Back-to-back converter control method, device and electronic equipment

Abstract

This application discloses a back-to-back converter control method, device, and electronic device, belonging to the field of power electronics technology. The method comprises: obtaining electrical parameters corresponding to the ripple voltage or ripple current in the back-to-back converter; after determining that the electrical parameters are greater than corresponding electrical parameter thresholds, determining a first reference voltage for the DC bus in the back-to-back converter based on the electrical parameters; and adjusting the voltage of the DC bus to the first reference voltage. This application can effectively suppress the ripple current and ripple voltage in the back-to-back converter, thereby reducing the bus capacitor capacity, volume, and cost, and increasing the service life of the bus capacitor.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a back-to-back converter control method, device, and electronic equipment. Background Art

[0002] A back-to-back converter is a circuit topology that can convert alternating current (AC) and direct current (DC), and is often used in devices such as uninterruptible power supplies (UPS) and inverters.

[0003] A back-to-back converter consists of a rectifier, an inverter, and a DC bus. The rectifier connects to the power grid, converts AC power from the grid into DC power, and transmits it to the DC bus. The inverter converts the DC power from the DC bus back into AC power and transmits it to the load. The rectifier and inverter each contain multiple switching transistors, which can be controlled to switch on and off to achieve conversion between AC and DC power.

[0004] However, each switch tube in the rectifier and inverter will generate ripple voltage and ripple current when it is closed and opened, and the generated ripple voltage will act on the DC bus, causing the bus capacitor ripple voltage in the DC bus to increase, affecting the safe operation and control ability of the switch tube. The generated ripple current causes the DC bus capacitor to increase loss and temperature, thereby affecting the service life of the bus capacitor itself. Summary of the Invention

[0005] Embodiments of the present application provide a back-to-back converter control method, device, and electronic device, which can suppress the ripple current and ripple voltage generated in the back-to-back converter and extend the service life of the bus capacitor.

[0006] The technical solution is as follows:

[0007] In a first aspect, a back-to-back converter control method is provided, the method comprising:

[0008] Obtaining electrical parameters corresponding to ripple voltage or ripple current in a back-to-back converter;

[0009] After determining that the electrical parameter is greater than a corresponding electrical parameter threshold, determining a first reference voltage of a DC bus in a back-to-back converter according to the electrical parameter;

[0010] The voltage of the DC bus is adjusted to the first reference voltage.

[0011] Optionally, the electrical parameter corresponding to the ripple current is a current parameter value, and the electrical parameter corresponding to the ripple voltage is a voltage parameter value.

[0012] Optionally, after determining that the electrical parameter is greater than the corresponding electrical parameter threshold, the method further includes:

[0013] Determining a target frequency of the carrier according to a voltage parameter value of the ripple voltage, wherein the target frequency is positively correlated with the voltage parameter value;

[0014] The frequency of the carrier wave is adjusted to a target frequency.

[0015] Optionally, before determining the first reference voltage of the DC bus in the back-to-back converter according to the electrical parameter, the method further includes:

[0016] It is determined that the electrical parameter is still greater than the corresponding electrical parameter threshold.

[0017] Optionally, after adjusting the voltage of the DC bus to the first reference voltage, the method further includes:

[0018] When it is determined that the first reference voltage is the rated voltage and the voltage parameter value is less than or equal to the electrical parameter threshold, the voltage of the DC bus is fixed at the rated voltage.

[0019] Optionally, after adjusting the voltage of the DC bus to the first reference voltage, the method further includes:

[0020] After determining that the first reference voltage is between a set maximum voltage and a set minimum voltage and determining that the current parameter value is greater than a corresponding electrical parameter threshold, determining a second reference voltage of the DC bus in the back-to-back converter according to the current parameter value;

[0021] The voltage of the DC bus is adjusted to the second reference voltage.

[0022] Optionally, after adjusting the voltage of the DC bus to the second reference voltage, the method further includes:

[0023] When it is determined that the second reference voltage is the rated voltage and it is determined that the electrical parameter is less than or equal to the corresponding electrical parameter threshold, the voltage of the DC bus is fixed at the rated voltage.

[0024] Optionally, after adjusting the voltage of the DC bus to the first reference voltage, the method further includes:

[0025] When it is determined that the voltage of the DC bus is adjusted to a set maximum voltage or a minimum voltage, and the voltage parameter value is greater than a corresponding electrical parameter threshold, the voltage of the DC bus is fixed at the maximum voltage or the minimum voltage.

[0026] Optionally, after fixing the voltage of the DC bus at a maximum or minimum voltage, the step further includes:

[0027] Determining a target frequency of the carrier according to a voltage parameter value of the ripple voltage, wherein the target frequency is positively correlated with the voltage parameter value;

[0028] The frequency of the carrier wave is adjusted to a target frequency.

[0029] Optionally, after adjusting the voltage of the DC bus to the first reference voltage, the method further includes:

[0030] determining that the current parameter value is less than a corresponding electrical parameter threshold, that the voltage of the DC bus is between a set maximum voltage and a set minimum voltage, and that the voltage parameter value is greater than the corresponding electrical parameter threshold, and determining a target frequency of the carrier according to the voltage parameter value of the ripple voltage, wherein the target frequency is positively correlated with the voltage parameter value;

[0031] The frequency of the carrier wave is adjusted to a target frequency.

[0032] Optionally, after adjusting the frequency of the carrier to the target frequency, the method further includes:

[0033] When it is determined that the frequency of the carrier is adjusted to the set minimum frequency and the voltage parameter value is less than or equal to the voltage parameter threshold, the frequency of the carrier is fixed at the minimum frequency.

[0034] Optionally, determining a first reference voltage of a DC bus in the back-to-back converter according to the electrical parameter includes:

[0035] The voltage parameter value and the current parameter value are calculated according to the set control algorithm and the corresponding second algorithm parameter to obtain a first reference voltage of the DC bus.

[0036] Optionally, determining a first reference voltage of a DC bus in the back-to-back converter according to the electrical parameter includes:

[0037] The voltage parameter value and the current parameter value are weightedly calculated according to a first weight value corresponding to the voltage parameter value and a second weight value corresponding to the current parameter value, and a first reference voltage of the DC bus is obtained by using the electrical parameter calculation obtained after the weighted calculation.

[0038] In a second aspect, a back-to-back converter control device is provided, the device comprising:

[0039] An acquisition module, used to obtain electrical parameters corresponding to the ripple voltage or ripple current in the back-to-back converter;

[0040] a determination module, configured to determine a first reference voltage of a DC bus in a back-to-back converter according to the electrical parameter after determining that the electrical parameter is greater than a corresponding electrical parameter threshold;

[0041] An adjustment module is used to adjust the voltage of the DC bus to the first reference voltage.

[0042] Optionally, the electrical parameter corresponding to the ripple current is a current parameter value, and the electrical parameter corresponding to the ripple voltage is a voltage parameter value.

[0043] Optionally, the determining module is further configured to:

[0044] Determining a target frequency of the carrier according to a voltage parameter value of the ripple voltage, wherein the target frequency is positively correlated with the voltage parameter value;

[0045] The frequency of the carrier wave is adjusted to a target frequency.

[0046] Optionally, the determining module is further configured to:

[0047] It is determined that the electrical parameter is still greater than the corresponding electrical parameter threshold.

[0048] Optionally, the determining module is further configured to:

[0049] When it is determined that the first reference voltage is the rated voltage and the voltage parameter value is less than or equal to the electrical parameter threshold, the voltage of the DC bus is fixed at the rated voltage.

[0050] Optionally, the determining module is further configured to:

[0051] After determining that the first reference voltage is between a set maximum voltage and a set minimum voltage and determining that the current parameter value is greater than a corresponding electrical parameter threshold, determining a second reference voltage of the DC bus in the back-to-back converter according to the current parameter value;

[0052] The adjustment module is further configured to adjust the voltage of the DC bus to the second reference voltage.

[0053] Optionally, the determining module is further configured to:

[0054] When it is determined that the second reference voltage is the rated voltage and it is determined that the electrical parameter is less than or equal to the corresponding electrical parameter threshold, the voltage of the DC bus is fixed at the rated voltage.

[0055] Optionally, the determining module is further configured to:

[0056] When it is determined that the voltage of the DC bus is adjusted to the set maximum voltage or minimum voltage, and the voltage parameter value is greater than the corresponding electrical parameter threshold, the voltage of the DC bus is fixed at the maximum voltage or the minimum voltage.

