Control method for frequency converter, and storage medium, controller and air conditioner

Abstract

A control method for a frequency converter, and a storage medium, a controller and an air conditioner, which relate to the technical field of frequency converters. The frequency converter comprises an inverter bridge and an electrolytic capacitor connected in parallel to a direct-current end of the inverter bridge, wherein an alternating-current end of the inverter bridge is used for being connected to a load, and the electrolytic capacitor is further used for being connected to a direct-current busbar. The method comprises: determining a comparison value of a switch device on each bridge arm according to the duty ratio and carrier period of a state signal which is output by the switch device on each bridge arm of an inverter bridge; and according to the comparison value and a carrier of the state signal, adjusting the state signal which is output by the switch device on each bridge arm, so as to reduce the number of fluctuations of a current of a direct-current busbar.

Description

Frequency converter control method, storage medium, controller, and air conditioner

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to Chinese patent application number 202310802862.5, filed on June 30, 2023, entitled “CONTROL METHOD AND STORAGE MEDIUM, CONTROLLER, AND AIR CONDITIONER FOR INVERTER,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to the technical field of inverters, and in particular to an inverter control method, a storage medium, a controller, and an air conditioner. Background Art

[0004] The compressor in a variable-frequency air conditioner is typically driven and controlled by an AC-DC-AC inverter. AC power is converted to DC voltage through a rectifier, which then passes through an electrolytic capacitor to provide a stable DC voltage to the inverter.

[0005] Related technologies typically use voltage space vector modulation to control the switching devices in the three bridge arms of the inverter, thereby outputting AC voltage to control the compressor. However, this technology causes two large fluctuations in bus current during each switching cycle of the inverter's switching devices, resulting in drastic charging and discharging of the electrolytic capacitors, which reduces their service life.

[0006] Summary of the Invention

[0007] The purpose of the present disclosure is to provide a control method and storage medium, a controller, and an air conditioner for an inverter, which can extend the service life of an electrolytic capacitor and improve the stability of the inverter by reducing the number of fluctuations of the DC bus current.

[0008] To achieve the above-mentioned objectives, an embodiment of the first aspect of the present disclosure proposes a control method for an inverter, wherein the inverter includes an inverter bridge and an electrolytic capacitor connected in parallel with the DC end of the inverter bridge, the AC end of the inverter bridge is used to connect the load, and the electrolytic capacitor is also used to connect the DC bus. The method includes: determining the comparison value of the switching device on each bridge arm of the inverter bridge according to the duty cycle and carrier period of the status signal output by the switching device on each bridge arm of the inverter bridge; adjusting the status signal output by the switching device on each bridge arm according to the comparison value and the carrier of the status signal to reduce the number of fluctuations of the DC bus current.

[0009] According to the control method of the inverter of the embodiment of the present disclosure, by re-determining the comparison value of the switching device on each bridge arm, the state signal output by the switching device on each bridge arm is adjusted according to the comparison value and the carrier of the state signal, so as to reduce the number of large fluctuations of the current on the DC bus, thereby reducing the number of times the electrolytic capacitor is violently charged and discharged, thereby achieving the purpose of extending the service life of the electrolytic capacitor.

[0010] In addition, the control method of the frequency converter proposed in the above embodiment of the present disclosure may also have the following additional technical features:

[0011] According to one embodiment of the present disclosure, the inverter bridge includes a three-phase bridge arm, and the state signal output by the switching device on each bridge arm is adjusted according to the comparison value and the carrier of the state signal, including: determining the maximum value, the intermediate value and the minimum value in the comparison value; obtaining the direction of the load phase current connected to the bridge arm corresponding to the intermediate value; if it is flowing out of the load direction, determining a new intermediate value and a new minimum value according to the maximum value, the intermediate value, the minimum value and the amplitude of the carrier; controlling the switching device on the bridge arm corresponding to the maximum value to continuously output a high level, and adjusting the output level of the switching device on the bridge arm corresponding to the new intermediate value according to the new intermediate value and the instantaneous value of the carrier, and adjusting the output level of the switching device on the bridge arm corresponding to the new minimum value according to the new minimum value and the instantaneous value of the carrier.

