Control method and apparatus for current-source-type converter, and circuit, device and medium

Abstract

The present application belongs to the technical field of converters. Provided are a control method and apparatus for a current-source-type converter, and a circuit, a device and a medium. The method comprises: on the basis of the current voltages of three phases in a three-phase alternating current, determining the maximum phase, the minimum phase and the intermediate phase; on the basis of the current voltage of the maximum phase, determining a first duty cycle corresponding to the maximum phase; on the basis of the current voltage of the intermediate phase, determining a second duty cycle corresponding to the intermediate phase; on the basis of the second duty cycle corresponding to the intermediate phase, determining a third duty cycle corresponding to the minimum phase, wherein the minimum phase and the intermediate phase complement each other; and on the basis of the current voltages of the three phases, the first duty cycle, the second duty cycle and the third duty cycle, controlling a plurality of controllable switch devices in a current-source-type converter to connect or disconnect. By using the present application, the voltage stress is reduced, and the EMI performance is improved.

Description

Control method, device, circuit, equipment and medium of current source converter

[0001] This application claims priority to Chinese patent application No. 202311871523.9 filed on December 29, 2023, entitled “Control method, device, circuit, equipment and medium for current source converter”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of converters, and in particular to a control method, device, circuit, equipment and medium for a current source converter. Background Art

[0003] Three-phase AC power can be converted into DC power through a current source converter to form a DC bus to power some load devices.

[0004] Typically, the maximum corresponding duty cycle is calculated based on the voltage of the maximum phase, the minimum corresponding duty cycle is calculated based on the voltage of the minimum phase, and the intermediate phase and the minimum phase complement each other.

[0005] However, in each switching cycle of the above control process, the DC output voltage of the bridge arm will jump directly from zero to the line voltage between the middle phase and the maximum phase, and will also jump directly from the line voltage between the middle phase and the maximum phase to zero. The jump amplitude is large, which can easily cause resonance between the inductor and capacitor, resulting in large voltage stress and poor EMI performance.

[0006] Summary of the Invention

[0007] The present invention provides a control method for a current source converter, which can reduce the amplitude of each jump of the DC output voltage of the bridge arm, thereby reducing voltage stress and improving EMI (Electro Magnetic Compatibility) performance. The technical solution is as follows:

[0008] In a first aspect, a control method for a current source converter is provided, the method comprising:

[0009] determining a maximum phase, a minimum phase, and an intermediate phase based on current voltages of the three phases of the three-phase alternating current;

[0010] Determining a first duty cycle corresponding to the maximum value based on the current voltage of the maximum phase;

[0011] Determining a second duty cycle corresponding to the middle phase based on a current voltage of the middle phase;

[0012] determining the minimum corresponding third duty cycle based on the intermediate corresponding second duty cycle, wherein the minimum phase is complementary to the intermediate phase;

[0013] Based on the first duty cycle, the second duty cycle, and the third duty cycle, a plurality of controllable switching devices in the current source converter are controlled to be turned on or off.

[0014] In one possible implementation, controlling the plurality of controllable switching devices in the current source converter to turn on or off based on the first duty cycle, the second duty cycle, and the third duty cycle includes:

[0015] In any switching cycle, when the controllable switching device corresponding to the middle is in the off state, the controllable switching device on the upper bridge arm corresponding to the minimum or the controllable switching device on the lower bridge arm corresponding to the minimum is controlled to be in the on state; when the controllable switching device corresponding to the middle is in the on state, the controllable switching device on the upper bridge arm corresponding to the minimum and the controllable switching device on the lower bridge arm corresponding to the minimum are both controlled to be in the off state.

[0016] In one possible implementation, controlling the plurality of controllable switching devices in the current source converter to turn on or off based on the first duty cycle, the second duty cycle, and the third duty cycle includes:

[0017] In any switching cycle, when the maximum corresponding controllable switching device and the middle corresponding controllable switching device are both in the off state, the controllable switching device on the upper bridge arm corresponding to the minimum and the controllable switching device on the lower bridge arm corresponding to the minimum are controlled to be in the on state; when the maximum corresponding controllable switching device is in the on state and the middle corresponding controllable switching device is in the off state, the controllable switching device on the upper bridge arm corresponding to the minimum or the controllable switching device on the lower bridge arm corresponding to the minimum is controlled to be in the on state.

[0018] In one possible implementation, controlling the plurality of controllable switching devices in the current source converter to turn on or off based on the first duty cycle, the second duty cycle, and the third duty cycle includes:

[0019] Controlling the controllable switch device on the upper bridge arm corresponding to the maximum and the controllable switch device on the lower bridge arm corresponding to the maximum to be turned on or turned off based on the first duty cycle;

[0020] Controlling the controllable switch device on the corresponding upper bridge arm and the controllable switch device on the corresponding lower bridge arm to be turned on or off based on the second duty cycle;

[0021] Based on the third duty cycle, the controllable switch device on the upper bridge arm corresponding to the minimum and the controllable switch device on the lower bridge arm corresponding to the minimum are controlled to be turned on or turned off.

[0022] In a possible implementation, determining the maximum corresponding first duty cycle based on the current voltage of the maximum phase includes:

[0023] The maximum corresponding first duty cycle is determined based on the sum of the squares of the current voltages of the three phases, the current voltage of the maximum phase, and the DC voltage.

[0024] In a possible implementation, determining the second duty cycle corresponding to the intermediate phase based on the current voltage of the intermediate phase includes:

[0025] A second duty cycle corresponding to the middle phase is determined based on the sum of the squares of the current voltages of the three phases, the current voltage of the middle phase, and the DC voltage.

