Control circuit, frequency converter, device, method, controller, medium and product

Abstract

The invention provides a control circuit, a frequency converter, equipment, a method, a controller, a medium and a product. The control circuit comprises: an acquisition module configured to acquire the current of the three-phase power output to the load by the inverter circuit and the bus voltage of the DC bus circuit; the control module is configured to obtain a quadrature-axis current component according to current decoupling calculation of the three-phase power, output a first voltage value according to the quadrature-axis current component and a preset first current parameter when the bus voltage is larger than a first voltage threshold value, and output a second voltage value according to the quadrature-axis current component and a preset second current parameter when the bus voltage is smaller than a second voltage threshold value. A second voltage value is output according to the quadrature-axis current component and a preset second current parameter, and the second voltage threshold value is smaller than the first voltage threshold value; and the adjusting module is configured to respond to the first voltage value and control the first switching device in the rectifying circuit to be switched off, and respond to the second voltage value and control the first switching device in the rectifying circuit to be switched on and switched off alternately.

Description

Technical Field

[0001] The present disclosure relates to the technical field of air conditioning, and in particular to a control circuit, a frequency converter, a device, a method, a controller, a medium and a product. Background Art

[0002] In the related technology, in order to solve the problem of easy leakage of electrolytic capacitors at high altitude and low air pressure, and to reduce the cost of using electrolytic capacitors in the DC bus of the inverter, combined with the working characteristics of the compressor motor in the air-conditioning system, the DC bus capacitor adopts metallized polypropylene film capacitors, referred to as film capacitors. The film capacitor is small in size and low in cost, but the problem it brings is that the DC bus voltage fluctuation increases, especially under severe working load conditions, the voltage fluctuation is more severe, and even affects the reliability of the compressor operation. Summary of the invention

[0003] A technical problem solved by the present disclosure is that in the related art, the DC bus capacitor adopts a film capacitor, which easily causes a large fluctuation in the DC bus voltage.

[0004] According to one aspect of the present disclosure, a control circuit for a frequency converter is provided, wherein the frequency converter includes a rectifier circuit, an inverter circuit and a DC bus circuit electrically connected between the rectifier circuit and the inverter circuit, the rectifier circuit includes an inductor and a first switch device electrically connected to the inductor, and the control circuit includes: an acquisition module configured to acquire the current of the three-phase electricity output by the inverter circuit to the load and the bus voltage of the DC bus circuit; a control module configured to obtain a quadrature-axis current component according to the current decoupling calculation of the three-phase electricity, output a first voltage value according to the quadrature-axis current component and a preset first current parameter when the bus voltage is greater than a first voltage threshold, and output a second voltage value according to the quadrature-axis current component and a preset second current parameter when the bus voltage is less than a second voltage threshold, wherein the second voltage threshold is less than the first voltage threshold; and a regulation module configured to control the first switch device to turn off in response to the first voltage value, and control the first switch device to be alternately turned on and off in response to the second voltage value.

[0005] In some embodiments, the control module is configured to calculate the sum of the cross-axis current component and the first current parameter, and obtain a first voltage value corresponding to the sum based on the sum and the correspondence between preset current values ​​and voltage values, and to calculate the difference between the cross-axis current component and the second current parameter, and obtain a second voltage value corresponding to the difference based on the difference and the correspondence between the current values ​​and voltage values.

[0006] In some embodiments, the regulation module includes: a comparison circuit, configured to output a first level signal in response to the first voltage value, and to output a second level signal in response to the second voltage value, wherein the first level signal is different from the second level signal; and a logic processing circuit, configured to output a first control signal to the first switching device in response to the first level signal to control the first switching device to turn off, and to output a second control signal to the first switching device in response to the second level signal to control the first switching device to be alternately turned on and off.

[0007] In some embodiments, the second control signal is a pulse width modulation signal.

[0008] In some embodiments, the comparison circuit includes: a first resistor and a second resistor connected in series between a first voltage terminal and a ground terminal, wherein the first voltage terminal is used to provide the bus voltage; and a comparator, wherein the first input terminal of the comparator is electrically connected to a connection point between the first resistor and the second resistor, the second input terminal of the comparator is electrically connected to an output terminal of the control module, the second input terminal of the comparator is used to receive the first voltage value or the second voltage value, and the output terminal of the comparator is electrically connected to the logic processing circuit, wherein the comparator is configured to output the first level signal based on a comparison result between the voltage at the connection point and the first voltage value, and to output the second level signal based on a comparison result between the voltage at the connection point and the second voltage value.

[0009] In some embodiments, the comparison circuit also includes: a third resistor, arranged between the second input terminal of the comparator and the output terminal of the control module; and a first capacitor, a first end of the first capacitor is electrically connected to the second input terminal of the comparator, and a second end of the first capacitor is electrically connected to the ground terminal.

[0010] In some embodiments, the logic processing circuit includes: a second switching device, a first terminal of the second switching device is electrically connected to a second voltage terminal, and a control terminal of the second switching device is electrically connected to the comparison circuit; a fourth resistor, a first terminal of the fourth resistor is electrically connected to a second terminal of the second switching device, and a second terminal of the fourth resistor is electrically connected to a ground terminal; and an AND gate device, a first input terminal of the AND gate device is electrically connected to a second terminal of the second switching device, a second input terminal of the AND gate device is configured to receive an initial control signal, and an output terminal of the AND gate device is electrically connected to the control terminal of the first switching device.

[0011] In some embodiments, the logic processing circuit also includes: a fifth resistor, arranged between the second end of the second switching device and the first input end of the AND gate device; and a second capacitor, the first end of the second capacitor is electrically connected to the second end of the fifth resistor, and the second end of the second capacitor is electrically connected to the ground terminal.

[0012] In some embodiments, the rectifier circuit includes a plurality of inductors and a plurality of first switching devices, wherein the plurality of inductors are electrically connected to the plurality of first switching devices in a one-to-one correspondence; the logic processing circuit includes a plurality of AND gate devices, wherein the first input terminals of the plurality of AND gate devices are electrically connected to the second terminal of the second switching device, the second input terminal of each AND gate device is configured to receive an initial control signal corresponding to each AND gate device, and the output terminals of the plurality of AND gate devices are electrically connected to the control terminals of the plurality of first switching devices in a one-to-one correspondence.

[0013] In some embodiments, the first voltage threshold is an upper limit value of an allowable range of the bus voltage; and the second voltage threshold is a lower limit value of an allowable range of the bus voltage.

[0014] In some embodiments, the control module is further configured to output a pulse width modulation signal to the first switching device to control the first switching device to alternately turn on and off when the bus voltage is less than or equal to the first voltage threshold and greater than or equal to the second voltage threshold.

[0015] According to another aspect of the present disclosure, a frequency converter is provided, comprising: the control circuit as described above.

[0016] In some embodiments, the inverter also includes: a rectifier circuit, the rectifier circuit includes an inductor and a first switching device electrically connected to the inductor, the first switching device is electrically connected to the control circuit; an inverter circuit, electrically connected to the control circuit; and a DC bus circuit, electrically connected between the rectifier circuit and the inverter circuit, and electrically connected to the control circuit; wherein the control circuit is configured to obtain the current of the three-phase electricity output by the inverter circuit to the load and the bus voltage of the DC bus circuit, and control the conduction and disconnection of the first switching device.

[0017] According to another aspect of the present disclosure, an air conditioning device is provided, comprising: the inverter as described.

