Clamping type converter and control method and device of clamping type converter

Abstract

The invention relates to a clamping type converter and a control method and device of the clamping type converter. The clamping type converter comprises a first frequency module, a second frequency module, a third frequency module, a shunt inductor module and a voltage-dividing capacitor module. The shunt inductance module is respectively connected with the second frequency module and the third frequency module, the first frequency module is respectively connected with the voltage-dividing capacitance module and the second frequency module, the second frequency module is connected with the third frequency module, and the voltage-dividing capacitance module is connected with a direct-current power supply; the first frequency module is used for working in a fundamental frequency switch state; the second frequency module is used for working in a first set switch state and circulating a first current; the third frequency module is used for working in a second set switch state, circulating second current and compensating harmonic current generated by the second frequency module; and the voltage-dividing capacitor module is used for carrying out voltage division on the direct-current power supply. By adopting the clamping converter, the overall capacity can be improved.

Description

Technical Field

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

[0002] With the increase of nonlinear power electronic devices such as distributed photovoltaic, energy storage, and charging piles in the distribution network, power quality problems such as high harmonic content and large reactive power shortage in the distribution network have become increasingly serious. Accordingly, the performance optimization of power quality management devices such as active power filters and static VAR compensators has gradually attracted attention.

[0003] In the related technology, power management devices are usually based on silicon (Si)-based devices and silicon carbide (SiC)-based devices. Compared with silicon-based devices, silicon carbide-based devices have stronger output performance but higher costs. Therefore, a hybrid multi-level converter can be built based on silicon carbide-based devices and silicon-based devices to achieve equivalent switching frequency and operating loss similar to that of a full SiC device converter.

[0004] However, due to the hybrid multi-level converter in the related art, the rated current of the silicon carbide-based device is limited to be small, so that the overall capacity of the converter is small. Summary of the invention

[0005] Based on this, it is necessary to provide a clamped-type converter, a control method and a device for the clamped-type converter that can improve the overall capacity of the converter in order to solve the above-mentioned technical problems.

[0006] In a first aspect, the present application provides a clamped converter, the clamped converter comprising: a first frequency module, a second frequency module, a third frequency module, a shunt inductor module and a voltage-dividing capacitor module;

[0007] The shunt inductor module is connected to the second frequency module and the third frequency module respectively, the first frequency module is connected to the voltage-dividing capacitor module and the second frequency module respectively, the second frequency module is connected to the third frequency module, and the voltage-dividing capacitor module is connected to a DC power supply;

[0008] The first frequency module is used to work when it is in the base frequency switch state; the second frequency module is used to work when it is in the first set switch state and flow the first current; the third frequency module is used to work when it is in the second set switch state, flow the second current and compensate for the harmonic current generated by the second frequency module; the voltage-dividing capacitor module is used to divide the voltage of the DC power supply; the shunt inductor module is used to aggregate the first current and the second current into a total output current;

[0009] Among them, the output performance of the switching devices in the third frequency module is stronger than the switching devices in the first frequency module and the second frequency module; the first current is greater than the second current, and the frequency corresponding to the first set switch state is less than the frequency corresponding to the second set switch state.

[0010] In one embodiment, the first frequency module and the second frequency module each include a plurality of silicon insulated gate bipolar transistors Si IGBTs, the third frequency module includes a plurality of silicon carbide metal oxide semiconductor field effect transistors SiC MOSFETs, and the number of Si IGBTs in the first frequency module is greater than the number of SiIGBTs in the second frequency module.

[0011] In one embodiment, the first frequency module includes a first Si IGBT, a second Si IGBT, a third Si IGBT and a fourth Si IGBT; the second frequency module includes a fifth Si IGBT and a sixth Si IGBT; the third frequency module includes a first SiC MOSFET and a second SiC MOSFET;

[0012] The first Si IGBT, the second Si IGBT, the third Si IGBT and the fourth Si IGBT are connected in series in sequence through the collector and the emitter; the collector of the fifth Si IGBT is connected to the emitter of the first Si IGBT and the collector of the second Si IGBT respectively; the collector of the sixth Si IGBT is connected to the emitter of the fifth Si IGBT, and the emitter of the sixth Si IGBT is connected to the emitter of the third Si IGBT and the collector of the fourth Si IGBT respectively; the drain of the first SiC MOSFET is connected to the emitter of the first Si IGBT and the collector of the second Si IGBT respectively; the drain of the second SiC MOSFET is connected to the source of the first SiC MOSFET, and the source of the second SiC MOSFET is connected to the emitter of the third Si IGBT and the collector of the fourth Si IGBT respectively.