[0026] In a possible implementation, the controllable switching device is any one of an IGBT (Insulated Gate Bipolar Transistor), a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), and a combination of an IGBT and a diode connected in parallel in opposite directions.

[0027] In a second aspect, a control device for a current source converter is provided, the device comprising:

[0028] a first determining module, configured to determine a maximum phase, a minimum phase, and an intermediate phase based on current voltages of the three phases in the three-phase alternating current;

[0029] A second determining module is configured to determine the maximum corresponding first duty cycle based on the current voltage of the maximum phase;

[0030] a third determining module, configured to determine a second duty cycle corresponding to the middle phase based on a current voltage of the middle phase;

[0031] a fourth determining module, configured to determine the minimum corresponding third duty cycle based on the intermediate corresponding second duty cycle, wherein the minimum phase is complementary to the intermediate phase;

[0032] A control module is used to control the conduction or disconnection of multiple controllable switching devices in the current source converter based on the current voltage of the three phases, the first duty cycle, the second duty cycle and the third duty cycle.

[0033] In a possible implementation, the control module is configured to:

[0034] In any switching cycle, when the controllable switching device corresponding to the middle is in the off state, the controllable switching device on the upper bridge arm corresponding to the minimum or the controllable switching device on the lower bridge arm corresponding to the minimum is controlled to be in the on state; when the controllable switching device corresponding to the middle is in the on state, the controllable switching device on the upper bridge arm corresponding to the minimum and the controllable switching device on the lower bridge arm corresponding to the minimum are both controlled to be in the off state.

[0035] In a possible implementation, the control module is further configured to:

[0036] In any switching cycle, when the maximum corresponding controllable switching device and the middle corresponding controllable switching device are both in the off state, the controllable switching device on the upper bridge arm corresponding to the minimum and the controllable switching device on the lower bridge arm corresponding to the minimum are controlled to be in the on state; when the maximum corresponding controllable switching device is in the on state and the middle corresponding controllable switching device is in the off state, the controllable switching device on the upper bridge arm corresponding to the minimum or the controllable switching device on the lower bridge arm corresponding to the minimum is controlled to be in the on state.

[0037] In a possible implementation, the control module is configured to:

[0038] Controlling the controllable switch device on the upper bridge arm corresponding to the maximum and the controllable switch device on the lower bridge arm corresponding to the maximum to be turned on or turned off based on the first duty cycle;

[0039] Controlling the controllable switch device on the corresponding upper bridge arm and the controllable switch device on the corresponding lower bridge arm to be turned on or off based on the second duty cycle;

[0040] Based on the third duty cycle, the controllable switch device on the upper bridge arm corresponding to the minimum and the controllable switch device on the lower bridge arm corresponding to the minimum are controlled to be turned on or turned off.

[0041] In a possible implementation, the second determining module is configured to:

[0042] The maximum corresponding first duty cycle is determined based on the sum of the squares of the current voltages of the three phases, the current voltage of the maximum phase, and the DC voltage.

[0043] In a possible implementation, the third determining module is configured to:

[0044] A second duty cycle corresponding to the middle phase is determined based on the sum of the squares of the current voltages of the three phases, the current voltage of the middle phase, and the DC voltage.

[0045] In a possible implementation, the controllable switch device is any one of an IGBT, a Mosfet, and a combination of an IGBT and a diode connected in parallel in opposite directions.

[0046] In a third aspect, a control circuit of a current source converter is provided, the control circuit comprising a current source converter and a controller;

[0047] The controller is used to:

[0048] determining a maximum phase, a minimum phase, and an intermediate phase based on current voltages of the three phases of the three-phase alternating current;

[0049] Determining a first duty cycle corresponding to the maximum value based on the current voltage of the maximum phase;

[0050] Determining a second duty cycle corresponding to the middle phase based on a current voltage of the middle phase;

[0051] determining the minimum corresponding third duty cycle based on the intermediate corresponding second duty cycle, wherein the minimum phase is complementary to the intermediate phase;

[0052] Based on the current voltage of the three phases, the first duty cycle, the second duty cycle and the third duty cycle, a plurality of controllable switching devices in the current source converter are controlled to be turned on or off.

[0053] In a possible implementation, the controller is configured to:

[0054] In any switching cycle, when the controllable switching device corresponding to the middle is in the off state, the controllable switching device on the upper bridge arm corresponding to the minimum or the controllable switching device on the lower bridge arm corresponding to the minimum is controlled to be in the on state; when the controllable switching device corresponding to the middle is in the on state, the controllable switching device on the upper bridge arm corresponding to the minimum and the controllable switching device on the lower bridge arm corresponding to the minimum are both controlled to be in the off state.

[0055] In a possible implementation, the controller is configured to:

[0056] In any switching cycle, when the maximum corresponding controllable switching device and the middle corresponding controllable switching device are both in the off state, the controllable switching device on the upper bridge arm corresponding to the minimum and the controllable switching device on the lower bridge arm corresponding to the minimum are controlled to be in the on state; when the maximum corresponding controllable switching device is in the on state and the middle corresponding controllable switching device is in the off state, the controllable switching device on the upper bridge arm corresponding to the minimum or the controllable switching device on the lower bridge arm corresponding to the minimum is controlled to be in the on state.

[0057] In a possible implementation, the controller is configured to:

[0058] Controlling the controllable switch device on the upper bridge arm corresponding to the maximum and the controllable switch device on the lower bridge arm corresponding to the maximum to be turned on or turned off based on the first duty cycle;

[0059] Controlling the controllable switch device on the corresponding upper bridge arm and the controllable switch device on the corresponding lower bridge arm to be turned on or off based on the second duty cycle;

[0060] Based on the third duty cycle, the controllable switch device on the upper bridge arm corresponding to the minimum and the controllable switch device on the lower bridge arm corresponding to the minimum are controlled to be turned on or turned off.