[0012] According to one embodiment of the present disclosure, if the current is flowing into the load direction, a new maximum value and a new intermediate value are determined based on the minimum value, the maximum value and the intermediate value; the switching device on the bridge arm corresponding to the minimum value is controlled to continuously output a low level, and the output level of the switching device on the bridge arm corresponding to the new intermediate value is adjusted according to the new intermediate value and the instantaneous value of the carrier, and the output level of the switching device on the bridge arm corresponding to the new maximum value is adjusted according to the new maximum value and the instantaneous value of the carrier.

[0013] According to one embodiment of the present disclosure, a new intermediate value and a new minimum value are determined based on the maximum value, the intermediate value, the minimum value and the amplitude of the carrier, including: calculating the difference between the maximum value and the amplitude to obtain a first offset value; calculating the sum of the intermediate value and the first offset value to obtain the new intermediate value; calculating the sum of the minimum value and the first offset value to obtain the new minimum value.

[0014] According to one embodiment of the present disclosure, a new maximum value and a new intermediate value are determined based on the minimum value, the maximum value and the intermediate value, including: calculating the difference between the minimum value and the intermediate value to obtain a new intermediate value; calculating the difference between the minimum value and the maximum value to obtain a new maximum value.

[0015] According to one embodiment of the present disclosure, adjusting the output level of the switching device on the bridge arm corresponding to the new intermediate value according to the new intermediate value and the instantaneous value of the carrier includes: if the instantaneous value of the carrier is greater than the new intermediate value, controlling the switching device on the bridge arm corresponding to the new intermediate value to output a low level; if the instantaneous value of the carrier is less than or equal to the new intermediate value, controlling the switching device on the bridge arm corresponding to the new intermediate value to output a high level; or, if the instantaneous value of the carrier is greater than the new intermediate value, controlling the switching device on the bridge arm corresponding to the new intermediate value to output a high level; if the instantaneous value of the carrier is less than or equal to the new intermediate value, controlling the switching device on the bridge arm corresponding to the new intermediate value to output a low level.

[0016] According to one embodiment of the present disclosure, adjusting the output level of the switching device on the bridge arm corresponding to the new minimum value according to the new minimum value and the instantaneous value of the carrier includes: if the instantaneous value of the carrier is greater than the new minimum value, controlling the output low level of the switching device on the bridge arm corresponding to the new minimum value; if the instantaneous value of the carrier is less than the new minimum value, controlling the output high level of the switching device on the bridge arm corresponding to the new minimum value.

[0017] According to one embodiment of the present disclosure, adjusting the output level of the switching device on the bridge arm corresponding to the new maximum value according to the new maximum value and the instantaneous value of the carrier includes: if the instantaneous value of the carrier is greater than the new maximum value, controlling the output low level of the switching device on the bridge arm corresponding to the new maximum value; if the instantaneous value of the carrier is less than the new maximum value, controlling the output high level of the switching device on the bridge arm corresponding to the new maximum value.

[0018] To achieve the above objectives, the second embodiment of the present disclosure proposes a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the control method of the inverter proposed in the first embodiment of the present disclosure is implemented.

[0019] To achieve the above-mentioned objectives, the third embodiment of the present disclosure proposes a controller, including a memory and a processor, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the control method of the inverter proposed in the first embodiment of the present disclosure is implemented.

[0020] To achieve the above-mentioned objectives, a fourth embodiment of the present disclosure provides an air conditioner, comprising an inverter and a controller as provided in the third embodiment of the present disclosure.

[0021] Additional aspects and advantages of the present disclosure will be given in part in the description below and in part will be obvious from the description below, or will be learned through practice of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG1 is a diagram showing the output states of the switching devices on each arm of the inverter bridge in the related space vector modulation technology;

[0023] FIG2 is a control circuit diagram of an inverter according to an embodiment of the present disclosure;

[0024] FIG3 is a flow chart of a method for controlling a frequency converter according to an embodiment of the present disclosure;

[0025] FIG4 is a flow chart of adjusting the state signals output by the switching devices on each bridge arm according to an embodiment of the present disclosure;