[0013] In one embodiment, the shunt inductor module includes a first inductor and a second inductor, and the voltage-dividing capacitor module includes a first capacitor and a second capacitor;

[0014] The first end of the first inductor is connected to the emitter of the fifth Si IGBT and the collector of the sixth Si IGBT respectively, the first end of the second inductor is connected to the source of the first SiC MOSFET and the drain of the second SiC MOSFET respectively; the second end of the first inductor is connected to the second end of the second inductor;

[0015] The positive electrode of the first capacitor is connected to the collector of the first Si IGBT, and the negative electrode of the first capacitor is connected to the emitter of the second Si IGBT and the collector of the third Si IGBT respectively; the positive electrode of the second capacitor is connected to the negative electrode of the first capacitor, and the negative electrode of the second capacitor is connected to the emitter of the fourth Si IGBT.

[0016] In a second aspect, a control method of a clamped converter is provided, which is applied to the clamped converter as described in the first aspect, and the method comprises:

[0017] receiving control information of the clamp-type converter, wherein the control information is used to indicate a switching mode of the clamp-type converter;

[0018] According to the switching mode of the clamped converter, a control signal is output to the clamped converter, wherein the control signal is used to control the working state of the switching devices in the second frequency module and the third frequency module, wherein the working state includes on or off.

[0019] In one of the embodiments, the control signal includes a first signal, and the first signal is used to control the fifth Si IGBT and the first SiC MOSFET to be turned on and the sixth Si IGBT and the second SiC MOSFET to be turned off, so that the first current increases, the second current decreases, and the total output current increases.

[0020] In one of the embodiments, the control signal includes a second signal, and the second signal is used to control the fifth Si IGBT and the second SiC MOSFET to be turned on and the sixth Si IGBT and the first SiC MOSFET to be turned off, so that the first current increases, the second current decreases, and the total output current decreases.

[0021] In one of the embodiments, the control signal includes a third signal, and the third signal is used to control the sixth Si IGBT and the first SiC MOSFET to be turned on and the fifth Si IGBT and the second SiC MOSFET to be turned off, so that the first current decreases, the second current increases, and the total output current increases.

[0022] In one of the embodiments, the control signal includes a fourth signal, and the fourth signal is used to control the sixth Si IGBT and the second SiC MOSFET to be turned on and the fifth Si IGBT and the first SiC MOSFET to be turned off, so that the first current decreases, the second current decreases, and the total output current decreases.

[0023] In a third aspect, a control device for a clamped converter is provided, which is applied to the clamped converter described in the first aspect, and the device comprises:

[0024] A receiving module, used for receiving control information of the clamped converter, wherein the control information is used for indicating a switching mode of the clamped converter;

[0025] A sending module is used to output a control signal to the clamped converter according to the switching mode of the clamped converter, wherein the control signal is used to control the working state of the switching devices in the second frequency module and the third frequency module, wherein the working state includes on or off.

[0026] In one of the embodiments, the control signal includes a first signal, and the first signal is used to control the fifth Si IGBT and the first SiC MOSFET to be turned on and the sixth Si IGBT and the second SiC MOSFET to be turned off, so that the first current increases, the second current decreases, and the total output current increases.

[0027] In one of the embodiments, the control signal includes a second signal, and the second signal is used to control the fifth Si IGBT and the second SiC MOSFET to be turned on and the sixth Si IGBT and the first SiC MOSFET to be turned off, so that the first current increases, the second current decreases, and the total output current decreases.

[0028] In one of the embodiments, the control signal includes a third signal, and the third signal is used to control the sixth Si IGBT and the first SiC MOSFET to be turned on and the fifth Si IGBT and the second SiC MOSFET to be turned off, so that the first current decreases, the second current increases, and the total output current increases.

[0029] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the control method of the clamp-type converter of the second aspect.

[0030] In a fifth aspect, the present application further provides a computer program product, including a computer program, which, when executed by a processor, implements the control method of the clamp-type converter of the second aspect.