[0061] In a possible implementation, the controller is configured to:

[0062] The maximum corresponding first duty cycle is determined based on the sum of the squares of the current voltages of the three phases, the current voltage of the maximum phase, and the DC voltage.

[0063] In a possible implementation, the controller is configured to:

[0064] A second duty cycle corresponding to the middle phase is determined based on the sum of the squares of the current voltages of the three phases, the current voltage of the middle phase, and the DC voltage.

[0065] In a possible implementation, the controllable switch device is any one of an IGBT, a Mosfet, and a combination of an IGBT and a diode connected in parallel in opposite directions.

[0066] In a fourth aspect, a computer device is provided, comprising a processor and a memory, wherein the memory stores at least one instruction, and the instruction is loaded and executed by the processor to implement the operations performed by the control method of the current source converter.

[0067] In a fifth aspect, a computer-readable storage medium is provided, wherein the storage medium stores at least one instruction, and the instruction is loaded and executed by a processor to implement the operations performed by the control method of the current source converter.

[0068] In a sixth aspect, a computer program product is provided, wherein the computer program product includes at least one instruction, and the at least one instruction is loaded and executed by a processor to implement the operations performed by the control method of the current source converter.

[0069] The beneficial effects brought about by the technical solution provided in the embodiments of the present application are: the solution mentioned in the embodiments of the present application determines the first duty cycle corresponding to the maximum based on the current voltage of the maximum phase, determines the second duty cycle corresponding to the middle based on the current voltage of the middle phase, and the minimum phase and the middle phase complement each other. In this way, within each switching cycle, the DC output voltage of the bridge arm will jump from zero to the line voltage between the minimum phase and the maximum phase, and then jump from the line voltage between the minimum phase and the maximum phase to the line voltage between the middle phase and the maximum phase, and then jump from the line voltage between the middle phase and the maximum phase to the line voltage between the minimum phase and the maximum phase, and then jump from the line voltage between the minimum phase and the maximum phase to the line voltage between the minimum phase and the maximum phase, and then jump from the line voltage between the minimum phase and the maximum phase to zero.

[0070] Since the line voltage between the minimum phase and the maximum phase in any sector of the 12 sectors is less than the line voltage between the middle phase and the maximum phase, the present application reduces the jump amplitude of the bridge arm DC output voltage, thereby reducing voltage stress and improving EMI performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] 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.

[0072] FIG1 is a topological diagram of a current source converter provided in an embodiment of the present application;

[0073] FIG2 is a flow chart of a control method of a current source converter provided in an embodiment of the present application;

[0074] FIG3 is a waveform diagram of a three-phase alternating current provided in an embodiment of the present application;

[0075] FIG4 is a driving timing diagram of a current source converter in the related art;

[0076] FIG5 is a schematic diagram showing changes in the DC output voltage of a bridge arm in the related art;

[0077] FIG6 is a driving timing diagram of a current source converter provided in an embodiment of the present application;

[0078] FIG7 is a schematic diagram of a change in a DC output voltage of a bridge arm provided in an embodiment of the present application;

[0079] FIG8 is a schematic structural diagram of a control device for a current source converter provided in an embodiment of the present application;

[0080] FIG9 is a structural block diagram of a terminal provided in an embodiment of the present application;

[0081] FIG10 is a structural block diagram of a server provided in an embodiment of the present application. DETAILED DESCRIPTION

[0082] 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.

[0083] See Figure 1, which is a topological diagram of a current source converter, where v a 、v b 、v c is the current voltage of the three phases in the three-phase AC power, V dc is the DC voltage, V PN The DC output voltage of the bridge arm is , and the current source converter can convert three-phase AC power into DC power, thereby forming a DC bus.

[0084] FIG2 is a flow chart of a control method for a current source converter provided by an embodiment of the present application. Referring to FIG2 , the embodiment includes:

[0085] 201. Based on the current voltages of the three phases in the three-phase alternating current, determine the maximum phase, the minimum phase, and the middle phase.

[0086] In practice, the current voltage of the three phases in the three-phase AC power can be periodically detected, that is, v in FIG1 a 、v b and v c The maximum phase, minimum phase and middle phase are determined according to the absolute values ​​of the current voltages of the three phases.

[0087] Among the three-phase current voltages, the phase with the largest absolute value of the current voltage is the maximum phase, the phase with the smallest absolute value of the current voltage is the minimum phase, and the phase with the middle absolute value of the current voltage is the middle phase.

[0088] Referring to Figure 3, in an embodiment of the present application, the cycle of three-phase alternating current is divided into 12 sectors, namely sector 1, sector 2, sector 3, sector 4, sector 5, sector 6, sector 7, sector 8, sector 9, sector 10, sector 11 and sector 12 in Figure 3.

[0089] In sector 1, v c >va >0>v b ,|v b |>|v c |>|v a |, then the maximum phase is v b , the intermediate phase is v c , the minimum phase is v a .

[0090] In sector 2, v a >v c >0>v b ,|v b |>|v a |>|v c |, then the maximum phase is v b , the intermediate phase is v a , the minimum phase is v c .

[0091] In sector 3, v a >0>v c >v b ,|v a |>|v b |>|v c |, then the maximum phase is v a , the intermediate phase is v b , the minimum phase is v c .

[0092] In sector 4, v a >v b >0>v c ,|v a |>|v c |>|v b |, then the maximum phase is v a , the intermediate phase is v c , the minimum phase is v b .

[0093] In sector 5, v a >v b >0>v c ,|v c |>|v a |>|v b |, then the maximum phase is v c , the intermediate phase is v a , the minimum phase is v b .

