and the converter unit operating in the second operating state based on the harmonic information in the first operating state and the harmonic information in the second operating state.

[0104] Step S53: Inject harmonic information in the first operating state into the converter unit operating in the first operating state to obtain the first operating loss;

[0105] Step S54: Inject harmonic information in the second operating state into the converter unit operating in the second operating state to obtain the second operating loss, and calculate the improved efficiency of the device or system based on the first operating loss and the second operating loss.

[0106] It should be noted that harmonic injection increases the modulation ratio of the converter unit from the traditional 1.15 to 1.27. Under the same DC voltage range, the AC side voltage range is increased by about 10% by applying harmonic injection, thus improving the operating range of the new hybrid transformer when facing grid voltage fluctuations.

[0107] Under the same AC voltage, applying harmonic injection can reduce the DC voltage requirements of the inverter stage in the converter unit. For a converter unit operating in a single mode, its DC voltage range increases by approximately 10%. When applied to a new type of hybrid transformer, the DC voltage range of the unit is further increased as shown in Formula 7:

[0108]

[0109] Where V d1 With V ac These are the DC and AC port voltages of the converter unit in its first operating state, respectively.

[0110] Under harmonic injection operation, both the fundamental frequency content and the injected low-frequency harmonic content increase with the increase of the modulation ratio. For the DC side of the novel hybrid transformer, harmonics can achieve power transfer between DC ports through the flow between converter units in either the first or second operating state, thus increasing the power transmission between DC ports. For the AC side, an increase in the fundamental frequency amplitude content will improve power transmission with the AC ports. Therefore, the coordinated operation of inter-unit harmonic injection and harmonic compensation can fully utilize the fundamental frequency and harmonics to improve the power transmission of the novel hybrid transformer.

[0111] Additionally, in one embodiment, reference is made to Figure 6 ,exist Figure 2Step S21 in the illustrated embodiment also includes, but is not limited to, the following steps:

[0112] Step S61: Obtain the power reference value, AC voltage value, DC voltage reference value and DC voltage feedback value of the converter unit in the first operating state;

[0113] Step S62: Calculate the current reference value of the converter unit in the first operating state based on the AC voltage value and the power reference value; or, input the DC voltage reference value and the DC voltage feedback value into the voltage compensator to obtain the current reference value of the converter unit in the first operating state.

[0114] Step S63: Obtain the current feedback value of the converter unit in the first operating state, input the current feedback value and the current reference value into the current compensator for calculation, obtain the modulation wave reference value of the converter unit, input the modulation wave reference value into the harmonic injection module, and perform harmonic injection on the converter unit operating in the first operating state.

[0115] Step S64: After the converter unit operating in the first operating state is injected with harmonics, the harmonic voltage value of the converter unit in the first operating state is obtained. The harmonic voltage value is input into the first formula to obtain the harmonic current value of the converter unit in the first operating state.

[0116] It should be noted that, referring to Figure 9 In this embodiment, a three-phase novel hybrid transformer is taken as an example, wherein P d1N =200kW, V d1 =750V, V ac1 =136.8V, V ac2 =243.2V, the converter unit in the first operating state works in the harmonic injection state, and the converter unit in the second operating state works in the harmonic compensation state to establish the model.

[0117] The ratios of the harmonic voltage / harmonic current amplitudes to the fundamental voltage / fundamental current amplitudes of the converter unit under different modulation ratios in the first operating state are shown in Figure 14. The lines and points represent the theoretical calculations and simulation measurements, respectively, demonstrating that the proposed harmonic injection method matches the theoretical results.

[0118] When M≤1.15, it only contains zero-sequence harmonic voltage (i.e., 3rd, 9th... harmonics), and the proportion of harmonic amplitude remains basically unchanged. The proportion of 3rd harmonic voltage amplitude is about 20.65%, and the proportion of 9th harmonic voltage amplitude is about 2.07%.

[0119] When 1.15≤M<1.21, as the modulation ratio increases, the proportion of zero-sequence harmonic voltage amplitude shows a slow increasing trend; at the same time, the proportion of 5th / 7th harmonic voltage / current amplitude gradually increases. When M1 approaches 1.21, the proportion of 5th / 7th harmonic voltage amplitude is 2.8%. Since the 5th harmonic impedance is less than the 7th harmonic impedance, the 5th harmonic current amplitude is greater than the 7th harmonic current amplitude, with contents of 5.6% and 4.5%, respectively; the proportion of 11th / 13th harmonic voltage / current amplitude shows a trend of first increasing, then decreasing, and then increasing again.

[0120] When M>1.21, as the modulation ratio increases, the proportion of the 3rd harmonic voltage amplitude increases rapidly, while the proportion of the 9th harmonic voltage amplitude shows a trend of first increasing, then decreasing, and then increasing again; the 5th harmonic voltage / current increases rapidly, while the 7th harmonic voltage / current first decreases and then increases; the amplitudes of the 11th and 13th harmonic voltage / current both show multiple increases and decreases. When M1 approaches 1.27, the proportion of the 3rd harmonic voltage amplitude is the highest at 32%. At this time, the proportions of the 5th harmonic voltage / current amplitude are 17.6% and 35.7%, respectively, and the proportions of the 7th harmonic voltage / current amplitude are 10.94% and 15.8%, respectively.