[0018] According to another aspect of the present disclosure, a control method for a frequency converter is provided, wherein the frequency converter includes a rectifier circuit, an inverter circuit and a DC bus circuit electrically connected between the rectifier circuit and the inverter circuit, the rectifier circuit includes an inductor and a first switch device electrically connected to the inductor, and the control method includes: obtaining the current of the three-phase electricity output by the inverter circuit to the load and the bus voltage of the DC bus circuit; obtaining the quadrature-axis current component according to the current decoupling calculation of the three-phase electricity; when the bus voltage is greater than a first voltage threshold, outputting a first voltage value to a regulating module according to the quadrature-axis current component and a preset first current parameter, so that the regulating module controls the first switch device to turn off; and when the bus voltage is less than a second voltage threshold, outputting a second voltage value to the regulating module according to the quadrature-axis current component and a preset second current parameter, so that the regulating module controls the first switch device to be alternately turned on and off, wherein the second voltage threshold is less than the first voltage threshold.

[0019] In some embodiments, outputting a first voltage value based on the cross-axis current component and a preset first current parameter includes: calculating the sum of the cross-axis current component and the first current parameter; and obtaining a first voltage value corresponding to the sum based on the correspondence between the sum and the preset current value and voltage value.

[0020] In some embodiments, outputting a second voltage value based on the cross-axis current component and a preset second current parameter includes: calculating the difference between the cross-axis current component and the second current parameter; and obtaining a second voltage value corresponding to the difference based on the correspondence between the difference and the preset current value and voltage value.

[0021] In some embodiments, the control method further includes: when the bus voltage is less than or equal to the first voltage threshold and greater than or equal to the second voltage threshold, outputting a pulse width modulation signal to the first switching device to control the first switching device to alternately turn on and off.

[0022] According to another aspect of the present disclosure, a controller for a frequency converter is provided, comprising: a memory; and a processor coupled to the memory, wherein the processor is configured to execute the aforementioned control method based on instructions stored in the memory.

[0023] According to another aspect of the present disclosure, a computer-readable storage medium is provided, on which computer instructions are stored. When the computer instructions are executed by a processor, the control method as described above is implemented.

[0024] According to another aspect of the present disclosure, a computer program product is provided. The computer program product includes a computer program or instructions. When the computer program or instructions are executed by a processor, the control method as described above is implemented.

[0025] In the above control circuit, when the bus voltage is greater than the first voltage threshold, the first switch device is controlled to be turned off, so that the energy stored in the inductor can be reduced, thereby reducing the bus voltage. When the bus voltage is less than the second voltage threshold, the first switch device is controlled to be alternately turned on and off, so that the energy stored in the inductor gradually increases, thereby increasing the bus voltage. In this way, the fluctuation of the DC bus voltage can be reduced, and the reliability and robustness of the system can be improved.

[0026] Other features and advantages of the present disclosure will become apparent from the following detailed description of exemplary embodiments of the present disclosure with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings, which constitute a part of the specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0028] The present disclosure may be more clearly understood from the following detailed description with reference to the accompanying drawings, in which:

[0029] Figure 1 is a structural connection diagram schematically showing a frequency converter according to some embodiments of the present disclosure;

[0030] Figure 2 is a circuit connection diagram schematically showing a partial structure of a frequency converter according to some embodiments of the present disclosure;

[0031] Figure 3 is a circuit connection diagram schematically showing a regulating module of a control circuit according to some embodiments of the present disclosure;

[0032] Figure 4 is a flow chart showing a control method for a frequency converter according to some embodiments of the present disclosure;

[0033] Figure 5 is a flow chart showing a control method for a frequency converter according to other embodiments of the present disclosure;

[0034] Figure 6 is a block diagram schematically showing a structure of a controller for a frequency converter according to some embodiments of the present disclosure;

[0035] Figure 7 is a block diagram schematically showing a structure of a controller for a frequency converter according to some other embodiments of the present disclosure.

[0036] It should be understood that the size of each part shown in the accompanying drawings is not drawn according to the actual proportional relationship. In addition, the same or similar reference numerals represent the same or similar components. DETAILED DESCRIPTION

[0037] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and is in no way intended to limit the present disclosure and its application or use. The present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present disclosure thorough and complete and to fully express the scope of the present disclosure to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of the components and steps, the composition of the materials, the numerical expressions and the numerical values ​​set forth in these embodiments should be interpreted as being merely exemplary and not as limiting.

[0038] The words "first", "second" and similar words used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different parts. The words "include" or "comprise" and similar words mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of including other elements. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0039] In the present disclosure, when a specific device is described as being located between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the second device. When a specific device is described as being connected to other devices, the specific device may be directly connected to the other device without an intermediate device, or may not be directly connected to the other device but have an intermediate device.

[0040] All terms (including technical terms or scientific terms) used in the present disclosure have the same meanings as those understood by ordinary technicians in the field to which the present disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries, such as general dictionaries, should be interpreted as having meanings consistent with their meanings in the context of the relevant technology, and should not be interpreted in an idealized or extremely formal sense, unless explicitly defined herein.

[0041] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0042] Figure 1 is a structural connection diagram schematically showing a frequency converter according to some embodiments of the present disclosure.

[0043] like Figure 1 As shown, the frequency converter includes a rectifier circuit 110, an inverter circuit 120, and a DC bus circuit 130 electrically connected between the rectifier circuit 110 and the inverter circuit 120. The rectifier circuit 110 includes an inductor and a first switch device electrically connected to the inductor.

[0044] Here, the rectifier circuit 110 , the inverter circuit 120 and the DC bus circuit 130 may adopt circuit structures known to those skilled in the art.

[0045] For example, Figure 2 Schematically shows a circuit connection diagram of a part of the structure of a frequency converter according to some embodiments of the present disclosure. Figure 2 The structures of the rectifier circuit 110 , the inverter circuit 120 , and the DC bus circuit 130 are shown as examples.

[0046] like Figure 2 As shown, the rectifier circuit 110 may include a rectifier bridge circuit composed of four diodes D1 to D4. For example, in the rectifier bridge circuit, the cathode terminal of the first diode D1 is electrically connected to the cathode terminal of the second diode D2, the anode terminal of the first diode D1 is electrically connected to the cathode terminal of the third diode D3, the anode terminal of the second diode D2 is electrically connected to the cathode terminal of the fourth diode D4, and the anode terminal of the third diode D3 is electrically connected to the anode terminal of the fourth diode D4. For example, the anode terminal of the first diode D1 is electrically connected to the live line AC_L of the alternating current, and the anode terminal of the second diode D2 is electrically connected to the neutral line AC_N of the alternating current.

[0047] The rectifier circuit 110 may also include one or more inductors and one or more first switching devices. The one or more inductors are electrically connected to the one or more first switching devices in a one-to-one correspondence. Figure 2 As shown, the rectifier circuit 110 may further include a first inductor L1, a second inductor L2, a first sub-switching device Q1 electrically connected to the first inductor L1, and a second sub-switching device Q2 electrically connected to the second inductor L2. The first sub-switching device Q1 and the second sub-switching device Q2 are both the first switching devices described above.

[0048] For example, the inductance value of the inductor can be selected according to the current value, which can be a few microhenries. The main function of the inductor is to store energy.

[0049] like Figure 2As shown, the first end of the first inductor L1 and the first end of the second inductor L2 are both electrically connected to the cathode end of the first diode D1. The second end of the first inductor L1 is electrically connected to the first end of the first sub-switching device Q1. The second end of the second inductor L2 is electrically connected to the first end of the second sub-switching device Q2. The second end of the first sub-switching device Q1 and the second end of the second sub-switching device Q2 are both electrically connected to the anode end of the third diode D3. The control end of the first sub-switching device Q1 and the control end of the second sub-switching device Q2 are respectively electrically connected to the control circuit to be described later.