[0094] In sector 6, v b >v a >0>v c ,|v c |>|v b|>|v a |, then the maximum phase is v c , the intermediate phase is v b , the minimum phase is v a .

[0095] In sector 7, v b >0>v a >v c ,|v b |>|v c |>|v a |, then the maximum phase is v b , the intermediate phase is v c , the minimum phase is v a .

[0096] In sector 8, v b >0>v c >v a ,|v b |>|v a |>|v c |, then the maximum phase is v b , the intermediate phase is v a , the minimum phase is v c .

[0097] In sector 9, v b >v c >0>v a ,|v a |>|v b |>|v c |, then the maximum phase is v a , the intermediate phase is v b , the minimum phase is v c .

[0098] In sector 10, v c >v b >0>v a ,|v a |>|v c |>|v b |, then the maximum phase is v a , the intermediate phase is v c , the minimum phase is v b .

[0099] In sector 11, v c >0>v b >v a ,|v c |>|v a |>|v b |, then the maximum phase is v c , the intermediate phase is v a, the minimum phase is v b .

[0100] In sector 12, v c >0>v a >v b ,|v c |>|v b |>|v a |, then the maximum phase is v c , the intermediate phase is v b , the minimum phase is v a .

[0101] The characteristics of these 12 sectors are: in any sector, the current voltage of the maximum phase is opposite to the current voltage of the minimum phase, and the current voltage of the maximum phase is also opposite to the current voltage of the middle phase.

[0102] 202. Determine a maximum corresponding first duty cycle based on the current voltage of the maximum phase.

[0103] In implementation, after determining the maximum phase, the maximum corresponding first duty cycle is calculated based on the current voltage of the maximum phase. The first duty cycle refers to the ratio of the conduction time of the maximum corresponding partial controllable switching device to the total duration of the switching cycle, wherein the maximum corresponding partial controllable switching device is the controllable switching device on the maximum corresponding upper bridge arm or the controllable switching device on the maximum corresponding lower bridge arm.

[0104] Since the first duty cycle is calculated based on the current voltage of the maximum phase, the maximum phase will be turned on in the middle of the switching cycle, and the on-time of the maximum phase is the time corresponding to the first duty cycle (that is, the product of the first duty cycle and the total time of the switching cycle).

[0105] The above-mentioned turning on of the maximum phase at the middle time of the switching cycle can also be understood as that in each switching cycle in the driving timing diagram, the driving signal of the maximum phase is symmetrically set relative to the middle moment of the switching cycle.

[0106] 203. Determine a second duty cycle corresponding to the middle phase based on the current voltage of the middle phase.

[0107] In implementation, after determining the middle phase, the second duty cycle corresponding to the middle phase is calculated based on the current voltage of the middle phase. The second duty cycle refers to the ratio of the conduction time of the part of the controllable switching devices corresponding to the middle phase to the total time of the switching cycle, wherein the part of the controllable switching devices corresponding to the middle phase are the controllable switching devices on the upper bridge arm corresponding to the middle phase or the controllable switching devices on the lower bridge arm corresponding to the middle phase.

[0108] Since the second duty cycle is calculated based on the current voltage of the middle phase, the middle phase will be turned on in the middle of the switching cycle, and the conduction time of the middle phase is the time corresponding to the second duty cycle (that is, the product of the second duty cycle and the total time of the switching cycle).

[0109] Turning on the middle phase at the middle time of the switching cycle can also be understood as that in each switching cycle in the driving timing diagram, the driving signal of the middle phase is symmetrically set relative to the middle moment of the switching cycle.

[0110] 204. Determine a minimum corresponding third duty cycle based on the middle corresponding second duty cycle.

[0111] Among them, the minimum phase and the intermediate phase complement each other.

[0112] In implementation, after the second duty cycle corresponding to the middle is determined, based on the principle that the minimum phase and the middle phase complement each other, the minimum corresponding third duty cycle is (1-second duty cycle).

[0113] The minimum phase will be turned on at the beginning and the end of the switching cycle, and the conduction time of the minimum phase is the time corresponding to the third duty cycle (that is, the product of the third duty cycle and the total time of the switching cycle), or it can be the difference between the total time of the switching cycle and the time corresponding to the second duty cycle.

[0114] The above-mentioned conduction of the minimum phase at the first time and the last time of the switching cycle can also be understood as that within each switching cycle in the drive timing diagram, the drive signal of the minimum phase is symmetrically located at both ends of the switching cycle, and the sum of the conduction time of the minimum phase at both ends is the time corresponding to the third duty cycle.

[0115] 205. Based on the current voltage of the three phases, the first duty cycle, the second duty cycle, and the third duty cycle, control the plurality of controllable switching devices in the current source converter to be turned on or off.

[0116] In implementation, after determining the first duty cycle, the second duty cycle and the third duty cycle, the multiple controllable switching devices in the current source converter can be controlled to be turned on or off based on the current voltage of the three phases, the first duty cycle, the second duty cycle and the third duty cycle.

[0117] In one possible implementation, the controllable switching device may be any one of an IGBT, a Mosfet, and a combination of an IGBT and a diode connected in parallel in opposite directions, or may be other reasonable switching devices, which is not specifically limited in the embodiments of the present application.