[0031] The above-mentioned clamped converter, control method and device of the clamped converter, the clamped converter includes: a first frequency module, a second frequency module, a third frequency module, a shunt inductance module and a voltage-dividing capacitor module. The shunt inductance module is connected to the second frequency module and the third frequency module respectively, the first frequency module is connected to the voltage-dividing capacitor module and the second frequency module respectively, the second frequency module is connected to the third frequency module, and the voltage-dividing capacitor module is connected to a DC power supply. The first frequency module is used to work when it is in a baseband switching state; the second frequency module is used to work and flow a first current when it is in a first set switching state; the third frequency module is used to work, flow a second current and compensate for the harmonic current generated by the second frequency module when it is in a second set switching state; the voltage-dividing capacitor module is used to divide the DC power supply; the shunt inductance module is used to aggregate the first current and the second current into a total output current. Among them, the output performance of the switch device in the third frequency module is stronger than that of the switch device in the first frequency module and the second frequency module; the first current is greater than the second current, and the frequency corresponding to the first set switching state is less than the frequency corresponding to the second set switching state. The clamped converter distributes most of the load current to the second frequency module by means of shunt output, while the third frequency module only passes a small part of the current, so that the required capacity of the switching device in the third frequency module is greatly reduced, so that the capacity of the clamped converter is no longer limited by the switching device in the third frequency module, thereby improving the overall capacity of the clamped converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 A schematic diagram of the structure of a clamped converter provided in an embodiment of the present application;

[0034] Figure 2 A schematic diagram of the structure of another clamp-type converter provided in an embodiment of the present application;

[0035] Figure 3 A schematic flow chart of a control method for a clamped converter provided in an embodiment of the present application;

[0036] Figure 4 A modulation strategy diagram of a clamped converter provided in an embodiment of the present application;

[0037] Figure 5 A current shunt control block diagram of a clamp-type converter provided in an embodiment of the present application;

[0038] Figure 6 A grid-side voltage and current waveform diagram provided in an embodiment of the present application;

[0039] Figure 7 A DC side voltage divider capacitor voltage diagram provided in an embodiment of the present application;

[0040] Figure 8 An output power diagram provided in an embodiment of the present application;

[0041] Figure 9a A device withstand voltage diagram provided in an embodiment of the present application;

[0042] Figure 9b Another device withstand voltage diagram provided in an embodiment of the present application;

[0043] Fig.9c A device withstand voltage diagram provided in another embodiment of the present application;

[0044] Fig.10 An output current waveform diagram provided in an embodiment of the present application;

[0045] Fig.11 A structural block diagram of a control device for a clamped converter provided in an embodiment of the present application;

[0046] Fig.12 An internal block diagram of a computer device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0048] In an exemplary embodiment, Figure 1 As shown, a clamped converter 100 is provided. The clamped converter 100 includes a first frequency module 101 , a second frequency module 102 , a third frequency module 103 , a shunt inductor module 104 and a voltage-dividing capacitor module 105 .

[0049] The shunt inductor module 104 is connected to the second frequency module 102 and the third frequency module 103 respectively, the first frequency module 101 is connected to the voltage-dividing capacitor module 105 and the second frequency module 102 respectively, the second frequency module 102 is connected to the third frequency module 103, and the voltage-dividing capacitor module 105 is connected to a DC power supply.

[0050] It should be understood that, since the clamped converter includes a frequency module composed of a plurality of unused switching devices, the clamped converter may be a hybrid active neutral-point-clamped converter (HANPC).

[0051] In some embodiments, the first frequency module 101 is used to work in a baseband switching state. The frequency corresponding to the baseband switching state can be specifically set according to actual conditions, and the embodiment of the present application does not limit this. Exemplarily, the frequency corresponding to the baseband switching state is 2 kilohertz (kHz) to 20kHz.

[0052] In some embodiments, the second frequency module 102 is used to operate and flow the first current when in the first set switch state. The frequency corresponding to the first set switch state can be specifically set according to actual conditions, and the embodiment of the present application does not limit this. Exemplarily, the frequency corresponding to the first set switch state is 1kHz to 2kHz.

[0053] In some embodiments, the third frequency module 103 is used to work in the second setting switch state, flow the second current and compensate for the harmonic current generated by the second frequency module 102. The frequency corresponding to the second setting switch state can be specifically set according to actual conditions, and the embodiment of the present application does not limit this. Exemplarily, the frequency corresponding to the second setting switch state is greater than 20kHz.

[0054] It should be understood that the first current is greater than the second current, that is, the second frequency module 102 flows most of the load current, and the third load module 103 flows a small part of the load current.

