Air conditioner compressor and PFC control method and system thereof

Abstract

The invention provides an air conditioner compressor and a PFC control method and system thereof, and belongs to the technical field of air conditioner compressors, and the method comprises the steps: collecting an input voltage, a bus voltage and an inductive current of a PFC circuit of the air conditioner compressor; calculating an instantaneous slope of the input voltage according to the sampling value of the input voltage, and obtaining a corresponding voltage phase angle through a table look-up mode according to the instantaneous slope; based on the voltage phase angle, converting the acquired inductive current signal in an alternating current form into a direct current signal; performing double closed-loop control on the bus voltage and the direct current signal, and outputting a direct current error signal; converting the direct current error signal into a voltage control signal in an alternating current form; and acting the voltage control signal on a switching tube of the PFC circuit so as to adjust the inductive current and the bus voltage. According to the invention, the problem of poor response of PFC AC signal control by a PI controller is solved.

Description

Technical Field

[0001] This invention belongs to the field of air conditioning compressor technology, and more specifically, relates to an air conditioning compressor and its PFC control method and system. Background Technology

[0002] Power factor correction (PFC) technology is crucial in modern air conditioning compressor drive systems. Its main functions are twofold: first, to improve the power factor on the AC input side; and second, to increase the bus voltage to ensure efficient and stable compressor operation. Currently, PFC control strategies are mainly divided into peak current control and average current control. Peak control has a fast dynamic response but is sensitive to noise; average current control provides a smoother output but has a relatively slower response. Given the requirements for dynamic performance, peak current control is widely used in air conditioners.

[0003] In traditional peak current control, the current loop is fed into an AC sinusoidal signal. However, conventional PI controllers inherently lack the ability to track AC signals, leading to waveform distortion and steady-state errors. To overcome this problem, a common approach in existing technologies is to simplify the circuit by eliminating input voltage sampling, thus reducing the need for a high-precision ADC. The core idea is to directly use the sampled value of the input voltage Ui or its proportional signal, multiplying it by the output signal of the voltage loop PI controller to reconstruct the AC feed signal for the current loop, thereby introducing the input voltage information into the control loop.

[0004] However, this method has a significant drawback: its control architecture is essentially still using a PI controller to control an AC quantity. The input voltage itself contains harmonic noise and fluctuations, and directly using it as a multiplication factor will introduce these disturbances into the current loop, affecting the system's anti-interference capability and stability. Especially when the input voltage changes abruptly, it can easily lead to distortion of the input current waveform, making it difficult to always maintain an ideal sine wave and limiting further improvement in the power factor. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an air conditioning compressor and its PFC control method and system.

[0006] The present invention adopts the following technical solution.

[0007] A first aspect of the present invention provides a PFC control method for an air conditioning compressor, comprising:

[0008] Collect the input voltage, bus voltage, and inductor current of the PFC circuit of the air conditioner compressor;

[0009] The instantaneous slope is calculated based on the sampled value of the input voltage, and the corresponding voltage phase angle is obtained by looking up a table based on the instantaneous slope.

[0010] Based on the voltage phase angle, the acquired AC inductor current signal is converted into a DC current signal;

[0011] The bus voltage and the DC current signal are subjected to dual closed-loop control, and a DC error signal is output.

[0012] The DC error signal is converted into an AC voltage control signal;

[0013] The voltage control signal is applied to the switching transistor of the PFC circuit to adjust the inductor current and the bus voltage.

[0014] Optionally, obtaining the corresponding voltage phase angle based on the instantaneous slope using a table lookup method includes:

[0015] The correspondence between the instantaneous slope value and the voltage phase angle value of different input voltages is pre-stored in a mapping table;

[0016] After calculating the current instantaneous slope value, query the mapping table:

[0017] If the mapping table contains a slope value that is equal to the current instantaneous slope value, then its corresponding angle value is directly obtained;

[0018] If there is no slope value in the mapping table that is equal to the current instantaneous slope value, the corresponding voltage phase angle is calculated by interpolation.