[0118] The beneficial effects of the control method of the current source converter provided by the present application are described in detail below:

[0119] In the related art, the duty cycle of the maximum phase and the minimum phase are typically calculated first, and then the middle phase and the minimum phase are complementary. Therefore, when a current source converter is operating, the maximum and minimum phases are turned on in the middle of a switching cycle, and the middle phase is turned on at the beginning and end of a switching cycle. Referring to FIG4 , at the beginning (time 0) of a switching cycle (0-T5 or T5-T10 in FIG4 ), the middle phase is in the on state. At time T1, the maximum phase is turned on. At time T2, the middle phase is turned off and the minimum phase is turned on. At time T3, the minimum phase is turned off and the middle phase is turned on. At time T4, the maximum phase is turned off. From time T4 to time T5, the middle phase remains in the on state until the next switching cycle begins, and the above process repeats. Among them, the duration corresponding to the duty cycle of the maximum phase is T1-T4, the duration corresponding to the duty cycle of the minimum phase is T2-T3, and the duration corresponding to the duty cycle of the intermediate phase is the sum of the duration of 0-T2 and the duration of T3-T5 (which is also equal to twice the duration of 0-T2 and twice the duration of T3-T5).

[0120] In the above control process, referring to FIG5 , during the 0-T1 process, since only the middle phase is turned on, a loop cannot be formed in the bridge arm. Therefore, the bridge arm DC output voltage V PN =0; at time T1, the maximum phase is turned on, and a loop is formed between the maximum phase and the middle phase. Therefore, at this time, the DC output voltage of the bridge arm V PN Jumps from 0 to "line voltage between the middle phase and the maximum phase"; at time T2, the middle phase is disconnected and the minimum phase is turned on, forming a loop between the maximum phase and the minimum phase. Therefore, at this time, the DC output voltage of the bridge arm V PN The line voltage between the middle phase and the maximum phase jumps to the line voltage between the minimum phase and the maximum phase; at time T3, the minimum phase is disconnected, the middle phase is turned on, and a loop is formed between the maximum phase and the middle phase. Therefore, at this time, the DC output voltage of the bridge arm V PN The line voltage between the minimum phase and the maximum phase jumps to the line voltage between the middle phase and the maximum phase; at time T4, the maximum phase is disconnected and only the middle phase is turned on, so a loop cannot be formed in the bridge arm. Therefore, the DC output voltage of the bridge arm V PN It jumps from the "line voltage between the middle phase and the maximum phase" to zero.

[0121] Since the current voltage of the maximum phase is opposite to the current voltage of the minimum phase in the same sector, and the current voltage of the maximum phase is also opposite to the current voltage of the minimum phase, the line voltage formed between the middle phase and the maximum phase will be greater than the line voltage between the minimum phase and the maximum phase. Therefore, in the related art, the DC output voltage V PN As shown in FIG5 , a relatively large jump will be performed between zero and the “line voltage formed between the middle phase and the maximum phase”.

[0122] In the embodiment of the present application, the first duty cycle corresponding to the maximum and the second duty cycle corresponding to the middle are calculated first, and then the minimum phase and the middle phase are complementary. Therefore, when the current source converter is operating, the maximum phase and the middle phase are turned on in the middle of a switching cycle, and the minimum phase is turned on at the beginning and end of a switching cycle. Referring to FIG6 , at the beginning (time 0) of a switching cycle (0-t5 or t5-t10 in FIG6 ), the minimum phase is in the on state. At time t1, the maximum phase is turned on. At time t2, the minimum phase is turned off and the middle phase is turned on. At time t3, the middle phase is turned off and the minimum phase is turned on. At time t4, the maximum phase is turned off. From time t4 to time t5, the minimum phase is always in the on state until the next switching cycle begins, and the above process is repeated. Among them, the duration corresponding to the first duty cycle of the maximum phase is t1-t4, the duration corresponding to the second duty cycle of the middle phase is t2-t3, and the duration corresponding to the third duty cycle of the minimum phase is the sum of the duration of 0-t2 and the duration of t3-t5 (which is also equal to twice the duration of 0-t2 and twice the duration of t3-t5).

[0123] In the above control process, referring to FIG7 , during the period 0-t1, since only the minimum phase is turned on, a loop cannot be formed in the bridge arm. Therefore, the bridge arm DC output voltage V PN =0; at time t1, the maximum phase is turned on, and a loop is formed between the maximum phase and the minimum phase. Therefore, at this time, the DC output voltage of the bridge arm V PN Jumps from 0 to "the line voltage between the minimum phase and the maximum phase"; at time t2, the minimum phase is disconnected and the middle phase is turned on, forming a loop between the maximum phase and the middle phase. Therefore, at this time, the DC output voltage of the bridge arm V PN The line voltage between the minimum phase and the maximum phase jumps to the line voltage between the middle phase and the maximum phase; at time t3, the middle phase is disconnected and the minimum phase is turned on, forming a loop between the maximum phase and the minimum phase. Therefore, at this time, the DC output voltage of the bridge arm V PN The line voltage between the middle phase and the maximum phase jumps to the line voltage between the minimum phase and the maximum phase; at time t4, the maximum phase is disconnected and only the minimum phase is turned on, so a loop cannot be formed in the bridge arm. Therefore, the DC output voltage of the bridge arm V PN It jumps from the "line voltage between the minimum phase and the maximum phase" to zero.

[0124] It can be seen that the technical solution provided by the embodiment of the present application can make the bridge arm DC output voltage V PNIt is only necessary to jump between zero and the "line voltage between the minimum phase and the maximum phase", or to jump between the "line voltage between the minimum phase and the maximum phase" and the "line voltage between the middle phase and the maximum phase". The amplitude of these two jumps is smaller than the amplitude of the jump between zero and the "line voltage between the middle phase and the maximum phase" in the related art. Therefore, the technical solution provided in the embodiment of the present application reduces the bridge arm DC output voltage V PN The jump amplitude is reduced, thereby reducing the voltage stress, ensuring good current waveform quality of the three-phase AC power, reducing the cost of the filter on the three-phase AC side, and improving the EMI performance.