[0026] FIG5 is a flowchart of determining a new intermediate value and a new minimum value according to an embodiment of the present disclosure;

[0027] FIG6 is a flowchart of determining a new maximum value and a new intermediate value according to an embodiment of the present disclosure;

[0028] 7 is a state diagram of the output of the switching devices on each bridge arm corresponding to the load phase current connected to the bridge arm corresponding to the intermediate value of a specific embodiment of the present disclosure, which is the direction of the load flowing out;

[0029] 8 is a state diagram of the output of the switching devices on each bridge arm corresponding to the load phase current connected to the bridge arm corresponding to the direction of flowing into the load in a specific embodiment of the present disclosure;

[0030] 9 is a state diagram of the output of the switching devices on each bridge arm corresponding to the load phase current connected to the bridge arm corresponding to the intermediate value of another specific embodiment of the present disclosure, which is the direction of the load flowing out;

[0031] 10 is a state diagram of the output of the switching devices on each bridge arm corresponding to the load phase current connected to the bridge arm corresponding to the direction of flowing into the load in another specific embodiment of the present disclosure;

[0032] FIG11 is a structural block diagram of a controller according to an embodiment of the present disclosure;

[0033] FIG12 is a schematic diagram of an air conditioner according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0034] The following describes in detail embodiments of the present disclosure, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present disclosure, and should not be construed as limiting the present disclosure.

[0035] The control method of the inverter, the storage medium, the controller, and the air conditioner of the embodiment of the present disclosure are described in detail below with reference to Figures 1 to 12 of the specification and specific implementation methods.

[0036] Figure 1 shows the output states of the switching devices in each arm of the inverter bridge in a related space vector modulation method. It should be noted that, based on the operating states of the switching devices in the three arms of the inverter, space vector modulation has eight basic voltage vectors: six effective voltage vectors and two zero voltage vectors. During each switching cycle of the switching devices, space vector modulation uses two effective voltage vectors and two zero voltage vectors to synthesize the required voltage vector. The zero voltage vectors in this space vector modulation method generate current on the DC bus, while the effective voltage vectors do not. Therefore, during each switching cycle of the switching devices in each arm of the inverter, the bus current experiences two significant fluctuations, causing drastic charging and discharging of the electrolytic capacitors.

[0037] The inverter in the inverter control method according to an embodiment of the present disclosure may include an inverter bridge and an electrolytic capacitor connected in parallel with the DC terminal of the inverter bridge. The AC terminal of the inverter bridge is used to connect to a load, and the electrolytic capacitor is also used to connect to a DC bus. FIG2 shows a control circuit diagram of an inverter according to an embodiment of the present disclosure.

[0038] FIG3 is a flow chart of a method for controlling a frequency converter according to an embodiment of the present disclosure. As shown in FIG3 , the method for controlling a frequency converter may include:

[0039] S101, determining a comparison value of the switching device on each bridge arm according to the duty cycle and carrier period of the output state signal of the switching device on each bridge arm of the inverter bridge;

[0040] S102 , adjusting the state signal output by the switch device on each bridge arm according to the comparison value and the carrier of the state signal, so as to reduce the number of fluctuations of the DC bus current.

[0041] In order to extend the service life of the electrolytic capacitor, the embodiment of the present disclosure re-determines the comparison value of the switching device on each bridge arm, and adjusts the state signal output by the switching device on each bridge arm according to the comparison value and the instantaneous value of the carrier, so as to reduce the number of large fluctuations in the current on the DC bus, thereby reducing the number of violent charging and discharging of the electrolytic capacitor, thereby achieving the purpose of extending the service life of the electrolytic capacitor, and at the same time improving the stability of the inverter.

[0042] Specifically, the comparison value of the switching devices on each bridge arm is determined based on the output state signal of the switching devices on each bridge arm of the inverter bridge, namely the duty cycle and carrier period of the PWM (Pulse Width Modulation) signal. The comparison values ​​of the switching devices on each bridge arm are compared, and the comparison values ​​of the switching devices on each bridge arm are re-determined based on the comparison results (maximum value, intermediate value, and minimum value) and the direction of the load phase current connected to the bridge arm corresponding to the intermediate value. The output state of the switching devices on each bridge arm is adjusted based on the re-determined comparison value and the instantaneous value of the carrier, thereby reducing the number of fluctuations in the DC bus current and thus reducing the number of violent charging and discharging of the electrolytic capacitor, thereby achieving the purpose of extending the service life of the electrolytic capacitor and improving the stability of the inverter.

