PFC circuit control method, operation control device and air conditioner

Abstract

The invention discloses a PFC circuit control method, an operation control device and an air conditioner, the PFC circuit comprises a bus capacitor, and the method comprises the following steps: firstly collecting the input current of the bus capacitor; determining a first current effective value, a first fundamental wave amplitude, a first odd harmonic amplitude, a first fundamental wave frequency value and a first odd harmonic phase value of the input current; obtaining a first odd harmonic current value according to the first current effective value, the first fundamental wave amplitude, the first odd harmonic amplitude, the first fundamental wave frequency value and the first odd harmonic phase value; and then controlling the PFC circuit according to the first odd harmonic current value and a preset current threshold value so as to increase the conduction angle of the input current. According to the method, the thickness of the PFC circuit applying the method can be safely and effectively reduced, so that the ultrathin design of the electric control board of the indoor unit can be realized.

Description

Technical Field

[0001] This invention relates to the field of air conditioner technology, and in particular to a control method, operation control device and air conditioner for a PFC circuit. Background Technology

[0002] Currently, to achieve ultra-thin electronic control in air conditioner indoor units, the electrolytic capacitors in the control board can be replaced with multiple thin, elongated capacitors, which are then arranged horizontally within the control board. However, this design increases the space occupied by the capacitors, hindering the miniaturization of the control board. Furthermore, the horizontally arranged capacitors require additional adhesive to enhance their resistance to vibration, increasing costs. Additionally, when these horizontally arranged capacitors leak or the high-pressure valve opens, the electrolyte can easily splash onto the control board, potentially causing secondary accidents and fires. Therefore, how to safely and effectively reduce the thickness of the indoor unit's electronic control board is a pressing technical problem that needs to be solved. Summary of the Invention

[0003] The purpose of this invention is to at least solve one of the technical problems existing in the prior art, and to provide a control method, operation control device, air conditioner and computer-readable storage medium for PFC circuit, which can safely and effectively reduce the thickness of the indoor unit's electrical control board.

[0004] In a first aspect, embodiments of the present invention provide a control method for a PFC circuit, the PFC circuit including a bus capacitor, the method comprising:

[0005] The input current of the bus capacitor is collected;

[0006] Determine the first effective value of the input current, the first fundamental amplitude, the first odd harmonic amplitude, the first fundamental frequency, and the first odd harmonic phase value;

[0007] The first odd harmonic current value is obtained based on the first current effective value, the first fundamental amplitude, the first odd harmonic amplitude, the first fundamental frequency value, and the first odd harmonic phase value.

[0008] The PFC circuit is controlled based on the first odd harmonic current value and a preset current threshold to increase the conduction angle of the input current.

[0009] The control method for the PFC circuit provided by the embodiments of the present invention has at least the following beneficial effects: When the PFC circuit is working, by acquiring the input current of the bus capacitor and determining the first effective value of the input current, the first fundamental amplitude, the first odd harmonic amplitude, the first fundamental frequency, and the first odd harmonic phase value, the first odd harmonic current value of the input current can be obtained based on the first effective value of the input current, the first fundamental amplitude, the first odd harmonic amplitude, the first fundamental frequency, and the first odd harmonic phase value. At this time, the PFC circuit can be controlled according to the first odd harmonic current value and a preset current threshold to increase the conduction angle of the input current. Since increasing the conduction angle of the input current can improve the stability of the bus voltage, and with the improved stability of the bus voltage, a bus capacitor with a smaller capacitance can be used. That is to say, the PFC circuit using the control method provided by the embodiments of the present invention can use a bus capacitor with a smaller capacitance. Since the smaller the capacitance of the bus capacitor, the smaller its volume, the PFC circuit using the control method provided in this embodiment of the invention can use a smaller bus capacitor, thereby achieving the goal of safely and effectively reducing the thickness of the indoor unit's electrical control board.

[0010] In some embodiments, determining the first effective value of the input current, the first fundamental amplitude, the first odd harmonic amplitude, the first fundamental frequency value, and the first odd harmonic phase value includes:

[0011] The first current waveform of the input current is obtained, and the first current waveform is decomposed to obtain the first fundamental waveform and the first odd harmonic waveform.

[0012] The first effective value of the input current is calculated based on the first fundamental waveform and the first odd harmonic waveform.

[0013] Based on the first fundamental waveform, the first fundamental amplitude and the first fundamental frequency of the input current are obtained;

[0014] Based on the first odd harmonic waveform, the amplitude and phase values ​​of the first odd harmonic of the input current are obtained.

[0015] In some embodiments, obtaining the first odd harmonic current value based on the first current RMS value, the first fundamental amplitude, the first odd harmonic amplitude, the first fundamental frequency value, and the first odd harmonic phase value includes:

[0016] The amplitude ratio term is calculated based on the first fundamental frequency amplitude and the first odd harmonic amplitude.

[0017] The phase term is calculated based on the first fundamental frequency value and the first odd harmonic phase value;

[0018] The first odd harmonic current value is calculated based on the first current effective value, the amplitude ratio term, and the phase term.