[0125] In the embodiments of the present application, there are several methods for controlling the on or off of multiple controllable switching devices in the current source converter, which are described below:

[0126] The first control method:

[0127] In any switching cycle, when the corresponding controllable switching device in the middle is in the off state, the controllable switching device on the upper bridge arm corresponding to the minimum or the controllable switching device on the lower bridge arm corresponding to the minimum is controlled to be in the on state; when the corresponding controllable switching device in the middle is in the on state, the controllable switching device on the upper bridge arm corresponding to the minimum and the controllable switching device on the lower bridge arm corresponding to the minimum are both controlled to be in the off state.

[0128] In implementation, within any switching cycle, referring to FIG6 , the portion of controllable switching devices corresponding to the minimum phase can be controlled to be turned on first. The portion of controllable switching devices corresponding to the minimum phase refers to: when the current voltage of the minimum phase is greater than zero, the controllable switching devices on the upper bridge arm corresponding to the minimum phase are controlled to be turned on, and the controllable switching devices on the lower bridge arm corresponding to the minimum phase are controlled to be turned off; when the current voltage of the minimum phase is less than zero, the controllable switching devices on the lower bridge arm corresponding to the minimum phase are controlled to be turned on, and the controllable switching devices on the upper bridge arm corresponding to the minimum phase are controlled to be turned off.

[0129] At time t1, the maximum corresponding part of the controllable switching devices is controlled to be turned on. First, the method for calculating the 0-t1 duration can be: first calculate the first difference between 1 and the first duty cycle, and then multiply the first difference by the total duration of the switching cycle to obtain the first duration, and half of the first duration is the 0-t1 duration. Secondly, the maximum corresponding part of the controllable switching devices refers to: when the current voltage of the maximum phase is greater than zero, the controllable switching device on the upper bridge arm corresponding to the maximum is controlled to be turned on, and the controllable switching device on the lower bridge arm corresponding to the maximum is controlled to be turned off; when the current voltage of the maximum phase is less than zero, the controllable switching device on the lower bridge arm corresponding to the maximum is controlled to be turned on, and the controllable switching device on the upper bridge arm corresponding to the maximum is controlled to be turned off.

[0130] At time t2, the portion of controllable switching devices corresponding to the minimum phase that is in the on state is controlled to be turned off, and the portion of controllable switching devices corresponding to the middle phase is controlled to be turned on. First, the calculation method of the 0-t2 duration can be: first calculate the second difference between 1 and the second duty cycle, and then multiply the second difference by the total duration of the switching cycle to obtain the second duration, and half of the second duration is the 0-t2 duration. Secondly, the portion of controllable switching devices corresponding to the middle phase refers to: when the current voltage of the middle phase is greater than zero, the controllable switching devices on the upper bridge arm corresponding to the middle phase are controlled to be turned on, and the controllable switching devices on the lower bridge arm corresponding to the middle phase are controlled to be turned off; when the current voltage of the middle phase is less than zero, the controllable switching devices on the lower bridge arm corresponding to the middle phase are controlled to be turned on, and the controllable switching devices on the upper bridge arm corresponding to the middle phase are controlled to be turned off.

[0131] At time t3, the portion of controllable switching devices corresponding to the middle portion that is in the on state is controlled to be turned off, and the portion of controllable switching devices corresponding to the smallest portion is controlled to be turned on. The duration t2-t3 is calculated by multiplying the second duty cycle by the total duration of the switching period to obtain t2-t3.

[0132] At time t4, the corresponding portion of the controllable switching devices in the on state is controlled to be turned off. The calculation method of the duration t1-t2 is: calculate the product of the first duty cycle and the total duration of the switching cycle to obtain t1-t2.

[0133] During the time period t4-t5, only the minimum corresponding portion of controllable switching devices is in the on state.

[0134] The second control method:

[0135] In any switching cycle, when the maximum corresponding controllable switching device and the middle corresponding controllable switching device are both in the off state, the controllable switching device on the upper bridge arm corresponding to the minimum and the controllable switching device on the lower bridge arm corresponding to the minimum are controlled to be in the on state; when the maximum corresponding controllable switching device is in the on state and the middle corresponding controllable switching device is in the off state, the controllable switching device on the upper bridge arm corresponding to the minimum or the controllable switching device on the lower bridge arm corresponding to the minimum is controlled to be in the on state.

[0136] In practice, in any switching cycle, referring to FIG6 , the controllable switch device on the upper bridge arm corresponding to the minimum and the controllable switch device on the lower bridge arm corresponding to the minimum can be controlled to be turned on. At this time, since only the controllable switch device corresponding to the minimum among the three corresponding bridge arms is turned on, the bridge arm DC output voltage V PNThe voltages at points P and N at both ends of the circuit are clamped to the current voltage of the minimum phase, so that the voltages at points P and N will not jump to exceed the current voltage of the minimum phase, realizing active clamping and reducing voltage stress.

[0137] Moreover, when all the controllable switch devices corresponding to the minimum phase are in the on state, the voltage drop across the series circuit of all the controllable switch devices of the minimum phase is greater than D dc Therefore, the current will flow through D dc , and will not flow through the series circuit where all the controllable switching devices of the smallest phase are located. Therefore, controlling all the controllable switching devices of the smallest phase to be turned on will not have any impact on the operation of the current source converter, ensuring that the three-phase AC input voltage (i.e., the current voltage of the three phases) is high and can still work reliably, ensuring a wide range of input voltage operating range.

