Control method and system for parallel power supply system, and device, medium and product

Abstract

A control method and system for a parallel power supply system, and a device, a medium and a product. Each controller controls within a preset duration the amplitude of an output voltage of an inverter to be maintained at a second preset voltage value, and then adjusts or maintains the phase of a modulation wave of the inverter on the basis of a first real-time output voltage and a first real-time bridge arm current until a timing value of a timer reaches the preset duration, such that the phases of output voltages of inverters are the same when the preset duration is reached; and then, on the basis of a second real-time output voltage and a rated voltage value, each controller synchronously adjusts the amplitude of the output voltage of each inverter to the rated voltage value, such that the inverters in a parallel power supply system can be synchronously started without the need for the network communication among the controllers. Therefore, the complexity of the control system for a parallel power supply system can be effectively reduced, and the dependence of the control system for a parallel power supply system on a network can be effectively reduced.

Description

A control method, system, equipment, medium, and product for a parallel power supply system. Technical Field

[0001] This application belongs to the field of converter power supply technology, and in particular relates to a control method, system, equipment, medium and product for a parallel power supply system. Background Technology

[0002] In rail transit, a power supply system consisting of multiple inverters connected in parallel to the AC bus is typically used to supply power to the loads in the train. This power supply method is crucial for ensuring the stability and safety of train operation.

[0003] Currently, multiple inverters in a parallel power supply system are controlled individually by multiple controllers. To avoid conflicts during the startup process of multiple inverters, the multiple controllers need to communicate through a network to control the multiple inverters to start one by one. However, this approach increases the complexity of the control system of the parallel power supply system and makes the control system of the parallel power supply system heavily dependent on the network. On the other hand, since the inverters start one by one, there is a capacity limit on the load directly connected to the AC bus to avoid overloading the first inverter to start.

[0004] Summary of the Invention

[0005] The purpose of this application is to provide a control method, system, device, medium, and product for a parallel power supply system. The control method, system, device, medium, and product for a parallel power supply system provided by this application can effectively reduce the complexity of the control system of the parallel power supply system, effectively reduce the dependence of the control system of the parallel power supply system on the network, and effectively improve the starting capability of the parallel power supply system with a directly connected load.

[0006] The technical solution provided in this application is as follows:

[0007] A control method for a parallel power supply system is applied to the control system of the parallel power supply system. The parallel power supply system includes multiple inverters, multiple contactors, and an AC bus. The multiple inverters are connected in parallel to the AC bus through the multiple contactors. A voltage sensor is respectively installed between each contactor and the AC bus, and a current sensor is installed on the bridge arm of each inverter. The control system of the parallel power supply system includes multiple controllers, each controller being connected in a one-to-one correspondence with each inverter, each contactor, each voltage sensor, and each current sensor. The method executed by each controller includes:

[0008] Obtain the first bus voltage collected by the voltage sensor;

[0009] When the amplitude of the first bus voltage is less than the first preset voltage value, the contactor is controlled to close, the timer is controlled to start timing, and the amplitude of the inverter's output voltage is controlled to remain at the second preset voltage value within a preset time period.

[0010] The first real-time output voltage of the inverter collected by the voltage sensor and the first real-time bridge arm current of the inverter collected by the current sensor are obtained.

[0011] Based on the first real-time output voltage and the first real-time bridge arm current, adjust or maintain the phase of the modulation wave of the inverter until the timer's timing value reaches the preset duration.

[0012] Obtain the second real-time output voltage of the inverter collected by the voltage sensor;

[0013] Based on the second real-time output voltage and the rated voltage value, adjust the amplitude of the modulation wave of the inverter until the amplitude of the inverter's output voltage is equal to the rated voltage value.

[0014] Optionally, adjusting or maintaining the phase of the inverter's modulation wave based on the first real-time output voltage and the first real-time bridge arm current until the timer's timing value reaches the preset duration includes:

[0015] The active power of the inverter is obtained based on the first real-time output voltage, the first real-time bridge arm current, and the active power calculation formula.

[0016] Based on the active power, adjust or maintain the phase of the inverter's modulation wave until the timer's timing value reaches the preset duration.

[0017] Optionally, the method executed by each of the controllers further includes:

[0018] The third real-time output voltage of the inverter collected by the voltage sensor and the second real-time bridge arm current of the inverter collected by the current sensor are obtained.

[0019] The voltage error is obtained based on the third real-time output voltage and the rated voltage value;

[0020] The reactive power of the inverter is obtained based on the third real-time output voltage, the second real-time bridge arm current, and the reactive power calculation formula.

[0021] The amplitude of the modulation wave of the inverter is controlled based on the voltage error and the reactive power.

[0022] Optionally, before acquiring the first bus voltage collected by the voltage sensor, the method further includes:

[0023] The first controller controls the corresponding contactor to close, acquires the second bus voltage collected by the corresponding voltage sensor, and samples the acquired second bus voltage to obtain a first sample value;

[0024] The other controllers acquire the third bus voltage collected by the corresponding voltage sensor, and sample the third bus voltage to obtain a second sample value. If the second sample value is not equal to the first sample value, the voltage sampling coefficient is adjusted so that the real-time sample value obtained based on the adjusted voltage sampling coefficient is equal to the first sample value.

[0025] The first controller controls the corresponding contactor to disconnect.