[0050] It should be noted that the first switch device may be a known device, for example, a MOS (Metal-Oxide-Semiconductor) transistor, for example, an NMOS (N-Metal-Oxide-Semiconductor) transistor or a PMOS (P-Metal-Oxide-Semiconductor) transistor. Of course, the first switch device may also be other types of switch devices. The scope of the present disclosure is not limited to the specific type of the first switch device.

[0051] It should also be noted that although Figure 2 Two inductors and two first switching devices electrically connected to the two inductors are shown, but the scope of the present disclosure is not limited to this. For example, the rectifier circuit may include an inductor and a first switching device electrically connected to the inductor, or more than two inductors and more than two first switching devices electrically connected to the more than two inductors.

[0052] The rectifier circuit 110 may include a diode electrically connected between the second end of the inductor and the DC bus circuit 130. For example, Figure 2 As shown, the rectifier circuit 110 may include a fifth diode D5 electrically connected to the second end of the first inductor L1 and a sixth diode D6 electrically connected to the second end of the second inductor L2. Here, the positive terminal of the fifth diode D5 is electrically connected to the second end of the first inductor L1, and the negative terminal of the fifth diode D5 is electrically connected to the DC bus circuit 130. The positive terminal of the sixth diode D6 is electrically connected to the second end of the second inductor L2, and the negative terminal of the sixth diode D6 is electrically connected to the DC bus circuit 130. Here, the number of diodes electrically connected between the second end of the inductor and the DC bus circuit 130 corresponds to the number of inductors. That is, the diodes are electrically connected to the inductors in a one-to-one correspondence.

[0053] It should be noted that Figure 2The circuit structure of the rectifier circuit 110 shown above is only exemplary, and the scope of the present disclosure is not limited to the specific structure of the rectifier circuit 110. The embodiments of the present disclosure may also adopt rectifier circuits 110 of other structures, which include an inductor and a first switching device electrically connected to the inductor.

[0054] like Figure 1 and Figure 2 As shown, the DC bus circuit 130 includes a DC bus capacitor C dc For example, the DC bus capacitor C dc It can be a film capacitor. DC bus capacitor C dc It can be selected according to the power of the inverter. Different power can select DC bus capacitors with different capacitance values. dc For example, the DC bus capacitor C dc The capacitance value can be several thousand microfarads.

[0055] like Figure 2 As shown, the inverter circuit 120 may include six switching devices Q3 to Q8, a sixth resistor R u and the seventh resistor R v .like Figure 2 As shown, in the inverter circuit 120, the first end of the third switching device Q3 is electrically connected to the DC bus capacitor C dc The first end of the third switching device Q3 is electrically connected to the first end of the sixth switching device Q6, and the second end of the sixth switching device Q6 is electrically connected to the sixth resistor R u The first end of the sixth resistor R u The second end is electrically connected to the DC bus capacitor C dc The first end of the fourth switching device Q4 is electrically connected to the DC bus capacitor C dc The first end of the fourth switching device Q4 is electrically connected to the first end of the seventh switching device Q7, and the second end of the seventh switching device Q7 is electrically connected to the seventh resistor R v The first end of the seventh resistor R v The second end is electrically connected to the DC bus capacitor C dc The first end of the fifth switching device Q5 is electrically connected to the DC bus capacitor C dc The first end of the fifth switching device Q5 is electrically connected to the first end of the eighth switching device Q8, and the second end of the eighth switching device Q8 is electrically connected to the DC bus capacitor C dc The second end of the third switch device Q3, the second end of the fourth switch device Q4 and the second end of the fifth switch device Q5 are electrically connected to the load (for example, the motor M). The control ends of the six switch devices Q3 to Q8 are all electrically connected to the control circuit ( Figure 2 not shown).

[0056] Back to Figure 1 The frequency converter further includes a control circuit 200. That is, the control circuit 200 is used for the frequency converter. Figure 1 As shown, the control circuit 200 includes an acquisition module 210 , a control module 220 and an adjustment module 230 .

[0057] The acquisition module 210 is configured to acquire the current of the three-phase electricity output by the inverter circuit 120 to the load and the bus voltage of the DC bus circuit 130 .

[0058] For example, the acquisition module 210 can collect the current of two phases of the three-phase power output from the inverter circuit 120 to the load through a current detector (e.g., a current sensor), and then calculate the current of the other phase based on the current of the two phases. u and I v Then, based on the principle that the sum of the three-phase currents equals 0, calculate the current I of the other phase w For I w =-(I u +I v ).

[0059] For another example, the acquisition module 210 can directly collect the three-phase current I output by the inverter circuit 120 to the load through the current detector. u ,I v and I w .

[0060] For example, the acquisition module 210 can measure the bus voltage U of the DC bus circuit 130 through a voltage detector. bus .

[0061] The acquisition module 210 can obtain the current I of the three-phase electricity u ,I v and I w and bus voltage U bus Transmitted to the control module 220.

[0062] The control module 220 is configured to obtain the quadrature axis current component according to the current decoupling calculation of the three-phase electricity, and output a first voltage value according to the quadrature axis current component and a preset first current parameter when the bus voltage is greater than a first voltage threshold, and output a second voltage value according to the quadrature axis current component and a preset second current parameter when the bus voltage is less than a second voltage threshold. The second voltage threshold is less than the first voltage threshold. For example, the control module may adopt a controller or a control subcircuit, etc.

[0063] For example, the control module 220 can calculate the current I of the three-phase electricity according to the u ,Iv and I w , through coordinate transformation and other methods, the direct axis current component I is calculated d and the quadrature axis current component I q Here, the direct-axis current component I is calculated based on the three-phase current d and the quadrature axis current component I q This is a technology known to those skilled in the art and will not be described in detail here.

[0064] The regulating module 230 is configured to control the first switching device to be turned off in response to the first voltage value, and to control the first switching device to be alternately turned on and off in response to the second voltage value.

[0065] It should be noted that the conduction and shutdown of the first switching device (for example, the first switching device Q1 and Q2) can affect the energy stored in the inductor (for example, the inductor L1 and L2), and the more energy stored in the inductor, the higher the downstream voltage (i.e., the bus voltage) is, and the less energy stored in the inductor, the lower the downstream voltage (i.e., the bus voltage) is.

[0066] Therefore, the regulating module controls the first switching device to turn off in response to the first voltage value, so that the energy stored in the inductor can be reduced when the bus voltage is greater than the first voltage threshold, thereby reducing the bus voltage; the regulating module controls the first switching device to be alternately turned on and off in response to the second voltage value, so that the energy stored in the inductor can be gradually increased when the bus voltage is less than the second voltage threshold, thereby increasing the bus voltage.

[0067] Moreover, the regulating module can also prevent the problem that the inductor continues to store energy until the energy storage is full and then short-circuits by controlling the first switch device to alternately turn on and off in response to the second voltage value. For example, the regulating module can output a pulse width modulation (PWM) signal to the control terminal of the first switch device to turn the first switch device on and off periodically.

[0068] It should be noted that the first voltage threshold can be set according to actual conditions or actual needs, for example, the first voltage threshold can be 380V or 400V, and the set value is different according to different control strategies; the second voltage threshold can also be set according to actual conditions or actual needs, for example, the second voltage threshold can be 360V or 380V, and the set value is different according to different control strategies. The scope of the present disclosure is not limited to the specific values ​​of the first voltage threshold and the second voltage threshold.