[0019] Optionally, the step of calculating the corresponding voltage phase angle through interpolation includes:

[0020] Select the slope value that is closest to the current instantaneous slope value from the mapping table as the center point;

[0021] Obtain the two discrete slope value points that are adjacent to the center point in the mapping table;

[0022] Based on the current instantaneous slope value and the slope and angle values ​​of the center point and its three adjacent points, the corresponding voltage phase angle is calculated by interpolation.

[0023] Optionally, dual closed-loop control of the bus voltage and the DC current signal includes:

[0024] The output current setting value is adjusted by proportional-integral method based on the error between the sampled value and the set value of the bus voltage through the voltage outer loop.

[0025] The DC error signal is output through proportional-integral adjustment based on the error between the current setpoint and the DC current signal via the inner current loop.

[0026] In a second aspect, the present invention provides an air conditioner compressor PFC control system for operating an air conditioner compressor PFC control method as described in the first aspect of the present invention, comprising:

[0027] Signal acquisition module, angle calculation module, signal conversion module, dual closed-loop control module, and execution module;

[0028] The signal acquisition module is used to acquire the input voltage, bus voltage, and inductor current of the PFC circuit of the air conditioner compressor;

[0029] The angle calculation module is used to calculate the instantaneous slope of the input voltage based on the sampled value, and to obtain the corresponding voltage phase angle by looking up a table based on the instantaneous slope.

[0030] The signal conversion module is used to convert the acquired AC inductor current signal into a DC current signal based on the voltage phase angle.

[0031] The dual closed-loop control module is used to perform dual closed-loop control on the bus voltage and the DC current signal, and outputs a DC error signal.

[0032] The execution module is used to convert the DC error signal into an AC voltage control signal and apply the voltage control signal to the switching transistor of the PFC circuit to adjust the inductor current and the bus voltage.

[0033] Optionally, the dual closed-loop control module includes:

[0034] The voltage outer loop controller is used to adjust the output current setpoint based on the error between the sampled value of the bus voltage and a setpoint via proportional-integral adjustment.

[0035] The current inner loop controller is used to output the DC error signal based on the error between the current setpoint and the DC current signal via proportional-integral adjustment.

[0036] Optionally, the execution module includes a direct-to-interval conversion unit and a drive circuit, wherein:

[0037] The DC-AC conversion unit is used to convert the DC error signal into an AC voltage control signal based on the voltage phase angle.

[0038] The driving circuit is used to generate a driving signal to drive the switching transistor of the PFC circuit to turn on and off according to the voltage control signal.

[0039] In a third aspect, the present invention provides an air conditioning compressor, including an air conditioning compressor PFC control system as described in the second aspect of the present invention.

[0040] In a fourth aspect, the present invention provides an electronic device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program, when loaded onto the processor, implements an air conditioning compressor PFC control method according to a second aspect of the present invention.

[0041] In a fifth aspect, the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements a PFC control method for an air conditioning compressor according to a second aspect of the present invention.

[0042] Compared with the prior art, the beneficial effects of the present invention include at least the following:

[0043] (1) This invention converts AC signals into DC signals for PI control, fundamentally solving the problems of poor response to AC signals and weak anti-interference ability of traditional PI controllers. Even when the voltage changes suddenly, it can ensure the sinusoidal nature of the input current and significantly improve the power factor.

[0044] (2) The present invention uses software algorithm to calculate voltage phase angle, without the need for additional hardware zero-crossing detection circuit, which reduces hardware cost and complexity, while avoiding zero-crossing detection error, making the system more reliable.

[0045] (3) The dual-loop control structure (voltage outer loop + current inner loop) of this invention has clear responsibilities, which makes the bus voltage stable, the current tracking fast, and the system dynamic performance and steady-state accuracy high.

[0046] (4) The method described in this invention has moderate requirements for processor computing power, high degree of system modularity, and is easy to develop, debug and maintain, and has good engineering application value. Attached Figure Description

[0047] Figure 1 This is a PFC control block diagram provided according to an embodiment of the present invention;

[0048] Figure 2 This is a PFC circuit diagram provided according to an embodiment of the present invention;

[0049] Figure 3 This is a flowchart of a method provided according to an embodiment of the present invention. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this invention.