[0026] Optionally, the method executed by each of the controllers further includes:

[0027] The fourth real-time output voltage of the inverter collected by the voltage sensor and the third real-time bridge arm current of the inverter collected by the current sensor are obtained.

[0028] Based on the fourth real-time output voltage and the third real-time bridge arm current, the phase and amplitude of the specific harmonic voltage and the amplitude of the specific harmonic current are obtained.

[0029] Based on the amplitude of the specific harmonic voltage and the preset harmonic amplitude, the harmonic suppression calculation amplitude is obtained;

[0030] Determine whether the amplitude of the specific harmonic current is greater than or equal to a preset current threshold. If not, use the harmonic suppression calculated amplitude as the target harmonic suppression amplitude. If yes, use the current harmonic suppression amplitude as the target harmonic suppression amplitude.

[0031] Based on the phase of the specific harmonic voltage and the target harmonic suppression amplitude, a harmonic suppression wave is obtained, and the modulation wave of the inverter is adjusted according to the harmonic suppression wave.

[0032] This application also provides a control system for a parallel power supply system, the parallel power supply system including multiple inverters, multiple contactors, and an AC bus. The multiple inverters are connected in parallel to the AC bus through the multiple contactors. A voltage sensor is respectively installed between each contactor and the AC bus, and a current sensor is installed on the bridge arm of each inverter. The control system of the parallel power supply system includes multiple controllers, each controller being connected one-to-one with each inverter, each contactor, each voltage sensor, and each current sensor. Each controller is used for:

[0033] Obtain the first bus voltage collected by the voltage sensor;

[0034] When the amplitude of the first bus voltage is less than the first preset voltage value, the contactor is controlled to close, the timer is controlled to start timing, and the amplitude of the inverter's output voltage is controlled to remain at the second preset voltage value within a preset time period.

[0035] The first real-time output voltage of the inverter collected by the voltage sensor and the first real-time bridge arm current of the inverter collected by the current sensor are obtained.

[0036] Based on the first real-time output voltage and the first real-time bridge arm current, adjust or maintain the phase of the modulation wave of the inverter until the timer's timing value reaches the preset duration.

[0037] Obtain the second real-time output voltage of the inverter collected by the voltage sensor;

[0038] Based on the second real-time output voltage and the rated voltage value, adjust the amplitude of the modulation wave of the inverter until the amplitude of the inverter's output voltage is equal to the rated voltage value.

[0039] Optionally, when each of the controllers adjusts or maintains the phase of the inverter's modulation wave based on the first real-time output voltage and the first real-time bridge arm current until the timer's count reaches the preset duration, it is specifically used for:

[0040] The active power of the inverter is obtained based on the first real-time output voltage, the first real-time bridge arm current, and the active power calculation formula.

[0041] Based on the active power, adjust or maintain the phase of the inverter's modulation wave until the timer's timing value reaches the preset duration.

[0042] Optionally, each of the controllers is further configured to:

[0043] The third real-time output voltage of the inverter collected by the voltage sensor and the second real-time bridge arm current of the inverter collected by the current sensor are obtained.

[0044] The voltage error is obtained based on the third real-time output voltage and the rated voltage value;

[0045] The reactive power of the inverter is obtained based on the third real-time output voltage, the second real-time bridge arm current, and the reactive power calculation formula.

[0046] The amplitude of the modulation wave of the inverter is controlled based on the voltage error and the reactive power.

[0047] Optionally,

[0048] The first controller is also used to control the corresponding contactor to close, acquire the second bus voltage collected by the corresponding voltage sensor, and sample the acquired second bus voltage to obtain a first sample value;

[0049] The remaining controllers are also used to acquire the third bus voltage collected by the corresponding voltage sensor, and sample the third bus voltage to obtain a second sample value. If the second sample value is not equal to the first sample value, the voltage sampling coefficient is adjusted so that the real-time sample value obtained based on the adjusted voltage sampling coefficient is equal to the first sample value.

[0050] The first controller is also used to control the corresponding contactor to disconnect.

[0051] Optionally, each of the controllers is further configured to:

[0052] The fourth real-time output voltage of the inverter collected by the voltage sensor and the third real-time bridge arm current of the inverter collected by the current sensor are obtained.

[0053] Based on the fourth real-time output voltage and the third real-time bridge arm current, the phase and amplitude of the specific harmonic voltage and the amplitude of the specific harmonic current are obtained.

[0054] Based on the amplitude of the specific harmonic voltage and the preset harmonic amplitude, the harmonic suppression calculation amplitude is obtained;

[0055] Determine whether the amplitude of the specific harmonic current is greater than or equal to a preset current threshold. If not, use the harmonic suppression calculated amplitude as the target harmonic suppression amplitude. If yes, use the current harmonic suppression amplitude as the target harmonic suppression amplitude.

[0056] Based on the phase of the specific harmonic voltage and the target harmonic suppression amplitude, a harmonic suppression wave is obtained, and the modulation wave of the inverter is adjusted according to the harmonic suppression wave.

[0057] This application also provides an electronic device, including: a processor, a memory, and a communication bus;

[0058] The communication bus is used to realize the connection and communication between the processor and the memory;

[0059] The processor is used to execute the control processing program of the parallel power supply system stored in the memory to implement the steps of the control method of the parallel power supply system as described in any of the above.

[0060] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when loaded and executed by a processor, implement the steps of the control method for the parallel power supply system as described in any of the preceding claims.

