DC power distribution system oscillation suppression method and device based on Buck converter

Abstract

The invention provides a DC power distribution system oscillation suppression method and device based on a Buck converter, and the system consists of a voltage source converter, a power electronic converter load and a bus voltage feed-forward Buck converter which are connected in parallel. According to the method, a rated value is obtained, an output voltage sampling value of a bus voltage feed-forward Buck converter and a bus direct current voltage sampling value are obtained in real time, a second-order filter and a proportional-integral controller are used for processing the values to generate a control signal, and the signal enables the bus voltage feed-forward Buck converter to provide positive damping for a direct current power distribution system. Therefore, oscillation generated when the power electronic load is connected to or disconnected from the system is eliminated. According to the method, the problem that a multi-source multi-load direct-current power distribution system in the prior art has an instability phenomenon under different load power operation conditions is solved.

Description

Technical Field

[0001] The present invention relates to the field of power grid control technology, and in particular to a method and device for suppressing oscillation of a direct current distribution system based on a Buck converter, a computer-readable storage medium, and a direct current distribution system. Background Art

[0002] In traditional power systems, energy storage devices in AC systems are connected to the power grid through AC / AC converters. However, new energy power generation equipment, such as wind power generation equipment and photovoltaic power generation equipment, uses DC energy storage devices for its internal energy storage devices. In wind power generation systems and photovoltaic power generation systems, DC energy storage devices are usually connected to power electronic loads through DC / DC converters. Therefore, DC energy storage devices are connected to power electronic loads through DC / DC converters.

[0003] The essence of the system oscillation problem is that the load port of the power electronic converter presents the negative damping characteristics of a constant power load, which causes the system damping to decrease and thus become instability. At the same time, the negative damping characteristics of the power electronic converter load are proportional to its power. The greater the power, the more significant the negative resistance characteristics, and the easier it is for the system to become unstable.

[0004] In the prior art, energy storage devices that use LC filters to suppress oscillations are bulky and costly, which is not conducive to the miniaturization of energy storage devices. Although energy storage devices that use PID algorithms to control energy storage devices to provide positive damping to the system are less expensive, the PID algorithm mainly depends on system parameters and is difficult to adapt to multi-source and multi-load DC distribution systems.

[0005] In summary, the prior art lacks a system oscillation suppression method applicable to a multi-source and multi-load DC power distribution system. Summary of the invention

[0006] The main purpose of the present application is to provide a method, device, computer-readable storage medium and DC distribution system for suppressing oscillation of a DC distribution system based on a Buck converter, so as to at least solve the problem of instability in a multi-source and multi-load DC distribution system under different load power operating conditions in the prior art.

[0007] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a method for suppressing oscillation of a DC distribution system based on a Buck converter is provided. The DC distribution system is composed of multiple voltage source converters, multiple power electronic converter loads and a bus voltage feedforward Buck converter in parallel. The method includes: acquiring an output voltage sampling value of the bus voltage feedforward Buck converter in real time to obtain a first voltage, and simultaneously acquiring a bus DC voltage sampling value to obtain a third voltage; obtaining a first control signal based on the first voltage, the second voltage and the third voltage, using a second-order filter to enable the bus voltage feedforward Buck converter to provide positive damping to the DC distribution system, effectively eliminating the oscillation generated by the power electronic converter load being connected to or cut out of the DC distribution system, and the second voltage is the output voltage rated value of the bus voltage feedforward Buck converter; performing PWM modulation based on the first control signal to obtain a second control signal, and controlling the on and off of the bus voltage feedforward Buck converter based on the second control signal to suppress the oscillation of the DC distribution system.

[0008] Optionally, before processing by the second-order filter and the proportional-integral controller, the method further includes: constructing a transfer function of the second-order filter to obtain a second-order filter: Among them, G vir,p (s) is a second-order filter, P cpl, ∑ is the sum of the power of all power electronic converter loads and the bus voltage feedforward Buck converter, P cpl is the power of the bus voltage feedforward Buck converter, n T is the voltage ratio between the secondary and primary sides of the transformer in the bus voltage feedforward Buck converter, V o,ref is the second voltage, V bus,ref is the bus voltage rating, f osc is the center frequency, Q z is the quality factor, and s is the variable after Laplace transformation.

[0009] Optionally, after being processed by a second-order filter and a proportional-integral controller, the method further comprises: calculating the bus voltage feedforward Buck converter providing positive damping to the DC power distribution system according to a preset formula: Among them, Z vir,p (s) is the positive damping.

[0010] Optionally, the first voltage is normalized based on the second voltage to obtain a first target value; the difference between the preset value and the first target value is calculated to obtain a second target value; the product of the third voltage and the second-order filter is calculated to obtain a third target value; the second target value and the third target value are summed to obtain a fourth target value; the fourth target value is input into a proportional-integral controller to obtain a first control signal, thereby generating a control signal for a bus voltage feedforward Buck converter.

[0011] Optionally, an instability frequency of the DC power distribution system is obtained, and the instability frequency is determined as the center frequency. The instability frequency is the oscillation frequency of the DC power distribution system, so as to optimize the parameter setting of the second-order filter.

[0012] Optionally, when the transformer is an isolation transformer, n T The value is the voltage ratio between the output terminal and the input terminal of the isolation transformer. In the case where the transformer is a non-isolation transformer, n T The value is 1.

[0013] Optionally, the voltage source converter is any one of an AC-DC converter, a DC-DC converter and a direct current power supply including an LC filter.

[0014] According to another aspect of the present application, a device for suppressing oscillation of a DC power distribution system based on a Buck converter is provided. The DC power distribution system is composed of a plurality of voltage source converters, a plurality of power electronic converter loads and a bus voltage feedforward Buck converter connected in parallel. The device comprises: a first acquisition unit, used to acquire an output voltage sampling value of the bus voltage feedforward Buck converter in real time to obtain a first voltage, and to acquire a bus DC voltage sampling value to obtain a third voltage; a first calculation unit, used to generate a control signal of the bus voltage feedforward Buck converter based on the first voltage, the second voltage and the third voltage, through a second-order filter and a proportional-integral controller to obtain a first control signal, the second-order filter being used to enable the bus voltage feedforward Buck converter to provide positive damping to the DC power distribution system to eliminate oscillations generated when the power electronic converter load is connected to or cut out of the DC power distribution system, and the second voltage is the output voltage rated value of the bus voltage feedforward Buck converter; a second calculation unit, used to perform PWM modulation based on the first control signal to obtain a second control signal, and to control the on and off of the bus voltage feedforward Buck converter based on the second control signal to suppress oscillations of the DC power distribution system.

[0015] According to another aspect of the present application, a computer-readable storage medium is provided, the computer-readable storage medium including a stored program, wherein when the program is executed, a device where the computer-readable storage medium is located is controlled to execute any one of the described methods.