[0121] The ratio of each harmonic voltage / harmonic current amplitude to the fundamental voltage / fundamental current amplitude in Unit 2 varies with the modulation ratio in Unit 1. It can be seen that the control effect of the proposed harmonic compensation method is consistent with the theoretical results, and its trend is similar to that of Unit 1. This embodiment will not be described in detail.

[0122] In addition, in one embodiment, the converter unit in the first operating state is further provided with a current compensator and a voltage compensator, as shown in the figure. Figure 7 and Figure 13 ,exist Figure 1 Step S14 of the illustrated embodiment also includes, but is not limited to, the following steps:

[0123] Step S71: Obtain the AC voltage value and harmonic current value of the converter unit operating in the first operating state, and the AC voltage value of the converter unit operating in the second operating state. Input the AC voltage value and harmonic current value, and the AC voltage value into the first formula and the second formula to obtain the reference value of the harmonic current value of the converter unit operating in the second operating state.

[0124] Step S72: Obtain the harmonic current feedback value of the converter unit operating in the second operating state, and input the harmonic current reference value and the harmonic current feedback value to the multi-frequency harmonic integrated current compensator to perform harmonic compensation on the converter unit operating in the first operating state.

[0125] It should be noted that the first preset formula is:

[0126] 1 / (sL1hn +R 1hn );

[0127] The second preset formula is:

[0128]

[0129] The third preset formula is:

[0130] 1 / (sL 2hn +R 2hn ).

[0131] like Figure 8 As shown, Figure 8 This is a structural diagram of a device for large-scale, high-efficiency collaborative control according to an embodiment of the present invention. It includes:

[0132] The processor 801 can be implemented using a general-purpose central processing unit (CPU), microprocessor, application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this application.

[0133] The memory 802 can be implemented as a read-only memory (ROM), static storage device, dynamic storage device, or random access memory (RAM). The memory 802 can store the operating system and other applications. When the technical solutions provided in the embodiments of this specification are implemented through software or firmware, the relevant program code is stored in the memory 802 and is called and executed by the processor 801 to implement the wide-ranging and highly efficient collaborative control method of the embodiments of this application.

[0134] The 803 input / output interface is used to implement information input and output.

[0135] The communication interface 804 is used to enable communication and interaction between this device and other devices. Communication can be achieved through wired means (such as USB, network cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.).

[0136] Bus 805 transmits information between various components of the device (e.g., processor 801, memory 802, input / output interface 803, and communication interface 804);

[0137] The processor 801, memory 802, input / output interface 803, and communication interface 804 are connected to each other within the device via bus 805.

[0138] This application also provides an electronic device, including the wide-range, high-efficiency collaborative control device described above.

[0139] This application embodiment also provides a storage medium, which is a computer-readable storage medium, storing a computer program that, when executed by a processor, implements the aforementioned control method for large-scale and high-efficiency coordinated control.

[0140] Memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, memory may optionally include memory remotely located relative to the processor, and these remote memories can be connected to the processor 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 device embodiments described above are merely illustrative, and the units described as separate components may or may not be physically separate, and may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0141] It will be understood by those skilled in the art that all or some of the steps and systems in the methods disclosed above can be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components can be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically include computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0142] The above provides a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the above embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of the present invention.

Claims

1. A large-scale, high-efficiency cooperative control method, characterized in that, The method is applicable to equipment or systems having two or more converter units operating in parallel on the AC side or coupled via a transformer, wherein the operating states of the converter units in the equipment or system include a first operating state and a second operating state, and the method includes: It is determined that one or more converter units in the device or system are operating in a first operating state, wherein the first operating state characterizes the harmonic injection state; Harmonic information of the converter unit during operation is obtained according to the operating conditions of the converter unit operating in the first operating state. The harmonic information is injected in the control loop to realize the harmonic injection function of the converter unit in the first operating state. The harmonic information includes harmonic voltage value and harmonic current value. The remaining converter units in the device or system are determined to be operating in a second operating state, wherein the second operating state characterizes the harmonic compensation state; The harmonic information corresponding to the converter unit when operating in the second operating state is calculated based on the harmonic information of the first operating state, wherein the harmonic information of the second operating state includes harmonic voltage value and harmonic current value. Based on the harmonic information in the second operating state, the converter unit in the second operating state is controlled to perform harmonic compensation on the converter unit in the first operating state, so that the harmonics only flow between the converter units in the first operating state and the second operating state, thereby achieving coordinated control and operation.

2. The large-scale, high-efficiency cooperative control method according to claim 1, characterized in that, The step of determining that one or more converter units in the device or system are operating in a first operating state includes: Obtain the operating conditions of the converter unit when it is in the first operating state; The modulation ratio is determined based on the operating conditions, the fundamental modulation coefficient and harmonic modulation coefficient are calculated based on the modulation ratio, a modulation wave function is established based on the fundamental modulation coefficient and the harmonic modulation coefficient, and the converter unit is modulated based on the modulation wave function.