[0019] In some embodiments, controlling the PFC circuit based on the first odd harmonic current value and a preset current threshold to increase the conduction angle of the input current includes:

[0020] The first odd harmonic current value is compared with a preset current threshold to obtain a comparison result;

[0021] A first PWM signal is generated based on the comparison result;

[0022] The PFC circuit is controlled using the first PWM signal to increase the conduction angle of the input current.

[0023] In some embodiments, generating a first PWM signal based on the comparison result includes:

[0024] If the comparison result is that the first odd harmonic current value is less than or equal to the current threshold, a first PWM signal is generated based on the first odd harmonic phase value.

[0025] In some embodiments, generating a first PWM signal based on the comparison result includes:

[0026] If the comparison result is that the first odd harmonic current value is greater than the current threshold, the first odd harmonic phase value is adjusted to obtain a new first odd harmonic phase value.

[0027] Based on the first current effective value, the first fundamental amplitude, the first odd harmonic amplitude, the first fundamental frequency value, and the new first odd harmonic phase value, a new first odd harmonic current value is obtained, and the new first odd harmonic current value is compared with the current threshold until the new first odd harmonic current value is less than or equal to the current threshold.

[0028] When the new first odd harmonic current value is less than or equal to the current threshold, a first PWM signal is generated based on the new first odd harmonic phase value used to obtain the new first odd harmonic current value.

[0029] In some embodiments, the PFC circuit is disposed in an air conditioner; before acquiring the input current of the bus capacitor, the method further includes:

[0030] Detect the overall power of the air conditioner;

[0031] When the total power of the machine reaches the preset total power threshold, the step of collecting the input current of the bus capacitor is executed.

[0032] In some embodiments, the method further includes:

[0033] When the total power of the machine reaches a preset allowable power threshold, the waveform of the input current of the bus capacitor is acquired to obtain a second current waveform of the input current, wherein the allowable power threshold is different from the total power threshold;

[0034] Based on the second current waveform, determine the second effective value of the input current, the second fundamental amplitude, the second odd harmonic amplitude, the second fundamental frequency value, and the second odd harmonic current value;

[0035] The second odd harmonic phase value is obtained based on the second current effective value, the second fundamental amplitude, the second odd harmonic amplitude, the second fundamental frequency value, and the second odd harmonic current value.

[0036] A second PWM signal is generated based on the second odd harmonic phase value, and the second PWM signal is used to control the PFC circuit to increase the conduction angle of the input current.

[0037] In some embodiments, determining the second effective value of the input current, the second fundamental amplitude, the second odd harmonic amplitude, the second fundamental frequency value, and the second odd harmonic current value based on the second current waveform includes:

[0038] The second current waveform is decomposed to obtain the second fundamental waveform and the second odd harmonic waveform;

[0039] The second effective value of the input current is calculated based on the second fundamental waveform and the second odd harmonic waveform.

[0040] Based on the second fundamental waveform, the second fundamental amplitude and the second fundamental frequency of the input current are obtained;

[0041] Based on the second odd harmonic waveform, the amplitude of the second odd harmonic and the current value of the second odd harmonic of the input current are obtained.

[0042] In a second aspect, embodiments of the present invention also provide an operation control device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the control method of the PFC circuit as described in the first aspect.

[0043] Thirdly, embodiments of the present invention also provide an air conditioner, including the operation control device as described in the second aspect.

[0044] Fourthly, embodiments of the present invention also provide a computer-readable storage medium storing computer-executable instructions for causing a computer to perform the control method of the PFC circuit as described in the first aspect.

[0045] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0046] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the technical solutions of the present invention, and do not constitute a limitation on the technical solutions of the present invention.

[0047] The present invention will be further described below with reference to the accompanying drawings and embodiments;

[0048] Figure 1 This is a waveform diagram of the input voltage and input current of the bus capacitor in an electronic control board that does not use a PFC circuit.

[0049] Figure 2 This is a waveform diagram of the input voltage and input current of the bus capacitor in an electronic control board that uses a PFC circuit.

[0050] Figure 3 This is a flowchart of a control method for a PFC circuit provided in an embodiment of the present invention;

[0051] Figure 4 This is a waveform diagram of the input current whose conduction angle is increased based on the control of the first PWM signal, according to an embodiment of the present invention.

[0052] Figure 5 This is a diagram showing the harmonic content distribution of the input current of the bus capacitor in a PFC circuit that does not use the control method of this embodiment of the invention.

[0053] Figure 6 This is a diagram showing the harmonic content distribution of the input current of the bus capacitor in a PFC circuit using the control method of this embodiment of the invention.

[0054] Figure 7 This is a circuit structure diagram of a PFC circuit used to execute the control method provided in the embodiments of the present invention;

[0055] Figure 8This is a circuit structure diagram of another PFC circuit used to execute the control method provided in the embodiments of the present invention;

[0056] Figure 9 This is a schematic diagram of the operation control device provided in an embodiment of the present invention. Detailed Implementation

[0057] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0058] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," "exceeding," etc. are understood to exclude the number itself, while "above," "below," "within," etc. are understood to include the number itself. "Any one" refers to one or more, and "at least one of the following" and similar expressions refer to any combination of these items, including any combination of single or multiple items. If "first" or "second" is used in the description, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the order of the indicated technical features.