[0016] According to another aspect of the present application, a direct current distribution system is provided, comprising: one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the one or more programs include methods for executing any one of the methods described.

[0017] By applying the technical solution of the present application, in the above-mentioned method for suppressing oscillation of a DC power distribution system based on a Buck converter, first, the output voltage sampling value of the above-mentioned bus voltage feedforward Buck converter is obtained in real time to obtain a first voltage, and the bus DC voltage sampling value is obtained to obtain a third voltage; then, based on the above-mentioned first voltage, the above-mentioned second voltage and the above-mentioned third voltage, a control signal of the above-mentioned bus voltage feedforward Buck converter is generated by processing through a second-order filter and a proportional-integral controller to obtain a first control signal, and the above-mentioned second-order filter is used to enable the above-mentioned bus voltage feedforward Buck converter to provide positive damping to the above-mentioned DC power distribution system to eliminate the oscillation generated by the above-mentioned power electronic converter load being connected to or cut out of the above-mentioned DC power distribution system, and the second voltage is the output voltage rated value of the above-mentioned bus voltage feedforward Buck converter; finally, PWM modulation is performed based on the above-mentioned first control signal to obtain a second control signal, and the on-off of the above-mentioned bus voltage feedforward Buck converter is controlled based on the above-mentioned second control signal to suppress the oscillation of the above-mentioned DC power distribution system. The present application configures a second-order filter in a bus voltage feedforward Buck converter for control. Through a single voltage closed-loop control and a DC bus feedforward voltage control method, when the load power of the power electronic converter changes, the second-order filter acts to generate corresponding positive damping to suppress the oscillation generated by the system, thereby solving the problem of instability in a multi-source and multi-load DC power distribution system under different load power operating conditions in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic flow chart of a method for suppressing oscillation of a DC power distribution system based on a Buck converter according to an embodiment of the present application is shown;

[0019] Figure 2 A schematic structural diagram of a DC power distribution system provided according to an embodiment of the present application is shown;

[0020] Figure 3 A topology diagram of a bus voltage feedforward Buck converter provided according to an embodiment of the present application is shown;

[0021] Figure 4 A schematic diagram of equivalent bandpass positive damping connected to a bus voltage feedforward Buck converter provided in accordance with an embodiment of the present application is shown;

[0022] Figure 5 A circuit topology diagram of a DC power distribution system provided according to an embodiment of the present application is shown;

[0023] Figure 6 A waveform diagram of a DC power distribution system before oscillation suppression is shown according to an embodiment of the present application;

[0024] Figure 7 A waveform diagram of a DC power distribution system after oscillation suppression is shown according to an embodiment of the present application;

[0025] Figure 8 A structural block diagram of an oscillation suppression device for a DC power distribution system based on a Buck converter provided according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0026] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0027] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0028] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0029] As introduced in the background technology, the prior art lacks a system oscillation suppression method that can be applicable to a multi-source and multi-load DC distribution system. In order to solve the problem of instability in the multi-source and multi-load DC distribution system under different load power operating conditions in the prior art, the embodiments of the present application provide a DC distribution system oscillation suppression method, device, computer-readable storage medium and DC distribution system based on Buck converter.

[0030] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0031] In this embodiment, a method for suppressing oscillations in a DC power distribution system based on a Buck converter and running on a mobile terminal, a computer terminal or a similar computing device is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0032] Figure 1 Flow chart of a method for suppressing oscillation of a DC power distribution system based on a Buck converter according to an embodiment of the present application. Figure 1 As shown, the method comprises the following steps:

[0033] Step S201, obtaining in real time an output voltage sampling value of the bus voltage feedforward Buck converter to obtain a first voltage, and obtaining a bus DC voltage sampling value to obtain a third voltage;

[0034] Specifically, Figure 2 As shown, the DC distribution system of the proposed application is composed of multiple voltage source converters, multiple power electronic converter loads and bus voltage feedforward Buck converters connected in parallel on the same bus.

[0035] It is understandable that the power electronic converter load can be a load based on a DC-AC converter or a load based on a DC-DC converter, which can present an approximate constant power load characteristic on the DC bus side. The topology of the bus voltage feedforward Buck converter can be an isolated or non-isolated Buck converter, which uses a single closed-loop output voltage control and a DC bus voltage feedforward control method to provide a stable DC voltage to the load resistor.

[0036] Due to the multi-source and multi-load DC distribution system, the system output often changes due to the connection and disconnection of the power electronic converter, that is, the above-mentioned third voltage changes, and the above-mentioned third voltage is mainly affected by the above-mentioned first voltage, and the first voltage is controlled by the second voltage. Therefore, before oscillation suppression is performed, the above-mentioned first voltage, the second voltage and the above-mentioned third voltage are obtained to determine the state of the DC distribution system.

[0037] Step S202: Based on the first voltage, the second voltage and the third voltage, a control signal of the bus voltage feedforward Buck converter is generated by processing through a second-order filter and a proportional-integral controller to obtain a first control signal, wherein the second-order filter is used to enable the bus voltage feedforward Buck converter to provide positive damping to the DC power distribution system to eliminate oscillations generated when the power electronic converter load is connected to or cut out of the DC power distribution system, and the second voltage is the output voltage rated value of the bus voltage feedforward Buck converter;

[0038] Specifically, after determining the state of the system based on the above-mentioned first voltage, the above-mentioned second voltage and the above-mentioned third voltage, the current state of the system can be input into the above-mentioned second-order filter for processing, and a control signal can be preliminarily generated, and then adaptively adjusted through a proportional-integral controller to obtain the above-mentioned first control signal, which is equivalent to obtaining a control signal that can control the above-mentioned bus voltage feedforward Buck converter to provide the above-mentioned DC distribution system with positive damping on behalf of the bucket.

[0039] Step S203, performing PWM modulation based on the first control signal to obtain a second control signal, and controlling the on and off of the bus voltage feedforward Buck converter based on the second control signal to suppress oscillation of the DC power distribution system.

[0040] Based on the PWM modulation of the above control signal, the above second control signal for controlling the on and off of the power electronic components in the bus voltage feedforward Buck converter is obtained, and the above bus voltage feedforward Buck converter is controlled based on the above second control signal to eliminate the oscillation of the above DC power distribution system.

[0041] In the above embodiment, the topology diagram of the bus voltage feedforward Buck converter is as follows: Figure 3 As shown, the power conversion link converts the DC bus voltage v bus Transformed to an amplitude of n T v bus , a square wave voltage with a duty cycle of d, which is then converted into a stable output voltage v through the LC filter link o .H v is the output voltage sampling factor, G v (s) = k vp +k vi / s is the transfer function of the voltage loop controller, G m is the PWM gain; R is the load resistance, and the power is P cpl , L is inductance, C is capacitance, R L is the inductor equivalent resistance, R C The output voltage single closed-loop control and DC bus voltage feed-forward control method are adopted to provide a stable DC voltage to the load resistor.