[0069] So far, a control circuit for a frequency converter according to some embodiments of the present disclosure is provided. The frequency converter includes a rectifier circuit, an inverter circuit, and a DC bus circuit electrically connected between the rectifier circuit and the inverter circuit, the rectifier circuit includes an inductor and a first switch device electrically connected to the inductor, and the control circuit includes: an acquisition module configured to acquire the current of the three-phase electricity output by the inverter circuit to the load and the bus voltage of the DC bus circuit; a control module configured to obtain the quadrature-axis current component according to the current decoupling calculation of the three-phase electricity, and output a first voltage value according to the quadrature-axis current component and a preset first current parameter when the bus voltage is greater than a first voltage threshold, and output a second voltage value according to the quadrature-axis current component and a preset second current parameter when the bus voltage is less than a second voltage threshold, wherein the second voltage threshold is less than the first voltage threshold; and a regulation module configured to control the first switch device to turn off in response to the first voltage value, and control the first switch device to alternately turn on and off in response to the second voltage value. In the control circuit, when the bus voltage is greater than the first voltage threshold, the first switch device is controlled to be turned off, so that the energy stored in the inductor can be reduced, thereby reducing the bus voltage. When the bus voltage is less than the second voltage threshold, the first switch device is controlled to be alternately turned on and off, so that the energy stored in the inductor gradually increases, thereby increasing the bus voltage. In this way, the fluctuation of the DC bus voltage can be reduced, and the reliability and robustness of the system can be improved.

[0070] In some embodiments, the control module 220 is configured to calculate the sum of the quadrature axis current component and the first current parameter, obtain the first voltage value corresponding to the sum according to the sum and the corresponding relationship between the preset current value and the voltage value, and calculate the difference between the quadrature axis current component and the second current parameter, and obtain the second voltage value corresponding to the difference according to the corresponding relationship between the difference and the current value and the voltage value. In this way, the first voltage value is calculated when the bus voltage is greater than the first voltage threshold, and the second voltage value is calculated when the bus voltage is less than the second voltage threshold. The method is simple and convenient to implement, and can improve the processing rate of the control module, thereby quickly reducing the fluctuation of the bus voltage.

[0071] For example, the control module may pre-store a corresponding relationship table of current values ​​and voltage values ​​(for example, the corresponding relationship table may be obtained based on multiple tests), and the control module calculates the quadrature-axis current component I when the bus voltage is greater than the first voltage threshold. q and the first current parameter I Δ1 The sum of I A , that is I A =I q +I Δ1 , then based on I A The corresponding first voltage value V can be found by looking up the above correspondence table. Q1, the control module calculates the quadrature axis current component I when the bus voltage is less than the second voltage threshold q and the second current parameter I Δ2 The difference I B , that is I B =I q -I Δ2 , then based on I B The corresponding second voltage value V can be found by looking up the above correspondence table. Q2 For example, the first voltage value V 1 Greater than the second voltage value V 2 .

[0072] In some embodiments, the first voltage value V Q1 and the second voltage value V Q2 The range of is 0V to 5V. For example, the first voltage value V Q1 is 5V, the second voltage value V Q2 Of course, the first voltage value V Q1 and the second voltage value V Q2 The above range is only exemplary, and the scope of the present disclosure is not limited to the first voltage value V Q1 and the second voltage value V Q2 A specific range or value.

[0073] It should be noted that the first current parameter I Δ1 and the second current parameter I Δ2 It can be set according to actual needs or actual conditions, or obtained through multiple tests. Therefore, the scope of the present disclosure is not limited to the first current parameter I Δ1 and the second current parameter I Δ2 For example, a suitable first current parameter I can be set Δ1 , so that the control module outputs the first voltage value V after calculation and table lookup Q1 is 5V, and a suitable second current parameter I can also be set Δ2 , so that the control module outputs a second voltage value V after calculation and table lookup Q2 is 0V.

[0074] In some embodiments, the first voltage threshold is the upper limit of the allowable range of the bus voltage; the second voltage threshold is the lower limit of the allowable range of the bus voltage. In this way, by setting the first voltage threshold and the second voltage threshold as the upper limit and lower limit of the allowable range of the bus voltage, after the control described above, the bus voltage can be adjusted within the allowable range, thereby improving the stability of system operation.

[0075] In some embodiments, the control module is further configured to output a pulse width modulation signal to the first switch device to control the first switch device to alternately turn on and off when the bus voltage is less than or equal to the first voltage threshold and greater than or equal to the second voltage threshold. In this embodiment, when the bus voltage is less than or equal to the first voltage threshold and greater than or equal to the second voltage threshold, the control module can control the on and off of the first switch device in the rectifier circuit according to normal logic, thereby achieving bus voltage stability.

[0076] For example, the control module may directly output the pulse width modulation signal to the first switching device when the bus voltage is less than or equal to the first voltage threshold and greater than or equal to the second voltage threshold.

[0077] Figure 3 is a circuit connection diagram schematically illustrating a regulating module of a control circuit according to some embodiments of the present disclosure.

[0078] like Figure 3 As shown, the adjustment module includes a comparison circuit 310 and a logic processing circuit 320 .

[0079] The comparison circuit 310 is configured to respond to the first voltage value V Q1 , output the first level signal V L1 , and in response to the second voltage value V Q2 , output the second level signal V L2 The first level signal is different from the second level signal. For example, the first level signal is lower than the second level signal, that is, the first level signal V L1 is a low level signal, the second level signal V L2 It is a high level signal.

[0080] The logic processing circuit 320 is configured to respond to the first level signal V L1 , outputs a first control signal (eg, a first control signal G1 or G3) to the first switch device to control the first switch device to be turned off, in response to the second level signal V L2 , outputting a second control signal (eg, a second control signal G2 or G4) to the first switching device to control the first switching device to be alternately turned on and off.

[0081] In the above embodiment, the regulation module is implemented by a comparison circuit and a logic processing circuit, so that the regulation module controls the first switching device to turn off in response to the first voltage value, and controls the first switching device to be alternately turned on and off in response to the second voltage value, thereby reducing the fluctuation of the DC bus voltage and improving the reliability and robustness of the system.

[0082] In some embodiments, the second control signal is a pulse width modulation signal. In this way, the first switch device can be periodically turned on and off, that is, when the bus voltage is less than the second voltage threshold, the energy stored in the inductor can be gradually increased, thereby increasing the bus voltage, and preventing the problem of the inductor continuously storing energy until the energy storage is full and short-circuiting due to the continuous conduction of the first switch device.

[0083] In some embodiments, Figure 3 As shown, the comparison circuit 310 includes a first resistor R1 and a second resistor R2. The first resistor R1 and the second resistor R2 are connected in series between the first voltage terminal 301 and the ground terminal GND. That is, the first end of the first resistor R1 is electrically connected to the first voltage terminal 301, the second end of the first resistor R1 is electrically connected to the first end of the second resistor R2, and the second end of the second resistor R2 is electrically connected to the ground terminal GND. The first voltage terminal 301 is used to provide a bus voltage U bus .

[0084] Here, the first resistor R1 and the second resistor R2 play the role of voltage-dividing resistors. For example, the first resistor R1 and the second resistor R2 may be resistors of several kilo-ohms (kΩ) respectively.

[0085] For example, the resistance of the first resistor R1 is 9kΩ, and the resistance of the second resistor R2 is 1kΩ, then the voltage at the connection point between the first resistor R1 and the second resistor R2 (as a voltage dividing point, for example, the second end of the first resistor R1) is 0.1 times the bus voltage.

[0086] For another example, the resistance of the first resistor R1 is 99kΩ, and the resistance of the second resistor R2 is 1kΩ, then the voltage at the connection point between the first resistor R1 and the second resistor R2 (as a voltage dividing point, for example, the second end of the first resistor R1) is 0.01 times the bus voltage. For example, if the bus voltage is 380V, then 0.01 times the bus voltage is 3.8V, which can facilitate the subsequent comparison with the first voltage value V Q1 and the second voltage value V Q2 compared with a voltage (e.g. 0V to 5V).