[0059] It should be noted that the terms "setting," "installing," and "connecting" in the embodiments of this invention should be interpreted broadly. Those skilled in the art can reasonably determine the specific meaning of the above terms in the embodiments of this invention in conjunction with the specific content of the technical solution. For example, the term "connection" can be a mechanical connection, an electrical connection, or a connection that allows for mutual communication; it can be a direct connection or an indirect connection through an intermediate medium.

[0060] It should be noted that the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0061] The thickness of the electronic control unit in an air conditioner's indoor unit depends on the height of the electronic control components on the control board. To achieve an ultra-thin electronic control system, the height of these components needs to be reduced. Currently, the taller electronic control components on the indoor unit's control board include common-mode inductors, transformers, and electrolytic capacitors. The height of common-mode inductors and transformers can be reduced by increasing the switching frequency and using flat transformers. As for the electrolytic capacitors used as bus capacitors in the PFC circuit, due to their capacitance requirements, the only current solution is to replace them with multiple thin, elongated capacitors to reduce their height.

[0062] However, the current design increases the space occupied by capacitors on the control board, hindering miniaturization. Furthermore, horizontally mounted capacitors require additional adhesive to enhance vibration resistance, increasing costs. Additionally, leaks or high-pressure valve openings in horizontally mounted capacitors can easily splash electrolyte onto the control board, potentially causing secondary accidents and fires. Therefore, achieving ultra-thin indoor unit control requires a safe and effective reduction in the height of the bus capacitors in the PFC circuit.

[0063] Research on how to safely and effectively reduce the thickness of the indoor unit's control board revealed that for control boards without PFC circuitry, the conduction angle of the input current to the bus capacitor is relatively small. For example... Figure 1 As shown, Figure 1 This is a waveform diagram of the input voltage and input current of the bus capacitor in an electronic control board that does not employ a PFC circuit. From... Figure 1 As can be seen, the conduction angle of the input current of the bus capacitor is relatively small. Because of this small conduction angle, a bus capacitor with a larger capacitance is required to ensure the stability of the bus voltage. For example, when the indoor electrical control power is less than 70W, a bus capacitor with a capacitance of 4W / uF is needed. Since a larger capacitance results in a larger capacitor size, this necessitates the use of a larger bus capacitor, thus affecting the realization of ultra-thin electrical control.

[0064] For control boards employing PFC circuits, the conduction angle of the input current to the bus capacitor is increased to a certain extent due to the effect of the PFC circuit. For example... Figure 2 As shown, Figure 2 This is a waveform diagram of the input voltage and input current of the bus capacitor in an electronic control board that uses a PFC circuit. From... Figure 2 As can be seen from this, compared to Figure 1 As shown in the waveform of the input current, the conduction angle of the input current of the bus capacitor in the control board using the PFC circuit is increased to a certain extent. Because the conduction angle of the input current of the bus capacitor is increased to a certain extent, a bus capacitor with a relatively smaller capacitance can be used to ensure the stability of the bus voltage. For example, when the indoor control power is less than 70W, a bus capacitor with a capacitance of 2.5W / uF can be used. Since a smaller capacitance results in a smaller capacitor size, a relatively smaller bus capacitor can be used. Although a relatively smaller bus capacitor can be used in this scheme, the realization of ultra-thin control is still not effectively achieved.

[0065] The above analysis shows that by increasing the conduction angle of the input current of the bus capacitor, the capacitance requirement for the bus capacitor can be reduced, thereby reducing the size of the required bus capacitor and facilitating the ultra-thin electronic control of the indoor unit. To achieve this, this invention provides a control method for a PFC circuit. This method further increases the conduction angle of the input current of the bus capacitor, allowing the PFC circuit using this control method to use a bus capacitor with a smaller capacitance, effectively reducing the required bus capacitor size and thus facilitating the ultra-thin electronic control of the indoor unit.

[0066] Reference Figure 3 As shown, Figure 3 This invention provides a control method for a PFC circuit, which includes, but is not limited to, steps S100 to S400.

[0067] Step S100: Collect the input current of the bus capacitor;

[0068] Step S200: Determine the first effective value of the input current, the first fundamental amplitude, the first odd harmonic amplitude, the first fundamental frequency, and the first odd harmonic phase value;

[0069] Step S300: Obtain the first odd harmonic current value based on the first current effective value, the first fundamental amplitude, the first odd harmonic amplitude, the first fundamental frequency value, and the first odd harmonic phase value;

[0070] Step S400: Control the PFC circuit according to the first odd harmonic current value and the preset current threshold to increase the conduction angle of the input current.

[0071] In some embodiments, when acquiring the input current of the bus capacitor, the current waveform information of the input current can be acquired. Then, the acquired current waveform information is analyzed to extract information such as the fundamental amplitude, odd harmonic amplitude, fundamental frequency, and odd harmonic phase. This information is used in subsequent steps to control the PFC circuit, thereby increasing the conduction angle of the bus capacitor's input current. It should be noted that the conduction angle refers to the angle at which the current conducts within one alternating current cycle. In a sinusoidal alternating current waveform, a complete cycle is 360 degrees. The conduction angle typically refers to the angle from the beginning of the alternating current cycle (usually zero degrees) to the point where the current begins to conduct.