[0043] In one embodiment of the present disclosure, as shown in FIG4 , the inverter bridge includes three-phase bridge arms, and adjusting the state signal output by the switching device on each bridge arm according to the comparison value and the carrier of the state signal includes:

[0044] S201, determining the maximum value, the middle value, and the minimum value among the comparison values;

[0045] S202, obtaining the load phase current direction connected to the bridge arm corresponding to the intermediate value;

[0046] S203, if it is an outflow load direction, determine a new middle value and a new minimum value based on the maximum value, middle value, minimum value and the amplitude of the carrier;

[0047] S204, controlling the switch device on the bridge arm corresponding to the maximum value to continuously output a high level, and adjusting the output level of the switch device on the bridge arm corresponding to the new intermediate value according to the new intermediate value and the instantaneous value of the carrier, and adjusting the output level of the switch device on the bridge arm corresponding to the new minimum value according to the new minimum value and the instantaneous value of the carrier.

[0048] Since the inverter bridge includes three-phase bridge arms, the comparison values ​​of the switching devices on the three-phase bridge arms can be obtained according to the duty cycle and carrier period of the output state signal of the switching devices on each bridge arm, that is, three comparison values ​​can be obtained.

[0049] The embodiment of the present disclosure compares the three obtained comparison values ​​to determine the largest comparison value (maximum value), the middle comparison value (middle value), and the smallest comparison value (minimum value) among the three comparison values.

[0050] In the disclosed embodiment, when re-determining the comparison value of the switch device on each bridge arm, the direction of the load phase current connected to the bridge arm corresponding to the intermediate value (intermediate comparison value) is also obtained. Based on the direction of the load phase current connected to the bridge arm corresponding to the intermediate value (intermediate comparison value), the comparison value that needs to be re-determined is determined.

[0051] Specifically, if the load phase current direction of the bridge arm connected to the intermediate value (intermediate comparison value) is outflowing from the load, the comparison value needs to be re-determined as the intermediate value (intermediate comparison value) and the minimum value (minimum comparison value). More specifically, the new intermediate value and new minimum value can be determined based on the maximum value, intermediate value, minimum value, and the amplitude of the carrier.

[0052] In this embodiment, as shown in FIG5 , determining a new middle value and a new minimum value based on the maximum value, the middle value, the minimum value, and the amplitude of the carrier may include:

[0053] S301, calculating the difference between the maximum value and the amplitude to obtain a first offset value;

[0054] S302, calculating the sum of the intermediate value and the first offset value to obtain a new intermediate value;

[0055] S303: Calculate the sum of the minimum value and the first offset value to obtain a new minimum value.

[0056] Specifically, the difference between the maximum value (maximum comparison value) of the switching devices on the three bridge arms and the amplitude of the carrier is calculated to obtain a first offset value. A new intermediate value and a new minimum value are re-determined based on the first offset value. More specifically, the sum of the intermediate value (intermediate comparison value) and the first offset value is calculated to obtain a new intermediate value. The sum of the minimum value (minimum comparison value) and the first offset value is calculated to obtain a new minimum value.

[0057] After determining the new intermediate value and the new minimum value, the switch device on the bridge arm corresponding to the maximum value (the largest comparison value) is controlled to continuously output a high level. The output level of the switch device on the bridge arm corresponding to the new intermediate value is adjusted based on the new intermediate value and the instantaneous value of the carrier. The output level of the switch device on the bridge arm corresponding to the new minimum value is adjusted based on the new minimum value and the instantaneous value of the carrier.

