Current loop control method and device and air conditioner

Abstract

The invention discloses a current loop control method and device and an air conditioner, and the current loop control method comprises the steps: obtaining the output voltage of a current loop, and calculating a corresponding voltage vector sum according to the output voltage; determining the output state of the current loop according to the preset reference voltage and the voltage vector sum; and when the output state comprises an overshoot state, performing feedback processing on the output voltage according to the reference voltage and the voltage vector sum to obtain a corresponding adjusting current, and outputting the adjusting current to the input end of the current loop so as to control the current loop to limit the output voltage. According to the invention, the problem of imbalance of the current loop in an overshoot state at present can be effectively relieved.

Description

Technical Field

[0001] This application relates to the field of electronic technologies, and particularly to a current loop control method, apparatus, and air conditioner. Background Art

[0002] The SVPWM (Space Vector Pulse Width Modulation) algorithm is an advanced motor control technology. By decomposing three-phase AC voltage into equivalent DC voltage vectors, the motor phase voltage is synthesized, thereby improving efficiency and performance. The core idea of SVPWM is to synthesize the desired output voltage vector by reasonably allocating time using a limited number of basic voltage vectors (usually six effective vectors and two zero vectors).

[0003] In the SVPWM algorithm of a motor, when the sum of voltage vectors exceeds the allowable range and is limited, the PI (Proportional-Integral) control in the current loop still adjusts in the overmodulation region, thus losing the adjustment function.

[0004] Therefore, the current technology still needs to be improved. Summary of the Invention

[0005] This application provides a current loop control method, apparatus, and air conditioner, which can effectively alleviate the out-of-regulation problem of the current loop in the overshoot state.

[0006] This application provides a current loop control method, including:

[0007] Obtain the output voltage of the current loop, and calculate the corresponding sum of voltage vectors according to the output voltage;

[0008] Determine the output state of the current loop according to a preset reference voltage and the sum of voltage vectors;

[0009] When the output state includes an overshoot state, perform feedback processing on the output voltage according to the reference voltage and the sum of voltage vectors to obtain a corresponding adjustment current, and output it to the input end of the current loop to control the current loop to limit the output voltage.

[0010] In the current loop control method in some embodiments, determining the output state of the current loop according to a preset reference voltage and the sum of voltage vectors includes:

[0011] Calculate the deviation value between the preset reference voltage and the sum of voltage vectors;

[0012] When the deviation value is greater than a preset reference value, determine that the output state includes an overshoot state;

[0013] Performing feedback processing on the output voltage according to the reference voltage and the sum of voltage vectors further includes:

[0014] Perform feedback processing on the output voltage according to the deviation value.

[0015] In the current loop control method in some embodiments, the output voltage includes the direct-axis voltage. The steps of performing feedback processing on the output voltage according to the reference voltage and the voltage vector sum to obtain the corresponding regulated current and outputting it to the input end of the current loop include:

[0016] Perform feedback processing on the direct-axis voltage according to the reference voltage and the voltage vector sum, and output the corresponding direct-axis regulated current to the current loop.

[0017] In the current loop control method in some embodiments, the output voltage includes the direct-axis voltage and the quadrature-axis voltage. The steps of performing feedback processing on the output voltage according to the reference voltage and the voltage vector sum and outputting the corresponding regulated current to the input end of the current loop include:

[0018] Perform feedback processing on the direct-axis voltage and the quadrature-axis voltage respectively according to the reference voltage and the voltage vector sum, and output the corresponding direct-axis regulated current and quadrature-axis regulated current to the current loop.

[0019] In the current loop control method in some embodiments, the output voltage includes the quadrature-axis voltage. The steps of performing feedback processing on the output voltage according to the reference voltage and the voltage vector sum and outputting the corresponding regulated current to the input end of the current loop include:

[0020] Perform feedback processing on the quadrature-axis voltage respectively according to the reference voltage and the voltage vector sum, and output the corresponding quadrature-axis regulated current to the current loop.

[0021] In the current loop control method in some embodiments, the current loop control method further includes:

[0022] When the output state includes the non-overshoot state, stop outputting the regulated current to the input end of the current loop to maintain the output voltage of the current loop.

[0023] An embodiment of the present application also provides a current loop control device, including:

[0024] An acquisition module for acquiring the output voltage of the current loop;

[0025] A calculation module, the calculation module is connected to the acquisition module. The calculation module is used to calculate the corresponding voltage vector sum according to the output voltage, and determine the output state of the current loop according to the preset reference voltage and the voltage vector sum;

[0026] A feedback module, the feedback module is connected to the calculation module. The feedback module is used to perform feedback processing on the output voltage according to the reference voltage and the voltage vector sum when the output state includes the overshoot state, and output the corresponding regulated current to the input end of the current loop to control the current loop to limit the output voltage.