[0051] In Embodiment 1, the present invention provides a PFC control method for an air conditioning compressor, such as... Figure 3 As shown, it includes the following steps:

[0052] Step 1, adjust the input voltage u of the PFC circuit of the air conditioner compressor. t Bus voltage u, inductor current i j Perform sampling.

[0053] By sampling key electrical parameters in real time, an accurate data foundation is provided for subsequent control, ensuring the real-time performance and accuracy of the system response.

[0054] Step 2: Calculate the instantaneous slope of the input voltage and obtain the voltage angle corresponding to the slope by looking up a table.

[0055] Calculate the instantaneous slope of the input voltage:

[0056]

[0057] Among them, u t Let u be the input voltage sample value at time t. t-1 Let T be the sampled value of the input voltage at time t-1. s For u t and u t-1 The sampling interval time;

[0058] If the mapping table contains a slope value that is equal to the current instantaneous slope value, then its corresponding angle value is directly obtained;

[0059] If there is no slope value in the mapping that is equal to the current instantaneous slope value, the corresponding voltage phase angle is calculated by interpolation.

[0060] More preferably, the step of calculating the corresponding voltage phase angle through interpolation includes:

[0061] Select the slope value that is closest to the current instantaneous slope value from the mapping table as the center point;

[0062] Obtain the two discrete slope value points that are adjacent to the center point in the mapping table;

[0063] Based on the current instantaneous slope value and the slope and angle values ​​of the center point and its three adjacent points, the corresponding voltage phase angle is calculated by interpolation.

[0064] Specifically, when the slope is not found in the slope-angle mapping table, since its slope is non-linear, the lookup table method is optimized using quadratic interpolation:

[0065] For slope X ITake three adjacent discrete points (X0, Y0), (X1, Y1), and (X2, Y2), X0 <X1<X2;

[0066] Then the slope X I The corresponding angle value is:

[0067]

[0068] Obtain the voltage phase angle θ = Y in polar coordinates I .

[0069] Preferably, the lookup table method includes writing the correspondence between the instantaneous slope value and the voltage phase angle value of different input voltages into a mapping table in advance.

[0070] By using software algorithms to replace hardware zero-crossing detection circuits, system costs and complexity are reduced, hardware costs are saved, and anti-interference capabilities and accuracy are improved.

[0071] Step 3: Based on the voltage phase angle, convert the acquired AC inductor current signal into a DC current signal.

[0072] Preferably, step 3 includes:

[0073] Converting alternating current signals to direct current signals:

[0074]

[0075] By transforming the AC control problem into a DC control problem, and giving full play to the advantages of the PI controller in terms of good DC signal response and strong anti-interference, the waveform distortion and steady-state error problems in AC signal control are fundamentally solved.

[0076] Step 4: Perform dual closed-loop control on the bus voltage and the DC current signal, and output a DC error signal, including:

[0077] Voltage loop control: Based on the error between the bus voltage setpoint and the sampled value, the output current setpoint is adjusted proportionally and integrally.

[0078] Current loop control: Based on the error between the current setpoint and the DC current signal, a DC error signal is output through proportional-integral adjustment.

[0079] Preferably, step 4 includes:

[0080] Voltage loop:

[0081] Set bus voltage Error with sampling bus voltage u → PI controller → output set current i * ;

[0082] Current loop:

[0083] Set current i * With DC current i z Error → PI controller → Output DC error signal u oz .

[0084] This structure decouples voltage stabilization and current tracking, resulting in a fast dynamic response and high steady-state accuracy.

[0085] Step 5: Apply the voltage control signal to the switching transistor of the PFC circuit to adjust the inductor current and the bus voltage.