[0055] In addition, the frequencies corresponding to the first setting switch state are all lower than the frequencies corresponding to the second setting switch state, that is, the first setting switch state is a low-frequency switch state, and the second setting switch state is a high-frequency switch state.

[0056] It should be understood that the third frequency module 103 can ensure the waveform quality of the total output current of the clamped converter by compensating the harmonic current generated by the second frequency module 102 .

[0057] It should be noted that the switching devices in the first frequency module 101 and the second frequency module 102 in the above-mentioned clamped converter are the same, the switching devices in the third frequency module 103 are different from the switching devices in the first frequency module 101 and the second frequency module 102 respectively, and the output performance of the switching devices in the third frequency module 103 is stronger than that of the switching devices in the first frequency module 101 and the second frequency module 102.

[0058] Exemplarily, the first frequency module 101 and the second frequency module 102 each include a plurality of silicon insulated gate bipolar transistors (Si IGBTs), the third frequency module 103 includes a plurality of silicon carbide metal-oxide-semiconductor field-effect transistors (SiC MOSFETs), and the number of Si IGBTs in the first frequency module 101 is greater than the number of Si IGBTs in the second frequency module.

[0059] The following is an explanation of each module in the clamp-type converter.

[0060] Figure 2 A schematic diagram of the structure of another clamped converter provided in an embodiment of the present application is shown in FIG. Figure 2 As shown, the first frequency module 101 in the clamped converter includes four Si IGBTs, namely the first Si IGBT (S1), the second Si IGBT (S2), the third Si IGBT (S3) and the fourth Si IGBT (S4). The second frequency module 102 in the clamped converter includes two Si IGBTs, namely the fifth Si IGBT (Sl1) and the sixth Si IGBT (Sl2). The third frequency module 103 includes two SiC MOSFETs, namely the first SiC MOSFET (Sh1) and the second SiC MOSFET (Sh2).

[0061] like Figure 2 As shown, S1, S2, S3 and S4 are connected in series through the collector and emitter in sequence. The collector of Sl1 is connected to the emitter of S1 and the collector of S2 respectively. The collector of Sl2 is connected to the emitter of Sl1, and the emitter of Sl2 is connected to the emitter of S3 and the collector of the fourth Si IGBT respectively. The drain of Sh1 is connected to the emitter of S1 and the collector of S2 respectively. The drain of Sh2 is connected to the source of Sh1, and the source of Sh2 is connected to the emitter of S3 and the collector of S4 respectively.

[0062] Continue to refer Figure 2 The shunt inductor module 104 includes a first inductor (L1) and a second inductor (L2), and the voltage dividing capacitor module 105 includes a first capacitor (C1) and a second capacitor (C2). The first end of L1 is connected to the emitter of S11 and the collector of S12, respectively, and the first end of L2 is connected to the source of Sh1 and the drain of Sh2, respectively. The second end of L1 is connected to the second end of L2.

[0063] The positive electrode of C1 is connected to the collector of S1, and the negative electrode of C1 is connected to the emitter of S2 and the collector of S3 respectively. The positive electrode of C2 is connected to the negative electrode of C1, and the negative electrode of C2 is connected to the emitter of S4.

[0064] It should be noted that the first capacitor and the second capacitor are capacitors with the same characteristics, and the two ends of the DC power supply are respectively connected to the first capacitor and the second capacitor, so that voltage division is performed through the first capacitor and the second capacitor. VC1 is the voltage of the first capacitor, VC2 is the voltage of the second capacitor, and Vdc is the voltage of the total voltage of the DC power supply. Il is the first current, Ih is the first current, and I is the total current of the output.

[0065] Next, a control method of the clamp-type converter is described. Figure 3 1 is a flow chart of a control method for a clamped converter provided in an embodiment of the present application. The control method for the clamped converter is applied to the above-mentioned clamped converter, such as Figure 3 As shown, the clamped converter includes S201-S202:

[0066] S201. Receive control information of a clamp-type converter, where the control information is used to indicate a switching mode of the clamp-type converter.

[0067] In the present application, the control device of the clamped converter can receive control information of the clamped converter to generate relevant control signals, so that the clamped converter outputs control signals to control the on or off of switching devices in various modules of the clamped converter.

[0068] It should be understood that the embodiment of the present application does not limit the switching mode of the clamped converter, and can be set according to the actual specific equipment. For example, Table 1 is a schematic table of the switching mode of a clamped converter provided in the embodiment of the present application, 0 in Table 1 is used to indicate that the corresponding switch device is closed, 1 in Table 1 is used to indicate that the corresponding switch device is turned on, M1-M8 are different switching modes, Vdc is the voltage of the DC power supply, uol is the minimum value of the output voltage, and uoh is the maximum value of the output voltage.