[0058] In another embodiment of the present disclosure, as shown in FIG4 ,

[0059] S205, if it is an inflow load direction, determine a new maximum value and a new middle value based on the minimum value, the maximum value and the middle value;

[0060] S206, controlling the switch device on the bridge arm corresponding to the minimum value to continuously output a low level, and adjusting the output level of the switch device on the bridge arm corresponding to the new intermediate value according to the new intermediate value and the instantaneous value of the carrier, and adjusting the output level of the switch device on the bridge arm corresponding to the new maximum value according to the new maximum value and the instantaneous value of the carrier.

[0061] Specifically, if the load phase current direction of the bridge arm corresponding to the intermediate value (intermediate comparison value) is in the direction of flowing into the load, the maximum value (maximum comparison value) and the intermediate value (intermediate comparison value) need to be re-determined. More specifically, a new maximum value and a new intermediate value are determined based on the minimum value (minimum comparison value), the maximum value (maximum comparison value), and the intermediate value (intermediate comparison value).

[0062] In this embodiment, as shown in FIG6 , determining a new maximum value and a new middle value based on the minimum value, the maximum value, and the middle value may include:

[0063] S401, calculating the difference between the minimum value and the middle value to obtain a new middle value;

[0064] S402: Calculate the difference between the minimum value and the maximum value to obtain a new maximum value.

[0065] Specifically, the difference between the minimum value (minimum comparison value) and the middle value (middle comparison value) of the switching devices on the three bridge arms is calculated, and the difference is used as the new middle value. The difference between the minimum value (minimum comparison value) and the maximum value (maximum comparison value) of the switching devices on the three bridge arms is calculated, and the difference is used as the new maximum value.

[0066] After determining the new maximum and intermediate values, the switch device on the bridge arm corresponding to the minimum value (minimum comparison value) is controlled to continuously output a low level. The output level of the switch device on the bridge arm corresponding to the new intermediate value is adjusted based on the new intermediate value and the instantaneous value of the carrier. The output level of the switch device on the bridge arm corresponding to the new maximum value is adjusted based on the new maximum value and the instantaneous value of the carrier.

[0067] In one embodiment of the present disclosure, adjusting the output level of the switch device on the bridge arm corresponding to the new intermediate value according to the new intermediate value and the instantaneous value of the carrier may include:

[0068] If the instantaneous value of the carrier is greater than the new intermediate value, the switch device on the bridge arm corresponding to the new intermediate value is controlled to output a low level; if the instantaneous value of the carrier is less than or equal to the new intermediate value, the switch device on the bridge arm corresponding to the new intermediate value is controlled to output a high level; or,

[0069] If the instantaneous value of the carrier is greater than the new intermediate value, the switch device on the bridge arm corresponding to the new intermediate value is controlled to output a high level; if the instantaneous value of the carrier is less than or equal to the new intermediate value, the switch device on the bridge arm corresponding to the new intermediate value is controlled to output a low level.

[0070] In the embodiment of the present disclosure, the output levels of the switch devices on the bridge arms corresponding to the new intermediate values ​​have the above two output control modes.

[0071] In one embodiment of the present disclosure, adjusting the output level of the switch device on the bridge arm corresponding to the new minimum value according to the new minimum value and the instantaneous value of the carrier may include:

[0072] If the instantaneous value of the carrier is greater than the new minimum value, the output level of the switching device on the bridge arm corresponding to the new minimum value is controlled to be low; if the instantaneous value of the carrier is less than the new minimum value, the output level of the switching device on the bridge arm corresponding to the new minimum value is controlled to be high.

[0073] In an embodiment of the present disclosure, the output level of the switch device on the bridge arm corresponding to the new minimum value is controlled by the above-mentioned output control method.

[0074] In one embodiment of the present disclosure, adjusting the output level of the switch device on the bridge arm corresponding to the new maximum value according to the new maximum value and the instantaneous value of the carrier may include:

[0075] If the instantaneous value of the carrier is greater than the new maximum value, the output level of the switching device on the bridge arm corresponding to the new maximum value is controlled to be low; if the instantaneous value of the carrier is less than the new maximum value, the output level of the switching device on the bridge arm corresponding to the new maximum value is controlled to be high.

[0076] In an embodiment of the present disclosure, the output level of the switch device on the bridge arm corresponding to the new maximum value is controlled by the above-mentioned output control method.