[0027] In some embodiments of the current loop control device, the current loop includes a first current integration module. The first input end of the feedback module is connected to the output end of the calculation module, the second input end of the feedback module is connected to the output end of the first current integration module, and the output end of the feedback module is connected to the input end of the first current integration module.

[0028] In some embodiments of the current loop control device, the current loop includes a second current integration module and an algorithm module connected in series in sequence. The first input end of the feedback module is connected to the output end of the calculation module, the second input end of the feedback module is connected to the output end of the algorithm module, and the output end of the feedback module is connected to the input end of the first current integration module.

[0029] An embodiment of the present application further provides an air conditioner, which includes a current loop and the above-mentioned current loop control device.

[0030] A current loop control method, device and air conditioner provided by the present application. In the current loop control method, after determining that the current loop is in an overshoot state through the output voltage of the current loop, an adjustment current is provided for the current loop according to the output voltage, so that the current loop limits the output voltage according to the adjustment current, thereby alleviating the problem of imbalance of the current loop in the overshoot state and improving the reliability of the current loop. Description of the Drawings

[0031] Combined with the following drawings, through the detailed description of the specific embodiments of the present application, the technical solutions and other beneficial effects of the present application will be obvious.

[0032] Figure 1 It is the first structural block diagram of the current loop provided by the embodiment of the present application.

[0033] Figure 2 It is the second structural block diagram of the current loop provided by the embodiment of the present application.

[0034] Figure 3 It is the first flow schematic diagram of the current loop control method provided by the embodiment of the present application.

[0035] Figure 4 It is the flow schematic diagram of step 200 in the current loop control method provided by the embodiment of the present application.

[0036] Figure 5 It is the second flow schematic diagram of the current loop control method provided by the embodiment of the present application.

[0037] Figure 6 It is the first logic schematic diagram in the current loop control method provided by the embodiment of the present application.

[0038] Figure 7The simulation waveform diagram without compensation parameters set in the current loop provided by the embodiment of the present application.

[0039] Figure 8 The simulation waveform diagram with compensation parameters set in the current loop provided by the embodiment of the present application.

[0040] Figure 9 The second logic schematic diagram in the current loop control method provided by the embodiment of the present application.

[0041] Figure 10 The third logic schematic diagram in the current loop control method provided by the embodiment of the present application.

[0042] Figure 11 The first structural block diagram of the current loop control device provided by the embodiment of the present application.

[0043] Figure 12 The second structural block diagram of the current loop control device provided by the embodiment of the present application. Detailed implementation manners

[0044] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative efforts belong to the scope of protection of the present application.

[0045] In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, "a plurality" means two or more unless otherwise specifically defined.

[0046] Please refer to Figure 1 , the embodiment of the present application provides a current loop control process. First, reference currents such as idref and iqref and actual currents such as id and iq are obtained. After performing PI operations based on the reference currents and actual currents, the adjusted output voltages such as ud and uq are output. Then, after sequentially performing PARK inverse transformation (REPARK transformation) and space vector pulse width modulation (i.e., SVPWM processing) on the adjusted output voltages, the current loop control signal PWM is obtained.

[0047] Among them, the PARK Transform, also known as the αβγ Transform, is a mathematical transform that converts signals in a three-phase coordinate system into signals in a rotating coordinate system; it is a common transform technology used in the fields of power systems and motor control. The purpose of the PARK Transform is to represent three-phase signals as two orthogonal rotating magnetic field components (usually referred to as the dq axes); this can simplify motor control algorithms and achieve vector control of motors; the specific conversion formulas are as follows: d = cos(θ) * α + sin(θ) * β, q = -sin(θ) * α + cos(θ) * β. Where α and β are the components of the three-phase signals, d and q are the components in the rotating coordinate system, and θ is the angle of the conversion signal (usually the rotor position of the motor or the difference between the grid frequency and the clock frequency).

[0048] The PARK Transform converts three-phase signals from a fixed coordinate system (usually the ABC coordinate system) to a rotating coordinate system (the dq coordinate system); in the dq coordinate system, the components of the rotating magnetic field are usually associated with the magnetic field and rotor position of the motor; in this way, it is easier to control and analyze the motor. It should be noted that the PARK Transform is a non-linear transform that involves trigonometric function calculations; in practical applications, the CLARK Transform is usually used to convert three-phase signals into αβ signals, and then the PARK Transform is performed. At the same time, there is an inverse transform (Inverse Park Transform) that can be used to convert dq signals back into ABC signals; the PARK Transform has important applications in aspects such as motor control, reactive power compensation, and power system stability, and can conveniently process, control, and protect signals.