[0087] It should be noted that the resistance values ​​of the first resistor R1 and the second resistor R2 are merely exemplary, and the scope of the present disclosure is not limited to the specific resistance values ​​of the first resistor R1 and the second resistor R2. The resistance values ​​of the first resistor R1 and the second resistor R2 can be set according to actual needs or actual conditions.

[0088] like Figure 3As shown, the comparison circuit 310 also includes a comparator 312. A first input terminal (e.g., a positive input terminal) of the comparator 312 is electrically connected to a connection point between the first resistor R1 and the second resistor R2, and a second input terminal (e.g., a negative input terminal) of the comparator 312 is electrically connected to an output terminal of the control module 220. The second input terminal of the comparator 312 is used to receive a first voltage value V Q1 Or the second voltage value V Q2 The output terminal of the comparator 312 is electrically connected to the logic processing circuit 320 .

[0089] The comparator 312 is configured to determine the voltage of the connection point based on the voltage of the connection point and the first voltage value V Q1 The comparison result outputs the first level signal V L1 , and based on the voltage of the connection point and the second voltage value V Q2 The comparison result outputs the second level signal V L2 .

[0090] For example, the first level signal V L1 is a low level signal, the second level signal V L2 is a high level signal. For example, when the voltage at the connection point is 3.8V, the first voltage value V Q1 When the voltage at the connection point is 3.8V, the second voltage value V Q2 When 0V, 3.8V is greater than 0V, and the comparator 312 outputs a high level signal.

[0091] So far, a comparison circuit according to some embodiments of the present disclosure is provided, and the comparison circuit includes a first resistor, a second resistor and a comparator. Through the comparison circuit structure, the comparison circuit can output a first level signal to the logic processing circuit in response to the first voltage value, and output a second level signal to the logic processing circuit in response to the second voltage value, so that the logic processing circuit can conveniently control the on and off of the first switching device, thereby reducing the fluctuation of the DC bus voltage and improving the reliability and robustness of the system. In addition, the circuit is relatively simple and can reduce costs.

[0092] like Figure 3 As shown, the comparison circuit 310 may further include a third resistor R3. The third resistor R3 is disposed between the second input terminal (e.g., the inverting input terminal) of the comparator 312 and the output terminal of the control module 220. That is, a first end of the third resistor R3 is electrically connected to the output terminal of the control module 220, and a second end of the third resistor R3 is electrically connected to the second input terminal of the comparator 312. The third resistor R3 may function as a current limiting resistor, thereby reducing the risk of damage to the comparator due to a large current that may occur.

[0093] For example, the resistance value of the third resistor R3 may be several kiloohms. For example, the resistance value of the third resistor R3 is 10 kΩ. It should be noted that the resistance value of the third resistor R3 is only exemplary, and the scope of the present disclosure is not limited to the specific resistance value of the third resistor R3. The resistance value of the third resistor R3 can be set according to actual needs or actual conditions.

[0094] like Figure 3 As shown, the comparison circuit 310 may further include a first capacitor C1. A first end of the first capacitor C1 is electrically connected to a second input end of the comparator 312, and a second end of the first capacitor C1 is electrically connected to a ground end GND. The first capacitor may play a filtering role to reduce signal interference.

[0095] For example, the capacitance value of the first capacitor C1 ranges from 0.1 microfarad to 1 microfarad. It should be noted that the capacitance value of the first capacitor C1 is only exemplary, and the scope of the present disclosure is not limited to the specific capacitance value of the first capacitor C1. The capacitance value of the first capacitor C1 can be set according to actual needs or actual conditions.

[0096] In some embodiments, Figure 3 As shown, the logic processing circuit 320 includes a second switch device Q9. A first terminal of the second switch device Q9 is electrically connected to a second voltage terminal 302, and a control terminal of the second switch device Q9 is electrically connected to a comparison circuit (e.g., electrically connected to an output terminal of a comparator 312). For example, the second voltage terminal 302 is used to provide a power supply voltage VDD.

[0097] For example, the second switch device Q9 may be an NPN transistor. Of course, those skilled in the art will appreciate that the second switch device Q9 here is only exemplary, and the embodiments of the present disclosure may also use other types of switch devices as the second switch device, such as a PNP transistor, an NMOS transistor, or a PMOS transistor. A corresponding type of switch device may be set as the second switch device according to actual conditions or actual needs, and the scope of the present disclosure is not limited to the specific type of the second switch device.

[0098] like Figure 3 As shown, the logic processing circuit 320 further includes a fourth resistor R4. A first end of the fourth resistor R4 is electrically connected to a second end of the second switch device Q9, and a second end of the fourth resistor R4 is electrically connected to a ground terminal GND. The fourth resistor can play a role in current limiting.

[0099] For example, the resistance value of the fourth resistor R4 may be several kiloohms. For example, the resistance value of the fourth resistor R4 is 10 kΩ. It should be noted that the resistance value of the fourth resistor R4 is only exemplary, and the scope of the present disclosure is not limited to the specific resistance value of the fourth resistor R4. The resistance value of the fourth resistor R4 can be set according to actual needs or actual conditions.

[0100] like Figure 3 As shown, the logic processing circuit 320 also includes an AND gate device (e.g., an AND gate device U1 or U2). The first input terminal of the AND gate device is electrically connected to the second terminal of the second switch device Q9. The second input terminal of the AND gate device is configured to receive an initial control signal. For example, the initial control signal is a PWM signal (e.g., a PWM1 signal or a PWM2 signal). The output terminal of the AND gate device is electrically connected to the control terminal of the first switch device (e.g., the first switch device Q1 or Q2).

[0101] So far, a logic processing circuit according to some embodiments of the present disclosure is provided. The logic processing circuit includes a second switch device, a fourth resistor and an AND gate device. Through the structure of the logic processing circuit, the logic processing circuit can output a first control signal to the first switch device in response to a first level signal to control the first switch device to turn off, and output a second control signal to the first switch device in response to a second level signal to control the first switch device to alternately turn on and off. In this way, the fluctuation of the DC bus voltage can be reduced, the reliability and robustness of the system can be improved, and the circuit is relatively simple, which can reduce costs.

[0102] Combine the following Figure 3 Describe the working process of the adjustment module in detail.

[0103] For example, when the bus voltage is greater than the first voltage threshold, the control module 220 outputs a first voltage value V according to the quadrature-axis current component and the preset first current parameter. Q1 , for example, the first voltage value V Q1 is high level, so that the second input terminal of the comparator 312 receives the first voltage value V Q1 , since the voltage at the connection point is less than the first voltage value V Q1 , the comparator 312 outputs a low level signal (ie, the first level signal V L1 ) to the second switching device Q9, and the second switching device Q9 is not turned on, then the AND gate device receives a low-level signal, and therefore, the AND gate device outputs a low-level first control signal (for example, signal G1 and / or G3) to the first switching device to control the first switching device (for example, Q1 and / or Q2) to turn off, thereby reducing the bus voltage.

[0104] For another example, when the bus voltage is less than the second voltage threshold, the control module 220 outputs a second voltage value V according to the quadrature-axis current component and a preset second current parameter. Q2 , for example, the second voltage value V Q2 is low level, so that the second input terminal of the comparator 312 receives the second voltage value V Q2 , since the voltage at the connection point is greater than the second voltage value V Q2 , the comparator 312 outputs a high level signal (ie, the second level signal V L2 ) to the second switching device Q9, the second switching device Q9 is turned on, and the AND gate device receives the high level signal, therefore, the AND gate device outputs a second control signal (for example, signal G2 and / or G4) to the first switching device, and the second control signal is the same as the initial control signal (for example, PWM1 signal and / or PWM2 signal), so that the first switching device (for example, Q1 and / or Q2) is controlled to be alternately turned on and off, thereby increasing the bus voltage.