[0072] In some embodiments, the amplitude of the first odd harmonic can be the amplitude of the 3rd harmonic, the amplitude of the 5th harmonic, the amplitude of the 7th harmonic, etc., and is not specifically limited here. Similarly, the phase value of the first odd harmonic can be the phase value of the 3rd harmonic, the phase value of the 5th harmonic, the phase value of the 7th harmonic, etc., and is not specifically limited here.

[0073] In some embodiments, the process of determining the first effective value of the input current, the first fundamental amplitude, the first odd harmonic amplitude, the first fundamental frequency, and the first odd harmonic phase value may include the following steps: firstly, acquiring the first current waveform of the input current and performing waveform decomposition on the first current waveform to obtain the first fundamental waveform and the first odd harmonic waveform; then, calculating the first effective value of the input current based on the first fundamental waveform and the first odd harmonic waveform; then, obtaining the first fundamental amplitude and the first fundamental frequency value of the input current based on the first fundamental waveform; and finally, obtaining the first odd harmonic amplitude and the first odd harmonic phase value of the input current based on the first odd harmonic waveform.

[0074] It should be noted that the input current waveform is the superposition of the fundamental waveform and multiple harmonic waveforms. For air conditioners, each harmonic of the current (e.g., the 3rd harmonic, 5th harmonic, etc.) must meet the overall harmonic requirements of the air conditioner, especially the odd harmonic current values ​​of the 3rd, 5th, and 7th harmonics must be less than or equal to a preset harmonic current threshold. Therefore, to meet the overall harmonic requirements of the air conditioner, the first current waveform of the input current can be decomposed to obtain the first fundamental waveform and the first odd harmonic waveform. Then, based on the first fundamental waveform and the first odd harmonic waveform, various parameters for calculating the first odd harmonic current value are obtained, so that subsequent steps can accurately calculate the first odd harmonic current value used to control the PFC circuit to increase the input current of the bus capacitor. The first odd harmonic waveform can be the 3rd harmonic waveform, the 5th harmonic waveform, the 7th harmonic waveform, etc., without specific limitations here.

[0075] In some embodiments, during the process of decomposing the first current waveform to obtain the first fundamental waveform and the first odd harmonic waveform, the first current waveform can be subjected to Fourier transform processing to obtain the first fundamental waveform and the first odd harmonic waveform.

[0076] In some embodiments, in the process of calculating the first effective value of the input current based on the first fundamental waveform and the first odd harmonic waveform, the effective value of the current of the first fundamental waveform and the effective value of the current of the first odd harmonic waveform can be calculated first, and then the sum of the effective value of the current of the first fundamental waveform and the effective value of the current of the first odd harmonic waveform can be calculated to obtain the first effective value of the input current.

[0077] In some embodiments, the first fundamental amplitude of the input current can be calculated based on the difference between the highest and lowest points of the first fundamental waveform. When calculating the first fundamental frequency of the input current, the first fundamental waveform can be sampled first, and then a fast Fourier transform can be performed on the sampled data to obtain the first fundamental frequency of the input current.

[0078] In some embodiments, the amplitude of the first odd harmonic of the input current can be calculated based on the difference between the highest and lowest points of the first odd harmonic waveform. When calculating the phase value of the first odd harmonic of the input current, the first odd harmonic waveform can be sampled first, and then a fast Fourier transform can be performed on the sampled data to obtain the frequency value of the first odd harmonic waveform. The phase value of the first odd harmonic of the input current can then be calculated based on this frequency value.

[0079] In some embodiments, the process of obtaining the first odd harmonic current value based on the first current effective value, the first fundamental amplitude, the first odd harmonic amplitude, the first fundamental frequency value, and the first odd harmonic phase value may include the following steps: firstly, calculating the amplitude ratio term based on the first fundamental amplitude and the first odd harmonic amplitude; then calculating the phase term based on the first fundamental frequency value and the first odd harmonic phase value; and finally calculating the first odd harmonic current value based on the first current effective value, the amplitude ratio term, and the phase term.

[0080] In some embodiments, the first odd harmonic current value can be calculated using the following formula (1):

[0081]

[0082] In formula (1), i in (t) is used to represent the value of the first odd harmonic current, such as the 3rd, 5th, or 7th harmonic current of the input current; I rms Used to represent the effective value of the first current; α n This term represents the amplitude ratio calculated based on the amplitude of the first fundamental wave and the amplitude of the first odd harmonic. 'n' represents the order of the harmonics; for example, α3 represents the amplitude ratio calculated based on the amplitude of the first fundamental wave and the amplitude of the 3rd harmonic, α5 represents the amplitude ratio calculated based on the amplitude of the first fundamental wave and the amplitude of the 5th harmonic, and α7 represents the amplitude ratio calculated based on the amplitude of the first fundamental wave and the amplitude of the 7th harmonic. 'f1' represents the first fundamental wave frequency value, and 't' represents time. Used to represent the phase value of the first odd harmonic, for example... This represents the harmonic phase value of the third harmonic of the input current. This represents the harmonic phase value of the 5th harmonic of the input current. The harmonic phase value representing the 7th harmonic of the input current; Used to represent the phase term. Wherein, when the first odd harmonic current value is the third harmonic current value of the input current, formula (1) can be expressed as: When the value of the first odd harmonic current is the value of the fifth harmonic current of the input current, formula (1) can be expressed as follows: When the value of the first odd harmonic current is the value of the 7th harmonic current of the input current, formula (1) can be expressed as follows: And so on.