[0057] Optionally, the determining module is further configured to:

[0058] Determining a target frequency of the carrier according to a voltage parameter value of the ripple voltage, wherein the target frequency is positively correlated with the voltage parameter value;

[0059] The adjustment module is further configured to adjust the frequency of the carrier to a target frequency.

[0060] Optionally, the determining module is further configured to:

[0061] determining that the current parameter value is less than a corresponding electrical parameter threshold, that the voltage of the DC bus is between a set maximum voltage and a set minimum voltage, and that the voltage parameter value is greater than the corresponding electrical parameter threshold, and determining a target frequency of the carrier according to the voltage parameter value of the ripple voltage, wherein the target frequency is positively correlated with the voltage parameter value;

[0062] The adjustment module is further configured to adjust the frequency of the carrier to a target frequency.

[0063] Optionally, the adjustment module is further configured to:

[0064] When it is determined that the frequency of the carrier is adjusted to the set minimum frequency and the voltage parameter value is less than or equal to the voltage parameter threshold, the frequency of the carrier is fixed at the minimum frequency.

[0065] Optionally, the determining module is further configured to:

[0066] The voltage parameter value and the current parameter value are calculated according to the set control algorithm and the corresponding second algorithm parameter to obtain a first reference voltage of the DC bus.

[0067] Optionally, the determining module is further configured to:

[0068] The voltage parameter value and the current parameter value are weightedly calculated according to a first weight value corresponding to the voltage parameter value and a second weight value corresponding to the current parameter value, and a first reference voltage of the DC bus is obtained by using the electrical parameter calculation obtained after the weighted calculation.

[0069] In a third aspect, an electronic device is provided, comprising a memory and a processor, wherein the memory is used to store computer instructions; and the processor is used to execute the computer instructions stored in the memory so that the electronic device executes the method provided in the first aspect.

[0070] In a fourth aspect, a readable storage medium is provided, wherein the readable storage medium stores a program code. When the program code is executed by an electronic device, the electronic device executes the method provided in the first aspect.

[0071] The beneficial effects of the technical solution provided by the embodiments of the present application are:

[0072] In an embodiment of the present application, the modulation coefficient in the back-to-back converter can be adjusted by adjusting the voltage of the DC bus. Generally, the magnitude of the ripple current and ripple voltage in the back-to-back converter is related to the modulation coefficient, and when the ripple current and ripple voltage are the highest, the corresponding modulation coefficients are relatively close. Therefore, by adjusting the voltage of the DC bus, the modulation coefficient of the back-to-back converter can be deviated from the modulation coefficient corresponding to when the ripple current and ripple voltage are large. In addition, it is possible to suppress the ripple voltage and ripple current in the back-to-back converter, reduce the loss of the bus capacitor caused by the ripple current, reduce the capacity, volume and cost of the DC bus capacitor pair, and increase the service life of the DC bus capacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0074] Figure 1 It is a structural diagram of a back-to-back converter;

[0075] Figure 2 It is a structural diagram of a back-to-back converter;

[0076] Figure 3 It is a schematic diagram of a method for controlling a back-to-back converter;

[0077] Figure 4 Schematic diagram of a method for controlling a back-to-back converter provided in an embodiment of the present application;

[0078] Figure 5 This is a flow chart of a back-to-back converter control method provided by an embodiment of the present application;

[0079] Figure 6 This is a flow chart of a back-to-back converter control method provided by an embodiment of the present application;

[0080] Figure 7 This is a flow chart of a back-to-back converter control method provided by an embodiment of the present application;

[0081] Figure 8 This is a flow chart of a back-to-back converter control method provided by an embodiment of the present application;

[0082] Figure 9 This is a schematic structural diagram of a back-to-back converter control device provided in an embodiment of the present application;

[0083] Figure 10 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0084] In order to make the objectives, technical solutions and advantages of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0085] Back-to-back converter generally refers to a three-phase back-to-back converter, which is a circuit topology that can convert AC and DC power. It is often used in uninterruptible power supply (UPS), inverter and other equipment. Figure 1 As shown, Figure 1 This is a schematic diagram of the structure of a traditional back-to-back converter. A back-to-back converter includes at least a rectifier, an inverter, and a DC bus, with at least one bus capacitor within the DC bus. The rectifier can be connected to the power grid, converting AC power from the grid into DC power and transmitting it to the DC bus. The inverter can convert the DC power from the DC bus back into AC power and transmit it to the load. The rectifier and inverter each include multiple switching transistors, which can be controlled to switch on and off to achieve conversion between AC and DC power.

[0086] Figure 2 This is a schematic diagram of the structure of a traditional back-to-back converter. Figure 2 ,exist Figure 2 The back-to-back converter shown in FIG1 may include two filters in addition to the rectifier, inverter and DC bus. The rectifier includes six switching tubes, namely S 1A1 、S 1A2 、S 1B1 、S 1B2 、S 1C1 and S 1C2 . S 1A1 and S 1A2 A pair of switch tubes, S 1B1 and S 1B2 A pair of switch tubes, S 1C1 and S 1C2 A pair of switch tubes. The inverter includes 6 switch tubes, namely S 2A1 、S 2A2 、S 2B1 、S 2B2 、S 2C1 and S 2C2 . S 2A1 and S 2A2 A pair of switch tubes, S 2B1 and S 2B2 A pair of switch tubes, S 2C1and S 2C2 A pair of switching transistors. In any pair of switching transistors in a rectifier or inverter, both switching transistors are never closed simultaneously. Rectifier and inverter circuit topologies are not limited to three-phase six-switch topologies; three-level DNPC and ANPC topologies are also applicable.

[0087] exist Figure 2 In the back-to-back converter shown in FIG, the three-phase AC power in the grid can first be input into the first filter to filter the three-phase AC power. Then the filtered three-phase AC power is input into the rectifier respectively, and the three-phase AC power is filtered by controlling S 1A1 、S 1A2 、S 1B1 、S 1B2 、S 1C1 and S 1C2 The three-phase AC is converted into DC by the closing and opening of the 1ABC is the voltage value of the input three-phase AC power, i 1ABC is the current value of the input three-phase AC power. At the same time, the S 2A1 、S 2A2 、S 2B1 、S 2B2 、S 2C1 and S 2C2 The DC power converted by the rectifier is converted into three-phase AC power again and transmitted to the second filter. The second filter filters the input three-phase AC power and transmits the filtered three-phase AC power to the load. 2ABC is the voltage value of the three sets of AC output, i 2ABC The three sets of AC current values ​​are output. In the case of motor load, the inverter part can also not include a filter.

[0088] The rectifier control unit controls the switching on and off of the switch in the rectifier, while the inverter control unit controls the switching on and off of the switch in the inverter. It should be noted that the rectifier control unit and the inverter control unit can each be considered to be different control units in the control program corresponding to the back-to-back converter, rather than physical hardware. Furthermore, the control program can run on any electronic device equipped with a processor, memory, and other components, and the electronic device can control the back-to-back converter. For example, the electronic device can be a microcontroller unit (MCU) that controls the back-to-back converter.

[0089] Figure 3 This is a schematic diagram of a method for controlling a back-to-back converter, see Figure 3The processing of the rectifier control unit includes: obtaining the AC parameters corresponding to the AC input to the back-to-back converter (such as the voltage RMS V 1ABC And the effective value of current I 1ABC ) and the DC bus voltage V dc Based on the AC parameters and the DC bus voltage, the modulation wave M corresponding to the different switching tubes in the output rectifier is 1ABC . After obtaining the modulation wave M corresponding to each switch tube in the rectifier 1ABC After that, the modulation wave M corresponding to each switch tube can be 1ABC With the preset switching frequency f s The carrier 1 is input to the modulation unit, and the modulation wave M corresponding to each switch tube is modulated by the modulation unit. 1ABC With the preset switching frequency f s The carrier 1 is modulated to output the control signal S corresponding to each switch tube 1ABC Then the control signal S 1ABC Control the closing and opening of the switch tube in the rectifier. For example, the control signal S 1ABC Separate control Figure 2 S in 1A1 、S 1A2 、S 1B1 、S 1B2 、S 1C1 and S 1C2 closing and opening.