[0061] This application also provides a computer program product, including computer-executable instructions, which, when loaded and executed by a processor, implement the steps of the control method for the parallel power supply system as described in any of the preceding claims.

[0062] Compared with existing technologies, this application provides a control method, system, device, medium, and product for a parallel power supply system. Each controller acquires a first bus voltage collected by a voltage sensor. When the amplitude of the acquired first bus voltage is less than a first preset voltage value, it controls a contactor to close and a timer to start timing. Within a preset time period, it controls the output voltage amplitude of the inverter to be maintained at a second preset voltage value. Then, it acquires the first real-time output voltage of the inverter collected by the voltage sensor and the first real-time bridge arm current of the inverter collected by the current sensor. Based on the first real-time output voltage and the first real-time bridge arm current, it adjusts or maintains the phase of the inverter's modulation wave until the timer's timing value reaches the preset time period, ensuring that the output voltage phases of each inverter are the same when the timer's timing value reaches the preset time period. Finally, it acquires the second real-time output voltage of the inverter collected by the voltage sensor. Based on the second real-time output voltage and the rated voltage value, it adjusts the amplitude of the inverter's modulation wave until the amplitude of the inverter's output voltage equals the rated voltage value. To ensure that the output voltage amplitudes of all inverters are the same, in this application, when the amplitude of the first bus voltage obtained by each controller is less than a first preset voltage value, the controller controls the contactor to close and controls the timer to start timing. Within a preset time period, the controller controls the output voltage amplitude of the inverter to be maintained at a second preset voltage value. Then, based on the first real-time output voltage and the first real-time bridge arm current, the controller adjusts or maintains the phase of the inverter's modulation wave until the timer reaches the preset time period, ensuring that the output voltage phases of all inverters are the same when the preset time period is reached. Finally, based on the second real-time output voltage and the rated voltage value, the controller synchronously adjusts the output voltage amplitude of each inverter to the rated voltage value. This allows for synchronous startup of all inverters in a parallel power supply system without network communication between the controllers. This effectively reduces the complexity of the control system in a parallel power supply system, effectively reduces the dependence of the control system on the network, and effectively improves the startup capability of the parallel power supply system with directly connected loads. Attached Figure Description

[0063] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0064] Figure 1 is a flowchart of a control method for a parallel power supply system disclosed in an embodiment of this application;

[0065] Figure 2 is a structural block diagram of the parallel power supply system disclosed in an embodiment of this application;

[0066] Figure 3 is a structural block diagram of a control system for a parallel power supply system disclosed in an embodiment of this application;

[0067] Figure 4 is a schematic diagram showing the connection between multiple controllers, multiple inverters, multiple contactors, multiple voltage sensors, and multiple current sensors disclosed in the embodiments of this application.

[0068] Figure 5 is a schematic diagram of the structure of an electronic device disclosed in an embodiment of this application. Detailed Implementation

[0069] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0070] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on or indirectly set on the other component; when a component is referred to as "connected to" another component, it can be directly connected to or indirectly connected to the other component.

[0071] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application 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 limitations on this application.

[0072] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "a plurality of" or "several" means two or more, unless otherwise explicitly specified.

[0073] It should be noted that the structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which this application can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce.

[0074] As shown in Figure 1, this application embodiment provides a control method for a parallel power supply system, applied to the control system of the parallel power supply system. As shown in Figure 2, the parallel power supply system includes multiple inverters 100, multiple contactors 200, and an AC bus. The multiple inverters 100 are connected in parallel to the AC bus through multiple contactors 200. A voltage sensor 300 is respectively installed between each contactor 200 and the AC bus. A current sensor 400 is installed on the bridge arm of each inverter 100. The voltage sensor 300 and the current sensor 400 are not shown in Figure 2. As shown in Figure 3, the control system of the parallel power supply system includes multiple controllers 500. As shown in Figure 4, each controller 500 is connected one-to-one with each inverter 100, each contactor 200, each voltage sensor 300, and each current sensor 400. The method executed by each controller includes:

[0075] S11. Obtain the first bus voltage collected by the voltage sensor;

[0076] S12. When the amplitude of the first bus voltage is less than the first preset voltage value, control the contactor to close, control the timer to start timing, and control the amplitude of the inverter's output voltage to remain at the second preset voltage value within a preset time period.

[0077] In this embodiment, the first preset voltage value and the second preset voltage value are pre-set voltage values, and the preset duration is a pre-set duration. The first preset voltage value can be 50V, the second preset voltage value can be 10V or 20V, and the preset duration can be 50ms. When the amplitude of the first bus voltage is less than the first preset voltage value, it indicates that there is no high voltage on the bus, meaning that other inverters have not yet been connected to the bus. The control contactor closes to allow the inverter to be connected to the bus, and the timer inside the controller starts counting. Then, within the preset duration, the amplitude of the inverter's output voltage is kept at a small, constant second preset voltage value. If the amplitude of the first bus voltage is greater than or equal to the first preset voltage value, the inverter can be controlled to lock the output.

[0078] S13. Obtain the first real-time output voltage of the inverter collected by the voltage sensor, and the first real-time bridge arm current of the inverter collected by the current sensor.

[0079] S14. Adjust or maintain the phase of the inverter's modulation wave according to the first real-time output voltage and the first real-time bridge arm current until the timer's timing value reaches the preset duration.