[0083] Therefore, when it is necessary to calculate the value of the first odd harmonic current, the effective value of the first current I can be obtained from the first current waveform of the input current. rms The amplitude of the first fundamental wave, the amplitude of the first odd harmonic, the frequency value of the first fundamental wave f1, and the phase value of the first odd harmonic. Then, the amplitude ratio term α is obtained based on the ratio between the amplitude of the first fundamental wave and the amplitude of the first odd harmonic. n Based on the first fundamental frequency value f1 and the first odd harmonic phase value The phase term was calculated. Then the first current effective value I rms Amplitude ratio term α n and phase term By multiplying them, the value of the first odd harmonic current i can be calculated. in (t).

[0084] In some embodiments, when controlling the PFC circuit based on the first odd harmonic current value and a preset current threshold to increase the conduction angle of the input current, the first odd harmonic current value and the preset current threshold can be compared first to obtain a comparison result. Then, a first PWM signal is generated based on the comparison result, and the first PWM signal is used to control the PFC circuit to increase the conduction angle of the input current. For example... Figure 4 As shown, Figure 4 This is a waveform diagram of the input current whose conduction angle has been increased based on the control of the first PWM signal. From... Figure 4 As can be seen from this, compared to Figure 1 and Figure 2As shown in the waveform of the input current, the conduction angle of the input current of the bus capacitor in the PFC circuit using the control method provided in this embodiment of the invention is significantly increased. Therefore, a bus capacitor with a smaller capacitance can be used to ensure the stability of the bus voltage. For example, when the indoor power control is less than 70W, a bus capacitor with a capacitance of 1W / uF can be used. Since a smaller capacitance results in a smaller capacitor size, a smaller bus capacitor can be used, which is beneficial for the realization of ultra-thin electronic control.

[0085] In some embodiments, when the comparison result shows that the first odd harmonic current value is less than or equal to the current threshold, it indicates that the current first odd harmonic current value meets the harmonic requirements of the entire unit, and no adjustment is needed. In this case, a first PWM signal can be generated based on the phase value of the first odd harmonic, and then the first PWM signal is sent to the switching transistor module of the PFC circuit to control the PFC circuit, increasing the conduction angle of the input current to the bus capacitor. Increasing the conduction angle of the input current improves the stability of the bus voltage. With improved bus voltage stability, a smaller bus capacitor can be used in the PFC circuit. Since a smaller bus capacitor has a smaller volume, a smaller bus capacitor can be used in the PFC circuit, thereby achieving a safe and effective reduction in the thickness of the indoor unit's control board.

[0086] In some embodiments, when the comparison result shows that the first odd harmonic current value is greater than the current threshold, it indicates that the current first odd harmonic current value cannot meet the harmonic requirements of the whole machine, and the first odd harmonic current value needs to be adjusted. At this time, the first odd harmonic phase value can be adjusted to obtain a new first odd harmonic phase value. Then, based on the first current effective value, the first fundamental amplitude, the first odd harmonic amplitude, the first fundamental frequency value, and the new first odd harmonic phase value, a new first odd harmonic current value is recalculated. Next, the new first odd harmonic current value is compared with the current threshold to obtain a new comparison result. If the new comparison result shows that the new first odd harmonic current value is less than or equal to the current threshold, it indicates that the adjusted first odd harmonic current value can meet the harmonic requirements of the whole machine. At this time, a first PWM signal can be generated based on the new first odd harmonic phase value used to obtain the new first odd harmonic current value, and the first PWM signal is sent to the switching transistor module of the PFC circuit to control the PFC circuit and increase the conduction angle of the input current of the PFC circuit to the bus capacitor. If the new comparison result shows that the new first odd harmonic current value is still greater than the current threshold, it indicates that the currently adjusted first odd harmonic current value still fails to meet the overall harmonic requirements. In this case, the new first odd harmonic phase value can be adjusted, and a new first odd harmonic current value can be recalculated based on the first current effective value, the first fundamental amplitude, the first odd harmonic amplitude, the first fundamental frequency value, and the adjusted first odd harmonic phase value, until the obtained new first odd harmonic current value is less than or equal to the current threshold. When the final obtained new first odd harmonic current value is less than or equal to the current threshold, a first PWM signal can be generated based on the new first odd harmonic phase value used to obtain the final obtained new first odd harmonic current value, and the first PWM signal can be used to control the PFC circuit to increase the conduction angle of the input current.