[0086] The DC error signal u output by the current loop oz The signal is converted into an AC voltage control signal u by a DC-AC converter module. oj ,include:

[0087] u oj =u oz sinθ=u oz Y I

[0088] AC voltage control signal u oj and input voltage u t Together they act on the PFC inductor model Control the inductor current and bus voltage.

[0089] In one implementation, such as Figure 1 As shown, the right side is the hardware side. This is a PFC inductor model, and the output is the inductor current i. j , This is a PFC capacitor model. The output is the bus voltage u. The left side of the dashed line represents the software side. The set bus voltage u* and the sampled bus voltage u are used as errors, which are then processed by a PI controller to output a set current i*. The inductor output current is sampled to obtain the AC inductor current i. j The DC current i is output after passing through the AC-DC converter module. z The error signal, i*, is calculated by comparing the voltage loop output set current i* with the output current through a PI controller, and outputs a DC current error signal u. oz The signal is converted into an AC voltage control signal u by a DC-AC converter module. oj AC voltage control signal u oj and input voltage u t Both factors act on the inductor; the AC inductor current i is calculated from the inductance value. j Then, the bus voltage u is calculated using capacitors.

[0090] like Figure 2As shown, this invention provides a PFC circuit structure. The figure illustrates the input voltage u of the PFC circuit for the air conditioner compressor in step 1. t The sampling points for bus voltage u and inductor current i are determined.

[0091] The PI controller includes k p k is the proportionality coefficient. i is the integral coefficient, and s is the Laplace operator.

[0092] Traditional methods use PI control for AC signals, which have weak anti-interference capabilities. This solution uses PI control for DC signals, and its characteristic is that the test input current can still maintain a good sinusoidal property when the input voltage changes abruptly.

[0093] In Embodiment 2, this invention provides an air conditioner compressor PFC control system for running the air conditioner compressor PFC control method described in Embodiment 1, comprising:

[0094] Signal acquisition module, angle calculation module, signal conversion module, dual closed-loop control module, and execution module;

[0095] The signal acquisition module is used to acquire the input voltage, bus voltage, and inductor current of the PFC circuit of the air conditioner compressor;

[0096] The angle calculation module is used to calculate the instantaneous slope of the input voltage based on the sampled value, and to obtain the corresponding voltage phase angle by looking up a table based on the instantaneous slope.

[0097] The signal conversion module is used to convert the acquired AC inductor current signal into a DC current signal based on the voltage phase angle.

[0098] The dual closed-loop control module is used to perform dual closed-loop control on the bus voltage and the DC current signal, and outputs a DC error signal.

[0099] The execution module is used to convert the DC error signal into an AC voltage control signal and apply the voltage control signal to the switching transistor of the PFC circuit to adjust the inductor current and the bus voltage.

[0100] Preferably, the dual closed-loop control module includes:

[0101] The voltage outer loop controller is used to adjust the output current setpoint based on the error between the sampled value of the bus voltage and a setpoint via proportional-integral adjustment.

[0102] The current inner loop controller is used to output the DC error signal based on the error between the current setpoint and the DC current signal via proportional-integral adjustment.

[0103] Preferably, the execution module includes a direct-to-interval conversion unit and a drive circuit, wherein:

[0104] The DC-AC conversion unit is used to convert the DC error signal into an AC voltage control signal based on the voltage phase angle.

[0105] The driving circuit is used to generate a driving signal to drive the switching transistor of the PFC circuit to turn on and off according to the AC voltage control signal.

[0106] In Embodiment 3, the present invention provides an air conditioning compressor, which includes the air conditioning compressor PFC control system described in Embodiment 2.

[0107] Embodiment 4 of the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is loaded onto the processor, it implements an air conditioner compressor PFC control method according to Embodiment 1.

[0108] Embodiment 5 of the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements an air conditioner compressor PFC control method according to Embodiment 1.