[0090] The processing of the inverter control unit includes: obtaining the AC parameters corresponding to the AC output of the back-to-back converter (such as the voltage RMS V 2ABC And the effective value of current I 2ABC ) and the phase θ corresponding to the output AC power or the speed n of the load motor, etc., and the modulation wave M corresponding to the different switching tubes in the output inverter 2ABC . After obtaining the modulation wave M corresponding to each switch tube in the inverter 2ABC After that, the modulation wave M corresponding to each switch tube can be 2ABC With the preset switching frequency f s The carrier 2 is input to the modulation unit, and the modulation wave M corresponding to each switch tube is modulated by the modulation unit. 2ABC With the preset switching frequency f s The carrier 2 is modulated to output the control signal S corresponding to each switch tube 2ABC Then the control signal S 2ABC Control the closing and opening of the switch tube in the inverter. For example, the Figure 2 S in 2A1 、S 2A2 、S 2B1 、S2B2 、S 2C1 and S 2C2 It should be noted that the carrier 1 input to the modulation unit corresponding to the rectifier control unit and the carrier 2 input to the modulation unit corresponding to the inverter control unit may have the same frequency but different phases.

[0091] However, each switch in the rectifier and inverter generates ripple current and ripple voltage on the DC bus capacitor when it switches on and off. These ripple currents and ripple voltages are high-frequency AC currents and voltages. These ripple currents and ripple voltages can act on the DC bus, causing fluctuations in the voltage of the bus capacitors, impacting the safe operation and precise control of the converter. Furthermore, ripple currents can increase DC bus capacitor losses and temperature, reducing the service life of the bus capacitors in back-to-back converters.

[0092] Figure 4 This is a schematic diagram of a method for controlling a back-to-back converter provided in this application. The software program controlling the back-to-back converter may include, in addition to a rectifier control unit and an inverter control unit, a frequency modulation control unit. This frequency modulation control unit adjusts the carrier frequency, increasing the switching frequency by adjusting the carrier frequency, thereby reducing the voltage parameter value of the ripple voltage. This suppresses the ripple voltage in the back-to-back converter and reduces the impact of the ripple voltage on the bus capacitance.

[0093] Since the control signals for the switches in the rectifier and inverter are derived by modulating the switching transistor's modulation wave with the carrier wave, increasing the carrier frequency can increase the frequency of the control signal that controls the switching transistor on or off, thereby increasing the frequency of the ripple current. The formula for calculating the bus capacitor's ripple voltage, v, can be approximated as follows:

[0094] v=i / 2πcf

[0095] Here, the bus capacitor ripple voltage is v, the ripple current is i, c is the bus capacitor capacitance, and f is the ripple current frequency. The above formula for calculating the bus capacitor voltage v shows that increasing the ripple current frequency f can reduce the bus capacitor ripple voltage v. Therefore, increasing the carrier frequency can reduce the DC bus capacitor ripple voltage in a back-to-back converter.

[0096] Continue to see Figure 4The software program controlling the back-to-back converter may also include a voltage regulation control unit. This voltage regulation control unit can reduce the impact of ripple current and ripple voltage on the bus capacitor and the operation of the back-to-back converter by adjusting the voltage of the DC bus. Adjusting the voltage of the DC bus means adjusting the voltage of the bus capacitor on the DC bus. Adjusting the voltage of the bus capacitor can change the modulation coefficient of the back-to-back converter. Generally, in a back-to-back converter, the magnitude of the ripple current and ripple voltage are related to the modulation coefficient, and when the ripple current and ripple voltage are the highest, the corresponding modulation coefficients are relatively close. These two modulation coefficients can be approximately considered as one modulation coefficient. Therefore, when the voltage of the bus capacitor deviates from the voltage value corresponding to the modulation coefficient, the ripple voltage and ripple current can each be reduced. Therefore, by adjusting the voltage of the DC bus, the ripple voltage and ripple current can be suppressed respectively.

[0097] The method for controlling the back-to-back converter provided in this application can be found in the following Figure 5 、 6 , 7, 8 corresponding method flow chart:

[0098] Figure 5 This is a flow chart of the method for suppressing ripple voltage and ripple current by the voltage regulation control unit of the present application, see Figure 5 The method may be executed by a voltage regulation control unit in a software program for controlling a back-to-back converter, and includes:

[0099] Step 501: Obtain electrical parameters corresponding to the ripple voltage or ripple current in the back-to-back converter.

[0100] Among them, the electrical parameter corresponding to the ripple current is the current parameter value in the DC bus in the back-to-back converter. The current parameter value can be obtained by first sampling the current of the DC bus, or by combining the current parameter values ​​on both sides of the back-to-back converter and the switching control signals corresponding to the rectifier and the inverter. It belongs to the existing technology and will not be described in detail here. The current parameter value can be the peak-to-peak value of the ripple current or the effective value of the ripple current.

[0101] The electrical parameter corresponding to the ripple voltage is the voltage parameter value in the DC bus in the back-to-back converter. The voltage parameter value can be obtained by sampling the voltage of the DC bus. The voltage parameter value can be the peak-to-peak value of the ripple voltage or the effective value of the ripple voltage.

[0102] Step 502: After determining that the electrical parameter is greater than the corresponding electrical parameter threshold, determine a first reference voltage of the DC bus in the back-to-back converter according to the electrical parameter.

[0103] The electrical parameter corresponding to the ripple current is the current parameter value, and the electrical parameter corresponding to the ripple voltage is the voltage parameter value.

[0104] Generally, when the electrical parameters of the ripple voltage or ripple current are relatively small, the impact on the bus capacitance and the operation of the back-to-back converter can be ignored. Therefore, the software program that controls the back-to-back converter can periodically obtain the voltage parameter value corresponding to the ripple voltage and the current parameter value corresponding to the ripple current in the back-to-back converter. After determining that the voltage parameter value is greater than the corresponding electrical parameter threshold, or after determining that the current parameter value is greater than the corresponding electrical parameter threshold, the ripple voltage or ripple current can be suppressed according to the voltage regulation control unit. Among them, the electrical parameter threshold corresponding to the voltage parameter value can be called the voltage parameter threshold, and the electrical parameter threshold corresponding to the current parameter value can be called the current parameter threshold. The voltage parameter threshold and the current parameter threshold can be pre-set by technicians, and their specific values ​​are not limited here.

[0105] In one embodiment, after determining that the voltage parameter value is greater than the voltage parameter threshold, a first reference voltage of the DC bus in the back-to-back converter can be determined based on the current voltage parameter value. For example, the voltage parameter value can be calculated based on a preset control algorithm and corresponding algorithm parameters to obtain the first reference voltage of the DC bus.

[0106] Technicians can conduct experimental tests on the back-to-back converter in advance to determine the DC bus voltage that can reduce the ripple voltage when the ripple voltage corresponds to different voltage parameter values. Then, based on the experimental data, the algorithm parameters of the control algorithm (such as the PID algorithm) can be adjusted to obtain the corresponding algorithm parameters. In this way, for back-to-back converters of the same production batch or the same model, the same control algorithm and corresponding algorithm parameters can be stored in the electronic device that controls the back-to-back converter. After determining that the voltage parameter value is greater than the voltage parameter threshold, the voltage parameter value can be calculated based on the control algorithm and the corresponding algorithm parameters to obtain the first reference voltage of the DC bus. In addition, the current parameter value of the ripple current can also be used as the input of the control algorithm to determine the first reference voltage of the DC bus.

[0107] Alternatively, the voltage parameter value and the current parameter value may be weightedly calculated based on a first weight value corresponding to the voltage parameter value and a second weight value corresponding to the current parameter value, and the first reference voltage of the DC bus may be calculated using the electrical parameters obtained by the weighted calculation.

[0108] Similarly, technicians can conduct experimental tests on the back-to-back converter in advance to determine the DC bus voltage that can suppress the ripple voltage under different voltage parameter values ​​and different current parameter values, and then obtain the first weight value corresponding to the voltage parameter value and the second weight value corresponding to the current parameter value by fitting the experimental data. In this way, for back-to-back converters of the same production batch or the same model, the first weight value and the second weight value can be stored in the electronic device that controls the back-to-back converter. After determining that the voltage parameter value is greater than the voltage parameter threshold, the voltage parameter value and the current parameter value can be weighted calculated based on the first weight value and the second weight value, and the electrical parameters obtained by the weighted calculation are used to obtain the first reference voltage of the DC bus.