[0069] Table 1

[0070] S1(S3) S2(S4) SI1 SI2 Sh1 Sh2 Uol Uoh M1 1 0 1 0 1 0 Vdc / 2 Vdc / 2 M2 1 0 1 0 0 1 Vdc / 2 0 M3 1 0 0 1 1 0 0 Vdc / 2 M4 1 0 0 1 0 1 0 0 M5 0 1 1 0 1 0 0 0 M6 O 1 1 O 0 1 0 -Vdc / 2 M7 0 1 0 1 1 0 -Vdc / 2 0 M8 0 1 0 1 0 1 -Vdc / 2 -Vdc / 2

[0071] As shown in Table 1, the switch function S1 can be defined by formula (1), and the switch function Sh can be defined by formula (2):

[0072]

[0073] Exemplarily, according to the switching mode in Table 1, S1, S2, S3, and S4 work at the industrial frequency, and the switching state does not change within half a cycle.

[0074] Accordingly, based on Kirchhoff's voltage and current laws and the above switching function, the mathematical model of the clamped converter can be generated as shown in formulas (3)-(6):

[0075]

[0076] I(t)=I l (t)+I(t) (3)

[0077]

[0078] Where Vdc is the voltage of the DC power supply, S l (t) is the switching function in formula (1) and S h (t) is the switching function in formula (3), L 1 is the first inductor, L 2 is the second inductor, I l is the first current, I h is the second current, I is the total output current, V o is the output voltage.

[0079] S202. Output a control signal to the clamped converter according to the switching mode of the clamped converter, where the control signal is used to control the working state of the switching devices in the second frequency module and the third frequency module, where the working state includes on or off.

[0080] In this step, after the control device of the clamped converter receives the control information of the clamped converter, it can output a control signal to the clamped converter according to the switching mode of the clamped converter.

[0081] In some embodiments, the control signal includes a first signal for controlling the fifth Si IGBT and the first SiC MOSFET to turn on and the sixth Si IGBT and the second SiC MOSFET to turn off, so that the first current increases, the second current decreases, and the total output current increases.

[0082] like Figure 4As shown, the fifth Si IGBT and the first SiC MOSFET are turned on, the sixth Si IGBT and the second SiC MOSFET are turned off, at this time, the neutral point of the DC side voltage divider capacitor is grounded, the first inductor corresponding to the second frequency module and the left end of the second inductor corresponding to the third frequency module are directly connected to the high potential end of the first capacitor on the DC side, and the voltage value is +Vdc / 2. Based on the mathematical model of the clamped converter, it can be obtained that the first current corresponding to the second frequency module increases, the second current corresponding to the third frequency module increases, and the total output current increases.

[0083] In some embodiments, the control signal includes a second signal for controlling the fifth Si IGBT and the second SiC MOSFET to turn on and the sixth Si IGBT and the first SiC MOSFET to turn off, so that the first current increases, the second current decreases, and the total output current decreases.

[0084] like Figure 4 As shown, the fifth Si IGBT and the second SiC MOSFET are turned on, the sixth Si IGBT and the first SiC MOSFET are turned off, at this time, the left end of the first inductor corresponding to the second frequency module is connected to the high potential end of the first capacitor on the DC side, the left end of the second inductor corresponding to the third frequency module is connected to the neutral point of the two capacitors on the DC side, and the first inductor corresponding to the second frequency module is larger than the second inductor corresponding to the third frequency module. Based on the mathematical model of the clamped converter, it can be obtained that the first current corresponding to the second frequency module increases, the second current corresponding to the third frequency module decreases, and the total output current decreases.

[0085] In some embodiments, the control signal includes a second signal, and the control signal includes a third signal, and the third signal is used to control the sixth Si IGBT and the first SiC MOSFET to be turned on and the fifth Si IGBT and the second SiC MOSFET to be turned off, so that the first current decreases, the second current increases, and the total output current increases.

[0086] like Figure 4 As shown, the sixth Si IGBT and the first SiC MOSFET are turned on, the fifth Si IGBT and the second SiC MOSFET are turned off, at this time, the left end of the first inductor corresponding to the second frequency module is connected to the neutral point of the two capacitors on the DC side, and the left end of the second inductor corresponding to the third frequency module is connected to the high potential end of the first capacitor on the DC side. Based on the mathematical model of the clamped converter, it can be obtained that the first current corresponding to the second frequency module decreases, the second current corresponding to the third frequency module increases, and the total output current increases.