[0080] In this embodiment, the active power of the inverter can be obtained according to the formula of the first real-time output voltage, the first real-time bridge arm current and the active power. Then, based on the active power, the phase of the modulation wave of the inverter is adjusted or maintained until the timer value reaches the preset duration, so that when the timer value reaches the preset duration, the phase of the output voltage of each inverter is the same.

[0081] S15. Obtain the second real-time output voltage of the inverter collected by the voltage sensor;

[0082] S16. Based on the second real-time output voltage and the rated voltage value, adjust the amplitude of the inverter's modulation wave until the amplitude of the inverter's output voltage equals the rated voltage value.

[0083] In this embodiment, the rated voltage value can be 380V. The amplitude of the inverter's modulation wave can be increased according to the second real-time output voltage, the rated voltage value, and the preset slope until the amplitude of the inverter's output voltage is equal to the rated voltage value. During the process of increasing the amplitude of the inverter's output voltage, if the amplitude of the inverter's output voltage suddenly becomes too large due to external interference, current limiting will be triggered to limit the excessive amplitude, so that the inverter can maintain the same or similar amplitude growth during startup.

[0084] Compared with existing technologies, this application provides a control method, system, device, medium, and product for a parallel power supply system. Each controller acquires a first bus voltage collected by a voltage sensor. When the amplitude of the acquired first bus voltage is less than a first preset voltage value, it controls a contactor to close and a timer to start timing. Within a preset time period, it controls the output voltage amplitude of the inverter to be maintained at a second preset voltage value. It then acquires the first real-time output voltage of the inverter collected by the voltage sensor and the first real-time bridge arm current of the inverter collected by the current sensor. Based on the first real-time output voltage and the first real-time bridge arm current, it adjusts or maintains the phase of the inverter's modulation wave until the timer's timing value reaches the preset time period, ensuring that the output voltage phases of each inverter are the same when the timer's timing value reaches the preset time period. Finally, it acquires the second real-time output voltage of the inverter collected by the voltage sensor. Based on the second real-time output voltage and the rated voltage value, it adjusts the amplitude of the inverter's modulation wave until the inverter's output voltage amplitude reaches the second real-time output voltage. The voltage is equal to the rated voltage value, so that the output voltage amplitude of each inverter is the same. When the amplitude of the first bus voltage obtained by each controller is less than the first preset voltage value, the controller controls the contactor to close and controls the timer to start timing. Within a preset time period, the controller controls the output voltage amplitude of the inverter to be maintained at the second preset voltage value. Then, according to the first real-time output voltage and the first real-time bridge arm current, the phase of the modulation wave of the inverter is adjusted or maintained until the timer reaches the preset time period, so that the output voltage phase of each inverter is the same when the preset time period is reached. Then, according to the second real-time output voltage and the rated voltage value, the output voltage amplitude of each inverter is synchronously adjusted to the rated voltage value. This allows the controllers to start synchronously with each inverter in the parallel power supply system without network communication. This can effectively reduce the complexity of the control system of the parallel power supply system, effectively reduce the dependence of the control system of the parallel power supply system on the network, and effectively improve the starting capability of the parallel power supply system with direct-connected loads.

[0085] As one implementation method, in this embodiment of the application, step S14 includes:

[0086] S141. The active power of the inverter is obtained based on the first real-time output voltage, the first real-time bridge arm current, and the active power calculation formula.

[0087] In this embodiment, the first real-time output voltage is a three-phase voltage, which includes the first real-time output phase a voltage, the first real-time output phase b voltage, and the first real-time output phase c voltage, specifically:

[0088] u a =Usin(θ+ωt);

[0089] Among them, ua For the first real-time output phase a voltage, u b For the first real-time output phase b voltage, u c This is the first real-time output of phase c voltage.

[0090] The first real-time bridge arm current is a three-phase current, which includes the first real-time bridge arm phase a current, the first real-time bridge arm phase b current, and the first real-time bridge arm phase c current, specifically as follows:

[0091] Among them, i a For the first real-time bridge arm phase a current, i b For the first real-time bridge arm phase b current, i c This represents the c-phase current of the first real-time bridge arm.

[0092] The effective value U of the first real-time output voltage, the effective value I of the first real-time bridge arm current, and the phase difference between the phase of the first real-time output voltage and the phase of the first real-time bridge arm current can be used. Substituting the values ​​into the active power calculation formula, we obtain the active power of the inverter. The specific active power calculation formula is as follows:

[0093] Where P is the active power of the inverter, U is the effective value of the first real-time output voltage, and I is the effective value of the first real-time bridge arm current. The phase difference is the phase difference between the phase of the first real-time output voltage and the phase of the first real-time bridge arm current.

[0094] S142. Adjust or maintain the phase of the inverter's modulation wave according to the active power until the timer's timing value reaches the preset duration.

[0095] In this embodiment, one or more inverters with active power greater than 0 adjust the phase of their modulation wave at a corresponding rate of change according to their corresponding active power P. That is, the phase of the modulation wave of each inverter with active power greater than 0 will change at different rates depending on the active power P. One or more inverters with active power of 0 will maintain the phase of their modulation wave so that when the timer reaches the preset duration, the active power of each inverter is 0, the phase of the modulation wave of each inverter is the same, the phase change stops, and phase synchronization is completed.