[0105] For another example, if the bus voltage is between the first voltage threshold and the second voltage threshold, the control circuit controls the first switching device on the rectifier side according to normal logic to achieve bus voltage stability.

[0106] In some embodiments, Figure 3 As shown, the logic processing circuit may further include a fifth resistor R5. The fifth resistor R5 is disposed between the second end of the second switch device Q9 and the first input end of the AND gate device (U1 and / or U2). That is, the first end of the fifth resistor R5 is electrically connected to the second end of the second switch device Q9, and the second end of the fifth resistor R5 is electrically connected to the AND gate device. The fifth resistor R5 can play a role in current limiting, reducing the risk of damage to the AND gate device caused by a possible large current.

[0107] For example, the resistance value of the fifth resistor R5 may be several kiloohms. For example, the resistance value of the fifth resistor R5 is 10 kΩ. It should be noted that the resistance value of the fifth resistor R5 is only exemplary, and the scope of the present disclosure is not limited to the specific resistance value of the fifth resistor R5. The resistance value of the fifth resistor R5 can be set according to actual needs or actual conditions.

[0108] like Figure 3 As shown, the logic processing circuit may further include a second capacitor C2. A first end of the second capacitor C2 is electrically connected to a second end of the fifth resistor R5, and a second end of the second capacitor C2 is electrically connected to a ground terminal GND. The second capacitor may play a filtering role to reduce signal interference.

[0109] For example, the capacitance value of the second capacitor C2 ranges from 0.1 microfarad to 1 microfarad. It should be noted that the capacitance value of the second capacitor C2 is only exemplary, and the scope of the present disclosure is not limited to the specific capacitance value of the second capacitor C2. The capacitance value of the second capacitor C2 can be set according to actual needs or actual conditions.

[0110] In some embodiments, the rectifier circuit 110 may include a plurality of inductors and a plurality of first switching devices, wherein the plurality of inductors are electrically connected to the plurality of first switching devices in a one-to-one correspondence. Figure 2 As shown, the rectifier circuit 110 includes two inductors L1 and L2, and two first switching devices Q1 and Q2 electrically connected to the two inductors L1 and L2 in a one-to-one correspondence.

[0111] Accordingly, the logic processing circuit may include a plurality of AND gate devices. The first input terminals of the plurality of AND gate devices are electrically connected to the second terminal of the second switch device, the second input terminal of each AND gate device is configured to receive an initial control signal corresponding to each AND gate device, and the output terminals of the plurality of AND gate devices are electrically connected to the control terminals of the plurality of first switch devices in a one-to-one correspondence. For example, the initial control signal is a PWM signal.

[0112] For example, Figure 3 As shown, the logic processing circuit 120 may include two AND gate devices U1 and U2. The first input terminals of the two AND gate devices U1 and U2 are both electrically connected to the second terminal of the second switch device Q9. The second input terminal of the first AND gate device U1 is configured to receive an initial control signal PWM1 corresponding to the first AND gate device U1. The second input terminal of the second AND gate device U2 is configured to receive an initial control signal PWM2 corresponding to the second AND gate device U2. The output terminals of the two AND gate devices U1 and U2 are electrically connected to the control terminals of the two first switch devices Q1 and Q2 in a one-to-one correspondence.

[0113] In the above embodiment, by providing a plurality of inductors and a plurality of first switching devices in the rectifier circuit and a plurality of AND gate devices in the logic processing circuit, it is possible to control each of the plurality of first switching devices, thereby more finely reducing the fluctuation of the bus voltage and further improving the reliability of the system operation.

[0114] It should be noted that although Figure 2 Two inductors and two first switching devices are shown in FIG. Figure 3Two AND gate devices are shown in the figure, but the scope of the present disclosure is not limited thereto. For example, in an embodiment of the present disclosure, the rectifier circuit may include an inductor and a first switch device and the logic processing circuit includes an AND gate device, or the rectifier circuit may include three or more inductors and three or more first switch devices and the logic processing circuit includes three or more AND gate devices. For example, a suitable number of inductors, first switch devices, and AND gate devices may be set according to actual conditions or actual needs.

[0115] So far, the control circuit according to some embodiments of the present disclosure has been described in detail. In the control circuit, the PFC (Power Factor Correction) control signal is adjusted in real time by hardware to open and close the circuit, so as to achieve bus voltage stability control when using thin film capacitors. The algorithm complexity is reduced, the failure rate is reduced, and the system reliability is improved through the torque feedforward control method. Moreover, the cost of implementing the solution of the present disclosure is low.

[0116] The controllable rectifier control scheme disclosed in the present invention can meet the requirement of fast controllable rectifier control response speed, and adopt the control strategy of post-stage motor current decoupling feedforward to achieve stable and controllable operation of the system.

[0117] In some embodiments of the present disclosure, a frequency converter is further provided, comprising: the control circuit as described above (for example, Figure 1 control circuit shown).

[0118] In some embodiments, Figure 1 As shown, the frequency converter may further include a rectifier circuit 110, an inverter circuit 120 and a DC bus circuit 130. The rectifier circuit 110 includes an inductor and a first switching device electrically connected to the inductor, and the first switching device is electrically connected to the control circuit 200. The inverter circuit 120 is electrically connected to the control circuit 200. The DC bus circuit 130 is electrically connected between the rectifier circuit 110 and the inverter circuit 120, and is electrically connected to the control circuit 200. The control circuit 200 is configured to obtain the current of the three-phase electricity output by the inverter circuit to the load and the bus voltage of the DC bus circuit, and control the conduction and shutdown of the first switching device. The frequency converter can reduce the fluctuation of the DC bus voltage and improve the reliability and robustness of the system.

[0119] In some embodiments of the present disclosure, an air conditioning device is further provided, comprising: a frequency converter as described above (for example, Figure 1 inverter shown).

[0120] Figure 41 is a flow chart showing a control method for a frequency converter according to some embodiments of the present disclosure. The frequency converter includes a rectifier circuit, an inverter circuit, and a DC bus circuit electrically connected between the rectifier circuit and the inverter circuit, and the rectifier circuit includes an inductor and a first switching device electrically connected to the inductor. For example, the control method can be implemented in a controller or a control module. Figure 4 As shown, the control method includes steps S402 to S408.

[0121] In step S402, the current of the three-phase electricity output by the inverter circuit to the load and the bus voltage of the DC bus circuit are obtained.

[0122] In step S404, a quadrature-axis current component is obtained according to the current decoupling calculation of the three-phase electricity.

[0123] In step S406, when the bus voltage is greater than the first voltage threshold, a first voltage value is output to the regulating module according to the quadrature-axis current component and a preset first current parameter, so that the regulating module controls the first switch device to turn off.

[0124] In step S408, when the bus voltage is less than a second voltage threshold, a second voltage value is output to the regulating module according to the quadrature-axis current component and a preset second current parameter, so that the regulating module controls the first switching device to be alternately turned on and off, wherein the second voltage threshold is less than the first voltage threshold.

[0125] So far, a control method for a frequency converter according to some embodiments of the present disclosure is provided. The control method includes: obtaining the current of the three-phase electricity output by the inverter circuit to the load and the bus voltage of the DC bus circuit; calculating the quadrature axis current component according to the current decoupling of the three-phase electricity; when the bus voltage is greater than the first voltage threshold, outputting a first voltage value to the regulating module according to the quadrature axis current component and the preset first current parameter, so that the regulating module controls the first switch device to turn off; and when the bus voltage is less than the second voltage threshold, outputting a second voltage value to the regulating module according to the quadrature axis current component and the preset second current parameter, so that the regulating module controls the first switch device to turn on and off alternately, wherein the second voltage threshold is less than the first voltage threshold. In the control method, by controlling the first switch device to turn off when the bus voltage is greater than the first voltage threshold, the energy stored in the inductor can be reduced, thereby reducing the bus voltage, and when the bus voltage is less than the second voltage threshold, the first switch device is controlled to turn on and off alternately, so that the energy stored in the inductor gradually increases, thereby increasing the bus voltage. In this way, the fluctuation of DC bus voltage can be reduced and the reliability and robustness of the system can be improved.