[0077] As a specific embodiment, when the load phase current connected to the bridge arm corresponding to the intermediate value is flowing out of the load, the comparison value needs to be re-determined as the intermediate value (intermediate comparison value) and the minimum value (minimum comparison value). After obtaining the new intermediate value and the new minimum value using the above-mentioned method for calculating the new intermediate value and the new minimum value, the above-mentioned control output method is used to control the level states of the switch devices on the bridge arm corresponding to the maximum value, the new intermediate value, and the new minimum value. The level states of the switch devices on the bridge arm corresponding to the maximum value, the new intermediate value, and the new minimum value are shown in FIG7 . It should be noted that in FIG7 , when the instantaneous value of the carrier is greater than the new intermediate value, the switch devices on the bridge arm corresponding to the new intermediate value are controlled to output a low level; when the instantaneous value of the carrier is less than or equal to the new intermediate value, the switch devices on the bridge arm corresponding to the new intermediate value are controlled to output a high level, so that the three-phase bridge arm of the inverter bridge only has one state where all three-phase bridge arm outputs are high, and there is no state where all three-phase bridge arm outputs are low, that is, there is only one zero voltage vector. The control method of the inverter of the embodiment of the present disclosure reduces the number of zero voltage vectors, thereby reducing the number of fluctuations of the DC bus current, thereby reducing the number of severe charging and discharging of the electrolytic capacitor, and achieving the purpose of extending the service life of the electrolytic capacitor.

[0078] When the load phase current connected to the bridge arm corresponding to the intermediate value is flowing out of the load, the maximum value (maximum comparison value) and intermediate value (intermediate comparison value) need to be re-determined. After obtaining the new intermediate value and the new maximum value using the above-mentioned method for calculating the new intermediate value and the new maximum value, the above-mentioned control output method is used to control the level states of the switch devices on the bridge arm corresponding to the minimum value, the new intermediate value, and the new maximum value. The level states of the switch devices on the bridge arm corresponding to the minimum value, the new intermediate value, and the new maximum value are shown in FIG8 . It should be noted that in FIG8 , when the instantaneous value of the carrier is greater than the new intermediate value, the switch devices on the bridge arm corresponding to the new intermediate value are controlled to output a low level; when the instantaneous value of the carrier is less than or equal to the new intermediate value, the switch devices on the bridge arm corresponding to the new intermediate value are controlled to output a high level. This ensures that the three-phase bridge arm of the inverter bridge only has one state where all three-phase bridge arm outputs are low, and there is no state where all three-phase bridge arm outputs are high, that is, there is only one zero voltage vector. The control method of the inverter in the embodiment of the present disclosure reduces the number of zero voltage vectors, thereby reducing the number of fluctuations of the DC bus current, thereby reducing the number of times the electrolytic capacitor is violently charged and discharged, thereby achieving the purpose of extending the service life of the electrolytic capacitor.

[0079] In another specific embodiment of the present disclosure, the level output by the switching device on the bridge arm corresponding to the new intermediate value, when the instantaneous value of the carrier is greater than the new intermediate value, the switching device on the bridge arm corresponding to the new intermediate value outputs a high level; when the instantaneous value of the carrier is less than or equal to the new intermediate value, the switching device on the bridge arm corresponding to the new intermediate value outputs a low level. The load phase current connected to the bridge arm corresponding to the intermediate value is in the direction of flowing out of the load, so that the three-phase bridge arm of the inverter bridge does not have a state in which the three-phase bridge arm outputs all high levels or a state in which the outputs are all low levels, see Figure 9. The load phase current connected to the bridge arm corresponding to the intermediate value is in the direction of flowing into the load, so that the three-phase bridge arm of the inverter bridge does not have a state in which the three-phase bridge arm outputs all low levels or a state in which the outputs are all high levels, see Figure 10. It can be seen that in this embodiment, there is no zero voltage vector, thereby further reducing the number of times the electrolytic capacitor is violently charged and discharged, thereby achieving the purpose of extending the service life of the electrolytic capacitor.