[0087] In some embodiments, the control signal includes a fourth signal, and the fourth signal is used to control the sixth Si IGBT and the second SiC MOSFET to be turned on and the fifth Si IGBT and the first SiC MOSFET to be turned off, so that the first current decreases, the second current decreases, and the total output current decreases.

[0088] like Figure 4 As shown, the sixth Si IGBT and the second SiC MOSFET are turned on, the fifth Si IGBT and the first SiC MOSFET are turned off, the left ends of the first inductor corresponding to the second frequency module and the second inductor corresponding to the third frequency module are directly connected to the neutral point of the two capacitors on the DC side. Based on the mathematical model of the clamped converter, it can be obtained that the first current corresponding to the second frequency module decreases, the second current corresponding to the third frequency module decreases, and the total output current decreases.

[0089] It should be noted that the above control signal is described using the positive half-cycle of voltage as an example, and the switching mode and control signal of the negative half-cycle of voltage can refer to the positive half-cycle of voltage, which will not be repeated here.

[0090] The first current and the second current are described below.

[0091] Figure 5 A schematic diagram of a current shunt control strategy for a clamped converter provided in an embodiment of the present application is shown in FIG. Figure 5 As shown, due to the shunt characteristics, the first current I1 and the second current I h The total current d-axis reference value can be formed into a current loop respectively. The d-axis reference value of the first current I1 is obtained by multiplying the power distribution ratio K by The same is true for the q-axis component. The d-axis and q-axis components (Ild, Ilq) of the first current Il are compared with the reference values ​​respectively, and the d-axis and q-axis components of the modulation wave of the second frequency module are obtained by the PI controller and the coupling component is subtracted. Since the total current power quality is independent of the switching frequency of the second frequency module and the power distribution ratio K, the second current I h The current loop needs to ensure the power quality of the total current, and then the total current reference value minus the actual output current of the second frequency module can be used to obtain the second current I h Current reference value ΔI lh , the second current I h As control feedback and the current ΔI that needs to be compensated by the third frequency module lh After comparison, the obtained error is input into the PI controller to obtain the modulation wave of the third frequency module.

[0092] The simulation results of the clamped converter and its control method are described below.

[0093] For example, Table 2 is a schematic table of simulation parameters of a clamped converter and a control method thereof. Based on the simulation parameters shown in Table 2, the simulation waveform of the clamped converter provided in the embodiment of the present application under reactive power compensation conditions is as follows: Figures 6 to 10 As shown in Figure 2. Among them, the grid-side voltage and current waveforms are as follows: Figure 6 As shown in Figure 1, the grid-side voltage and current are in phase. The voltage waveform of the DC-side voltage divider capacitor of the clamped converter is shown in Figure 1. Figure 7 As shown in FIG. 1 , after the clamped converter is put into operation, it maintains good stability and the fluctuation amplitude is less than 5%. The output power of the clamped converter is shown in FIG. Figure 8 As shown, the output reactive power is 10kVar and the active power is close to zero. Figure 9a is the withstand voltage of the first frequency module, Figure 9b is the withstand voltage of the second frequency module, Fig.9c The current of the first frequency module, the current of the second frequency module, the current of the third frequency module and the total output current in the clamped converter provided in the embodiment of the present application are as follows: Fig.10 As shown, the current of the second frequency module (i.e., the first current mentioned above) is 9.35%, while the total current is 2.92%. The current of the third frequency module (i.e., the second current mentioned above) has a better compensation effect on the current of the second frequency module. The switching devices in the second frequency module operate at a low frequency, and the switching devices in the third frequency module operate at a high frequency, thereby fully utilizing the advantage of low switching loss of SiC MOSFET devices.

[0094] Table 2

[0095]

[0096] The control method of the clamped converter provided in the embodiment of the present application first receives control information of the clamped converter, and the control information is used to indicate the switching mode of the clamped converter. Subsequently, according to the switching mode of the clamped converter, a control signal is output to the clamped converter, and the control signal is used to control the working state of the switching devices in the second frequency module and the third frequency module. Due to the control method of the clamped converter, the high-frequency switching action of the output voltage is concentrated on the switching devices with strong output performance in the third frequency module, and the switching devices with weak output performance work at the industrial frequency and low frequency, so that the advantages of low switching loss of the switching devices with weak output performance such as SiC can be fully utilized, and the operating efficiency of the grid-connected converter can be effectively improved.