[0042] Through this embodiment, first, the output voltage sampling value of the above-mentioned bus voltage feedforward Buck converter is obtained in real time to obtain a first voltage, and the bus DC voltage sampling value is obtained to obtain a third voltage; then, based on the above-mentioned first voltage, the above-mentioned second voltage and the above-mentioned third voltage, a control signal of the above-mentioned bus voltage feedforward Buck converter is generated through a second-order filter and a proportional-integral controller to obtain a first control signal, and the above-mentioned second-order filter is used to enable the above-mentioned bus voltage feedforward Buck converter to provide positive damping to the above-mentioned DC power distribution system to eliminate the oscillation generated by the above-mentioned power electronic converter load being connected to or cut out of the above-mentioned DC power distribution system, and the above-mentioned second voltage is the output voltage rated value of the above-mentioned bus voltage feedforward Buck converter; finally, PWM modulation is performed based on the above-mentioned first control signal to obtain a second control signal, and the on-off of the above-mentioned bus voltage feedforward Buck converter is controlled based on the above-mentioned second control signal to suppress the oscillation of the above-mentioned DC power distribution system. The present application configures a second-order filter in a bus voltage feedforward Buck converter for control. Through a single voltage closed-loop control and a DC bus feedforward voltage control method, when the load power of the power electronic converter changes, the second-order filter acts to generate corresponding positive damping to suppress the oscillation generated by the system, thereby solving the problem of instability in a multi-source and multi-load DC power distribution system under different load power operating conditions in the prior art.

[0043] In order to obtain the above second-order filter, in an optional implementation manner, before the second-order filter and the proportional-integral controller are used for processing, the above method further includes:

[0044] Step S301, constructing the transfer function of the second-order filter to obtain the second-order filter:

[0045] Among them, G vir,p (s) is the second-order filter mentioned above, P cpl, ∑ is the sum of the power of all the above power electronic converter loads and the above bus voltage feedforward Buck converter, P cpl is the power of the above bus voltage feedforward Buck converter, n T is the voltage ratio between the secondary and primary sides of the transformer in the above bus voltage feedforward Buck converter, V o,ref is the second voltage, V bus,ref is the bus voltage rating, f osc is the center frequency, Q z is the quality factor, and s is the variable after Laplace transformation.

[0046] Specifically, the purpose of designing the above-mentioned second-order filter is to enable the above-mentioned bus voltage feedforward Buck converter to provide a bandpass positive damping to the DC distribution system that can be adaptively changed according to the system's load power and instability frequency (related to the above-mentioned center frequency) to suppress the oscillation of the system.

[0047] In a specific embodiment, when the above-mentioned transformer is an isolation transformer, the value is the voltage ratio between the output end and the input end of the above-mentioned isolation transformer; when the above-mentioned transformer is a non-isolation transformer, the value is 1.

[0048] In order to control the bandpass positive damping output by the bus voltage feedforward Buck converter, in an optional implementation, after being processed by a second-order filter and a proportional-integral controller, the method further includes:

[0049] Step S401, the positive damping provided by the bus voltage feedforward Buck converter to the DC power distribution system is calculated according to a preset formula:

[0050] Among them, Z vir,p (s) is the positive damping mentioned above.

[0051] Specifically, the equivalent bandpass positive damping of the above bus voltage feedforward Buck converter is connected, as Figure 4 shown.

[0052] In order to implement the control of the bus voltage feedforward Buck converter by the second-order filter, in an optional implementation, the step S202 includes:

[0053] Step S2021, normalizing the first voltage based on the second voltage to obtain a first target value;

[0054] Specifically, the output voltage sampling value is normalized according to the output voltage rated value to obtain a first value.

[0055] Step S2022, calculating the difference between the preset value and the first target value to obtain a second target value;

[0056] Specifically, the first value is subtracted from the constant 1 to obtain the second value.

[0057] Step S2023, calculating the product of the third voltage and the second-order filter to obtain a third target value;

[0058] Specifically, the third voltage is multiplied by the second-order filter to obtain a third value.

[0059] Step S2024, summing the second target value and the third target value to obtain a fourth target value;

[0060] Specifically, the second value is added to the third value to obtain the fourth value.

[0061] Step S2025: input the fourth target value into the proportional-integral controller to obtain the first control signal.

[0062] Specifically, the fourth value is multiplied by the proportional-integral controller to obtain the control signal of the bus voltage feedforward Buck converter, that is, the above-mentioned first control signal.

[0063] In order to make the positive damping change with the instability frequency of the DC power distribution system, in an optional implementation manner, before the processing by the second-order filter and the proportional-integral controller, the method further includes:

[0064] Step S501, obtaining the instability frequency of the DC power distribution system, and determining the instability frequency as the center frequency, wherein the instability frequency is the oscillation frequency of the DC power distribution system.

[0065] Specifically, when taking a value of the center frequency, the value of the instability frequency is filled in, that is, the change of the instability frequency is ensured to be substituted into the budget process of the second-order filter.

[0066] In a specific implementation, the voltage source converter is any one of an AC-DC converter, a DC-DC converter and a direct current power supply including an LC filter.

[0067] The above power converter control adopts a DC bus voltage droop control method.

[0068] The power electronic converter load can be a load based on a DC-AC converter or a load based on a DC-DC converter, which can present an approximately constant power load characteristic on the DC bus side (referring to the frequency band in which the input impedance of the power electronic converter load has a phase of -90 degrees to -180 degrees, or the frequency band in which the real part of the input impedance of the power electronic converter load has a negative value).

[0069] In a specific embodiment, Figure 5 As shown in the figure, the above method is applied to a schematic diagram of a DC power distribution system. In the figure, the #1 and #2 voltage source converters use droop control based on the output current to control the DC bus voltage to 24V; the power electronic converter load and bus voltage feedforward Buck converter provide a stable output voltage v to the load resistors R3 and R4 respectively. o，3 and v o，4 ; C n，3 and C n，4 are the input capacitance, R Cn，3 and R Cn，4 Cn，3 and C n，4 According to the different values ​​of the load resistance R4 of the power electronic converter load, three system conditions are set, namely, condition 1: R4 = 3Ω, condition 2: R4 = 1.5Ω, corresponding to system power of 123W and 171W respectively. dc is the DC power supply of the voltage source converter, L is the inductor, C is the capacitor, H d and H v is the output power sampling coefficient mixed with the output voltage sampling coefficient.

[0070] Based on the above embodiments, Figure 6 As shown in the figure, the experimental waveforms of the DC power distribution system when the above method is not adopted, it can be seen that the system is unstable under both working conditions, and due to the increase in the load power of the power electronic converter, the instability of the system is deepened, the oscillation amplitude of each electrical quantity waveform is significantly increased, and the oscillation frequency of the DC bus voltage is reduced from 343Hz in working condition 1 to 340Hz.