[0087] In some embodiments, when adjusting the phase value of the first odd harmonic to obtain a new phase value, a step value can be added to the first odd harmonic phase value to obtain the new phase value. When adjusting the new phase value, the step value can be increased first, and then the increased step value can be added to the new phase value. Specifically, when increasing the step value, it can start from 1. For example, when adding the step value to the first odd harmonic phase value for the first time, the step value is 1; when adding the step value to the first odd harmonic phase value for the second time, the step value is 2; when adding the step value to the first odd harmonic phase value for the nth time, the step value is n, and so on.

[0088] In some embodiments, the preset current threshold can be appropriately selected according to actual application requirements, and no specific limitation is made here. For example, for the 3rd harmonic, the preset current threshold can be 2.3A or a value less than 2.3A; for the 5th harmonic, the preset current threshold can be 1.14A or a value less than 1.14A; for the 7th harmonic, the preset current threshold can be 0.77A or a value less than 0.77A. Figure 5 and Figure 6 As shown, Figure 5 This is a diagram showing the harmonic content distribution of the input current of the bus capacitor in a PFC circuit that does not use the control method of this embodiment. Figure 6 This is a harmonic content distribution diagram of the input current of the bus capacitor in a PFC circuit using the control method of this embodiment of the invention. Figure 5 and Figure 6 In the diagram, curve one represents the maximum current peak value that cannot be exceeded in the overall harmonic requirements, curve two represents the effective current value that cannot be exceeded in the overall harmonic requirements, and the bar chart represents the effective current value of each harmonic. According to... Figure 5 and Figure 6 It can be seen that in the PFC circuit using the control method provided in the embodiments of the present invention, the effective values ​​of the current of each harmonic of the input current of the bus capacitor can meet the harmonic requirements of the whole machine.

[0089] In some embodiments, the control method can be applied to, for example... Figure 7 or Figure 8 The PFC circuit shown. Figure 7 In this circuit, the PFC circuit may include a first switching transistor module 710 and a first bus capacitor 720. After the indoor unit controller generates a first PWM signal, it can send the first PWM signal to the first switching transistor module 710 to control the on and off of the first switching transistor module 710, thereby increasing the conduction angle of the input current input to the first bus capacitor 720. Figure 8 In this circuit, the PFC circuit may include a second switching transistor module 810 and a second bus capacitor 820. After the indoor unit controller generates a first PWM signal, it can send the first PWM signal to the second switching transistor module 810 to control the switching on and off of the second switching transistor module 810, thereby increasing the conduction angle of the input current input to the second bus capacitor 820. Since the PFC circuit can improve the stability of the bus voltage after the conduction angle of the input current increases, a bus capacitor with a smaller capacitance can be used in the PFC circuit. Because the smaller the capacitance of the bus capacitor, the smaller its size, a smaller bus capacitor can be used in the PFC circuit, thereby achieving the goal of safely and effectively reducing the thickness of the indoor unit's electronic control board.

[0090] In some embodiments, the PFC circuit is installed in the air conditioner. Before collecting the input current of the bus capacitor, the total power of the air conditioner can be detected first. If the total power reaches a preset total power threshold, then the step of collecting the input current of the bus capacitor is performed. That is, before performing step S100, the total power of the air conditioner can be detected first, and then step S100 is performed only if the total power reaches the preset total power threshold. It should be noted that the preset total power threshold can be appropriately selected according to actual application requirements, and is not specifically limited here. For example, the preset total power threshold can be 600W or 1000W, etc.

[0091] In some embodiments, for regions where harmonic content is related to input power, when the detected total power of the air conditioner reaches 600W, the preset current threshold for the 3rd harmonic can be 2.645A or a value less than 2.645A; for the 5th harmonic, the preset current threshold can be 1.311A or a value less than 1.311A; and for the 7th harmonic, the preset current threshold can be 0.886A or a value less than 0.886A. In other embodiments, for regions where harmonic content is related to input power, when the detected total power of the air conditioner reaches 1000W, the preset current threshold for the 3rd harmonic can be 3.947A or a value less than 3.947A; for the 5th harmonic, the preset current threshold can be 1.633A or a value less than 1.633A; and for the 7th harmonic, the preset current threshold can be 1.267A or a value less than 1.267A.

[0092] In some embodiments, after detecting the overall power of the air conditioner, when the overall power reaches a preset allowable power threshold, the waveform of the input current of the bus capacitor can be acquired first to obtain the second current waveform of the input current; then, based on the second current waveform, the second current effective value, the second fundamental amplitude, the second odd harmonic amplitude, the second fundamental frequency value, and the second odd harmonic current value of the input current can be determined; then, based on the second current effective value, the second fundamental amplitude, the second odd harmonic amplitude, the second fundamental frequency value, and the second odd harmonic current value, the second odd harmonic phase value can be obtained; then, based on the second odd harmonic phase value, a second PWM signal can be generated, and the second PWM signal can be used to control the PFC circuit to increase the conduction angle of the input current.