[0097] It should be understood that, although the steps in the flowcharts involved in the above embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps is not strictly limited in order, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above embodiments may include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0098] Based on the same inventive concept, the embodiment of the present application also provides a control device for a clamped converter for implementing the control method for the clamped converter involved above. The implementation scheme for solving the problem provided by the control device for the clamped converter is similar to the implementation scheme recorded in the above method, so the specific limitations in the embodiments of the control device for one or more clamped converters provided below can refer to the limitations of the control method for the clamped converter above, and will not be repeated here.

[0099] In an exemplary embodiment, Fig.11 As shown, a control device 300 of a clamped type converter is provided, which is applied to the above-mentioned bit converter, including: a receiving module 301 and a sending module 302, wherein:

[0100] The receiving module 301 is used to receive control information of the clamped converter, where the control information is used to indicate a switching mode of the clamped converter.

[0101] The sending module 302 is used to output a control signal to the clamped converter according to the switching mode of the clamped converter, and the control signal is used to control the working state of the switching devices in the second frequency module and the third frequency module, and the working state includes on or off.

[0102] In one embodiment, the control signal includes a first signal, and the first signal is used to control the fifth Si IGBT and the first SiC MOSFET to be turned on and the sixth Si IGBT and the second SiC MOSFET to be turned off, so that the first current increases, the second current decreases, and the total output current increases.

[0103] In one of the embodiments, the control signal includes a second signal, and the second signal is used to control the fifth Si IGBT and the second SiC MOSFET to be turned on and the sixth Si IGBT and the first SiC MOSFET to be turned off, so that the first current increases, the second current decreases, and the total output current decreases.

[0104] In one of the embodiments, the control signal includes a third signal, and the third signal is used to control the sixth Si IGBT and the first SiC MOSFET to be turned on and the fifth Si IGBT and the second SiC MOSFET to be turned off, so that the first current decreases, the second current increases, and the total output current increases.

[0105] In one of the embodiments, the control signal includes a fourth signal, and the fourth signal is used to control the sixth Si IGBT and the second SiC MOSFET to be turned on and the fifth Si IGBT and the first SiC MOSFET to be turned off, so that the first current is reduced, the second current is reduced, and the total output current is reduced.

[0106] Each module in the control device of the clamped converter can be implemented in whole or in part by software, hardware or a combination thereof. Each module can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to each module.

[0107] In an exemplary embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as shown in FIG. Fig.12 As shown. The computer device includes a processor, a memory, an input / output interface, a communication interface, a display unit and an input device. The processor, the memory and the input / output interface are connected via a system bus, and the communication interface, the display unit and the input device are connected to the system bus via the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, a mobile cellular network, near field communication (NFC) or other technologies. When the computer program is executed by the processor, a control method for a clamp-type converter is implemented.

[0108] Those skilled in the art will understand that Fig.12 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0109] In an exemplary embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the control method of the clamp-type converter when executing the computer program.

[0110] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the control method of the clamp-type converter is implemented.

[0111] In one embodiment, a computer program product is provided, comprising a computer program, wherein when the computer program is executed by a processor, the control method of the clamp-type converter is implemented.

[0112] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., but are not limited to this.

[0113] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0114] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A clamped converter, characterized in that: The clamped converter comprises: a first frequency module, a second frequency module, a third frequency module, a shunt inductor module and a voltage-dividing capacitor module; The shunt inductor module is connected to the second frequency module and the third frequency module respectively, the first frequency module is connected to the voltage-dividing capacitor module and the second frequency module respectively, the second frequency module is connected to the third frequency module, and the voltage-dividing capacitor module is connected to a DC power supply; The first frequency module is used to work when it is in the base frequency switch state; the second frequency module is used to work when it is in the first set switch state and flow the first current; the third frequency module is used to work when it is in the second set switch state, flow the second current and compensate for the harmonic current generated by the second frequency module; the voltage-dividing capacitor module is used to divide the voltage of the DC power supply; the shunt inductor module is used to aggregate the first current and the second current into a total output current; Among them, the output performance of the switching devices in the third frequency module is stronger than the switching devices in the first frequency module and the second frequency module; the first current is greater than the second current, and the frequency corresponding to the first set switch state is less than the frequency corresponding to the second set switch state.