[0096] Specifically, for one or more inverters with active power greater than 0, the corresponding active power can be substituted into the preset formula for the initial phase of the modulation wave to calculate the adjusted phase of the inverter's modulation wave. The preset formula is as follows:

[0097] In this embodiment, the preset formula can be specifically as follows:

[0098] θ=ω0-∫k×P;

[0099] Where θ is the adjusted phase of the modulated wave of the inverter, ω0 is the initial phase of the modulated wave of the inverter, k is a constant, and P is the active power of the inverter.

[0100] k can be 0.001. The phase of the modulation wave of each inverter with active power greater than 0 will be changed by using the integral of the constant k and the corresponding active power P as the corresponding phase adjustment rate. One or more inverters with active power of 0 will maintain the phase of the inverter's modulation wave so that when the timer reaches the preset duration, the active power of each inverter is 0 and the phase of the modulation wave of each inverter is the same.

[0101] As one implementation method, in this embodiment of the application, the method executed by each controller further includes:

[0102] S21. Obtain the third real-time output voltage of the inverter collected by the voltage sensor, and the second real-time bridge arm current of the inverter collected by the current sensor.

[0103] S22. Obtain the voltage error based on the third real-time output voltage and the rated voltage value;

[0104] In this embodiment, the voltage error can be obtained by subtracting the collected third real-time output voltage from the rated voltage value.

[0105] S23. Based on the third real-time output voltage, the second real-time bridge arm current, and the reactive power calculation formula, the reactive power of the inverter is obtained.

[0106] In this embodiment, the effective value of the third real-time output voltage, the effective value of the second real-time bridge arm current, the phase difference between the phase of the third real-time output voltage and the phase of the second real-time bridge arm current can be substituted into the reactive power calculation formula to calculate the reactive power of the inverter. Since the reactive power calculation formula is an existing formula, it will not be described again here.

[0107] S24. Control the amplitude of the modulation wave of the inverter based on the voltage error and reactive power.

[0108] In this embodiment, since the output reactive power of the inverter is proportional to the amplitude of the output voltage, and the amplitude of the output voltage of the inverter is proportional to the amplitude of the modulation wave of the inverter, the difference in the amplitude of the modulation wave of multiple inverters can be reflected by the difference in reactive power.

[0109] The rated output voltage U of each inverter ref The voltage is kept constant at 380V, obtained by subtracting the rated voltage value from the third real-time output voltage U. fSubtraction yields the voltage error, which is then fed into the adaptive voltage controller. Through error weighting control, the controller's two coefficients, Ke and Kc, are adjusted in real time according to the current reactive power of the inverter to control the amplitude of the inverter's modulation wave. This ensures that the amplitude of the bus voltage output from multiple inverters connected in parallel is dynamically kept constant at the rated voltage value or within an acceptable error range of the rated voltage value.

[0110] Specifically, in the third real-time output voltage U f Below the rated voltage U ref At that time, the inverter with the lower reactive power among multiple inverters will have larger Ke and Kc values ​​during adaptive adjustment, resulting in a higher target voltage; in the third real-time output voltage U f Higher than the rated voltage U ref When multiple inverters are used, the inverter with the smaller reactive power will have smaller Ke and Kc values ​​during adaptive adjustment, resulting in a higher target voltage. This allows the amplitude of the bus voltage output from the parallel power supply of multiple inverters to be dynamically kept constant at the rated voltage value or within an acceptable error range of the rated voltage value (e.g., the bus voltage error is within ±1% of the rated voltage value) after the amplitude of the modulation wave of each inverter is dynamically adjusted. This effectively improves the accuracy of the output voltage of the inverters in parallel power supply.

[0111] In one embodiment of this application, before step S11, the method further includes:

[0112] S31. The first controller controls the corresponding contactor to close, and acquires the second bus voltage collected by the corresponding voltage sensor, and samples the acquired second bus voltage to obtain the first sample value;

[0113] In this embodiment, the first controller controls the corresponding connected contactor to close and acquires the second bus voltage collected by the corresponding connected voltage sensor. The acquired second bus voltage is sampled to obtain the first sampled value.

[0114] S32. The other controllers acquire the third bus voltage collected by the corresponding voltage sensor, and sample the third bus voltage to obtain the second sample value. If the second sample value is not equal to the first sample value, the voltage sampling coefficient is adjusted so that the real-time sample value obtained based on the adjusted voltage sampling coefficient is equal to the first sample value.

[0115] In this embodiment, there can be N controllers, where N is a positive integer greater than 1. The N-1 controllers other than the first controller acquire N-1 third bus voltages collected by the corresponding connected voltage sensors, and sample the N-1 third bus voltages to obtain N-1 second sample values. If one or more of the second sample values ​​are not equal to the first sample value, the one or more voltage sampling coefficients corresponding to these one or more second sample values ​​are adjusted so that the one or more real-time sample values ​​obtained based on the adjusted one or more voltage sampling coefficients are equal to the first sample value. This allows each voltage sampling coefficient to be effectively corrected, reducing the risk of circulating current and uneven power distribution caused by differences in the device parameters of each inverter or the accuracy of the sensors.

[0116] S33, the first controller controls the corresponding contactor to disconnect.

[0117] As one implementation method, in this embodiment of the application, the method executed by each controller further includes:

[0118] S41. Obtain the fourth real-time output voltage of the inverter collected by the voltage sensor, and the third real-time bridge arm current of the inverter collected by the current sensor.