[0126] In some embodiments, outputting a first voltage value according to the quadrature-axis current component and a preset first current parameter includes: calculating the sum of the quadrature-axis current component and the first current parameter; and obtaining a first voltage value corresponding to the sum according to the correspondence between the sum and the preset current value and voltage value. In this way, a method of calculating and obtaining the first voltage value when the bus voltage is greater than the first voltage threshold is realized, which is simple and convenient to implement, can improve the processing rate, and thus can quickly reduce the fluctuation of the bus voltage.

[0127] In some embodiments, outputting the second voltage value according to the quadrature-axis current component and the preset second current parameter includes: calculating the difference between the quadrature-axis current component and the second current parameter; and obtaining the second voltage value corresponding to the difference according to the difference and the corresponding relationship between the preset current value and the voltage value. In this way, a method of calculating and obtaining the second voltage value when the bus voltage is less than the second voltage threshold is realized, which is simple and convenient to implement, can improve the processing rate, and thus can quickly reduce the fluctuation of the bus voltage.

[0128] In some embodiments, the control method further includes: when the bus voltage is less than or equal to the first voltage threshold and greater than or equal to the second voltage threshold, outputting a pulse width modulation signal to the first switch device to control the first switch device to alternately turn on and off. In this embodiment, when the bus voltage is less than or equal to the first voltage threshold and greater than or equal to the second voltage threshold, the on and off of the first switch device in the rectifier circuit can be controlled according to normal logic, thereby achieving bus voltage stability.

[0129] Figure 5 FIG. 1 is a flow chart showing a control method for a frequency converter according to other embodiments of the present disclosure. Figure 5 As shown, the control method includes steps S502 to S522.

[0130] In step S502, the bus voltage U is detected. bus .

[0131] In step S504, the motor current is detected, that is, the current of the three-phase power output from the inverter circuit to the motor (as a load) is detected.

[0132] It should be noted that step S502 may be executed before step S504, or after step S504, or simultaneously with step S504, and the scope of the present disclosure is not limited to the sequence of step S502 and step S504.

[0133] In step S506, the decoupling calculation current I q For example, the quadrature-axis current component I is obtained by calculating the current decoupling of the three-phase electricity. q and the direct axis current component I d .

[0134] In step S508, determine bus Is it greater than U th1 Here, U th1 is the first voltage threshold. If yes, the process proceeds to step S510; otherwise, the process proceeds to step S514.

[0135] In step S510, the output voltage V Q1 For example, to calculate the quadrature-axis current component I q and the preset first current parameter, and then according to the corresponding relationship between the sum value and the preset current value and the voltage value, obtain and output the first voltage value V corresponding to the sum value Q1 .

[0136] In step S512, the first switching device is turned off.

[0137] In step S514, it is determined that bus Is it less than U th2 Here, U th2 is the second voltage threshold. If yes, the process proceeds to step S516; otherwise, the process proceeds to step S520.

[0138] In step S516, the output voltage V Q2 For example, to calculate the quadrature-axis current component I q The difference between the second current parameter and the preset current parameter is obtained, and then the second voltage value V corresponding to the difference is obtained and output according to the corresponding relationship between the difference and the current value and the voltage value. Q2 .

[0139] In step S518, the first switching device is alternately turned on and off. For example, the first switching device may be turned on and off periodically.

[0140] In step S520, the first switch device is normally controlled. bus Less than or equal to the first voltage threshold U th1 and is greater than or equal to the second voltage threshold U th2 In the case of the present invention, a pulse width modulation signal is output to the first switching device to control the first switching device to be alternately turned on and off.

[0141] In step S522, the process is executed in a loop, that is, steps S502 to S520 are executed in a loop.

[0142] For example, in U bus Greater than U th1 After the first switch device is turned off, U bus Still greater than U th1, then go through steps S502 to S512 again, that is, still turn off the first switch device until U bus No longer greater than U th1 until.

[0143] For example, in U bus Less than U th2 After the first switch device is alternately turned on and off, U bus Still smaller than U th2 , then go through steps S502 to S506 and S514 to S518 again, that is, still alternately turn on and off the first switch device until U bus No longer less than U th2 until.

[0144] So far, a control method for a frequency converter according to other embodiments of the present disclosure is provided. In the control method, by controlling the first switch device to turn off when the bus voltage is greater than the first voltage threshold, the energy stored in the inductor can be reduced, thereby reducing the bus voltage. When the bus voltage is less than the second voltage threshold, the first switch device is controlled to be alternately turned on and off, so that the energy stored in the inductor gradually increases, thereby increasing the bus voltage. In this way, the fluctuation of the DC bus voltage can be reduced, and the reliability and robustness of the system can be improved.

[0145] Figure 6 6 is a block diagram schematically showing a structure of a controller for a frequency converter according to some embodiments of the present disclosure. The controller includes a memory 610 and a processor 620. Among them:

[0146] The memory 610 can be a disk, a flash memory, or any other non-volatile storage medium. The memory is used to store Figure 4 and / or Figure 5 The instructions in the corresponding embodiment.

[0147] The processor 620 is coupled to the memory 610 and can be implemented as one or more integrated circuits, such as a microprocessor or a microcontroller. The processor 620 is used to execute instructions stored in the memory, which can reduce fluctuations in the DC bus voltage and improve the reliability and robustness of the system.

[0148] In one embodiment, it is also possible to Figure 7 As shown, the controller 700 includes a memory 710 and a processor 720. The processor 720 is coupled to the memory 710 via a BUS bus 730. The controller 700 can also be connected to an external storage device 750 via a storage interface 740 to call external data, and can also be connected to a network or another computer system (not shown) via a network interface 760, which will not be described in detail here.

[0149] In this embodiment, by storing data instructions in a memory and processing the instructions through a processor, fluctuations in the DC bus voltage can be reduced and the reliability and robustness of the system can be improved.

[0150] In another embodiment, the present disclosure also provides a computer-readable storage medium (eg, a non-transitory computer-readable storage medium) having computer program instructions stored thereon, which are executed by a processor to implement Figure 4 and / or Figure 5 The steps of the method in the corresponding embodiment. Those skilled in the art will appreciate that the embodiments of the present disclosure may be provided as methods, devices, or computer program products. Therefore, the present disclosure may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present disclosure may take the form of a computer program product implemented on one or more computer-usable non-transient storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0151] The present disclosure is described with reference to flowcharts and / or block diagrams of methods, devices (systems) and computer program products according to embodiments of the present disclosure. It should be understood that each process and / or block in the flowchart and / or block diagram and the combination of processes and / or blocks in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0152] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0153] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1The steps for the functions specified in one or more boxes.

[0154] In some embodiments of the present disclosure, a computer program product is further provided. The computer program product includes a computer program or instructions. When the computer program or instructions are executed by a processor, the control method as described above is implemented.

[0155] In some embodiments of the present disclosure, a computer program is further provided, comprising: instructions, which, when executed by a processor, cause the processor to execute the control method as described above.

[0156] So far, the present disclosure has been described in detail. In order to avoid obscuring the concept of the present disclosure, some details known in the art are not described. Based on the above description, those skilled in the art can fully understand how to implement the technical solution disclosed here.