[0109] Alternatively, the corresponding relationship between each voltage parameter value, each current parameter value and the reference voltage may be obtained, and the voltage parameter value and the target voltage corresponding to the voltage parameter value may be determined according to the corresponding relationship.

[0110] Technicians can directly store the voltage and current parameter values ​​in the experimental data as the voltage values ​​corresponding to the DC bus. For back-to-back converters of the same production batch or model, the same correspondence between the voltage and current parameter values ​​and the reference voltage can be stored in the electronic equipment that controls the back-to-back converters. After determining that the voltage parameter value is greater than the voltage parameter threshold, the first reference voltage corresponding to the voltage and current parameter values ​​is determined based on the stored correspondence. This reduces the computational effort required to obtain the first reference voltage and improves the efficiency of determining the target voltage.

[0111] In another embodiment, after determining that the current parameter value is greater than the current parameter threshold, a first reference voltage of the DC bus in the back-to-back converter can be determined based on the current parameter value. For example, the first reference voltage of the DC bus can be obtained by calculating the current parameter value based on a preset control algorithm and corresponding algorithm parameters.

[0112] Technicians can conduct experimental tests on the back-to-back converter in advance to determine the DC bus voltage that can reduce the ripple current when the ripple current corresponds to different current parameter values. Then, based on the experimental data, the algorithm parameters of the control algorithm (such as the PID algorithm) can be adjusted to obtain the corresponding algorithm parameters. In this way, for back-to-back converters of the same production batch or the same model, the same control algorithm and corresponding algorithm parameters can be stored in the electronic device that controls the back-to-back converter. After determining that the current parameter value is greater than the current parameter threshold, the current parameter value can be calculated according to the control algorithm and the corresponding algorithm parameters to obtain the first reference voltage of the DC bus. In another possible scenario, the voltage parameter value of the ripple voltage can also be used as the input of the control algorithm to determine the first reference voltage of the DC bus.

[0113] Alternatively, the voltage parameter value and the current parameter value may be weightedly calculated based on a first weight value corresponding to the voltage parameter value and a second weight value corresponding to the current parameter value, and the first reference voltage of the DC bus may be obtained using the electrical parameters obtained by the weighted calculation.

[0114] Similarly, technicians can conduct experimental tests on the back-to-back converter in advance to determine the DC bus voltage that can suppress the ripple current under different voltage parameter values ​​and different current parameter values, and then obtain the first weight value corresponding to the voltage parameter value and the second weight value corresponding to the current parameter value by fitting the experimental data. In this way, for back-to-back converters of the same production batch or the same model, the first weight value and the second weight value can be stored in the electronic device that controls the back-to-back converter. After determining that the current parameter value is greater than the current parameter threshold, the voltage parameter value and the current parameter value can be weighted according to the first weight value and the second weight value. The electrical parameters obtained by the weighted calculation are used to obtain the first reference voltage of the DC bus. In addition, the first weight value corresponding to the voltage parameter value can be 0, that is, the weight value can be set only for the current parameter value. After determining that the current parameter value is greater than the current parameter threshold, the current parameter value and the corresponding weight value can be calculated to obtain the first reference voltage of the DC bus.

[0115] Alternatively, the corresponding relationship between each voltage parameter value, each current parameter value and the reference voltage may be obtained, and the voltage parameter value and the target voltage corresponding to the voltage parameter value may be determined according to the corresponding relationship.

[0116] Step 503: Adjust the voltage of the DC bus to a first reference voltage.

[0117] After obtaining the first reference voltage corresponding to the DC bus, the first reference voltage can be input into the rectifier control unit, which outputs the modulation wave corresponding to each switch tube in the rectifier, and then modulates the modulation wave corresponding to each switch tube with the corresponding carrier to obtain a control signal for controlling each switch tube, and then each switch tube can be controlled separately according to the control signal.

[0118] It can be seen that the embodiment of the present application can suppress the ripple voltage and ripple current by adjusting the voltage of the DC bus, thereby reducing the loss of the bus capacitor caused by the ripple voltage and ripple current, reducing the usage capacity, volume and cost of the DC bus capacitor, and extending the service life of the bus capacitor.

[0119] Figure 6 This is a flow chart of the method for suppressing ripple voltage by the frequency modulation control unit of the present application, see Figure 6 The method may be executed by a frequency modulation control unit in a software program for controlling a back-to-back converter, comprising:

[0120] Step 601: Obtain a voltage parameter value corresponding to a ripple voltage in a back-to-back converter.

[0121] The processing of step 601 may refer to the above-mentioned step 501 and will not be described in detail here.

[0122] Step 602: After determining that the voltage parameter value is greater than the corresponding voltage parameter threshold, determine the target frequency of the carrier according to the voltage parameter value of the ripple voltage.

[0123] The carrier in this step refers to carrier 1 input to the modulation unit corresponding to the rectifier control unit, and carrier 2 input to the modulation unit corresponding to the inverter control unit.

[0124] After determining that the voltage parameter value is greater than the corresponding voltage parameter threshold, the target frequency of the carrier may be determined based on the voltage parameter value. Specifically, the following two processes may be included:

[0125] Processing 1: Calculate the voltage parameter value and the current parameter value according to the preset control algorithm and the corresponding algorithm parameters to obtain the target frequency of the carrier.

[0126] Technicians can conduct experimental tests on the back-to-back converter in advance to determine the carrier frequency that can reduce the ripple voltage under different voltage parameter values. Then, based on the experimental data, the algorithm parameters of the control algorithm (such as the PID algorithm) can be adjusted to obtain the corresponding algorithm parameters. In this way, for back-to-back converters of the same production batch or the same model, the same control algorithm and corresponding algorithm parameters can be stored in the electronic equipment that controls the back-to-back converter. After determining that the voltage parameter value is greater than the voltage parameter threshold, the voltage parameter value can be calculated based on the control algorithm and the corresponding algorithm parameters to obtain the target frequency of the carrier.

[0127] Process 2: Obtain the corresponding relationship between each voltage parameter value and frequency, and determine the voltage parameter value and the target frequency corresponding to the voltage parameter value based on the corresponding relationship.

[0128] Technicians can directly store the voltage parameter values ​​in the experimental data as corresponding frequencies to the carrier waves. For back-to-back converters of the same production batch or model, the same correspondence between the voltage parameter values ​​and frequencies can be stored in the electronic equipment that controls the back-to-back converters. After determining that the voltage parameter value is greater than the voltage parameter threshold, the target frequency corresponding to the voltage parameter value is determined based on the stored correspondence. This reduces the computational effort required to determine the target frequency and improves the efficiency of determining the target frequency.

[0129] Step 603: Adjust the frequency of the carrier to the target frequency.

[0130] After determining the target frequency corresponding to the carrier, the frequency of the carrier can be adjusted to the target frequency. The carrier with the adjusted frequency is then input into the modulation unit corresponding to the rectifier, and the modulation unit corresponding to the rectifier modulates the input carrier and the modulation wave corresponding to each control unit in the rectifier to obtain a control signal for controlling each switch tube in the rectifier. The carrier with the adjusted frequency is then input into the modulation unit corresponding to the inverter, and the modulation unit corresponding to the inverter modulates the input carrier and the modulation wave corresponding to each switch tube in the inverter to obtain a control signal for controlling each switch tube in the inverter. After obtaining the control signal for controlling each switch tube in the rectifier and inverter, the closing and opening of the switches in the rectifier and inverter can be controlled according to the control signal.

[0131] By increasing the carrier frequency, the embodiments of the present application can increase the frequency of the switch opening and closing, thereby increasing the frequency of the ripple current passing through the bus capacitor. Because the ripple voltage generated by the ripple current acting on the bus capacitor is inversely proportional to the frequency of the ripple current, increasing the carrier frequency can suppress the ripple voltage, thereby reducing its impact on the safe operation of the bus capacitor and the precise control of the back-to-back converter.

[0132] Figure 7 This is a flow chart of a method for suppressing ripple voltage and ripple current in a back-to-back converter by using a frequency modulation control unit and a voltage modulation control unit, see Figure 7 The method may be executed by a voltage regulation control unit and a voltage regulation control unit in a software program for controlling a back-to-back converter, and includes:

[0133] Step 701: Obtain a voltage parameter value corresponding to a ripple voltage in a back-to-back converter.