[0049] Please refer to Figure 2 , the embodiment of the present application also provides a current loop control process. In order to improve the control accuracy of the current loop, new algorithms, such as decoupling and feed-forward control algorithms, need to be added after the PI control of the current loop. The uncertainty of the newly added voltage value in the newly added algorithms increases the sum of voltage vectors, resulting in the sum of voltage vectors exceeding the allowable range. The sum of voltage vectors is calculated from ud1 and uq1. For the SVPWM algorithm control, the sum of voltage vectors must be within the hexagon and not exceed the set value. Therefore, in this embodiment, the regulated output voltages ud and uq after being processed by the new algorithm are limited to ensure that the sum of voltage vectors does not exceed the set value. However, only through the limiting process, when there is a difference in the input of the PI controller, the PI control process will still continue to adjust in the overshoot direction and is in an uncontrollable state.

[0050] Please refer to Figure 3 , the embodiment of the present application also provides a current loop control method, and this current loop control method includes:

[0051] 100. Obtain the output voltage of the current loop and calculate the corresponding voltage vector sum according to the output voltage;

[0052] 200. Determine the output state of the current loop according to the preset reference voltage and the voltage vector sum;

[0053] 300. When the output state includes an overshoot state, perform feedback processing on the output voltage according to the reference voltage and the voltage vector sum to obtain the corresponding adjustment current, and output it to the input end of the current loop to control the current loop to limit the output voltage.

[0054] In this application, by obtaining the output voltage in the current loop, calculating and obtaining the voltage vector sum based on the output voltage, then comparing the voltage vector sum with the reference voltage, and determining the output state of the current loop according to the comparison result, that is, whether the current loop is in an overshoot state. If the current loop is in an overshoot state, then perform feedback processing on the output voltage according to the reference voltage and the voltage vector sum and output the corresponding adjustment current, and use this adjustment current as the input signal of the current loop, so that the current loop limits the output voltage according to this adjustment current, thereby alleviating the out-of-balance problem of the current loop in the overshoot state.

[0055] Please refer to Figure 4 , in some embodiments, step 200 includes:

[0056] 210. Calculate the deviation value between the preset reference voltage and the voltage vector sum;

[0057] 220. When the deviation value is greater than the preset reference value, determine that the output state includes an overshoot state.

[0058] In the process of determining the output state of the current loop, subtract the voltage vector sum from the reference voltage to obtain the deviation value, and judge whether the deviation value is less than zero, that is, the reference value. If the deviation value is less than zero, it indicates that the voltage vector sum is greater than the preset reference voltage, then determine the output state of the current loop as the overshoot state, so as to facilitate subsequent feedback processing.

[0059] After determining that the output state of the current loop is the overshoot state, step 300 further includes: performing feedback processing on the output voltage according to the deviation value. That is, perform calculation processing on the deviation value obtained by subtracting the voltage vector sum from the reference voltage to obtain the corresponding adjustment current.

[0060] Please refer to Figure 5, in some embodiments, the current loop control method further includes: 400. When the output state includes an overshoot-free state, stop outputting the regulated current to the input end of the current loop to maintain the output voltage of the current loop. During the process of determining the output state of the current loop, subtract the voltage vector sum from the reference voltage to obtain a deviation value, and determine whether the deviation value is less than zero, that is, the reference value. If the deviation value is greater than or equal to zero, it indicates that the voltage vector sum is less than or equal to the preset reference voltage, and then determine that the output state of the current loop is the overshoot-free state, and stop outputting the regulated current to the current loop to maintain the output voltage of the current loop.

[0061] Please refer to Figure 6 , as an embodiment, the output voltage includes a direct-axis voltage and a quadrature-axis voltage. The direct-axis voltage can be the voltage directly output after integral proportional adjustment operations in the current loop, such as ud and uq, or can be the voltage calculated based on a newly added algorithm after integral proportional adjustment, such as ud1 and uq1. In this application, taking ud1 and uq1 as the output voltage as an example to illustrate the current loop control method. Step 300 then includes: performing feedback processing on the direct-axis voltage and the quadrature-axis voltage respectively according to the reference voltage and the voltage vector sum, and outputting the corresponding direct-axis regulated current and quadrature-axis regulated current to the current loop. In this embodiment, feedback processing is performed on the direct-axis voltage and the quadrature-axis voltage based on the deviation value. For example, proportional adjustment is performed on the direct-axis voltage and the quadrature-axis voltage according to the deviation value. On the one hand, the magnitude of the DC regulated current is determined, and on the other hand, the direction of adjustment in the current loop is determined, that is, whether to provide positive adjustment parameters or negative adjustment parameters for the current loop, so as to avoid the current loop from losing balance in the overshoot state, thereby playing the role of anti-saturation of the current loop.