[0071] Further, such as Figure 7 As shown in the figure, the experimental waveform of the DC power distribution system using the above method shows that: when the DC power distribution system adaptive oscillation suppression method based on bus voltage feedforward Buck converter is added to the system, the unstable oscillation of the system under working condition 1 and working condition 2 can be completely suppressed relatively quickly, so that the whole system returns to a stable state. Even if the load power of the power electronic converter increases, the system can still maintain stable operation, indicating the effectiveness and correctness of the above method of the present application.

[0072] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0073] The embodiment of the present application also provides a device for suppressing oscillations of a DC power distribution system based on a Buck converter. It should be noted that the device for suppressing oscillations of a DC power distribution system based on a Buck converter in the embodiment of the present application can be used to execute the method for suppressing oscillations of a DC power distribution system based on a Buck converter provided in the embodiment of the present application. The device is used to implement the above-mentioned embodiments and preferred implementation modes, and those that have been described will not be repeated. As used below, the term "module" can implement a combination of software and / or hardware for a predetermined function. Although the device described in the following embodiments is preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0074] The following is an introduction to the oscillation suppression device for a DC power distribution system based on a Buck converter provided in an embodiment of the present application.

[0075] Figure 8 is a structural block diagram of a DC power distribution system oscillation suppression device based on a Buck converter according to an embodiment of the present application. Figure 8 As shown, the device comprises:

[0076] The first acquisition unit 10 is used to acquire the output voltage sampling value of the above-mentioned bus voltage feedforward Buck converter in real time to obtain the first voltage, and acquire the bus DC voltage sampling value to obtain the third voltage;

[0077] Specifically, Figure 2 As shown, the DC distribution system of the proposed application is composed of multiple voltage source converters, multiple power electronic converter loads and bus voltage feedforward Buck converters connected in parallel on the same bus.

[0078] It is understandable that the power electronic converter load can be a load based on a DC-AC converter or a load based on a DC-DC converter, which can present an approximate constant power load characteristic on the DC bus side. The topology of the bus voltage feedforward Buck converter can be an isolated or non-isolated Buck converter, which uses a single closed-loop output voltage control and a DC bus voltage feedforward control method to provide a stable DC voltage to the load resistor.

[0079] Due to the multi-source and multi-load DC distribution system, the system output often changes due to the connection and disconnection of the power electronic converter, that is, the above-mentioned third voltage changes, and the above-mentioned third voltage is mainly affected by the above-mentioned first voltage, and the first voltage is controlled by the second voltage. Therefore, before oscillation suppression is performed, the above-mentioned first voltage, the second voltage and the above-mentioned third voltage are obtained to determine the state of the DC distribution system.

[0080] The first calculation unit 20 is used to generate a control signal of the bus voltage feedforward Buck converter based on the first voltage, the second voltage and the third voltage through a second-order filter and a proportional-integral controller to obtain a first control signal, wherein the second-order filter is used to enable the bus voltage feedforward Buck converter to provide positive damping to the DC power distribution system to eliminate oscillations generated when the power electronic converter load is connected to or cut out of the DC power distribution system, and the second voltage is an output voltage rated value of the bus voltage feedforward Buck converter;

[0081] Specifically, after determining the state of the system based on the above-mentioned first voltage, the above-mentioned second voltage and the above-mentioned third voltage, the current state of the system can be input into the above-mentioned second-order filter for processing, and a control signal can be preliminarily generated, and then adaptively adjusted through a proportional-integral controller to obtain the above-mentioned first control signal, which is equivalent to obtaining a control signal that can control the above-mentioned bus voltage feedforward Buck converter to provide the above-mentioned DC distribution system with positive damping on behalf of the bucket.

[0082] The second calculation unit 30 is used to perform PWM modulation based on the first control signal to obtain a second control signal, and control the on and off of the bus voltage feedforward Buck converter based on the second control signal to suppress the oscillation of the DC power distribution system.

[0083] Based on the PWM modulation of the above control signal, the above second control signal for controlling the on and off of the power electronic components in the bus voltage feedforward Buck converter is obtained, and the above bus voltage feedforward Buck converter is controlled based on the above second control signal to eliminate the oscillation of the above DC power distribution system.

[0084] In the above embodiment, the topology diagram of the bus voltage feedforward Buck converter is as follows: Figure 3 As shown, the power conversion link converts the DC bus voltage v bus Transformed to an amplitude of n T v bus , a square wave voltage with a duty cycle of d, which is then converted into a stable output voltage v through the LC filter link o .H v is the output voltage sampling factor, G v (s) = k vp +k vi / s is the transfer function of the voltage loop controller, G m is the PWM gain; R is the load resistance, and the power is P cpl , L is inductance, C is capacitance, R L is the inductor equivalent resistance, R C The output voltage single closed-loop control and DC bus voltage feed-forward control method are adopted to provide a stable DC voltage to the load resistor.

[0085] Through this embodiment, the first acquisition unit acquires the output voltage sampling value of the above-mentioned bus voltage feedforward Buck converter in real time to obtain the first voltage, and acquires the bus DC voltage sampling value to obtain the third voltage; the first calculation unit generates the control signal of the above-mentioned bus voltage feedforward Buck converter through a second-order filter and a proportional-integral controller based on the above-mentioned first voltage, the above-mentioned second voltage and the above-mentioned third voltage to obtain the first control signal, and the above-mentioned second-order filter is used to enable the above-mentioned bus voltage feedforward Buck converter to provide positive damping to the above-mentioned DC power distribution system to eliminate the oscillation generated by the above-mentioned power electronic converter load being connected to or cut out of the above-mentioned DC power distribution system, and the above-mentioned second voltage is the output voltage rated value of the above-mentioned bus voltage feedforward Buck converter; the second calculation unit performs PWM modulation based on the above-mentioned first control signal to obtain the second control signal, and controls the on-off of the above-mentioned bus voltage feedforward Buck converter based on the above-mentioned second control signal to suppress the oscillation of the above-mentioned DC power distribution system. The present application configures a second-order filter in a bus voltage feedforward Buck converter for control. Through a single voltage closed-loop control and a DC bus feedforward voltage control method, when the load power of the power electronic converter changes, the second-order filter acts to generate corresponding positive damping to suppress the oscillation generated by the system, thereby solving the problem of instability in a multi-source and multi-load DC power distribution system under different load power operating conditions in the prior art.