[0093] In some embodiments, the amplitude of the second odd harmonic can be the amplitude of the 3rd harmonic, the amplitude of the 5th harmonic, the amplitude of the 7th harmonic, etc., and is not specifically limited here. Similarly, the current value of the second odd harmonic can be the current value of the 3rd harmonic, the current value of the 5th harmonic, the current value of the 7th harmonic, etc., and is not specifically limited here.

[0094] In some embodiments, the process of determining the second effective value of the input current, the second fundamental amplitude, the second odd harmonic amplitude, the second fundamental frequency, and the second odd harmonic current value based on the second current waveform may include the following steps: first, decomposing the second current waveform to obtain the second fundamental waveform and the second odd harmonic waveform; then, calculating the second effective value of the input current based on the second fundamental waveform and the second odd harmonic waveform; then, obtaining the second fundamental amplitude and the second fundamental frequency value of the input current based on the second fundamental waveform; and finally, obtaining the second odd harmonic amplitude and the second odd harmonic current value of the input current based on the second odd harmonic waveform.

[0095] It should be noted that the second odd harmonic waveform can be the harmonic waveform of the 3rd harmonic, the harmonic waveform of the 5th harmonic, the harmonic waveform of the 7th harmonic, etc., and no specific limitation is made here.

[0096] In some embodiments, during the process of decomposing the second current waveform to obtain the second fundamental waveform and the second odd harmonic waveform, the second current waveform can be subjected to Fourier transform processing to obtain the second fundamental waveform and the second odd harmonic waveform.

[0097] In some embodiments, in the process of calculating the second effective value of the input current based on the second fundamental waveform and the second odd harmonic waveform, the effective value of the current of the second fundamental waveform and the effective value of the current of the second odd harmonic waveform can be calculated first, and then the sum of the effective value of the current of the second fundamental waveform and the effective value of the current of the second odd harmonic waveform can be calculated to obtain the second effective value of the input current.

[0098] In some embodiments, the second fundamental amplitude of the input current can be calculated based on the difference between the highest and lowest points of the second fundamental waveform. When calculating the second fundamental frequency of the input current, the second fundamental waveform can be sampled first, and then a fast Fourier transform can be performed on the sampled data to obtain the second fundamental frequency of the input current.

[0099] In some embodiments, the amplitude of the second odd harmonic of the input current can be calculated based on the difference between the highest and lowest points of the second odd harmonic waveform. When calculating the value of the second odd harmonic current of the input current, the second odd harmonic waveform can be squared, averaged, and then the square root can be taken to obtain the specific value of the second odd harmonic current.

[0100] In some embodiments, the process of obtaining the phase value of the second odd harmonic based on the effective value of the second current, the amplitude of the second fundamental wave, the amplitude of the second odd harmonic, the frequency of the second fundamental wave, and the current value of the second odd harmonic may include the following steps: first, calculating the amplitude ratio term based on the amplitude of the second fundamental wave and the amplitude of the second odd harmonic; then, substituting the effective value of the second current, the amplitude ratio term, the frequency of the second fundamental wave, and the current value of the second odd harmonic into the formula (1) described above to calculate the phase value of the second odd harmonic. For example, substituting the current value of the second odd harmonic into the i in formula (1) in In (t), substitute the effective value of the second current into I in formula (1). rms In the middle, the amplitude ratio term is substituted into α in formula (1). n In the formula (1), the second fundamental frequency value is substituted into f1, and the result of the calculation is obtained in formula (1). The value obtained from this calculation The value is the value of the phase value of the second odd harmonic.

[0101] In some embodiments, after calculating the second odd harmonic phase value, a second PWM signal can be generated based on the second odd harmonic phase value, and the second PWM signal can be used to control the PFC circuit to increase the conduction angle of the input current. It should be noted that the process of generating the second PWM signal based on the second odd harmonic phase value can refer to the process of generating the first PWM signal based on the first odd harmonic phase value described in the previous embodiments, and the process of using the second PWM signal to control the PFC circuit to increase the conduction angle of the input current can refer to the process of using the first PWM signal to control the PFC circuit to increase the conduction angle of the input current described in the previous embodiments, and will not be repeated here.

[0102] Additionally, refer to Figure 9 A second aspect of the present invention provides an operation control device 900, including a memory 910, a processor 920, and a computer program stored in the memory 910 and executable on the processor 920. The processor 920 executes the program to implement the control method of the PFC circuit of the first aspect embodiment described above, for example, executing... Figure 3 Method steps S100 to S400.

[0103] In addition, a third aspect of the present invention provides an air conditioner including the operation control device 900 of the second aspect embodiment.

[0104] Furthermore, a fourth aspect of the present invention provides a computer-readable storage medium storing computer-executable instructions for causing a computer to perform a control method of a PFC circuit as described in the first aspect embodiment, for example, executing... Figure 3 Method steps S100 to S400.