[0062] Specifically, denote the deviation value as uerr, the adjustment ratio as P, the direct-axis regulated current as idc, and the quadrature-axis regulated current as iqc. After proportional adjustment, the direct-axis regulated current and the quadrature-axis regulated current are respectively: idc = P * uerr * ud1, iqc = P * uerr * uq1. Among them, the P value can be debugged according to actual needs and the debugged P value is stored in advance.

[0063] Please refer to Figure 7 and Figure 8 , Figure 7 is the simulation waveform diagram of the current loop without regulated current provided by the embodiment of the present application; Figure 8 is the simulation waveform diagram of the current loop with regulated current provided by the embodiment of the present application. By comparison, it can be seen that in the current loop with regulated current, the voltage vector sum does not exceed 1, and the actual speed fluctuation becomes significantly smaller. Relatively speaking, the current loop control device 10 can improve the reliability of the current loop by providing regulated current for the current loop.

[0064] Please refer to Figure 9 and Figure 10, as another embodiment, the direct-axis regulating current or the quadrature-axis regulating current can be output separately. When the direct-axis regulating current is output separately, step 300 includes: performing feedback processing on the direct-axis voltage according to the reference voltage and the voltage vector sum, and outputting the corresponding direct-axis regulating current to the current loop. At this time, only proportional regulation is performed on the direct-axis voltage output by the current loop to output the direct-axis regulating current, corresponding to idc = P * uerr * ud1. When the quadrature-axis regulating current is output separately, step 300 includes: performing feedback processing on the quadrature-axis voltage according to the reference voltage and the voltage vector sum respectively, and outputting the corresponding quadrature-axis regulating current to the current loop. At this time, only proportional regulation is performed on the quadrature-axis voltage output by the current loop to output the quadrature-axis regulating current, corresponding to iqc = P * uerr * uq1. Thus, while improving the reliability of the current loop, the feedback processing process in the current loop control method can be simplified.

[0065] Please refer to Figure 11 , an embodiment of the present application further provides a current loop control device 10. The current loop control device 10 includes an acquisition module 11, a calculation module 12, and a feedback module 13 that are connected in sequence. Among them, the acquisition module 11 is used to obtain the output voltage of the current loop; the calculation module 12 is used to calculate the corresponding voltage vector sum according to the output voltage, and determine the output state of the current loop according to the preset reference voltage and the voltage vector sum; the feedback module 13 is used to perform feedback processing on the output voltage according to the reference voltage and the voltage vector sum when the output state includes an overshoot state, and output the corresponding regulating current to the input end of the current loop to control the current loop to limit the output voltage.

[0066] The current loop control device 10 in this embodiment obtains the output voltage of the current loop through the acquisition module 11, and then calculates the voltage vector sum according to the output voltage through the calculation module 12, compares the voltage vector sum with the reference voltage, and determines the output state of the current loop according to the comparison result, that is, whether the current loop is in an overshoot state. If the current loop is in an overshoot state, the feedback module 13 performs feedback processing on the output voltage according to the reference voltage and the voltage vector sum and then outputs the corresponding regulating current, and uses this regulating current as the input signal of the current loop to ensure the input error value of the current loop, so that the current loop limits the output voltage according to this regulating current, thereby alleviating the out-of-balance problem of the current loop in the overshoot state.

[0067] In some embodiments, the current loop includes a first current integration module 21. The first input terminal of the feedback module 13 is connected to the output terminal of the calculation module 12. The second input terminal of the feedback module 13 is connected to the output terminal of the first current integration module 21. The output terminal of the feedback module 13 is connected to the input terminal of the first current integration module 21. In this embodiment, the feedback module 13 is connected to the output terminal of the first current integration module 21. The feedback module 13 can directly obtain the output voltage of the first current integration module 21, such as the direct-axis voltage ud and / or the quadrature-axis voltage uq, and calculate the voltage vector sum according to ud and / or uq to implement the feedback processing process.