[0138] At time t1, the part of the controllable switching devices corresponding to the maximum is controlled to be turned on, and the part of the controllable switching devices corresponding to the minimum is controlled to be turned off. First, the calculation method of the 0-t1 time length can be: first calculate the first difference between 1 and the first duty cycle, and then multiply the first difference by the total time length of the switching cycle to obtain the first time length, and half of the first time length is the 0-t1 time length. Secondly, the part of the controllable switching devices corresponding to the maximum refers to: when the current voltage of the maximum phase is greater than zero, the controllable switching device on the upper bridge arm corresponding to the maximum is controlled to be turned on, and the controllable switching device on the lower bridge arm corresponding to the maximum is controlled to be turned off; when the current voltage of the maximum phase is less than zero, the controllable switching device on the lower bridge arm corresponding to the maximum is controlled to be turned on, and the controllable switching device on the upper bridge arm corresponding to the maximum is controlled to be turned off. Then, controlling the part of the controllable switching devices corresponding to the minimum to be disconnected means: when the current voltage of the minimum phase is greater than zero, controlling the controllable switching devices on the lower bridge arm corresponding to the minimum to be disconnected, and the controllable switching devices on the upper bridge arm corresponding to the minimum are still in the on state; when the current voltage of the minimum phase is less than zero, controlling the controllable switching devices on the upper bridge arm corresponding to the minimum to be disconnected, and the controllable switching devices on the lower bridge arm corresponding to the minimum are still in the on state.

[0139] At time t2, the portion of controllable switching devices corresponding to the minimum phase that is in the on state is controlled to be turned off, and the portion of controllable switching devices corresponding to the middle phase is controlled to be turned on. First, the calculation method of the 0-t2 duration can be: first calculate the second difference between 1 and the second duty cycle, and then multiply the second difference by the total duration of the switching cycle to obtain the second duration, and half of the second duration is the 0-t2 duration. Secondly, the portion of controllable switching devices corresponding to the middle phase refers to: when the current voltage of the middle phase is greater than zero, the controllable switching devices on the upper bridge arm corresponding to the middle phase are controlled to be turned on, and the controllable switching devices on the lower bridge arm corresponding to the middle phase are controlled to be turned off; when the current voltage of the middle phase is less than zero, the controllable switching devices on the lower bridge arm corresponding to the middle phase are controlled to be turned on, and the controllable switching devices on the upper bridge arm corresponding to the middle phase are controlled to be turned off.

[0140] At time t3, the portion of controllable switching devices corresponding to the middle portion that is in the on state is controlled to be turned off, and the portion of controllable switching devices corresponding to the smallest portion is controlled to be turned on. The duration t2-t3 is calculated by multiplying the second duty cycle by the total duration of the switching period to obtain t2-t3.

[0141] At time t4, the portion of controllable switching devices corresponding to the maximum duty cycle that is in the on state is controlled to be turned off, and the portion of controllable switching devices corresponding to the minimum duty cycle that is in the off state is controlled to be turned on. The duration t1-t2 is calculated by multiplying the first duty cycle by the total duration of the switching period to obtain t1-t2.

[0142] During the time period t4-t5, the controllable switching devices on the upper bridge arm corresponding to the minimum and the controllable switching devices on the lower bridge arm corresponding to the minimum are both in the on state, so that the voltage at point P and the voltage at point N will not jump to a current voltage exceeding the minimum phase, realizing active clamping and thus reducing voltage stress.

[0143] The third control method:

[0144] In any switching cycle, based on the first duty cycle, the controllable switching devices on the upper bridge arm corresponding to the maximum and the controllable switching devices on the lower bridge arm corresponding to the maximum are both turned on or turned off; based on the second duty cycle, the controllable switching devices on the upper bridge arm corresponding to the middle and the controllable switching devices on the lower bridge arm corresponding to the middle are both turned on or turned off; based on the third duty cycle, the controllable switching devices on the upper bridge arm corresponding to the minimum and the controllable switching devices on the lower bridge arm corresponding to the minimum are both controlled to be turned on or turned off.

[0145] In implementation, referring to FIG6 , taking the switching cycle 0-t5 as an example, based on the first duty cycle and the total duration of the switching cycle, the conduction period of the maximum phase in the switching cycle (i.e., t1-t4 in FIG6 ) can be determined. Then, at time t1, the controllable switching device on the maximum corresponding upper bridge arm and the controllable switching device on the maximum corresponding lower bridge arm can be controlled to be turned on. At time t4, the controllable switching device on the maximum corresponding upper bridge arm and the controllable switching device on the maximum corresponding lower bridge arm can be controlled to be turned off.

[0146] Based on the second duty cycle and the total duration of the switching cycle, the conduction period of the middle phase in the switching cycle (i.e., t2-t3 in Figure 6) can be determined. Then, at time t2, the controllable switching devices on the corresponding upper bridge arm in the middle and the controllable switching devices on the corresponding lower bridge arm in the middle can be controlled to be turned on. At time t3, the controllable switching devices on the corresponding upper bridge arm in the middle and the controllable switching devices on the corresponding lower bridge arm in the middle can be controlled to be turned off.

[0147] Based on the third duty cycle and the total duration of the switching cycle, the conduction period of the minimum phase in the switching cycle (i.e., 0-t2 and t3-t5 in Figure 6) can be determined. Then, at time t3, the controllable switching device on the upper bridge arm corresponding to the minimum and the controllable switching device on the lower bridge arm corresponding to the minimum can be controlled to be turned on. At time t7 of the next switching cycle, the controllable switching device on the upper bridge arm corresponding to the minimum and the controllable switching device on the lower bridge arm corresponding to the minimum can be controlled to be turned off.

[0148] Such an arrangement can achieve the beneficial effect of the second control method of "when the maximum corresponding controllable switch device and the middle corresponding controllable switch device are both in the off state, controlling the controllable switch device on the minimum corresponding upper bridge arm and the controllable switch device on the minimum corresponding lower bridge arm to be in the on state; when the maximum corresponding controllable switch device is in the on state and the middle corresponding controllable switch device is in the off state, controlling the controllable switch device on the minimum corresponding upper bridge arm or the controllable switch device on the minimum corresponding lower bridge arm to be in the on state", that is, reducing voltage stress, ensuring a wide range of input voltage operating range, and reducing the complexity of the control method.