[0086] In order to obtain the above second-order filter, in an optional implementation manner, the above device further includes:

[0087] The first construction unit is used to construct a transfer function of the second-order filter before processing by the second-order filter and the proportional-integral controller to obtain the second-order filter:

[0088] Among them, G vir,p (s) is the second-order filter mentioned above, P cpl, ∑ is the sum of the power of all the above power electronic converter loads and the above bus voltage feedforward Buck converter, P cpl is the power of the above bus voltage feedforward Buck converter, n T is the voltage ratio between the secondary and primary sides of the transformer in the above bus voltage feedforward Buck converter, V o,ref is the second voltage, V bus,ref is the bus voltage rating, f osc is the center frequency, Q z is the quality factor, and s is the variable after Laplace transformation.

[0089] Specifically, the purpose of designing the above-mentioned second-order filter is to enable the above-mentioned bus voltage feedforward Buck converter to provide a bandpass positive damping to the DC distribution system that can be adaptively changed according to the system's load power and instability frequency (related to the above-mentioned center frequency) to suppress the oscillation of the system.

[0090] In a specific embodiment, when the above-mentioned transformer is an isolation transformer, the value is the voltage ratio between the output end and the input end of the above-mentioned isolation transformer; when the above-mentioned transformer is a non-isolation transformer, the value is 1.

[0091] In order to control the passband positive damping output by the bus voltage feedforward Buck converter, the device further comprises:

[0092] A third calculation unit is used, in an optional implementation manner, to calculate the positive damping provided by the bus voltage feedforward Buck converter to the DC power distribution system according to a preset formula after being processed by a second-order filter and a proportional-integral controller:

[0093] Among them, Z vir,p (s) is the positive damping mentioned above.

[0094] Specifically, the equivalent bandpass positive damping of the above bus voltage feedforward Buck converter is connected, as Figure 4 shown.

[0095] In order to realize the control of the bus voltage feedforward Buck converter by the second-order filter, in an optional implementation manner, the first calculation unit includes:

[0096] A first calculation module, used for normalizing the first voltage based on the second voltage to obtain a first target value;

[0097] Specifically, the output voltage sampling value is normalized according to the output voltage rated value to obtain a first value.

[0098] A second calculation module is used to calculate the difference between the preset value and the first target value to obtain a second target value;

[0099] Specifically, the first value is subtracted from the constant 1 to obtain the second value.

[0100] a third calculation module, used for calculating the product of the third voltage and the second-order filter to obtain a third target value;

[0101] Specifically, the third voltage is multiplied by the second-order filter to obtain a third value.

[0102] a fourth calculation module, configured to sum the second target value and the third target value to obtain a fourth target value;

[0103] Specifically, the second value is added to the third value to obtain the fourth value.

[0104] The fifth calculation module is used to input the fourth target value into the proportional-integral controller to obtain the first control signal.

[0105] Specifically, the fourth value is multiplied by the proportional-integral controller to obtain the control signal of the bus voltage feedforward Buck converter, that is, the above-mentioned first control signal.

[0106] In order to make the positive damping change with the instability frequency of the DC power distribution system, in an optional implementation manner, the device further includes:

[0107] The second acquisition unit is used to acquire the instability frequency of the DC power distribution system before processing by the second-order filter and the proportional-integral controller, and determine the instability frequency as the center frequency. The instability frequency is the oscillation frequency of the DC power distribution system.

[0108] Specifically, when taking a value of the center frequency, the value of the instability frequency is filled in, that is, the change of the instability frequency is ensured to be substituted into the budget process of the second-order filter.

[0109] In a specific implementation, the voltage source converter is any one of an AC-DC converter, a DC-DC converter and a direct current power supply including an LC filter.

[0110] The above power converter control adopts a DC bus voltage droop control method.

[0111] The power electronic converter load can be a load based on a DC-AC converter or a load based on a DC-DC converter, which can present an approximately constant power load characteristic on the DC bus side (referring to the frequency band in which the input impedance of the power electronic converter load has a phase of -90 degrees to -180 degrees, or the frequency band in which the real part of the input impedance of the power electronic converter load has a negative value).

[0112] The above-mentioned DC power distribution system oscillation suppression device based on Buck converter includes a processor and a memory. The above-mentioned first acquisition unit, the first calculation unit, the second calculation unit, etc. are all stored in the memory as program units, and the processor executes the above-mentioned program units stored in the memory to realize the corresponding functions. The above-mentioned modules are all located in the same processor; or, the above-mentioned modules are located in different processors in the form of any combination.

[0113] The processor includes a kernel, which calls the corresponding program unit from the memory. One or more kernels can be set, and the stability of the DC power distribution system can be improved by adjusting the kernel parameters.

[0114] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0115] An embodiment of the present invention provides a computer-readable storage medium, which includes a stored program, wherein when the program is running, the device where the computer-readable storage medium is located is controlled to execute the DC distribution system oscillation suppression method based on Buck converter.

[0116] Specifically, the oscillation suppression method of the DC power distribution system based on Buck converter includes:

[0117] Step S201, obtaining in real time an output voltage sampling value of the bus voltage feedforward Buck converter to obtain a first voltage, and obtaining a bus DC voltage sampling value to obtain a third voltage;

[0118] Specifically, Figure 2 As shown, the DC distribution system of the proposed application is composed of multiple voltage source converters, multiple power electronic converter loads and bus voltage feedforward Buck converters connected in parallel on the same bus.

[0119] It is understandable that the power electronic converter load can be a load based on a DC-AC converter or a load based on a DC-DC converter, which can present an approximate constant power load characteristic on the DC bus side. The topology of the bus voltage feedforward Buck converter can be an isolated or non-isolated Buck converter, which uses a single closed-loop output voltage control and a DC bus voltage feedforward control method to provide a stable DC voltage to the load resistor.

[0120] Due to the multi-source and multi-load DC distribution system, the system output often changes due to the connection and disconnection of the power electronic converter, that is, the above-mentioned third voltage changes, and the above-mentioned third voltage is mainly affected by the above-mentioned first voltage, and the first voltage is controlled by the second voltage. Therefore, before oscillation suppression is performed, the above-mentioned first voltage, the second voltage and the above-mentioned third voltage are obtained to determine the state of the DC distribution system.

[0121] Step S202: Based on the first voltage, the second voltage and the third voltage, a control signal of the bus voltage feedforward Buck converter is generated by processing through a second-order filter and a proportional-integral controller to obtain a first control signal, wherein the second-order filter is used to enable the bus voltage feedforward Buck converter to provide positive damping to the DC power distribution system to eliminate oscillations generated when the power electronic converter load is connected to or cut out of the DC power distribution system, and the second voltage is the output voltage rated value of the bus voltage feedforward Buck converter;

[0122] Specifically, after determining the state of the system based on the above-mentioned first voltage, the above-mentioned second voltage and the above-mentioned third voltage, the current state of the system can be input into the above-mentioned second-order filter for processing, and a control signal can be preliminarily generated, and then adaptively adjusted through a proportional-integral controller to obtain the above-mentioned first control signal, which is equivalent to obtaining a control signal that can control the above-mentioned bus voltage feedforward Buck converter to provide the above-mentioned DC distribution system with positive damping on behalf of the bucket.