[0119] S42. Based on the fourth real-time output voltage and the third real-time bridge arm current, obtain the phase and amplitude of the specific harmonic voltage and the amplitude of the specific harmonic current.

[0120] In this embodiment, specific harmonics can be extracted from the fourth real-time output voltage to obtain the phase and amplitude of the specific harmonic voltage. Specific harmonics can also be extracted from the third real-time bridge arm current to obtain the amplitude of the specific harmonic current. The specific harmonics can be either the fifth or seventh harmonic.

[0121] S43. Based on the amplitude of a specific harmonic voltage and the preset harmonic amplitude, obtain the harmonic suppression calculation amplitude;

[0122] In this embodiment, the preset harmonic amplitude is a pre-set harmonic amplitude value, which can be 0. The harmonic suppression calculation amplitude can be obtained by calculating based on the amplitude of a specific harmonic voltage and the preset harmonic amplitude.

[0123] S44. Determine whether the amplitude of a specific harmonic current is greater than or equal to a preset current threshold. If not, use the harmonic suppression calculated amplitude as the target harmonic suppression amplitude. If yes, use the current harmonic suppression amplitude as the target harmonic suppression amplitude.

[0124] In this embodiment, the preset current threshold can be a pre-set current threshold. It is determined whether the amplitude of a specific harmonic current is greater than or equal to the preset current threshold. If the amplitude of the specific harmonic current is less than the preset current threshold, the harmonic suppression calculation amplitude is used as the target harmonic suppression amplitude. If the amplitude of the specific harmonic current is greater than or equal to the preset current threshold, the current harmonic suppression amplitude is used as the target harmonic suppression amplitude.

[0125] S45. Based on the phase of a specific harmonic voltage and the target harmonic suppression amplitude, obtain the harmonic suppression wave, and adjust the modulation wave of the inverter according to the harmonic suppression wave.

[0126] In this embodiment, a harmonic suppression wave is obtained based on the phase of a specific harmonic voltage and the target harmonic suppression amplitude. The modulation wave of the inverter is then adjusted based on the harmonic suppression wave, which can effectively suppress harmonics and reduce the risk of inverter failure due to harmonic problems.

[0127] This application also provides a control system for a parallel power supply system, as shown in Figure 2. The parallel power supply system includes multiple inverters 100, multiple contactors 200, and an AC bus. The multiple inverters 100 are connected in parallel to the AC bus through multiple contactors 200. A voltage sensor 300 is respectively installed between each contactor 200 and the AC bus. A current sensor 400 is installed on the bridge arm of each inverter 100. The voltage sensor 300 and the current sensor 400 are not shown in Figure 2, as shown in Figure 3. The control system of the parallel power supply system includes multiple controllers 500, as shown in Figure 4. Each controller 500 is connected one-to-one with each inverter 100, each contactor 200, each voltage sensor 300, and each current sensor 400. Each controller is used for:

[0128] Obtain the first bus voltage collected by the voltage sensor;

[0129] When the amplitude of the first bus voltage is less than the first preset voltage value, the control contactor closes, the control timer starts timing, and the control inverter output voltage amplitude is kept at the second preset voltage value within a preset time period.

[0130] The first real-time output voltage of the inverter is acquired by the voltage sensor, and the first real-time bridge arm current of the inverter is acquired by the current sensor.

[0131] Based on the first real-time output voltage and the first real-time bridge arm current, adjust or maintain the phase of the inverter's modulation wave until the timer's timing value reaches the preset duration.

[0132] Obtain the second real-time output voltage of the inverter collected by the voltage sensor;

[0133] Based on the second real-time output voltage and the rated voltage value, adjust the amplitude of the inverter's modulation wave until the amplitude of the inverter's output voltage equals the rated voltage value.

[0134] As one implementation method, in this embodiment of the application, when each controller adjusts or maintains the phase of the inverter's modulation wave based on the first real-time output voltage and the first real-time bridge arm current until the timer's timing value reaches a preset duration, it is specifically used for:

[0135] The active power of the inverter is obtained based on the first real-time output voltage, the first real-time bridge arm current, and the active power calculation formula.

[0136] Based on the active power, adjust or maintain the phase of the inverter's modulation wave until the timer's timing value reaches the preset duration.

[0137] In one implementation method, in this embodiment of the application, each controller is further configured to:

[0138] The third real-time output voltage of the inverter is acquired by the voltage sensor, and the second real-time bridge arm current of the inverter is acquired by the current sensor.

[0139] The voltage error is obtained based on the third real-time output voltage and the rated voltage value;

[0140] The reactive power of the inverter is obtained based on the third real-time output voltage, the second real-time bridge arm current, and the reactive power calculation formula.

[0141] The amplitude of the inverter's modulation wave is controlled based on voltage error and reactive power.

[0142] As one implementation method, in the embodiments of this application,

[0143] The first controller is also used to control the closing of the corresponding contactor, acquire the second bus voltage collected by the corresponding voltage sensor, and sample the acquired second bus voltage to obtain the first sample value;

[0144] The remaining controllers are also used to acquire the third bus voltage collected by the corresponding voltage sensor, and sample the third bus voltage to obtain a second sample value. If the second sample value is not equal to the first sample value, the voltage sampling coefficient is adjusted so that the real-time sample value obtained based on the adjusted voltage sampling coefficient is equal to the first sample value.