[0080] The control method of the inverter of the embodiment of the present disclosure adjusts the state signal output by the switching device on each bridge arm according to the direction of the motor phase current, the comparison value of the switching device on each bridge arm and the instantaneous value of the carrier, thereby reducing the number of bus current fluctuations and the number of charge and discharge times of the electrolytic capacitor, and improving the service life of the electrolytic capacitor.

[0081] The present disclosure provides a computer-readable storage medium.

[0082] In this embodiment, a computer program is stored on a computer-readable storage medium. When the computer program is executed by a processor, the above-mentioned inverter control method is implemented.

[0083] The present disclosure provides a controller.

[0084] In this embodiment, the controller includes a memory and a processor. The memory stores a computer program. When the computer program is executed by the processor, the above-mentioned inverter control method is implemented.

[0085] Figure 11 is a block diagram of the controller according to one embodiment of the present disclosure. As shown in Figure 11, the controller 500 includes a processor 501 and a memory 503. The processor 501 and the memory 503 are connected, for example, via a bus 502. Optionally, the controller 500 may also include a transceiver 504. It should be noted that in actual applications, the number of transceivers 504 is not limited to one, and the structure of the controller 500 does not constitute a limitation on the embodiments of the present disclosure.

[0086] The processor 501 may be a CPU (Central Processing Unit), a general-purpose processor, a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It may implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the present disclosure. The processor 501 may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, and the like.

[0087] Bus 502 may include a path for transmitting information between the aforementioned components. Bus 502 may be a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus, for example. Bus 502 may be divided into an address bus, a data bus, a control bus, and the like. For ease of illustration, FIG11 shows only one thick line, but this does not indicate that there is only one bus or only one type of bus.

[0088] Memory 503 is used to store a computer program corresponding to the inverter control method of the above-mentioned embodiment of the present disclosure. The computer program is controlled and executed by processor 501. Processor 501 is used to execute the computer program stored in memory 503 to implement the contents of the above-mentioned method embodiment. The controller 500 shown in Figure 11 is only an example and should not impose any limitations on the functionality and scope of use of the embodiments of the present disclosure.

[0089] The present disclosure provides an air conditioner.

[0090] FIG12 is a schematic diagram of an air conditioner according to an embodiment of the present disclosure. As shown in FIG12 , the air conditioner 1000 may include an inverter 600 and the controller 500 described above.

[0091] The inverter 600 in the air conditioner of the embodiment of the present disclosure is controlled by the inverter control method stored in the above-mentioned controller 500, so as to reduce the number of times the electrolytic capacitor is violently charged and discharged, and extend the service life of the electrolytic capacitor, so as to improve the stability of the inverter and thus improve the performance of the air conditioner.

[0092] It should be noted that the logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transmit a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection portion having one or more wires (electronic device), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and portable compact disc read-only memory (CDROM). Furthermore, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing it in another suitable manner if necessary, and then storing it in a computer memory.

[0093] It should be understood that various parts of the present disclosure can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used to implement: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0094] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0095] In the description of the present disclosure, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present disclosure.

[0096] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. Throughout the present disclosure, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0097] In this disclosure, unless otherwise expressly specified or limited, terms such as "installed," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components, unless otherwise expressly limited. Those skilled in the art will understand the specific meanings of the above terms in this disclosure based on specific circumstances.

[0098] In the present disclosure, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0099] Although the embodiments of the present disclosure have been shown and described above, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present disclosure. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present disclosure.

Claims

1. A method for controlling a frequency converter, wherein: The frequency converter includes an inverter bridge and an electrolytic capacitor connected in parallel with a DC terminal of the inverter bridge, the AC terminal of the inverter bridge is used to connect a load, and the electrolytic capacitor is also used to connect a DC bus. The method includes: Determine the comparison value of the switch devices on each bridge arm according to the duty cycle and carrier period of the output state signal of the switch devices on each bridge arm of the inverter bridge; The state signal output by the switch device on each bridge arm is adjusted according to the comparison value and the carrier of the state signal to reduce the number of fluctuations of the DC bus current.