[0123] Step S203, performing PWM modulation based on the first control signal to obtain a second control signal, and controlling the on and off of the bus voltage feedforward Buck converter based on the second control signal to suppress oscillation of the DC power distribution system.

[0124] Based on the PWM modulation of the above control signal, the above second control signal for controlling the on and off of the power electronic components in the bus voltage feedforward Buck converter is obtained, and the above bus voltage feedforward Buck converter is controlled based on the above second control signal to eliminate the oscillation of the above DC power distribution system.

[0125] In the above embodiment, the topology diagram of the bus voltage feedforward Buck converter is as follows: Figure 3 As shown, the power conversion link converts the DC bus voltage v bus Transformed to an amplitude of n T v bus , a square wave voltage with a duty cycle of d, which is then converted into a stable output voltage v through the LC filter link o .H v is the output voltage sampling factor, G v (s) = k vp +k vi / s is the transfer function of the voltage loop controller, G m is the PWM gain; R is the load resistance, and the power is P cpl , L is inductance, C is capacitance, R L is the inductor equivalent resistance, R C The output voltage single closed-loop control and DC bus voltage feed-forward control method are adopted to provide a stable DC voltage to the load resistor.

[0126] An embodiment of the present invention provides a processor, and the processor is used to run a program, wherein the program executes the oscillation suppression method of a direct current distribution system based on Buck converter when running.

[0127] Specifically, the oscillation suppression method of the DC power distribution system based on Buck converter includes:

[0128] Step S201, obtaining in real time an output voltage sampling value of the bus voltage feedforward Buck converter to obtain a first voltage, and obtaining a bus DC voltage sampling value to obtain a third voltage;

[0129] Specifically, Figure 2 As shown, the DC distribution system of the proposed application is composed of multiple voltage source converters, multiple power electronic converter loads and bus voltage feedforward Buck converters connected in parallel on the same bus.

[0130] It is understandable that the power electronic converter load can be a load based on a DC-AC converter or a load based on a DC-DC converter, which can present an approximate constant power load characteristic on the DC bus side. The topology of the bus voltage feedforward Buck converter can be an isolated or non-isolated Buck converter, which uses a single closed-loop output voltage control and a DC bus voltage feedforward control method to provide a stable DC voltage to the load resistor.

[0131] Due to the multi-source and multi-load DC distribution system, the system output often changes due to the connection and disconnection of the power electronic converter, that is, the above-mentioned third voltage changes, and the above-mentioned third voltage is mainly affected by the above-mentioned first voltage, and the first voltage is controlled by the second voltage. Therefore, before oscillation suppression is performed, the above-mentioned first voltage, the second voltage and the above-mentioned third voltage are obtained to determine the state of the DC distribution system.

[0132] Step S202: Based on the first voltage, the second voltage and the third voltage, a control signal of the bus voltage feedforward Buck converter is generated by processing through a second-order filter and a proportional-integral controller to obtain a first control signal, wherein the second-order filter is used to enable the bus voltage feedforward Buck converter to provide positive damping to the DC power distribution system to eliminate oscillations generated when the power electronic converter load is connected to or cut out of the DC power distribution system, and the second voltage is the output voltage rated value of the bus voltage feedforward Buck converter;

[0133] Specifically, after determining the state of the system based on the above-mentioned first voltage, the above-mentioned second voltage and the above-mentioned third voltage, the current state of the system can be input into the above-mentioned second-order filter for processing, and a control signal can be preliminarily generated, and then adaptively adjusted through a proportional-integral controller to obtain the above-mentioned first control signal, which is equivalent to obtaining a control signal that can control the above-mentioned bus voltage feedforward Buck converter to provide the above-mentioned DC distribution system with positive damping on behalf of the bucket.

[0134] Step S203, performing PWM modulation based on the first control signal to obtain a second control signal, and controlling the on and off of the bus voltage feedforward Buck converter based on the second control signal to suppress oscillation of the DC power distribution system.

[0135] Based on the PWM modulation of the above control signal, the above second control signal for controlling the on and off of the power electronic components in the bus voltage feedforward Buck converter is obtained, and the above bus voltage feedforward Buck converter is controlled based on the above second control signal to eliminate the oscillation of the above DC power distribution system.

[0136] In the above embodiment, the topology diagram of the bus voltage feedforward Buck converter is as follows: Figure 3 As shown, the power conversion link converts the DC bus voltage v bus Transformed to an amplitude of n T v bus , a square wave voltage with a duty cycle of d, which is then converted into a stable output voltage v through the LC filter link o .H v is the output voltage sampling factor, G v (s) = k vp +k vi / s is the transfer function of the voltage loop controller, G m is the PWM gain; R is the load resistance, and the power is P cpl , L is inductance, C is capacitance, R L is the inductor equivalent resistance, R C The output voltage single closed-loop control and DC bus voltage feed-forward control method are adopted to provide a stable DC voltage to the load resistor.

[0137] An embodiment of the present invention provides a direct current power distribution system, the direct current power distribution system comprising a processor, a memory, and a program stored in the memory and executable on the processor, and when the processor executes the program, at least the following steps are implemented:

[0138] Step S201, obtaining in real time an output voltage sampling value of the bus voltage feedforward Buck converter to obtain a first voltage, and obtaining a bus DC voltage sampling value to obtain a third voltage;

[0139] Specifically, Figure 2 As shown, the DC distribution system of the proposed application is composed of multiple voltage source converters, multiple power electronic converter loads and bus voltage feedforward Buck converters connected in parallel on the same bus.

[0140] It is understandable that the power electronic converter load can be a load based on a DC-AC converter or a load based on a DC-DC converter, which can present an approximate constant power load characteristic on the DC bus side. The topology of the bus voltage feedforward Buck converter can be an isolated or non-isolated Buck converter, which uses a single closed-loop output voltage control and a DC bus voltage feedforward control method to provide a stable DC voltage to the load resistor.

[0141] Due to the multi-source and multi-load DC distribution system, the system output often changes due to the connection and disconnection of the power electronic converter, that is, the above-mentioned third voltage changes, and the above-mentioned third voltage is mainly affected by the above-mentioned first voltage, and the first voltage is controlled by the second voltage. Therefore, before oscillation suppression is performed, the above-mentioned first voltage, the second voltage and the above-mentioned third voltage are obtained to determine the state of the DC distribution system.