[0145] The first controller is also used to control the corresponding contactor to disconnect.

[0146] In one implementation method, in this embodiment of the application, each controller is further configured to:

[0147] The fourth real-time output voltage of the inverter is acquired by the voltage sensor, and the third real-time bridge arm current of the inverter is acquired by the current sensor.

[0148] Based on the fourth real-time output voltage and the third real-time bridge arm current, the phase and amplitude of the specific harmonic voltage and the amplitude of the specific harmonic current are obtained.

[0149] The harmonic suppression calculation amplitude is obtained based on the amplitude of a specific harmonic voltage and the preset harmonic amplitude.

[0150] Determine whether the amplitude of a specific harmonic current is greater than or equal to a preset current threshold. If not, use the harmonic suppression calculated amplitude as the target harmonic suppression amplitude. If so, use the current harmonic suppression amplitude as the target harmonic suppression amplitude.

[0151] Based on the phase of a specific harmonic voltage and the target harmonic suppression amplitude, a harmonic suppression wave is obtained, and the modulation wave of the inverter is adjusted according to the harmonic suppression wave.

[0152] As shown in Figure 5, this application embodiment also provides an electronic device, including: a processor 600, a memory 700, and a communication bus 800;

[0153] Communication bus 800 is used to realize the connection and communication between processor 600 and memory 700;

[0154] The processor 600 is used to execute the control processing program of the parallel power supply system stored in the memory 700 to implement the steps of the control method of any of the parallel power supply systems described above.

[0155] This application also provides a computer-readable storage medium storing computer-executable instructions. When the computer-executable instructions are loaded and executed by a processor, they implement the steps of the control method for any of the parallel power supply systems described above.

[0156] This application also provides a computer program product, including computer-executable instructions, which, when loaded and executed by a processor, implement the steps of the control method for any of the parallel power supply systems described above.

[0157] It should be understood that the use of terms such as "system," "device," "unit," and / or "module" in this application is merely one method of distinguishing different components, elements, parts, sections, or assemblies at different levels. However, if other terms can achieve the same purpose, they may be replaced by other expressions.

[0158] The embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other.

[0159] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A control method of a parallel power supply system, characterized by, A control system for a parallel power supply system, the parallel power supply system including multiple inverters, multiple contactors, and an AC bus, wherein the multiple inverters are connected in parallel to the AC bus through the multiple contactors, a voltage sensor is respectively installed between each contactor and the AC bus, and a current sensor is installed on the bridge arm of each inverter. The control system for the parallel power supply system includes multiple controllers, each controller being connected one-to-one with each inverter, each contactor, each voltage sensor, and each current sensor, and each controller executing a method including: Obtain the first bus voltage collected by the voltage sensor; When the amplitude of the first bus voltage is less than the first preset voltage value, the contactor is controlled to close, the timer is controlled to start timing, and the amplitude of the inverter's output voltage is controlled to remain at the second preset voltage value within a preset time period. The first real-time output voltage of the inverter collected by the voltage sensor and the first real-time bridge arm current of the inverter collected by the current sensor are obtained. Based on the first real-time output voltage and the first real-time bridge arm current, adjust or maintain the phase of the modulation wave of the inverter until the timer's timing value reaches the preset duration. Obtain the second real-time output voltage of the inverter collected by the voltage sensor; Based on the second real-time output voltage and the rated voltage value, adjust the amplitude of the modulation wave of the inverter until the amplitude of the inverter's output voltage is equal to the rated voltage value.

2. The control method according to claim 1, characterized by, The step of adjusting or maintaining the phase of the inverter's modulation wave based on the first real-time output voltage and the first real-time bridge arm current until the timer's timing value reaches the preset duration includes: The active power of the inverter is obtained based on the first real-time output voltage, the first real-time bridge arm current, and the active power calculation formula. Based on the active power, adjust or maintain the phase of the inverter's modulation wave until the timer's timing value reaches the preset duration.

3. The control method according to claim 2, characterized by, The methods executed by each of the aforementioned controllers further include: The third real-time output voltage of the inverter, acquired by the voltage sensor, and the... The second real-time bridge arm current of the inverter is collected by the current sensor; The voltage error is obtained based on the third real-time output voltage and the rated voltage value; The reactive power of the inverter is obtained based on the third real-time output voltage, the second real-time bridge arm current, and the reactive power calculation formula. The amplitude of the modulation wave of the inverter is controlled based on the voltage error and the reactive power.

4. The control method according to claim 3, characterized by Before acquiring the first bus voltage collected by the voltage sensor, the method further includes: The first controller controls the corresponding contactor to close, acquires the second bus voltage collected by the corresponding voltage sensor, and samples the acquired second bus voltage to obtain a first sample value; The other controllers acquire the third bus voltage collected by the corresponding voltage sensor, and sample the third bus voltage to obtain a second sample value. If the second sample value is not equal to the first sample value, the voltage sampling coefficient is adjusted so that the real-time sample value obtained based on the adjusted voltage sampling coefficient is equal to the first sample value. The first controller controls the corresponding contactor to disconnect.