[0134] Step 702: After determining that the voltage parameter value is greater than the corresponding voltage parameter threshold, determine the target frequency of the carrier according to the voltage parameter value of the ripple voltage.

[0135] Among them, the target frequency is positively correlated with the voltage parameter value.

[0136] Step 703: Adjust the frequency of the carrier to the target frequency.

[0137] Among them, the processing of steps 701-703 is the same as that of steps 601-603, and will not be repeated here.

[0138] Step 704: Determine whether the electrical parameter is still greater than the corresponding electrical parameter threshold.

[0139] In this method, maximum and minimum frequency values ​​can be set for the carrier frequency in a back-to-back converter. This prevents excessively high carrier frequency adjustment, which would cause the switching transistor to open and close at excessively high frequencies, thus shortening its service life. It also prevents excessively low carrier frequency adjustment, which would affect the back-to-back converter's conversion performance between AC and DC.

[0140] Among them, the minimum frequency value and the maximum frequency value can be pre-set by a technician, and their specific values ​​are not limited here. If the target frequency value obtained in step 703 is less than the set minimum frequency value, the target frequency value can be adjusted to the minimum frequency value. In this way, in step 704, the frequency of the carrier can be set to the minimum frequency value to ensure that the frequency of opening and closing of the switching tubes in the rectifier and the inverter is not too low. If the target frequency value obtained in step 703 is greater than the set maximum frequency value, the target frequency value can be adjusted to the maximum frequency value. In this way, in step 704, the frequency of the carrier can be adjusted to the maximum frequency value to ensure that the frequency of opening and closing of the switching tubes in the rectifier and the inverter is not too high.

[0141] When the carrier target frequency is adjusted to its maximum value, it indicates that the frequency modulation control unit cannot further suppress the ripple voltage. Therefore, the voltage regulation control unit can be turned on again to further suppress the ripple voltage or ripple current in the back-to-back converter, that is, to perform the following processing steps 705-706.

[0142] Step 705: Determine a first reference voltage of the DC bus in the back-to-back converter according to the electrical parameters.

[0143] Step 706: Adjust the voltage of the DC bus to a first reference voltage.

[0144] In step 704, if it is determined that the voltage parameter value is greater than the voltage parameter threshold and the target frequency value is the maximum frequency value, it means that the frequency modulation control unit is unable to further suppress the ripple voltage. Therefore, in steps 705-706, the voltage regulation control unit can be used to determine the first reference voltage of the DC bus based on the voltage parameter value, adjust the voltage of the DC bus to the first reference voltage, and then further suppress the ripple voltage in the back-to-back converter by adjusting the voltage of the DC bus. In this way, the ripple voltage in the back-to-back converter can be suppressed successively by the frequency modulation control unit and the voltage regulation control unit, which can reduce the loss of the bus capacitor caused by the ripple voltage and increase the service life of the bus capacitor.

[0145] In step 704, if it is determined that the current parameter value is greater than the current parameter threshold, then in steps 705-706, the voltage regulation control unit can determine a first reference voltage of the DC bus based on the current parameter value, and then adjust the voltage of the DC bus to the first reference voltage. The ripple current in the back-to-back converter can be further suppressed by adjusting the voltage of the DC bus. In this way, the ripple voltage in the back-to-back converter can be first suppressed by the frequency modulation control unit, and then the ripple current in the back-to-back converter can be suppressed by the voltage regulation control unit. This can reduce the loss of the bus capacitor caused by the ripple voltage and ripple current, thereby increasing the service life of the bus capacitor.

[0146] The processing of steps 705-706 may refer to the above steps 502-503 and will not be repeated here.

[0147] Optionally, corresponding to the above-mentioned situation where the voltage parameter value is determined to be greater than the voltage parameter threshold, if in step 706, the voltage regulation control unit determines the first reference voltage through the voltage parameter value, and determines that the first reference voltage is the rated voltage, and determines that the voltage parameter value is less than or equal to the voltage parameter threshold, then the voltage of the DC bus can be fixed at the rated voltage.

[0148] The rated voltage of the back-to-back converter is the voltage value of the DC bus when the back-to-back converter is in optimal operating condition. If, during the process of determining the first reference voltage by the voltage regulation control unit, the determined first reference voltage is equal to the rated voltage, and the voltage parameter value is less than or equal to the electrical parameter threshold, it indicates that the ripple voltage in the current back-to-back converter no longer needs to be suppressed. In this case, the voltage regulation control unit can stop suppressing the ripple voltage, and the DC bus voltage can be fixed at the rated voltage.

[0149] Optionally, corresponding to the above-mentioned situation where the current parameter value is greater than the current parameter threshold, if in step 706, the voltage regulation control unit determines the first reference voltage through the current parameter value, and determines that the first reference voltage is the rated voltage, and determines that the current parameter value is less than or equal to the current parameter threshold, the voltage of the DC bus is fixed at the rated voltage.

[0150] Similarly, if, during the process of determining the first reference voltage by the voltage regulation control unit, the determined first reference voltage is equal to the rated voltage, and the current parameter value is less than or equal to the current parameter threshold, it indicates that the ripple current in the back-to-back converter no longer needs to be suppressed. In this case, the voltage regulation control unit can stop suppressing the ripple current and fix the DC bus voltage at the rated voltage.

[0151] In an exemplary embodiment, the processing of steps 701 to 706 may first suppress the ripple voltage using the frequency modulation control module and the voltage regulation control unit. Thus, after step 706, the ripple current may be suppressed again by the voltage regulation control unit. The processing may further include:

[0152] Step 707: After determining that the first reference voltage is between the set maximum voltage and minimum voltage and that the current parameter value is greater than the corresponding electrical parameter threshold, determine the second reference voltage of the DC bus in the back-to-back converter according to the current parameter value.

[0153] Among them, the maximum voltage and minimum voltage can be set for the voltage of the DC bus, thereby preventing the bus capacitor from breaking down when the voltage of the DC bus is too high. It can also prevent the voltage of the DC bus from being too low, affecting the conversion effect between AC and DC by the back-to-back converter. The minimum voltage and maximum voltage can be pre-set by a technician, and their specific values ​​are not limited here. It should be noted that if the first reference voltage obtained in step 706 is less than the set minimum voltage, the first reference voltage can be adjusted to the minimum voltage value. If the first reference voltage obtained in step 706 is greater than the set maximum voltage, the first reference voltage can be adjusted to the maximum voltage. In this way, it can be ensured that the DC bus voltage is not too large or too small.

[0154] If, in steps 701-706, the ripple voltage is suppressed by the frequency modulation control module and the voltage regulation control unit and the DC bus voltage is determined to be between the maximum voltage and the minimum voltage, the ripple voltage in the back-to-back converter has been suppressed. Otherwise, the voltage regulation control unit will adjust the DC bus voltage to the maximum voltage or the minimum voltage. At this point, if the current parameter value corresponding to the ripple current in the back-to-back converter is determined to be greater than the current parameter threshold, the ripple current can be further suppressed by the voltage regulation control unit. In other words, the second reference voltage of the DC bus is determined based on the current parameter value.

[0155] Step 708: Adjust the voltage of the DC bus to a second reference voltage.

[0156] The processing of steps 707-708 may refer to the above steps 502-503 and will not be repeated here.

[0157] Optionally, after adjusting the voltage of the DC bus to the second reference voltage, if it is determined that the second reference voltage is the rated voltage and the electrical parameter is determined to be less than or equal to the corresponding electrical parameter threshold, the voltage of the DC bus can be fixed at the rated voltage.

[0158] If, during the process of determining the second reference voltage, the determined second reference voltage is equal to the rated voltage and the current parameter value is less than or equal to the current parameter threshold, it indicates that the ripple current in the back-to-back converter no longer needs to be suppressed. In this case, the voltage regulation control unit can stop suppressing the ripple current and fix the DC bus voltage at the rated voltage.

[0159] The added steps 707-708 can suppress the ripple current in the back-to-back converter after the frequency modulation control unit and the voltage regulation control unit suppress the ripple voltage in the back-to-back converter, thereby reducing the loss of the bus capacitor caused by the ripple voltage and ripple current and increasing the service life of the bus capacitor.