[0142] Step S202: Based on the first voltage, the second voltage and the third voltage, a control signal of the bus voltage feedforward Buck converter is generated by processing through a second-order filter and a proportional-integral controller to obtain a first control signal, wherein the second-order filter is used to enable the bus voltage feedforward Buck converter to provide positive damping to the DC power distribution system to eliminate oscillations generated when the power electronic converter load is connected to or cut out of the DC power distribution system, and the second voltage is the output voltage rated value of the bus voltage feedforward Buck converter;

[0143] Specifically, after determining the state of the system based on the above-mentioned first voltage, the above-mentioned second voltage and the above-mentioned third voltage, the current state of the system can be input into the above-mentioned second-order filter for processing, and a control signal can be preliminarily generated, and then adaptively adjusted through a proportional-integral controller to obtain the above-mentioned first control signal, which is equivalent to obtaining a control signal that can control the above-mentioned bus voltage feedforward Buck converter to provide the above-mentioned DC distribution system with positive damping on behalf of the bucket.

[0144] Step S203, performing PWM modulation based on the first control signal to obtain a second control signal, and controlling the on and off of the bus voltage feedforward Buck converter based on the second control signal to suppress oscillation of the DC power distribution system.

[0145] Based on the PWM modulation of the above control signal, the above second control signal for controlling the on and off of the power electronic components in the bus voltage feedforward Buck converter is obtained, and the above bus voltage feedforward Buck converter is controlled based on the above second control signal to eliminate the oscillation of the above DC power distribution system.

[0146] In the above embodiment, the topology diagram of the bus voltage feedforward Buck converter is as follows: Figure 3 As shown, the power conversion link converts the DC bus voltage v bus Transformed to an amplitude of n T v bus , a square wave voltage with a duty cycle of d, which is then converted into a stable output voltage v through the LC filter link o .H v is the output voltage sampling factor, G v (s) = k vp +k vi / s is the transfer function of the voltage loop controller, G m is the PWM gain; R is the load resistance, and the power is P cpl , L is inductance, C is capacitance, R L is the inductor equivalent resistance, R C The output voltage single closed-loop control and DC bus voltage feed-forward control method are adopted to provide a stable DC voltage to the load resistor.

[0147] The present application also provides a computer program product, which, when executed on a data processing device, is suitable for executing a program for initializing at least the following method steps:

[0148] Step S201, obtaining in real time an output voltage sampling value of the bus voltage feedforward Buck converter to obtain a first voltage, and obtaining a bus DC voltage sampling value to obtain a third voltage;

[0149] Specifically, Figure 2 As shown, the DC distribution system of the proposed application is composed of multiple voltage source converters, multiple power electronic converter loads and bus voltage feedforward Buck converters connected in parallel on the same bus.

[0150] It is understandable that the power electronic converter load can be a load based on a DC-AC converter or a load based on a DC-DC converter, which can present an approximate constant power load characteristic on the DC bus side. The topology of the bus voltage feedforward Buck converter can be an isolated or non-isolated Buck converter, which uses a single closed-loop output voltage control and a DC bus voltage feedforward control method to provide a stable DC voltage to the load resistor.

[0151] Due to the multi-source and multi-load DC distribution system, the system output often changes due to the connection and disconnection of the power electronic converter, that is, the above-mentioned third voltage changes, and the above-mentioned third voltage is mainly affected by the above-mentioned first voltage, and the first voltage is controlled by the second voltage. Therefore, before oscillation suppression is performed, the above-mentioned first voltage, the second voltage and the above-mentioned third voltage are obtained to determine the state of the DC distribution system.

[0152] Step S202: Based on the first voltage, the second voltage and the third voltage, a control signal of the bus voltage feedforward Buck converter is generated by processing through a second-order filter and a proportional-integral controller to obtain a first control signal, wherein the second-order filter is used to enable the bus voltage feedforward Buck converter to provide positive damping to the DC power distribution system to eliminate oscillations generated when the power electronic converter load is connected to or cut out of the DC power distribution system, and the second voltage is the output voltage rated value of the bus voltage feedforward Buck converter;

[0153] Specifically, after determining the state of the system based on the above-mentioned first voltage, the above-mentioned second voltage and the above-mentioned third voltage, the current state of the system can be input into the above-mentioned second-order filter for processing, and a control signal can be preliminarily generated, and then adaptively adjusted through a proportional-integral controller to obtain the above-mentioned first control signal, which is equivalent to obtaining a control signal that can control the above-mentioned bus voltage feedforward Buck converter to provide the above-mentioned DC distribution system with positive damping on behalf of the bucket.

[0154] Step S203, performing PWM modulation based on the first control signal to obtain a second control signal, and controlling the on and off of the bus voltage feedforward Buck converter based on the second control signal to suppress oscillation of the DC power distribution system.

[0155] Based on the PWM modulation of the above control signal, the above second control signal for controlling the on and off of the power electronic components in the bus voltage feedforward Buck converter is obtained, and the above bus voltage feedforward Buck converter is controlled based on the above second control signal to eliminate the oscillation of the above DC power distribution system.

[0156] In the above embodiment, the topology diagram of the bus voltage feedforward Buck converter is as follows: Figure 3 As shown, the power conversion link converts the DC bus voltage v bus Transformed to an amplitude of n T v bus , a square wave voltage with a duty cycle of d, which is then converted into a stable output voltage v through the LC filter link o .H v is the output voltage sampling factor, G v (s) = k vp +kvi / s is the transfer function of the voltage loop controller, G m is the PWM gain; R is the load resistance, and the power is P cpl , L is inductance, C is capacitance, R L is the inductor equivalent resistance, R C The output voltage single closed-loop control and DC bus voltage feed-forward control method are adopted to provide a stable DC voltage to the load resistor.

[0157] Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general computing device, they can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices, they can be implemented by a program code executable by a computing device, so that they can be stored in a storage device and executed by the computing device, and in some cases, the steps shown or described can be executed in a different order than here, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. Thus, the present invention is not limited to any specific combination of hardware and software.

[0158] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0159] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0160] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0161] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0162] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0163] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0164] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0165] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0166] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0167] 1) The oscillation suppression method of a DC power distribution system based on a Buck converter of the present application, first, the output voltage sampling value of the above-mentioned bus voltage feedforward Buck converter is obtained in real time to obtain a first voltage, and the bus DC voltage sampling value is obtained to obtain a third voltage; then, based on the above-mentioned first voltage, the above-mentioned second voltage and the above-mentioned third voltage, a control signal of the above-mentioned bus voltage feedforward Buck converter is generated through a second-order filter and a proportional-integral controller to obtain a first control signal, and the above-mentioned second-order filter is used to enable the above-mentioned bus voltage feedforward Buck converter to provide positive damping to the above-mentioned DC power distribution system to eliminate the oscillation generated by the above-mentioned power electronic converter load being connected to or cut out of the above-mentioned DC power distribution system, and the above-mentioned second voltage is the output voltage rated value of the above-mentioned bus voltage feedforward Buck converter; finally, PWM modulation is performed based on the above-mentioned first control signal to obtain a second control signal, and the above-mentioned bus voltage feedforward Buck converter is controlled to be turned on and off based on the above-mentioned second control signal to suppress the oscillation of the above-mentioned DC power distribution system. The present application configures a second-order filter in a bus voltage feedforward Buck converter for control. Through a single voltage closed-loop control and a DC bus feedforward voltage control method, when the load power of the power electronic converter changes, the second-order filter acts to generate corresponding positive damping to suppress the oscillation generated by the system, thereby solving the problem of instability in a multi-source and multi-load DC power distribution system under different load power operating conditions in the prior art.