[0105] It will be understood by those skilled in the art that all or some of the steps and systems in the methods disclosed above can be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components can be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which may include computer storage media or non-transitory media and communication media or transient media. As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information such as computer-readable instructions, data structures, program modules, or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc DVD or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0106] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A control method for a PFC circuit, characterized in that, The PFC circuit includes a bus capacitor, and the method includes: The input current of the bus capacitor is collected; Determine the first effective value of the input current, the first fundamental amplitude, the first odd harmonic amplitude, the first fundamental frequency, and the first odd harmonic phase value; The first odd harmonic current value is obtained based on the first current effective value, the first fundamental amplitude, the first odd harmonic amplitude, the first fundamental frequency value, and the first odd harmonic phase value. The PFC circuit is controlled based on the first odd harmonic current value and a preset current threshold to increase the conduction angle of the input current.

2. The control method according to claim 1, characterized in that, The determination of the first effective value of the input current, the first fundamental amplitude, the first odd harmonic amplitude, the first fundamental frequency value, and the first odd harmonic phase value includes: The first current waveform of the input current is obtained, and the first current waveform is decomposed to obtain the first fundamental waveform and the first odd harmonic waveform. The first effective value of the input current is calculated based on the first fundamental waveform and the first odd harmonic waveform. Based on the first fundamental waveform, the first fundamental amplitude and the first fundamental frequency of the input current are obtained; Based on the first odd harmonic waveform, the amplitude and phase values ​​of the first odd harmonic of the input current are obtained.

3. The control method according to claim 1, characterized in that, The step of obtaining the first odd harmonic current value based on the first current effective value, the first fundamental amplitude, the first odd harmonic amplitude, the first fundamental frequency value, and the first odd harmonic phase value includes: The amplitude ratio term is calculated based on the first fundamental frequency amplitude and the first odd harmonic amplitude. The phase term is calculated based on the first fundamental frequency value and the first odd harmonic phase value; The first odd harmonic current value is calculated based on the first current effective value, the amplitude ratio term, and the phase term.

4. The control method according to claim 1, characterized in that, The step of controlling the PFC circuit based on the first odd harmonic current value and a preset current threshold to increase the conduction angle of the input current includes: The first odd harmonic current value is compared with a preset current threshold to obtain a comparison result; A first PWM signal is generated based on the comparison result; The PFC circuit is controlled using the first PWM signal to increase the conduction angle of the input current.

5. The control method according to claim 4, characterized in that, The step of generating a first PWM signal based on the comparison result includes: If the comparison result is that the first odd harmonic current value is less than or equal to the current threshold, a first PWM signal is generated based on the first odd harmonic phase value.

6. The control method according to claim 4, characterized in that, The step of generating a first PWM signal based on the comparison result includes: If the comparison result is that the first odd harmonic current value is greater than the current threshold, the first odd harmonic phase value is adjusted to obtain a new first odd harmonic phase value. Based on the first current effective value, the first fundamental amplitude, the first odd harmonic amplitude, the first fundamental frequency value, and the new first odd harmonic phase value, a new first odd harmonic current value is obtained, and the new first odd harmonic current value is compared with the current threshold until the new first odd harmonic current value is less than or equal to the current threshold. When the new first odd harmonic current value is less than or equal to the current threshold, a first PWM signal is generated based on the new first odd harmonic phase value used to obtain the new first odd harmonic current value.

7. The control method according to claim 1, characterized in that, The PFC circuit is installed in the air conditioner; before acquiring the input current of the bus capacitor, the method further includes: Detect the overall power of the air conditioner; When the total power of the machine reaches the preset total power threshold, the step of collecting the input current of the bus capacitor is executed.

8. The control method according to claim 7, characterized in that, The method further includes: When the total power of the machine reaches a preset allowable power threshold, the waveform of the input current of the bus capacitor is acquired to obtain a second current waveform of the input current, wherein the allowable power threshold is different from the total power threshold; Based on the second current waveform, determine the second effective value of the input current, the second fundamental amplitude, the second odd harmonic amplitude, the second fundamental frequency value, and the second odd harmonic current value; The second odd harmonic phase value is obtained based on the second current effective value, the second fundamental amplitude, the second odd harmonic amplitude, the second fundamental frequency value, and the second odd harmonic current value. A second PWM signal is generated based on the second odd harmonic phase value, and the second PWM signal is used to control the PFC circuit to increase the conduction angle of the input current.

9. The control method according to claim 8, characterized in that, The step of determining the second effective value of the input current, the second fundamental amplitude, the second odd harmonic amplitude, the second fundamental frequency value, and the second odd harmonic current value based on the second current waveform includes: The second current waveform is decomposed to obtain the second fundamental waveform and the second odd harmonic waveform; The second effective value of the input current is calculated based on the second fundamental waveform and the second odd harmonic waveform. Based on the second fundamental waveform, the second fundamental amplitude and the second fundamental frequency of the input current are obtained; Based on the second odd harmonic waveform, the amplitude of the second odd harmonic and the current value of the second odd harmonic of the input current are obtained.

10. An operation control device, characterized in that, The device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, the processor executing the program to implement the control method for the PFC circuit as described in any one of claims 1 to 9.

11. An air conditioner, characterized in that, Includes the operation control device as described in claim 10.

12. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions for causing a computer to perform the control method of the PFC circuit as described in any one of claims 1 to 9.

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