[0160] Figure 8 This is a flow chart of a method for suppressing ripple voltage and ripple current in a back-to-back converter by using a frequency modulation control unit and a voltage modulation control unit. Figure 8 The method may be executed by a voltage regulation control unit and a voltage regulation control unit in a software program for controlling a back-to-back converter, and includes:

[0161] Step 801: Obtain electrical parameters corresponding to the ripple voltage or ripple current in the back-to-back converter.

[0162] Step 802: After determining that the electrical parameter is greater than the corresponding electrical parameter threshold, determine a first reference voltage of the DC bus in the back-to-back converter according to the electrical parameter.

[0163] Step 803: Adjust the voltage of the DC bus to a first reference voltage.

[0164] Among them, the processing of steps 801-803 is the same as that of steps 501-503, and will not be repeated here.

[0165] In one scenario, the electrical parameters in steps 801-803 are voltage parameter values, and the corresponding voltage regulation control unit determines the first reference voltage of the DC bus based on the voltage parameter value, and then suppresses the ripple voltage in the back-to-back converter by adjusting the voltage of the DC bus. In this case, the method flow further includes:

[0166] Step 804 : When it is determined that the voltage of the DC bus is adjusted to the set maximum voltage or minimum voltage, and the voltage parameter value is greater than the corresponding electrical parameter threshold, the voltage of the DC bus is fixed at the maximum voltage or minimum voltage.

[0167] If the DC bus voltage is at its maximum or minimum voltage, it indicates that the voltage regulation control unit is unable to further suppress the ripple voltage or ripple current. In this case, the DC bus voltage can be fixed at the maximum or minimum voltage, and the frequency modulation control unit can be enabled to further suppress the ripple voltage. Specifically, if the DC bus voltage is determined to be at its maximum voltage and the voltage parameter value is greater than the corresponding electrical parameter threshold, the DC bus voltage can be fixed at the maximum voltage. If the DC bus voltage is determined to be at its minimum voltage and the voltage parameter value is greater than the corresponding electrical parameter threshold, the DC bus voltage can be fixed at the minimum voltage.

[0168] Step 805: Determine the target frequency of the carrier according to the voltage parameter value of the ripple voltage.

[0169] Among them, the target frequency is positively correlated with the voltage parameter value.

[0170] Step 806: Adjust the frequency of the carrier to the target frequency.

[0171] The processing of steps 805-806 is the same as that of steps 602-603 above and will not be further described here. In this way, the ripple voltage in the back-to-back converter can be suppressed by the voltage regulation control unit and the frequency regulation control unit in sequence, thereby reducing the loss of the bus capacitor caused by the ripple voltage and ripple current, thereby increasing the service life of the bus capacitor.

[0172] In another case, the electrical parameter in steps 801-803 is a current parameter value. The corresponding voltage regulation control unit determines the first reference voltage of the DC bus based on the current parameter value, and then suppresses the ripple current in the back-to-back converter by adjusting the voltage of the DC bus. In this case, after steps 801-803, the method further includes:

[0173] Step 807: Determine that the current parameter value is less than the corresponding electrical parameter threshold, the DC bus voltage is between the set maximum voltage and minimum voltage, and the voltage parameter value is greater than the corresponding electrical parameter threshold, and determine the target frequency of the carrier based on the voltage parameter value of the ripple voltage.

[0174] If the current parameter value is determined to be less than the corresponding electrical parameter threshold and the DC bus voltage is within the set maximum and minimum voltages, the voltage regulation control unit has suppressed the ripple current in the back-to-back converter. If the voltage parameter value is also determined to be greater than the corresponding electrical parameter threshold, the ripple voltage in the back-to-back converter still needs to be suppressed. In this case, the ripple voltage can be further suppressed by the frequency modulation control unit.

[0175] Step 808: Adjust the frequency of the carrier to the target frequency.

[0176] The processing of steps 807-808 can refer to the processing of steps 602-603 above and will not be repeated here. In this way, the ripple voltage in the back-to-back converter can be suppressed by the voltage regulation control unit first, and then the ripple voltage in the back-to-back converter can be suppressed by the frequency modulation control unit. This can reduce the loss of the bus capacitor caused by ripple voltage and ripple current, thereby increasing the service life of the bus capacitor.

[0177] It should be noted that steps 807-808 and steps 804-806 are processing flows for two different situations after executing step 803. In actual practice, either of the two different processing flows can be executed according to actual needs. For example, when the back-to-back converter only needs to suppress the ripple voltage, steps 801-806 can be performed. When the back-to-back converter needs to suppress both the ripple voltage and the ripple current, steps 801-803 and steps 807-808 can be performed.

[0178] Optionally, when it is determined that the carrier frequency is adjusted to a set minimum frequency and the voltage parameter value is less than or equal to the voltage parameter threshold, the carrier frequency is fixed at the minimum frequency. The initial frequency of the back-to-back converter is generally the minimum frequency. Therefore, during the frequency adjustment process in step 808, when it is determined that the carrier frequency is the minimum frequency and the voltage parameter value is less than or equal to the voltage parameter threshold, it indicates that the current ripple voltage has been suppressed. Therefore, the ripple voltage suppression by the frequency modulation control unit can be stopped, and the carrier frequency can be fixed at the minimum frequency.

[0179] It can be seen that the back-to-back converter control method provided in the present application can suppress the ripple current and ripple voltage in the back-to-back converter through the voltage regulation control unit and the frequency regulation control unit respectively, thereby reducing the loss of the bus capacitor caused by the ripple current and ripple voltage, increasing the service life of the bus capacitor, and thereby increasing the service life of the back-to-back converter.

[0180] Figure 9 The present invention provides a back-to-back converter control device, which may be the electronic device in the above embodiment. The device includes:

[0181] An acquisition module 910 is configured to acquire electrical parameters corresponding to a ripple voltage or a ripple current in a back-to-back converter;

[0182] a determination module 920 for determining a first reference voltage of a DC bus in the back-to-back converter according to the electrical parameter after determining that the electrical parameter is greater than a corresponding electrical parameter threshold;

[0183] The adjustment module 930 is configured to adjust the voltage of the DC bus to the first reference voltage.

[0184] Optionally, the electrical parameter corresponding to the ripple current is a current parameter value, and the electrical parameter corresponding to the ripple voltage is a voltage parameter value.

[0185] Optionally, the determining module 920 is further configured to:

[0186] Determining a target frequency of the carrier according to a voltage parameter value of the ripple voltage, wherein the target frequency is positively correlated with the voltage parameter value;

[0187] The frequency of the carrier wave is adjusted to a target frequency.

[0188] Optionally, the determining module 920 is further configured to:

[0189] It is determined that the electrical parameter is still greater than the corresponding electrical parameter threshold.

[0190] Optionally, the determining module 920 is further configured to:

[0191] When it is determined that the first reference voltage is the rated voltage and the voltage parameter value is less than or equal to the electrical parameter threshold, the voltage of the DC bus is fixed at the rated voltage.

[0192] Optionally, the determining module 920 is further configured to:

[0193] After determining that the first reference voltage is between a set maximum voltage and a set minimum voltage and determining that the current parameter value is greater than a corresponding electrical parameter threshold, determining a second reference voltage of the DC bus in the back-to-back converter according to the current parameter value;

[0194] The adjustment module 930 is further configured to adjust the voltage of the DC bus to the second reference voltage.

[0195] Optionally, the determining module 920 is further configured to:

[0196] When it is determined that the second reference voltage is the rated voltage and it is determined that the electrical parameter is less than or equal to the corresponding electrical parameter threshold, the voltage of the DC bus is fixed at the rated voltage.

[0197] Optionally, the determining module 920 is further configured to:

[0198] When it is determined that the voltage of the DC bus is adjusted to a set maximum voltage or a minimum voltage, and the voltage parameter value is greater than a corresponding electrical parameter threshold, the voltage of the DC bus is fixed at the maximum voltage or the minimum voltage.

[0199] Optionally, the determining module 920 is further configured to:

[0200] Determining a target frequency of the carrier according to a voltage parameter value of the ripple voltage, wherein the target frequency is positively correlated with the voltage parameter value;

[0201] The adjustment module is further configured to adjust the frequency of the carrier to a target frequency.

[0202] Optionally, the determining module 920 is further configured to:

[0203] determining that the current parameter value is less than a corresponding electrical parameter threshold, that the voltage of the DC bus is between a set maximum voltage and a set minimum voltage, and that the voltage parameter value is greater than the corresponding electrical parameter threshold, and determining a target frequency of the carrier according to the voltage parameter value of the ripple voltage, wherein the target frequency is positively correlated with the voltage parameter value;

[0204] The adjustment module 930 is further configured to adjust the frequency of the carrier to a target frequency.