2. The control method of the frequency converter according to claim 1, wherein: The inverter bridge includes three-phase bridge arms, and the state signal output by the switch device on each bridge arm is adjusted according to the comparison value and the carrier of the state signal, including: Determine the maximum value, the middle value and the minimum value among the comparison values; Obtaining the load phase current direction connected to the bridge arm corresponding to the intermediate value; If the flow is out of the load direction, a new middle value and a new minimum value are determined according to the maximum value, the middle value, the minimum value and the amplitude of the carrier; Control the switch device on the bridge arm corresponding to the maximum value to continuously output a high level, and adjust the output level of the switch device on the bridge arm corresponding to the new intermediate value according to the new intermediate value and the instantaneous value of the carrier, and adjust the output level of the switch device on the bridge arm corresponding to the new minimum value according to the new minimum value and the instantaneous value of the carrier.

3. The control method of the frequency converter according to claim 2, wherein: If it is flowing into the load direction, determining a new maximum value and a new middle value according to the minimum value, the maximum value and the middle value; Control the switch device on the bridge arm corresponding to the minimum value to continuously output a low level, and adjust the output level of the switch device on the bridge arm corresponding to the new intermediate value according to the new intermediate value and the instantaneous value of the carrier, and adjust the output level of the switch device on the bridge arm corresponding to the new maximum value according to the new maximum value and the instantaneous value of the carrier.

4. The control method of the frequency converter according to claim 3, wherein: Determining a new intermediate value and a new minimum value according to the maximum value, the intermediate value, the minimum value, and the amplitude of the carrier wave comprises: Calculate the difference between the maximum value and the amplitude to obtain a first offset value; Calculating a sum of the intermediate value and the first offset value to obtain the new intermediate value; The sum of the minimum value and the first offset value is calculated to obtain the new minimum value.

5. The control method of the frequency converter according to claim 3 or 4, wherein: Determining a new maximum value and a new middle value according to the minimum value, the maximum value and the middle value includes: Calculate the difference between the minimum value and the intermediate value to obtain a new intermediate value; The difference between the minimum value and the maximum value is calculated to obtain a new maximum value.

6. The control method of the frequency converter according to any one of claims 3 to 5, wherein: The adjusting the output level of the switch device on the bridge arm corresponding to the new intermediate value according to the new intermediate value and the instantaneous value of the carrier comprises: If the instantaneous value of the carrier is greater than the new intermediate value, the switch device on the bridge arm corresponding to the new intermediate value is controlled to output a low level; if the instantaneous value of the carrier is less than or equal to the new intermediate value, the switch device on the bridge arm corresponding to the new intermediate value is controlled to output a high level; or, If the instantaneous value of the carrier is greater than the new intermediate value, the switch device on the bridge arm corresponding to the new intermediate value is controlled to output a high level; if the instantaneous value of the carrier is less than or equal to the new intermediate value, the switch device on the bridge arm corresponding to the new intermediate value is controlled to output a low level.

7. The control method of the frequency converter according to any one of claims 2 to 6, wherein: The adjusting the output level of the switch device on the bridge arm corresponding to the new minimum value according to the new minimum value and the instantaneous value of the carrier comprises: If the instantaneous value of the carrier is greater than the new minimum value, the output level of the switch device on the bridge arm corresponding to the new minimum value is controlled to be low; if the instantaneous value of the carrier is less than the new minimum value, the output level of the switch device on the bridge arm corresponding to the new minimum value is controlled to be high.

8. The control method of the frequency converter according to any one of claims 3 to 7, wherein: The step of adjusting the output level of the switch device on the bridge arm corresponding to the new maximum value according to the new maximum value and the instantaneous value of the carrier wave comprises: If the instantaneous value of the carrier is greater than the new maximum value, the output level of the switch device on the bridge arm corresponding to the new maximum value is controlled to be low; if the instantaneous value of the carrier is less than the new maximum value, the output level of the switch device on the bridge arm corresponding to the new maximum value is controlled to be high.

9. A computer-readable storage medium having a computer program stored thereon, wherein: When the computer program is executed by a processor, the control method of the frequency converter according to any one of claims 1 to 8 is implemented.

10. A controller comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the computer program is executed by the processor, the control method of the frequency converter according to any one of claims 1 to 8 is implemented.

11. An air conditioner, wherein: It comprises a frequency converter and a controller as claimed in claim 10.

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