[0157] Although some specific embodiments of the present disclosure have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present disclosure. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A control circuit for a frequency converter, wherein: The frequency converter includes a rectifier circuit, an inverter circuit, and a DC bus circuit electrically connected between the rectifier circuit and the inverter circuit, the rectifier circuit includes an inductor and a first switch device electrically connected to the inductor, and the control circuit includes: An acquisition module, configured to acquire the current of the three-phase electricity output by the inverter circuit to the load and the bus voltage of the DC bus circuit; a control module configured to obtain a quadrature-axis current component according to the current decoupling calculation of the three-phase electricity, output a first voltage value according to the quadrature-axis current component and a preset first current parameter when the bus voltage is greater than a first voltage threshold, and output a second voltage value according to the quadrature-axis current component and a preset second current parameter when the bus voltage is less than a second voltage threshold, wherein the second voltage threshold is less than the first voltage threshold; and The regulating module is configured to control the first switching device to be turned off in response to the first voltage value, and to control the first switching device to be alternately turned on and off in response to the second voltage value.

2. The control circuit according to claim 1, wherein: The control module is configured to calculate the sum of the cross-axis current component and the first current parameter, obtain a first voltage value corresponding to the sum according to the sum and a correspondence between preset current values ​​and voltage values, and calculate the difference between the cross-axis current component and the second current parameter, and obtain a second voltage value corresponding to the difference according to the difference and a correspondence between the current values ​​and voltage values.

3. The control circuit according to claim 1, wherein: The adjustment module comprises: a comparison circuit configured to output a first level signal in response to the first voltage value, and to output a second level signal in response to the second voltage value, wherein the first level signal is different from the second level signal; and The logic processing circuit is configured to output a first control signal to the first switching device in response to the first level signal to control the first switching device to be turned off, and to output a second control signal to the first switching device in response to the second level signal to control the first switching device to be alternately turned on and off.

4. The control circuit according to claim 3, wherein: The second control signal is a pulse width modulation signal.

5. The control circuit according to claim 3, wherein: The comparison circuit comprises: a first resistor and a second resistor connected in series between a first voltage terminal and a ground terminal, wherein the first voltage terminal is used to provide the bus voltage; and A comparator, wherein a first input terminal of the comparator is electrically connected to a connection point between the first resistor and the second resistor, a second input terminal of the comparator is electrically connected to an output terminal of the control module, the second input terminal of the comparator is used to receive the first voltage value or the second voltage value, and an output terminal of the comparator is electrically connected to the logic processing circuit, wherein the comparator is configured to output the first level signal based on a comparison result between the voltage at the connection point and the first voltage value, and to output the second level signal based on a comparison result between the voltage at the connection point and the second voltage value.

6. The control circuit according to claim 5, wherein: The comparison circuit further comprises: a third resistor, arranged between the second input terminal of the comparator and the output terminal of the control module; and A first capacitor, wherein a first terminal of the first capacitor is electrically connected to the second input terminal of the comparator, and a second terminal of the first capacitor is electrically connected to the ground terminal.

7. The control circuit according to any one of claims 3 to 6, wherein: The logic processing circuit comprises: a second switch device, a first terminal of the second switch device being electrically connected to the second voltage terminal, and a control terminal of the second switch device being electrically connected to the comparison circuit; a fourth resistor, a first end of the fourth resistor being electrically connected to the second end of the second switching device, and a second end of the fourth resistor being electrically connected to a ground terminal; and An AND gate device, wherein a first input terminal of the AND gate device is electrically connected to a second terminal of the second switch device, a second input terminal of the AND gate device is configured to receive an initial control signal, and an output terminal of the AND gate device is electrically connected to a control terminal of the first switch device.

8. The control circuit according to claim 7, wherein: The logic processing circuit further includes: a fifth resistor, disposed between the second terminal of the second switch device and the first input terminal of the AND gate device; and A second capacitor, a first end of the second capacitor is electrically connected to the second end of the fifth resistor, and a second end of the second capacitor is electrically connected to the ground end.

9. The control circuit according to claim 7, wherein: The rectifier circuit includes a plurality of inductors and a plurality of first switch devices, wherein the plurality of inductors are electrically connected to the plurality of first switch devices in a one-to-one correspondence; The logic processing circuit includes a plurality of AND gate devices, wherein the first input terminals of the plurality of AND gate devices are electrically connected to the second terminal of the second switch device, the second input terminal of each AND gate device is configured to receive an initial control signal corresponding to each AND gate device, and the output terminals of the plurality of AND gate devices are electrically connected to the control terminals of the plurality of first switch devices in a one-to-one correspondence.

10. The control circuit according to claim 1, wherein: The first voltage threshold is an upper limit value of an allowable range of the bus voltage; The second voltage threshold is a lower limit value of an allowable range of the bus voltage.

11. The control circuit according to claim 1, wherein: The control module is further configured to output a pulse width modulation signal to the first switching device to control the first switching device to be alternately turned on and off when the bus voltage is less than or equal to the first voltage threshold and greater than or equal to the second voltage threshold.

12. A frequency converter, comprising: A control circuit as claimed in any one of claims 1 to 11.

13. The frequency converter according to claim 12, further comprising: a rectifier circuit, the rectifier circuit comprising an inductor and a first switch device electrically connected to the inductor, the first switch device electrically connected to the control circuit; an inverter circuit electrically connected to the control circuit; and a DC bus circuit, electrically connected between the rectifier circuit and the inverter circuit, and electrically connected to the control circuit; The control circuit is configured to obtain the current of the three-phase electricity output by the inverter circuit to the load and the bus voltage of the DC bus circuit, and control the on and off of the first switching device.

14. An air conditioning device, comprising: A frequency converter as claimed in claim 12 or 13.

15. A control method for a frequency converter, wherein: The frequency converter includes a rectifier circuit, an inverter circuit, and a DC bus circuit electrically connected between the rectifier circuit and the inverter circuit, the rectifier circuit includes an inductor and a first switch device electrically connected to the inductor, and the control method includes: Acquire the current of the three-phase electricity output by the inverter circuit to the load and the bus voltage of the DC bus circuit; Obtaining a quadrature-axis current component according to the current decoupling calculation of the three-phase electricity; When the bus voltage is greater than a first voltage threshold, outputting a first voltage value to a regulating module according to the quadrature-axis current component and a preset first current parameter, so that the regulating module controls the first switching device to turn off; and When the bus voltage is less than a second voltage threshold, a second voltage value is output to the regulating module according to the quadrature-axis current component and a preset second current parameter, so that the regulating module controls the first switching device to be alternately turned on and off, wherein the second voltage threshold is less than the first voltage threshold.

16. The control method according to claim 15, wherein: Outputting a first voltage value according to the quadrature-axis current component and a preset first current parameter includes: Calculating the sum of the quadrature-axis current component and the first current parameter; and According to the sum value and the corresponding relationship between the preset current value and the voltage value, a first voltage value corresponding to the sum value is obtained.

17. The control method according to claim 15, wherein: Outputting a second voltage value according to the quadrature-axis current component and a preset second current parameter includes: Calculating a difference between the quadrature-axis current component and the second current parameter; and According to the difference and a preset correspondence between a current value and a voltage value, a second voltage value corresponding to the difference is obtained.

18. The control method according to claim 15, further comprising: When the bus voltage is less than or equal to the first voltage threshold and greater than or equal to the second voltage threshold, a pulse width modulation signal is output to the first switching device to control the first switching device to be alternately turned on and off.

19. A controller for a frequency converter, comprising: Memory; as well as A processor coupled to the memory, wherein the processor is configured to execute the control method according to any one of claims 15 to 18 based on instructions stored in the memory.

20. A computer-readable storage medium having computer instructions stored thereon, wherein the computer instructions, when executed by a processor, implement the control method according to any one of claims 15 to 18.

21. A computer program product, comprising a computer program or instructions, which implements the control method according to any one of claims 15 to 18 when executed by a processor.

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