[0205] Optionally, the adjustment module 930 is further configured to:

[0206] When it is determined that the frequency of the carrier is adjusted to the set minimum frequency and the voltage parameter value is less than or equal to the voltage parameter threshold, the frequency of the carrier is fixed at the minimum frequency.

[0207] Optionally, the determining module 920 is further configured to:

[0208] The voltage parameter value and the current parameter value are calculated according to the set control algorithm and the corresponding second algorithm parameter to obtain a first reference voltage of the DC bus.

[0209] Optionally, the determining module 920 is further configured to:

[0210] The voltage parameter value and the current parameter value are weightedly calculated according to a first weight value corresponding to the voltage parameter value and a second weight value corresponding to the current parameter value, and a first reference voltage of the DC bus is obtained using the electrical parameters obtained by the weighted calculation.

[0211] It should be noted that the apparatus for controlling a back-to-back converter provided in the above embodiment only uses the division of the above functional modules as an example to illustrate the control of the back-to-back converter. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the electronic device can be divided into different functional modules to complete all or part of the functions described above. In addition, the apparatus for controlling a back-to-back converter provided in the above embodiment and the method embodiment for controlling a back-to-back converter are based on the same concept. The specific implementation process is detailed in the method embodiment and will not be repeated here.

[0212] Figure 10The following is a block diagram of an electronic device 1000 provided by an exemplary embodiment of the present application. The electronic device may be a microcontroller unit (MCU) that controls a back-to-back converter. In one possible scenario, the electronic device 1000 may also be a portable mobile terminal, such as a smartphone, a tablet computer, an MP3 player (moving picture experts group audio layer III), an MP4 player (moving picture experts group audio layer IV), a laptop computer, or a desktop computer. The electronic device 1000 may also be referred to as a user device, a portable terminal, a laptop terminal, a desktop terminal, or other names.

[0213] Typically, the electronic device 1000 includes a processor 1001 and a memory 1002 .

[0214] The processor 1001 may include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor 1001 may be implemented in at least one hardware form of DSP (digital signal processing), FPGA (field-programmable gate array), or PLA (programmable logic array). The processor 1001 may also include a main processor and a coprocessor. The main processor is a processor for processing data in the awake state, also known as a CPU (central processing unit); the coprocessor is a low-power processor for processing data in the standby state. In some embodiments, the processor 1001 may be integrated with a GPU (graphics processing unit), which is responsible for rendering and drawing the content to be displayed on the display screen. In some embodiments, the processor 1001 may also include an AI (artificial intelligence) processor, which is used to process computing operations related to machine learning.

[0215] Memory 1002 may include one or more computer-readable storage media, which may be non-transitory. Memory 1002 may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices or flash memory storage devices. In some embodiments, the non-transitory computer-readable storage medium in memory 1002 is used to store at least one instruction, which is executed by processor 1001 to implement the back-to-back converter control method provided in the method embodiment of the present application.

[0216] In some embodiments, electronic device 1000 may optionally include a peripheral device interface 1003 and at least one peripheral device. Processor 1001, memory 1002, and peripheral device interface 1003 may be connected via a bus or signal lines. Each peripheral device may be connected to peripheral device interface 1003 via a bus, signal lines, or circuit boards. Specifically, the peripheral device may include at least one of a radio frequency circuit 1004, a display screen 1005, a camera assembly 1006, an audio circuit 1007, a positioning assembly 1008, and a power supply 1009.

[0217] The peripheral device interface 1003 can be used to connect at least one I / O (input / output)-related peripheral device to the processor 1001 and the memory 1002. In some embodiments, the processor 1001, the memory 1002, and the peripheral device interface 1003 are integrated on the same chip or circuit board; in some other embodiments, any one or two of the processor 1001, the memory 1002, and the peripheral device interface 1003 can be implemented on separate chips or circuit boards, which is not limited in this embodiment.

[0218] The RF circuit 1004 is used to receive and transmit RF (radio frequency) signals, also known as electromagnetic signals. The RF circuit 1004 communicates with communication networks and other communication devices via electromagnetic signals. The RF circuit 1004 converts electrical signals into electromagnetic signals for transmission, or converts received electromagnetic signals into electrical signals. Optionally, the RF circuit 1004 includes an antenna system, an RF transceiver, one or more amplifiers, a tuner, an oscillator, a digital signal processor, a codec chipset, a user identity module card, and the like. The RF circuit 1004 can communicate with other terminals via at least one wireless communication protocol. Such wireless communication protocols include, but are not limited to, the World Wide Web, a metropolitan area network, an intranet, various generations of mobile communication networks (2G, 3G, 4G, and 5G), a wireless local area network, and / or a WiFi (wireless fidelity) network. In some embodiments, the RF circuit 1004 may also include circuits related to near field communication (NFC), which is not limited in this application.

[0219] Display screen 1005 is used to display a user interface (UI). This UI may include graphics, text, icons, videos, or any combination thereof. When display screen 1005 is a touchscreen display, it is also capable of collecting touch signals on or above the surface of display screen 1005. These touch signals can be input as control signals to processor 1001 for processing. Display screen 1005 can also be used to provide virtual buttons and / or a virtual keyboard, also known as soft buttons and / or a soft keyboard. In some embodiments, there can be a single display screen 1005, located on the front panel of electronic device 1000. In other embodiments, there can be at least two display screens 1005, located on different surfaces of electronic device 1000 or in a foldable design. In still other embodiments, display screen 1005 can be a flexible display, located on a curved or foldable surface of electronic device 1000. Display screen 1005 can also be configured as a non-rectangular, irregular shape, also known as a special-shaped screen. Display screen 1005 can be made of materials such as LCD (liquid crystal display) and OLED (organic light-emitting diode).

[0220] The camera assembly 1006 is used to capture images or videos. Optionally, the camera assembly 1006 includes a front camera and a rear camera. Typically, the front camera is arranged on the front panel of the terminal, and the rear camera is arranged on the back of the terminal. In some embodiments, there are at least two rear cameras, which are any one of a main camera, a depth of field camera, a wide-angle camera, and a telephoto camera, so as to realize the fusion of the main camera and the depth of field camera to realize the background blur function, the fusion of the main camera and the wide-angle camera to realize panoramic shooting and VR (virtual reality) shooting function or other fusion shooting functions. In some embodiments, the camera assembly 1006 may also include a flash. The flash can be a single-color temperature flash or a dual-color temperature flash. A dual-color temperature flash refers to a combination of a warm light flash and a cold light flash, which can be used for light compensation at different color temperatures.

[0221] The audio circuit 1007 may include a microphone and a speaker. The microphone is used to collect sound waves from the user and the environment, and convert the sound waves into electrical signals to be input into the processor 1001 for processing, or input into the radio frequency circuit 1004 to achieve voice communication. For the purpose of stereo sound collection or noise reduction, there may be multiple microphones, each disposed at different locations of the electronic device 1000. The microphone may also be an array microphone or an omnidirectional collection microphone. The speaker is used to convert electrical signals from the processor 1001 or the radio frequency circuit 1004 into sound waves. The speaker may be a traditional thin film speaker or a piezoelectric ceramic speaker. When the speaker is a piezoelectric ceramic speaker, it can not only convert electrical signals into sound waves audible to humans, but also convert electrical signals into sound waves inaudible to humans for purposes such as distance measurement. In some embodiments, the audio circuit 1007 may also include a headphone jack.

[0222] The positioning component 1008 is used to locate the current geographic location of the electronic device 1000 to implement navigation or LBS (location based service). The positioning component 1008 can be a positioning component based on the GPS (global positioning system), Beidou system or Galileo system.

[0223] Power supply 1009 is used to power the various components of electronic device 1000. Power supply 1009 can be AC ​​power, DC power, a disposable battery, or a rechargeable battery. When power supply 1009 includes a rechargeable battery, the rechargeable battery can be a wired rechargeable battery or a wireless rechargeable battery. A wired rechargeable battery is a battery that is charged via a wired line, while a wireless rechargeable battery is a battery that is charged via a wireless coil. The rechargeable battery can also be used to support fast charging technology.

