A quasi-real-time grid voltage feedforward control method and system for grid-connected inverter

Abstract

The present invention discloses a quasi-real-time grid voltage feedforward control method and system for a grid-connected inverter. The method comprises: triggering a first interrupt signal at the moment when the carrier passes through zero; in response to the first interrupt signal, reading the voltage and current sampling values at the current moment, and obtaining a first three-phase modulation voltage through calculations using the power outer loop, the phase-locked loop, and the current inner loop; triggering a second interrupt signal after a set delay time after the carrier passes through zero; in response to the second interrupt signal, reading the grid voltage sampling value at the current moment, and obtaining a second three-phase modulation voltage through grid voltage feedforward calculation; calculating a final three-phase modulation voltage based on the first three-phase modulation voltage and the second three-phase modulation voltage; and performing sinusoidal pulse width modulation calculation using the final three-phase modulation voltage to obtain a modulation ratio for the next carrier cycle. The present invention can shorten the control delay of the grid voltage feedforward control link in the grid-connected inverter, increase the phase margin in the high-frequency band of the grid-connected inverter, and avoid high-frequency oscillation of the grid-connected inverter.

Description

Technical Field

[0001] The present invention belongs to the technical field of grid-connected inverter control, and relates to a quasi-real-time grid voltage feedforward control method and system for a grid-connected inverter. Background Art

[0002] In recent years, high-frequency oscillations have become a frequent problem in grid-connected inverters. Extensive research has focused on this issue, with the primary conclusion being that high-frequency oscillations in grid-connected inverters are primarily related to the voltage feedforward circuit. Current improvements primarily involve adding filters to the voltage feedforward circuit, but this approach fails to completely eliminate the oscillation problem and may even push the problem further into the mid-frequency range.

[0003] Therefore, there is currently no more thorough improvement method for the problem of high-frequency oscillation of grid-connected inverters. Summary of the Invention

[0004] The technical problem to be solved by the present invention is that, in response to the problem of high-frequency oscillation in the above-mentioned grid-connected inverter, a quasi-real-time grid voltage feedforward control method and system for the grid-connected inverter are provided, which can increase the phase margin of the high-frequency band of the grid-connected inverter and avoid high-frequency oscillation of the grid-connected inverter.

[0005] In order to solve the above problems, the technical solution adopted by the present invention is:

[0006] In one aspect, the present invention provides a quasi-real-time grid voltage feedforward control method for a grid-connected inverter, comprising:

[0007] Triggering a first interrupt signal when the carrier passes through 0;

[0008] In response to the first interrupt signal, the voltage and current sampling values at the current moment are read, and a first three-phase modulated voltage is obtained through calculations by a power outer loop, a phase-locked loop, and a current inner loop;

[0009] After the carrier passes through 0, a delay of a set time is set to trigger the second interrupt signal;

[0010] In response to the second interrupt signal, reading the current grid voltage sampling value, and obtaining a second three-phase modulated voltage through grid voltage feedforward calculation;

[0011] Calculating a final three-phase modulation voltage according to the first three-phase modulation voltage and the second three-phase modulation voltage;

[0012] The final three-phase modulation voltage is used to perform sinusoidal pulse width modulation calculation to obtain the modulation ratio of the next carrier cycle and output it to the pulse width modulation output module for execution.

[0013] Furthermore, the set time is calculated according to the following formula:

[0014] Δt = carrier period - (second three-phase modulation voltage calculation time + final three-phase modulation voltage calculation time + modulation ratio calculation time) - grid voltage sampling period

[0015] Where Δt is the delay setting time.

[0016] Furthermore, the final three-phase modulation voltage is calculated according to the following formula:

[0017] V p =V i +V g

[0018] Where V p is the final three-phase modulation voltage, V i is the first three-phase modulation voltage; V g is the second three-phase modulation voltage.

[0019] In another aspect, the present invention provides a quasi-real-time grid voltage feedforward control system for a grid-connected inverter, comprising:

[0020] A first timer is configured to trigger a first interrupt signal when the carrier passes through 0;

[0021] A first interrupt control module is configured to respond to the first interrupt signal, read the voltage and current sampling values at the current moment, and obtain a first three-phase modulated voltage through calculations of a power outer loop, a phase-locked loop, and a current inner loop;

[0022] A second timer is configured to trigger a second interrupt signal after a delay of a set time after the carrier passes through 0;

[0023] The second interrupt control module is configured to respond to the second interrupt signal, read the grid voltage sampling value at the current moment, and obtain the second three-phase modulation voltage through grid voltage feedforward calculation; calculate the final three-phase modulation voltage based on the first three-phase modulation voltage and the second three-phase modulation voltage; and use the final three-phase modulation voltage to perform sinusoidal pulse width modulation calculation to obtain the modulation ratio of the next carrier cycle, and output it to the pulse width modulation output module for execution.

[0024] Furthermore, the set time is calculated according to the following formula:

[0025] Δt = carrier period - calculation time of the second interrupt control module - grid voltage sampling period

[0026] Where Δt is the delay setting time.