[0068] Please refer to Figure 12 , in some other embodiments, the current loop includes a second current integration module 22 and an algorithm module 23 connected in series in sequence. The first input terminal of the feedback module 13 is connected to the output terminal of the calculation module 12. The second input terminal of the feedback module 13 is connected to the output terminal of the algorithm module 23. The output terminal of the feedback module 13 is connected to the input terminal of the first current integration module 21. That is, in this embodiment, the current loop is provided with an algorithm module 23 to perform algorithm processing on the voltage output by the second current integration module 22 and output ud1 and uq1. The feedback module 13 is connected to the output terminal of the algorithm module 23, and the feedback module 13 obtains the output voltage after being processed by the algorithm module 23, that is, ud1 and / or uq1, to calculate the voltage vector sum. This is equivalent to considering the factors that cause changes in the output voltage during the processing of the algorithm module 23, which is beneficial to improving the control accuracy of the current loop.

[0069] The embodiment of the present application also provides an air conditioner, which includes the above-mentioned current loop control device. Since the above-mentioned current loop control device has been described in detail, it will not be repeated here.

[0070] In the above embodiments, the descriptions of each embodiment have their own focuses. For the parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0071] The above has introduced the current loop control method provided by the embodiments of the present application in detail. In this article, specific examples are used to elaborate on the principle and implementation manner of the present application. The descriptions of the above embodiments are only used to help understand the technical solution and its core idea of the present application; those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A current loop control method, characterized in that: include: Obtaining the output voltage of the current loop, and calculating the corresponding voltage vector sum according to the output voltage; Determining the output state of the current loop according to a preset reference voltage and the voltage vector sum; When the output state includes an overshoot state, the output voltage is fed back according to the reference voltage and the voltage vector to obtain a corresponding regulating current, which is output to the input end of the current loop to control the current loop to limit the output voltage.

2. The current loop control method according to claim 1, characterized in that: Determining the output state of the current loop according to the preset reference voltage and the voltage vector includes: Calculating a deviation value between a preset reference voltage and the voltage vector sum; When the deviation value is greater than a preset reference value, determining that the output state includes an overshoot state; The performing feedback processing on the output voltage according to the reference voltage and the voltage vector also includes: Feedback processing is performed on the output voltage according to the deviation value.

3. The current loop control method according to claim 1, characterized in that: The output voltage includes a direct-axis voltage, and the step of performing feedback processing on the output voltage according to the reference voltage and the voltage vector to obtain a corresponding regulation current and outputting the corresponding regulation current to the input end of the current loop includes: Feedback processing is performed on the direct-axis voltage according to the reference voltage and the voltage vector, and a corresponding direct-axis regulating current is output to the current loop.

4. The current loop control method according to claim 1, characterized in that: The output voltage includes a direct-axis voltage and a quadrature-axis voltage, and the step of performing feedback processing on the output voltage according to the reference voltage and the voltage vector and outputting a corresponding regulating current to the input end of the current loop includes: Feedback processing is performed on the direct-axis voltage and the quadrature-axis voltage respectively according to the reference voltage and the voltage vector, and the corresponding direct-axis regulating current and quadrature-axis regulating current are output to the current loop.

5. The current loop control method according to claim 1, characterized in that: The output voltage includes a quadrature-axis voltage, and the step of performing feedback processing on the output voltage according to the reference voltage and the voltage vector and outputting a corresponding regulating current to the input end of the current loop includes: Feedback processing is performed on the quadrature-axis voltage according to the reference voltage and the voltage vector sum, and a corresponding quadrature-axis regulating current is output to the current loop.

6. The current loop control method according to claim 1, characterized in that: The current loop control method further includes: When the output state includes a non-overshoot state, outputting the regulated current to the input end of the current loop is stopped to maintain the output voltage of the current loop.

7. A current loop control device, characterized in that: include: An acquisition module, used for acquiring the output voltage of the current loop; A calculation module, the calculation module is connected to the acquisition module, the calculation module is used to calculate the corresponding voltage vector sum according to the output voltage, and determine the output state of the current loop according to a preset reference voltage and the voltage vector sum; A feedback module is connected to the calculation module, and is used for performing feedback processing on the output voltage according to the reference voltage and the voltage vector when the output state includes an overshoot state, and outputting a corresponding regulating current to the input end of the current loop to control the current loop to limit the output voltage.

8. The current loop control device according to claim 7, characterized in that: The current loop includes a first current integration module, a first input end of the feedback module is connected to the output end of the calculation module, a second input end of the feedback module is connected to the output end of the first current integration module, and the output end of the feedback module is connected to the input end of the first current integration module.

9. The current loop control device according to claim 7, characterized in that: The current loop includes a second current integration module and an algorithm module connected in series in sequence, the first input end of the feedback module is connected to the output end of the calculation module, the second input end of the feedback module is connected to the output end of the algorithm module, and the output end of the feedback module is connected to the input end of the first current integration module.

10. An air conditioner, characterized in that: The air conditioner comprises a current loop and a current loop control device as described in any one of claims 7 to 9.

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