[0109] Method Embodiments This disclosure may be a system, method, and / or computer program product. A computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for causing a processor to implement various aspects of this disclosure.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A PFC control method for an air conditioning compressor, characterized in that, include: Collect the input voltage, bus voltage, and inductor current of the PFC circuit of the air conditioner compressor; The instantaneous slope is calculated based on the sampled value of the input voltage, and the corresponding voltage phase angle is obtained by looking up a table based on the instantaneous slope. Based on the voltage phase angle, the acquired AC inductor current signal is converted into a DC current signal; The bus voltage and the DC current signal are subjected to dual closed-loop control, and a DC error signal is output. The DC error signal is converted into an AC voltage control signal; The voltage control signal is applied to the switching transistor of the PFC circuit to adjust the inductor current and the bus voltage.

2. The PFC control method for an air conditioning compressor according to claim 1, characterized in that: The step of obtaining the corresponding voltage phase angle based on the instantaneous slope by looking up a table includes: The correspondence between the instantaneous slope value and the voltage phase angle value of different input voltages is pre-stored in a mapping table; After calculating the current instantaneous slope value, query the mapping table: If the mapping table contains a slope value that is equal to the current instantaneous slope value, then its corresponding angle value is directly obtained; If there is no slope value in the mapping table that is equal to the current instantaneous slope value, the corresponding voltage phase angle is calculated by interpolation.

3. The PFC control method for an air conditioning compressor according to claim 2, characterized in that: The calculation of the corresponding voltage phase angle by interpolation includes: Select the slope value that is closest to the current instantaneous slope value from the mapping table as the center point; Obtain the two discrete slope value points that are adjacent to the center point in the mapping table; Based on the current instantaneous slope value and the slope and angle values ​​of the center point and its three adjacent points, the corresponding voltage phase angle is calculated by interpolation.

4. The PFC control method for an air conditioning compressor according to claim 1, characterized in that: Dual closed-loop control of the bus voltage and the DC current signal includes: The output current setting value is adjusted by proportional-integral method based on the error between the sampled value and the set value of the bus voltage through the voltage outer loop. The DC error signal is output through proportional-integral adjustment based on the error between the current setpoint and the DC current signal via the inner current loop.

5. An air conditioning compressor PFC control system, used to operate an air conditioning compressor PFC control method as described in any one of claims 1 to 4, characterized in that, include: Signal acquisition module, angle calculation module, signal conversion module, dual closed-loop control module, and execution module; The signal acquisition module is used to acquire the input voltage, bus voltage, and inductor current of the PFC circuit of the air conditioner compressor; The angle calculation module is used to calculate the instantaneous slope of the input voltage based on the sampled value, and to obtain the corresponding voltage phase angle by looking up a table based on the instantaneous slope. The signal conversion module is used to convert the acquired AC inductor current signal into a DC current signal based on the voltage phase angle. The dual closed-loop control module is used to perform dual closed-loop control on the bus voltage and the DC current signal, and outputs a DC error signal. The execution module is used to convert the DC error signal into an AC voltage control signal and apply the voltage control signal to the switching transistor of the PFC circuit to adjust the inductor current and the bus voltage.

6. The PFC control system for an air conditioner compressor according to claim 5, characterized in that: The dual closed-loop control module includes: The voltage outer loop controller is used to adjust the output current setpoint based on the error between the sampled value of the bus voltage and a setpoint via proportional-integral adjustment. The current inner loop controller is used to output the DC error signal based on the error between the current setpoint and the DC current signal via proportional-integral adjustment.

7. The PFC control system for an air conditioner compressor according to claim 5, characterized in that: The execution module includes a direct-to-interval conversion unit and a drive circuit, wherein: The DC-AC conversion unit is used to convert the DC error signal into an AC voltage control signal based on the voltage phase angle. The driving circuit is used to generate a driving signal to drive the switching transistor of the PFC circuit to turn on and off according to the voltage control signal.

8. An air conditioning compressor, characterized in that, Includes an air conditioning compressor PFC control system as described in any one of claims 5-7.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the computer program is loaded into the processor, it implements a PFC control method for an air conditioning compressor according to any one of claims 1 to 4.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements a PFC control method for an air conditioning compressor according to any one of claims 1 to 4.

Images