[0027] Furthermore, the second interrupt control module calculates the final three-phase modulation voltage according to the following formula:

[0028] V p =V i+V g

[0029] Where V p is the final three-phase modulation voltage, V i is the first three-phase modulation voltage; V g is the second three-phase modulation voltage.

[0030] On the other hand, the present invention provides an electronic device comprising one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include instructions for executing any of the aforementioned methods.

[0031] On the other hand, the present invention provides a readable storage medium having one or more programs stored thereon, wherein the one or more programs include instructions that, when executed by a computing device, cause the computing device to perform any of the aforementioned methods.

[0032] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0033] The present invention separates the grid voltage feedforward control from the original control process and accurately delays the sampling time of the grid voltage, thereby shortening the control delay of the grid voltage feedforward control link in the grid-connected inverter, increasing the phase margin of the high-frequency band of the grid-connected inverter, and avoiding high-frequency oscillation of the grid-connected inverter. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Flow chart of the method of the present invention;

[0035] Figure 2 This is a system structure diagram of the present invention;

[0036] Figure 3 This is a flow chart of an example of the present invention. DETAILED DESCRIPTION

[0037] The present invention will be further described below in conjunction with specific examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0038] like Figure 1 As shown, a quasi-real-time grid voltage feedforward control method for a grid-connected inverter includes:

[0039] Step 1: triggering a first interrupt signal when the carrier passes through 0;

[0040] Step 2: In response to the first interrupt signal, read the voltage and current sampling values at the current moment, and obtain the first three-phase modulated voltage through calculations using the power outer loop, the phase-locked loop, and the current inner loop;

[0041] The voltage and current used in the calculation of the power outer loop, phase-locked loop, and current inner loop are the sampled values when the carrier passes through zero.

[0042] Step 3, triggering a second interrupt signal after a delay of a set time after the carrier passes through 0;

[0043] Step 4: In response to the second interrupt signal, read the current grid voltage sampling value, and obtain the second three-phase modulated voltage through grid voltage feedforward calculation;

[0044] Step 5, calculating a final three-phase modulation voltage according to the first three-phase modulation voltage and the second three-phase modulation voltage;

[0045] Specifically, the final three-phase modulation voltage is calculated according to the following formula:

[0046] V p =V i +V g

[0047] Where V p is the final three-phase modulation voltage, V i is the first three-phase modulation voltage; V g is the second three-phase modulation voltage.

[0048] Step 6: Use the final three-phase modulation voltage to perform sinusoidal pulse width modulation calculation to obtain the modulation ratio of the next carrier cycle and output it to the pulse width modulation (PWM) output module for execution.

[0049] In step 3, the delay setting time is calculated according to the following formula:

[0050] Δt = carrier period - (second three-phase modulation voltage calculation time + final three-phase modulation voltage calculation time + modulation ratio calculation time) - grid voltage sampling period

[0051] Where Δt is the delay setting time.

[0052] In step 4, the grid voltage used for performing grid voltage feedforward calculation is a sampling value at a time delay of Δt after the carrier passes through zero.

[0053] In step 1 and step 3, both the first interrupt signal and the second interrupt signal can be triggered by a timer.

[0054] like Figure 2 As shown, a quasi-real-time grid voltage feedforward control system for a grid-connected inverter includes:

[0055] A first timer is configured to trigger a first interrupt signal when the carrier passes through 0;

[0056] A first interrupt control module is configured to respond to the first interrupt signal, read the voltage and current sampling values at the current moment, and obtain a first three-phase modulated voltage through calculations of a power outer loop, a phase-locked loop, and a current inner loop;

[0057] A second timer is configured to trigger a second interrupt signal after a delay of a set time after the carrier passes through 0;

[0058] The second interrupt control module is configured to respond to the second interrupt signal, read the grid voltage sampling value at the current moment, and obtain the second three-phase modulation voltage through grid voltage feedforward calculation; calculate the final three-phase modulation voltage based on the first three-phase modulation voltage and the second three-phase modulation voltage; and use the final three-phase modulation voltage to perform sinusoidal pulse width modulation calculation to obtain the modulation ratio of the next carrier cycle, and output it to the pulse width modulation output module for execution.

[0059] The set delay time Δt of the second timer can be calculated according to the following formula:

[0060] Δt = carrier period - calculation time of the second interrupt control module - grid voltage sampling period.

[0061] The final three-phase modulation voltage is calculated according to the first three-phase modulation voltage and the second three-phase modulation voltage, specifically according to the following formula:

[0062] V p =V i +V g

[0063] Where V p is the final three-phase modulation voltage, V i is the first three-phase modulation voltage; V g is the second three-phase modulation voltage.