2. The clamped converter according to claim 1, characterized in that: The first frequency module and the second frequency module each include a plurality of silicon insulated gate bipolar transistors Si IGBTs, the third frequency module includes a plurality of silicon carbide metal oxide semiconductor field effect transistors SiC MOSFETs, and the number of Si IGBTs in the first frequency module is greater than the number of Si IGBTs in the second frequency module.

3. The clamped converter according to claim 2, characterized in that: The first frequency module includes a first Si IGBT, a second Si IGBT, a third Si IGBT and a fourth Si IGBT; the second frequency module includes a fifth Si IGBT and a sixth Si IGBT; the third frequency module includes a first SiC MOSFET and a second SiC MOSFET; The first Si IGBT, the second Si IGBT, the third Si IGBT and the fourth Si IGBT are connected in series in sequence through the collector and the emitter; the collector of the fifth Si IGBT is connected to the emitter of the first Si IGBT and the collector of the second Si IGBT respectively; the collector of the sixth Si IGBT is connected to the emitter of the fifth Si IGBT, and the emitter of the sixth Si IGBT is connected to the emitter of the third Si IGBT and the collector of the fourth Si IGBT respectively; the drain of the first SiC MOSFET is connected to the emitter of the first Si IGBT and the collector of the second Si IGBT respectively; the drain of the second SiC MOSFET is connected to the source of the first SiC MOSFET, and the source of the second SiC MOSFET is connected to the emitter of the third Si IGBT and the collector of the fourth Si IGBT respectively.

4. The clamped converter according to claim 3, characterized in that: The shunt inductor module includes a first inductor and a second inductor, and the voltage-dividing capacitor module includes a first capacitor and a second capacitor; The first end of the first inductor is connected to the emitter of the fifth Si IGBT and the collector of the sixth Si IGBT respectively, the first end of the second inductor is connected to the source of the first SiC MOSFET and the drain of the second SiC MOSFET respectively; the second end of the first inductor is connected to the second end of the second inductor; The positive electrode of the first capacitor is connected to the collector of the first Si IGBT, and the negative electrode of the first capacitor is connected to the emitter of the second Si IGBT and the collector of the third Si IGBT respectively; the positive electrode of the second capacitor is connected to the negative electrode of the first capacitor, and the negative electrode of the second capacitor is connected to the emitter of the fourth Si IGBT.

5. A control method for a clamped converter, characterized in that: Applied to the clamped converter according to any one of claims 1 to 4, the method comprises: receiving control information of the clamp-type converter, wherein the control information is used to indicate a switching mode of the clamp-type converter; According to the switching mode of the clamped converter, a control signal is output to the clamped converter, wherein the control signal is used to control the working state of the switching devices in the second frequency module and the third frequency module, wherein the working state includes on or off.

6. The method according to claim 5, characterized in that The control signal includes a first signal, and the first signal is used to control the fifth Si IGBT and the first SiC MOSFET to be turned on and the sixth SiIGBT and the second SiC MOSFET to be turned off, so that the first current increases, the second current decreases, and the total output current increases.

7. The method according to claim 5, characterized in that The control signal includes a second signal, and the second signal is used to control the fifth Si IGBT and the second SiC MOSFET to be turned on and the sixth Si IGBT and the first SiC MOSFET to be turned off, so that the first current increases, the second current decreases, and the total output current decreases.

8. The method according to claim 5, characterized in that The control signal includes a third signal, and the third signal is used to control the sixth Si IGBT and the first SiC MOSFET to be turned on and the fifth Si IGBT and the second SiC MOSFET to be turned off, so that the first current decreases, the second current increases, and the total output current increases.

9. The method according to claim 5, characterized in that The control signal includes a fourth signal, and the fourth signal is used to control the sixth Si IGBT and the second SiC MOSFET to be turned on and the fifth Si IGBT and the first SiC MOSFET to be turned off, so that the first current is reduced, the second current is reduced, and the total output current is reduced.

10. A control device for a clamped converter, characterized in that: Applied to the clamped converter according to any one of claims 1 to 4, the device comprises: A receiving module, used for receiving control information of the clamped converter, wherein the control information is used for indicating a switching mode of the clamped converter; A sending module is used to output a control signal to the clamped converter according to the switching mode of the clamped converter, wherein the control signal is used to control the working state of the switching devices in the second frequency module and the third frequency module, wherein the working state includes on or off.

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