[0224] In some embodiments, the electronic device 1000 further includes one or more sensors 1100 , including but not limited to: an acceleration sensor 1011 , a gyroscope sensor 1012 , a pressure sensor 1013 , a fingerprint sensor 1014 , an optical sensor 1015 , and a proximity sensor 1016 .

[0225] The accelerometer 1011 can detect the magnitude of acceleration along the three coordinate axes of the coordinate system established by the electronic device 1000. For example, the accelerometer 1011 can be used to detect the components of gravity acceleration along the three coordinate axes. The processor 1001 can control the display screen 1005 to display the user interface in a landscape or portrait view based on the gravity acceleration signal collected by the accelerometer 1011. The accelerometer 1011 can also be used to collect game or user motion data.

[0226] The gyro sensor 1012 can detect the orientation and rotation angle of the electronic device 1000. It can work in conjunction with the accelerometer 1011 to collect the user's 3D movements of the electronic device 1000. Based on the data collected by the gyro sensor 1012, the processor 1001 can implement the following functions: motion sensing (for example, changing the UI based on the user's tilt operation), image stabilization during shooting, game control, and inertial navigation.

[0227] The pressure sensor 1013 can be set on the side frame of the electronic device 1000 and / or the lower layer of the display screen 1005. When the pressure sensor 1013 is set on the side frame of the electronic device 1000, it can detect the user's grip signal of the electronic device 1000, and the processor 1001 performs left and right hand recognition or shortcut operations based on the grip signal collected by the pressure sensor 1013. When the pressure sensor 1013 is set on the lower layer of the display screen 1005, the processor 1001 controls the operable controls on the UI interface based on the user's pressure operation on the display screen 1005. The operable controls include at least one of a button control, a scroll bar control, an icon control, and a menu control.

[0228] The fingerprint sensor 1014 is used to collect the user's fingerprint. The processor 1001 identifies the user's identity based on the fingerprint collected by the fingerprint sensor 1014, or the fingerprint sensor 1014 identifies the user's identity based on the collected fingerprint. When the user's identity is recognized as a trusted identity, the processor 1001 authorizes the user to perform relevant sensitive operations, such as unlocking the screen, viewing encrypted information, downloading software, making payments, and changing settings. The fingerprint sensor 1014 can be set on the front, back, or side of the electronic device 1000. When a physical button or manufacturer logo is provided on the electronic device 1000, the fingerprint sensor 1014 can be integrated with the physical button or manufacturer logo.

[0229] Optical sensor 1015 is used to detect ambient light intensity. In one embodiment, processor 1001 can control the display brightness of display screen 1005 based on the ambient light intensity detected by optical sensor 1015. Specifically, when the ambient light intensity is high, the display brightness of display screen 1005 is increased; when the ambient light intensity is low, the display brightness of display screen 1005 is decreased. In another embodiment, processor 1001 can also dynamically adjust the shooting parameters of camera assembly 1006 based on the ambient light intensity detected by optical sensor 1015.

[0230] Proximity sensor 1016, also known as a distance sensor, is typically located on the front panel of electronic device 1000. Proximity sensor 1016 is used to detect the distance between the user and the front of electronic device 1000. In one embodiment, when proximity sensor 1016 detects that the distance between the user and the front of electronic device 1000 is gradually decreasing, processor 1001 controls display screen 1005 to switch from the screen-on state to the screen-off state. When proximity sensor 1016 detects that the distance between the user and the front of electronic device 1000 is gradually increasing, processor 1001 controls display screen 1005 to switch from the screen-off state to the screen-on state.

[0231] Those skilled in the art will understand that Figure 10 The structure shown in the figure does not constitute a limitation on the electronic device 1000, and the electronic device 1000 may include more or fewer components than shown in the figure, or combine certain components, or adopt a different component arrangement.

[0232] In an exemplary embodiment, a computer-readable storage medium is also provided, such as a memory including instructions. The instructions are executable by a processor in a terminal to implement the control method of the back-to-back converter in the above embodiment. The computer-readable storage medium can be non-transitory. For example, the computer-readable storage medium can be a ROM (read-only memory), a RAM (random access memory), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, or the like.

[0233] Those skilled in the art will understand that all or part of the steps to implement the above embodiments may be accomplished by hardware, or by a program to instruct the relevant hardware, and the program may be stored in a computer-readable storage medium, which may be a read-only memory, a disk, or an optical disk, etc.

[0234] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A back-to-back converter control method, characterized in that: The method comprises: Obtaining an electrical parameter corresponding to a ripple voltage or a ripple current in a back-to-back converter, wherein the electrical parameter corresponding to the ripple current is a current parameter value, and the electrical parameter corresponding to the ripple voltage is a voltage parameter value; After determining that the electrical parameter is greater than a corresponding electrical parameter threshold, determining a first reference voltage of a DC bus in the back-to-back converter according to the electrical parameter, and determining a target frequency of the carrier according to a voltage parameter value of the ripple voltage, wherein the target frequency is positively correlated with the voltage parameter value; adjusting the frequency of the carrier wave to a target frequency; The voltage of the DC bus is adjusted to the first reference voltage.

2. The method according to claim 1, characterized in that Before determining the first reference voltage of the DC bus in the back-to-back converter according to the electrical parameter, the method further includes: It is determined that the electrical parameter is still greater than the corresponding electrical parameter threshold.

3. The method according to claim 2, characterized in that After adjusting the voltage of the DC bus to the first reference voltage, the method further includes: When it is determined that the first reference voltage is the rated voltage and the voltage parameter value is less than or equal to the electrical parameter threshold, the voltage of the DC bus is fixed at the rated voltage.

4. The method according to claim 2, characterized in that After adjusting the voltage of the DC bus to the first reference voltage, the method further includes: After determining that the first reference voltage is between a set maximum voltage and a set minimum voltage and determining that the current parameter value is greater than a corresponding electrical parameter threshold, determining a second reference voltage of the DC bus in the back-to-back converter according to the current parameter value; The voltage of the DC bus is adjusted to the second reference voltage.

5. The method according to claim 4, characterized in that After adjusting the voltage of the DC bus to the second reference voltage, the method further includes: When it is determined that the second reference voltage is the rated voltage and it is determined that the electrical parameter is less than or equal to the corresponding electrical parameter threshold, the voltage of the DC bus is fixed at the rated voltage.

6. The method according to claim 1, characterized in that After adjusting the voltage of the DC bus to the first reference voltage, the method further includes: When it is determined that the voltage of the DC bus is adjusted to a set maximum voltage or a minimum voltage, and the voltage parameter value is greater than a corresponding electrical parameter threshold, the voltage of the DC bus is fixed at the maximum voltage or the minimum voltage.

7. The method according to any one of claims 1 to 6, characterized in that Determining a first reference voltage of a DC bus in the back-to-back converter according to the electrical parameter includes: The electrical parameters are calculated according to a set control algorithm and corresponding algorithm parameters to obtain a first reference voltage of the DC bus.

8. The method according to any one of claims 1 to 6, characterized in that Determining a first reference voltage of a DC bus in the back-to-back converter according to the electrical parameter includes: The voltage parameter value and the current parameter value are weightedly calculated according to a first weight value corresponding to the voltage parameter value and a second weight value corresponding to the current parameter value, and a first reference voltage of the DC bus is obtained by using the electrical parameter calculation obtained after the weighted calculation.

9. A back-to-back converter control device, characterized in that: The device comprises: An acquisition module, configured to acquire an electrical parameter corresponding to a ripple voltage or a ripple current in a back-to-back converter, wherein the electrical parameter corresponding to the ripple current is a current parameter value, and the electrical parameter corresponding to the ripple voltage is a voltage parameter value; a determination module, configured to, after determining that the electrical parameter is greater than a corresponding electrical parameter threshold, determine a first reference voltage of a DC bus in the back-to-back converter based on the electrical parameter, and determine a target frequency of the carrier based on a voltage parameter value of the ripple voltage, wherein the target frequency is positively correlated with the voltage parameter value; An adjustment module is used to adjust the frequency of the carrier to a target frequency and adjust the voltage of the DC bus to the first reference voltage.

10. An electronic device, characterized in that: The electronic device includes a memory and a processor, the memory is used to store computer instructions; the processor is used to execute the computer instructions stored in the memory, so that the electronic device executes the method according to any one of claims 1 to 8.

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