[0168] 2) The oscillation suppression device for a DC power distribution system based on a Buck converter of the present application, the first acquisition unit acquires the output voltage sampling value of the above-mentioned bus voltage feedforward Buck converter in real time to obtain the first voltage, acquires the bus DC voltage sampling value to obtain the third voltage; the first calculation unit generates the control signal of the above-mentioned bus voltage feedforward Buck converter through a second-order filter and a proportional-integral controller based on the above-mentioned first voltage, the above-mentioned second voltage and the above-mentioned third voltage to obtain the first control signal, the above-mentioned second-order filter is used to enable the above-mentioned bus voltage feedforward Buck converter to provide positive damping to the above-mentioned DC power distribution system to eliminate the oscillation generated by the above-mentioned power electronic converter load being connected or cut out of the above-mentioned DC power distribution system, and the above-mentioned second voltage is the output voltage rated value of the above-mentioned bus voltage feedforward Buck converter; the second calculation unit performs PWM modulation based on the above-mentioned first control signal to obtain the second control signal, and controls the on and off of the above-mentioned bus voltage feedforward Buck converter based on the above-mentioned second control signal to achieve the suppression of the oscillation of the above-mentioned DC power distribution system. The present application configures a second-order filter in a bus voltage feedforward Buck converter for control. Through a single voltage closed-loop control and a DC bus feedforward voltage control method, when the load power of the power electronic converter changes, the second-order filter acts to generate corresponding positive damping to suppress the oscillation generated by the system, thereby solving the problem of instability in a multi-source and multi-load DC power distribution system under different load power operating conditions in the prior art.

[0169] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for suppressing oscillation of a DC power distribution system based on a Buck converter, characterized in that: The DC power distribution system is composed of a plurality of voltage source converters, a plurality of power electronic converter loads and a bus voltage feedforward Buck converter connected in parallel, and the method comprises: Acquire the output voltage sampling value of the bus voltage feedforward Buck converter in real time to obtain the first voltage, acquire the bus DC voltage sampling value to obtain the third voltage; Based on the first voltage, the second voltage and the third voltage, a control signal of the bus voltage feedforward Buck converter is generated by processing through a second-order filter and a proportional-integral controller to obtain a first control signal, wherein the second-order filter is used to enable the bus voltage feedforward Buck converter to provide positive damping to the DC power distribution system to eliminate oscillations generated when the power electronic converter load is connected to or cut out of the DC power distribution system, and the second voltage is an output voltage rated value of the bus voltage feedforward Buck converter; PWM modulation is performed based on the first control signal to obtain a second control signal, and the on and off of the bus voltage feedforward Buck converter is controlled based on the second control signal to suppress oscillation of the DC power distribution system.

2. The method according to claim 1, characterized in that Before processing through the second-order filter and the proportional-integral controller, the method further includes: Construct the transfer function of the second-order filter to obtain the second-order filter: Among them, G vir,p (s) is the second-order filter, P cpl, ∑ is the sum of the power of all the power electronic converter loads and the bus voltage feedforward Buck converter, P cpl is the power of the bus voltage feedforward Buck converter, n T is the voltage ratio between the secondary side and the primary side of the transformer in the bus voltage feedforward Buck converter, V o,ref For the second voltage, V bus,ref is the bus voltage rating, f osc is the center frequency, Q z is the quality factor, and s is the variable after Laplace transformation.

3. The method according to claim 2, characterized in that After processing through the second-order filter and the proportional-integral controller, the method further includes: The bus voltage feedforward Buck converter provides positive damping to the DC power distribution system according to a preset formula: Among them, Z vir,p (s) is the positive damping.

4. The method according to claim 2, characterized in that: Based on the first voltage, the second voltage and the third voltage, a control signal of the bus voltage feedforward Buck converter is generated by processing through a second-order filter and a proportional-integral controller, including: Normalizing the first voltage based on the second voltage to obtain a first target value; Calculate the difference between the preset value and the first target value to obtain a second target value; Calculating a product of the third voltage and the second-order filter to obtain a third target value; Summing the second target value and the third target value to obtain a fourth target value; The fourth target value is input into the proportional-integral controller to obtain the first control signal.

5. The method according to claim 2, characterized in that: Before processing through the second-order filter and the proportional-integral controller, the method further includes: An instability frequency of the DC power distribution system is acquired, and the instability frequency is determined as the center frequency, where the instability frequency is the oscillation frequency of the DC power distribution system.

6. The method according to claim 2, characterized in that In the case where the transformer is an isolation transformer, n T The value is the voltage ratio between the output terminal and the input terminal of the isolation transformer; In the case where the transformer is a non-isolating transformer, n T The value is 1.

7. The method according to claim 1, characterized in that The voltage source converter is any one of an AC-DC converter, a DC-DC converter and a direct current power supply including an LC filter.

8. A DC power distribution system oscillation suppression device based on Buck converter, characterized in that: The DC power distribution system is composed of a plurality of voltage source converters, a plurality of power electronic converter loads and a bus voltage feedforward Buck converter connected in parallel, and the device comprises: A first acquisition unit is used to acquire the output voltage sampling value of the bus voltage feedforward Buck converter in real time to obtain the first voltage, and acquire the bus DC voltage sampling value to obtain the third voltage; a first calculation unit, configured to generate a control signal of the bus voltage feedforward Buck converter by processing the first voltage, the second voltage and the third voltage through a second-order filter and a proportional-integral controller to obtain a first control signal, wherein the second-order filter is configured to enable the bus voltage feedforward Buck converter to provide positive damping to the DC power distribution system to eliminate oscillations generated when the power electronic converter load is connected to or disconnected from the DC power distribution system, and the second voltage is an output voltage rated value of the bus voltage feedforward Buck converter; The second calculation unit is used to perform PWM modulation based on the first control signal to obtain a second control signal, and control the on and off of the bus voltage feedforward Buck converter based on the second control signal to suppress the oscillation of the DC power distribution system.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored program, wherein when the program is executed, the device where the computer-readable storage medium is located is controlled to execute the method according to any one of claims 1 to 7.

10. A DC power distribution system, characterized in that: include: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the one or more programs include methods for executing any one of claims 1 to 7.

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