3. The large-scale, high-efficiency collaborative control method according to claim 1, characterized in that, The step of determining that the remaining converter units in the device or system are operating in the second operating state includes: The harmonic information for operating in the second operating state is determined based on the harmonic information in the first operating state. The harmonic information in the second operating state is used as the control reference information for the converter unit; Based on the control reference information, multi-frequency harmonic comprehensive control is performed on the harmonic information in the second operating state to achieve harmonic compensation of the converter unit.

4. The large-scale, high-efficiency collaborative control method according to claim 1, characterized in that, The device or system has two or more converter units, which operate in parallel on the AC side or coupled via a transformer. Determining the equivalent model of the device includes: The AC side of the converter unit is equivalent to an inductor and a resistor connected in series. The transformer winding connected to the converter unit is equivalent to a leakage inductance and a leakage resistance connected in series. The inductance and resistance of the converter unit operating in the first operating state and the leakage inductance and leakage resistance of the transformer winding connected to the converter unit are equivalently calculated as a first inductance and a first resistance. The inductance and resistance of the converter unit operating in the second operating state and the leakage inductance and leakage resistance of the transformer winding connected to the converter unit are equivalently calculated as a second inductance and a second resistance. The number of converter units operating in the first operating state is determined. When the number is greater than 1, the first inductance and first resistance of the multiple converter units are equivalently calculated as a first integrated inductor and a first integrated resistor. The number of converter units operating in the second operating state is determined. When the number is greater than 1, the second inductance and second resistance of the multiple converter units are equivalently calculated as a second integrated inductor and a second integrated resistor. The device or system is connected to an external grid-side unit, which can be equivalently calculated as a third integrated inductor and a third integrated resistor.

5. The large-scale, high-efficiency collaborative control method according to claim 1, characterized in that, The control of the converter unit in the second operating state to perform harmonic compensation on the converter unit in the first operating state includes: Determine the AC voltage and DC voltage of the converter unit when it is in the first operating state, and calculate the voltage range of the converter unit based on the AC voltage and DC voltage; The transmission power range between the converter unit operating in the first operating state and the converter unit operating in the second operating state is calculated based on the harmonic information in the first operating state and the harmonic information in the second operating state. The harmonic information in the first operating state is injected into the converter unit operating in the first operating state to obtain the first operating loss; The harmonic information in the second operating state is injected into the converter unit operating in the second operating state to obtain the second operating loss. The improved efficiency of the device or system is calculated based on the first operating loss and the second operating loss.

6. The large-scale, high-efficiency collaborative control method according to claim 1, characterized in that, The control unit of the converter in the first operating state is equipped with a voltage compensator and a current compensator. The step of injecting harmonic information in the control loop to achieve the harmonic injection function of the converter unit in the first operating state includes: Obtain the power reference value, AC voltage value, DC voltage reference value, and DC voltage feedback value of the converter unit in the first operating state; The current reference value of the converter unit in the first operating state is calculated based on the AC voltage value and the power reference value, or the current reference value of the converter unit in the first operating state is obtained by inputting the DC voltage reference value and the DC voltage feedback value into the voltage compensator. Obtain the current feedback value of the converter unit in the first operating state, input the current feedback value and the current reference value into the current compensator to calculate the modulation wave reference value of the converter unit, and input the modulation wave reference value into the harmonic injection module to perform harmonic injection on the converter unit operating in the first operating state; After a harmonic is injected into the converter unit operating in the first operating state, the harmonic voltage value of the converter unit in the first operating state is obtained. The harmonic voltage value is then input into the first formula to obtain the harmonic current value of the converter unit in the first operating state.

7. The large-scale, high-efficiency collaborative control method according to claim 1, characterized in that, The converter unit in the second operating state is equipped with a comprehensive current compensator for multi-frequency harmonics. Controlling the converter unit in the second operating state to perform harmonic compensation on the converter unit in the first operating state includes: The AC voltage and harmonic current values ​​of the converter unit operating in the first operating state and the AC voltage value of the converter unit operating in the second operating state are obtained. The AC voltage and harmonic current values ​​and the AC voltage value are input into the first formula and the second formula to obtain the reference value of the harmonic current value of the converter unit operating in the second operating state. Obtain the harmonic current feedback value of the converter unit operating in the second operating state, and input the harmonic current reference value and the harmonic current feedback value to the multi-frequency harmonic integrated current compensator to perform harmonic compensation on the converter unit operating in the first operating state.

8. A control device for large-scale, high-efficiency collaborative control and operation, characterized in that, It includes at least one control processor and a memory for communicatively connecting to the at least one control processor; the memory stores instructions executable by the at least one control processor to enable the at least one control processor to perform the control method as described in any one of claims 1 to 7.

9. An electronic device, characterized in that, The control device for large-scale, high-efficiency collaborative control and operation as described in claim 8.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions for causing a computer to perform the control method as described in any one of claims 1 to 7.

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