5. The control method according to any one of claims 1 to 4, characterized by, The methods executed by each of the aforementioned controllers further include: The fourth real-time output voltage of the inverter collected by the voltage sensor and the third real-time bridge arm current of the inverter collected by the current sensor are obtained. Based on the fourth real-time output voltage and the third real-time bridge arm current, the phase and amplitude of the specific harmonic voltage and the amplitude of the specific harmonic current are obtained. Based on the amplitude of the specific harmonic voltage and the preset harmonic amplitude, the harmonic suppression calculation amplitude is obtained; Determine whether the amplitude of the specific harmonic current is greater than or equal to a preset current threshold. If not, use the harmonic suppression calculated amplitude as the target harmonic suppression amplitude. If yes, use the current harmonic suppression amplitude as the target harmonic suppression amplitude. Based on the phase of the specific harmonic voltage and the target harmonic suppression amplitude, a harmonic suppression wave is obtained, and the modulation wave of the inverter is adjusted according to the harmonic suppression wave.

6. A control system for a parallel power supply system, characterized by The parallel power supply system includes multiple inverters, multiple contactors, and an AC bus. The multiple inverters are connected in parallel to the AC bus via the multiple contactors. Each contactor is equipped with a voltage sensor between itself and the AC bus. Each inverter's bridge arm is equipped with a current sensor. The control system of the parallel power supply system includes multiple controllers. Each controller is connected in a one-to-one correspondence with each inverter, each contactor, each voltage sensor, and each current sensor. Each controller is used for: Obtain the first bus voltage collected by the voltage sensor; When the amplitude of the first bus voltage is less than the first preset voltage value, the contactor is controlled to close, the timer is controlled to start timing, and the amplitude of the inverter's output voltage is controlled to remain at the second preset voltage value within a preset time period. The first real-time output voltage of the inverter collected by the voltage sensor and the first real-time bridge arm current of the inverter collected by the current sensor are obtained. Based on the first real-time output voltage and the first real-time bridge arm current, adjust or maintain the phase of the modulation wave of the inverter until the timer's timing value reaches the preset duration. Obtain the second real-time output voltage of the inverter collected by the voltage sensor; Based on the second real-time output voltage and the rated voltage value, adjust the amplitude of the modulation wave of the inverter until the amplitude of the inverter's output voltage is equal to the rated voltage value.

7. The control system of claim 6, wherein, When each of the controllers performs the action of adjusting or maintaining the phase of the inverter's modulation wave based on the first real-time output voltage and the first real-time bridge arm current until the timer's count reaches the preset duration, specifically, it is used for: The active power of the inverter is obtained based on the first real-time output voltage, the first real-time bridge arm current, and the active power calculation formula. Based on the active power, adjust or maintain the phase of the inverter's modulation wave until the timer's timing value reaches the preset duration.

8. The control system of claim 7, wherein, Each of the aforementioned controllers is also used for: The third real-time output voltage of the inverter collected by the voltage sensor and the second real-time bridge arm current of the inverter collected by the current sensor are obtained. The voltage error is obtained based on the third real-time output voltage and the rated voltage value; The reactive power of the inverter is obtained based on the third real-time output voltage, the second real-time bridge arm current, and the reactive power calculation formula. The amplitude of the modulation wave of the inverter is controlled based on the voltage error and the reactive power.

9. The control system according to claim 8, characterized in that, The first controller is also used to control the corresponding contactor to close, acquire the second bus voltage collected by the corresponding voltage sensor, and sample the acquired second bus voltage to obtain a first sample value; The remaining controllers are also used to acquire the third bus voltage collected by the corresponding voltage sensor, and sample the third bus voltage to obtain a second sample value. If the second sample value is not equal to the first sample value, the voltage sampling coefficient is adjusted so that the real-time sample value obtained based on the adjusted voltage sampling coefficient is equal to the first sample value. The first controller is also used to control the corresponding contactor to disconnect.

10. A control system according to any one of claims 6 to 9, characterised in that, Each of the aforementioned controllers is also used for: The fourth real-time output voltage of the inverter collected by the voltage sensor and the third real-time bridge arm current of the inverter collected by the current sensor are obtained. Based on the fourth real-time output voltage and the third real-time bridge arm current, the phase and amplitude of the specific harmonic voltage and the amplitude of the specific harmonic current are obtained. Based on the amplitude of the specific harmonic voltage and the preset harmonic amplitude, the harmonic suppression calculation amplitude is obtained; Determine whether the amplitude of the specific harmonic current is greater than or equal to a preset current threshold. If not, use the harmonic suppression calculated amplitude as the target harmonic suppression amplitude. If yes, use the current harmonic suppression amplitude as the target harmonic suppression amplitude. Based on the phase of the specific harmonic voltage and the target harmonic suppression amplitude, a harmonic suppression wave is obtained, and the modulation wave of the inverter is adjusted according to the harmonic suppression wave.

11. An electronic device, comprising: include: Processor, memory, and communication bus; The communication bus is used to realize the connection and communication between the processor and the memory; The processor is used to execute the control processing program of the parallel power supply system stored in the memory. The sequence is to implement the steps of the control method for the parallel power supply system as described in any one of claims 1-5.

12. A computer-readable storage medium, characterized in that, The readable storage medium stores computer-executable instructions, which, when loaded and executed by a processor, implement the steps of the control method for the parallel power supply system as described in any one of claims 1 to 5.

13. A computer program product, characterised in that, Computer executable instructions comprising the steps of the control method of the parallel power supply system according to any one of claims 1 to 5, when loaded and executed by a processor.

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