[0064] like Figure 3 FIG. 1 is a flow chart of a method for controlling active power of a new energy station taking into account losses within the station according to an embodiment of the present invention, comprising the following steps:

[0065] Setting a first timer so that the first timer triggers a first interrupt signal when the carrier passes through 0, and enters a first interrupt control module;

[0066] The first interrupt control module responds to the first interrupt signal, reads the voltage and current sampling values at the current moment, and obtains the three-phase modulation voltage V after calculation by the power outer loop, phase-locked loop, and current inner loop. i , and write to the register;

[0067] Setting a second timer so that the second timer triggers a second interrupt signal after a delay of Δt after the carrier passes through 0, and enters a second interrupt control module;

[0068] The second interrupt control module responds to the second interrupt signal, reads the grid voltage sampling value at the current moment, and obtains the three-phase modulation voltage V after grid voltage feedforward calculation. g ;

[0069] The second interrupt control module reads the three-phase modulation voltage V calculated by the first interrupt control module from the register i , and calculate the final three-phase modulation voltage V p =V i +V g ;

[0070] The second interrupt control module uses a three-phase modulation voltage V p Perform sinusoidal pulse width modulation calculations to obtain the modulation ratio of the next carrier cycle and output it to the pulse width modulation output module for execution.

[0071] The present invention separates the grid voltage feedforward control from the original control process and accurately delays the sampling time of the grid voltage, thereby shortening the control delay of the grid voltage feedforward control link in the grid-connected inverter, increasing the phase margin of the high-frequency band of the grid-connected inverter, and avoiding high-frequency oscillation of the grid-connected inverter.

[0072] The present invention also provides an electronic device comprising one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include instructions for executing any of the aforementioned methods.

[0073] The present invention also provides a readable storage medium having one or more programs stored thereon, wherein the one or more programs include instructions, which, when executed by a computing device, enable the computing device to perform any of the aforementioned methods.

[0074] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can 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 can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0075] 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 produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. 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.

[0076] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work 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 The function specified in one or more boxes.

[0077] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0078] The present invention has been disclosed above with preferred embodiments, which are not intended to limit the present invention. Any technical solutions obtained by adopting equivalent replacement or equivalent transformation solutions fall within the protection scope of the present invention.

Claims

1. A quasi-real-time grid voltage feedforward control method for a grid-connected inverter, characterized in that: include: Triggering a first interrupt signal when the carrier passes through 0; In response to the first interrupt signal, the voltage and current sampling values at the current moment are read, and a first three-phase modulated voltage is obtained through calculations by a power outer loop, a phase-locked loop, and a current inner loop; After the carrier passes through 0, a delay of a set time is set to trigger the second interrupt signal; In response to the second interrupt signal, reading the current grid voltage sampling value, and obtaining a second three-phase modulated voltage through grid voltage feedforward calculation; Calculating a final three-phase modulation voltage according to the first three-phase modulation voltage and the second three-phase modulation voltage; The final three-phase modulation voltage is used to perform sinusoidal pulse width modulation calculation to obtain the modulation ratio of the next carrier cycle and output it to the pulse width modulation output module for execution; The set time is calculated according to the following formula: Δt = carrier period - (second three-phase modulation voltage calculation time + final three-phase modulation voltage calculation time + modulation ratio calculation time) - grid voltage sampling period Where, Δt is the delay setting time; The final three-phase modulation voltage is calculated according to the following formula: V p =V i +V g Where V p is the final three-phase modulation voltage, V i is the first three-phase modulation voltage; V g is the second three-phase modulation voltage.

2. A quasi-real-time grid voltage feedforward control system for a grid-connected inverter, characterized in that: include: A first timer is configured to trigger a first interrupt signal when the carrier passes through 0; A first interrupt control module is configured to respond to the first interrupt signal, read the voltage and current sampling values at the current moment, and obtain a first three-phase modulated voltage through calculations of a power outer loop, a phase-locked loop, and a current inner loop; A second timer is configured to trigger a second interrupt signal after a delay of a set time after the carrier passes through 0; a second interrupt control module configured to, in response to the second interrupt signal, read the current grid voltage sampling value, obtain a second three-phase modulated voltage through grid voltage feedforward calculation; calculate a final three-phase modulated voltage based on the first three-phase modulated voltage and the second three-phase modulated voltage; and perform sinusoidal pulse width modulation calculation using the final three-phase modulated voltage to obtain a modulation ratio for the next carrier cycle, and output the modulation ratio to the pulse width modulation output module for execution; The set time is calculated according to the following formula: Δt = carrier period - calculation time of the second interrupt control module - grid voltage sampling period Where, Δt is the delay setting time; The final three-phase modulation voltage is calculated according to the following formula: V p =V i +V g Where V p is the final three-phase modulation voltage, V i is the first three-phase modulation voltage; V g is the second three-phase modulation voltage.

3. An electronic device, characterized in that: The method comprises one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include instructions for executing the method according to claim 1.

4. A readable storage medium, characterized in that: One or more programs are stored thereon, the one or more programs comprising instructions which, when executed by a computing device, cause the computing device to perform the method according to claim 1 .

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