[0149] The above control methods are only examples. The control method in the embodiment of the present application may also be other reasonable methods, and the embodiment of the present application does not make specific limitations on this.

[0150] In the embodiment of the present application, the method for determining the maximum corresponding first duty cycle may be as follows:

[0151] A maximum corresponding first duty cycle is determined based on the sum of the squares of the current voltages of the three phases, the current voltage of the maximum phase, and the DC voltage.

[0152] In a possible implementation, the maximum corresponding first duty cycle may be determined based on the following formula (1):

[0153] Among them, d Max is the first duty cycle, V dc is the DC voltage, v a 、v b 、v c They are the current voltages of the three-phase alternating current respectively.

[0154] In the embodiment of the present application, the method for determining the second duty cycle corresponding to the middle may be as follows:

[0155] A second duty cycle corresponding to the middle phase is determined based on the sum of the squares of the current voltages of the three phases, the current voltage of the middle phase, and the DC voltage.

[0156] In a possible implementation, the second duty cycle corresponding to the middle may be determined based on the following formula (2):

[0157] Among them, d Mid is the second duty cycle, V dc is the DC voltage, v a 、v b 、v c They are the current voltages of the three-phase alternating current respectively.

[0158] Below, referring to Table 1, the calculation methods of the three corresponding duty cycles in each sector are summarized and introduced:

[0159] Table 1

[0160] In the embodiment of the present application, the calculation method of the three corresponding duty cycles can also be other reasonable methods, and the embodiment of the present application does not specifically limit this.

[0161] All of the above optional technical solutions can be combined in any way to form optional embodiments of the present application, and will not be described in detail here.

[0162] The solution mentioned in the embodiment of the present application is to determine the first duty cycle corresponding to the maximum based on the current voltage of the maximum phase, and to determine the second duty cycle corresponding to the middle based on the current voltage of the middle phase. The minimum phase and the middle phase complement each other. In this way, in each switching cycle, the bridge arm DC output voltage V PNIt will jump from zero to the line voltage between the minimum phase and the maximum phase, then jump from the line voltage between the minimum phase and the maximum phase to the line voltage between the middle phase and the maximum phase, then jump from the line voltage between the middle phase and the maximum phase to the line voltage between the minimum phase and the maximum phase, and then jump from the line voltage between the minimum phase and the maximum phase to zero.

[0163] Since the line voltage between the minimum phase and the maximum phase in any sector of the 12 sectors is less than the line voltage between the middle phase and the maximum phase, the bridge arm DC output voltage V PN The jump amplitude is reduced, thereby reducing the voltage stress, ensuring good current waveform quality of the three-phase AC power, reducing the cost of the filter on the three-phase AC side, and improving the EMI performance.

[0164] An embodiment of the present application provides a control device for a current source converter, which may be the computer device in the above embodiment. As shown in FIG8 , the device includes:

[0165] A first determining module 810 is configured to determine a maximum phase, a minimum phase, and an intermediate phase based on current voltages of the three phases of the three-phase alternating current;

[0166] A second determining module 820 is configured to determine the maximum corresponding first duty cycle based on the current voltage of the maximum phase;

[0167] A third determining module 830 is configured to determine a second duty cycle corresponding to the middle phase based on the current voltage of the middle phase;

[0168] A fourth determining module 840 is configured to determine a third duty cycle corresponding to the minimum based on the second duty cycle corresponding to the middle, wherein the minimum phase is complementary to the middle phase;

[0169] The control module 850 is used to control the conduction or disconnection of multiple controllable switching devices in the current source converter based on the current voltage of the three phases, the first duty cycle, the second duty cycle and the third duty cycle.

[0170] In a possible implementation, the control module 850 is configured to:

[0171] In any switching cycle, when the controllable switching device corresponding to the middle is in the off state, the controllable switching device on the upper bridge arm corresponding to the minimum or the controllable switching device on the lower bridge arm corresponding to the minimum is controlled to be in the on state; when the controllable switching device corresponding to the middle is in the on state, the controllable switching device on the upper bridge arm corresponding to the minimum and the controllable switching device on the lower bridge arm corresponding to the minimum are both controlled to be in the off state.

[0172] In a possible implementation, the control module 850 is further configured to:

[0173] In any switching cycle, when the maximum corresponding controllable switching device and the middle corresponding controllable switching device are both in the off state, the controllable switching device on the upper bridge arm corresponding to the minimum and the controllable switching device on the lower bridge arm corresponding to the minimum are controlled to be in the on state; when the maximum corresponding controllable switching device is in the on state and the middle corresponding controllable switching device is in the off state, the controllable switching device on the upper bridge arm corresponding to the minimum or the controllable switching device on the lower bridge arm corresponding to the minimum is controlled to be in the on state.

[0174] In a possible implementation, the control module 850 is configured to:

[0175] Controlling the controllable switch device on the upper bridge arm corresponding to the maximum and the controllable switch device on the lower bridge arm corresponding to the maximum to be turned on or turned off based on the first duty cycle;

[0176] Controlling the controllable switch device on the corresponding upper bridge arm and the controllable switch device on the corresponding lower bridge arm to be turned on or off based on the second duty cycle;

[0177] Based on the third duty cycle, the controllable switch device on the upper bridge arm corresponding to the minimum and the controllable switch device on the lower bridge arm corresponding to the minimum are controlled to be turned on or turned off.

[0178] In a possible implementation, the second determining module 820 is configured to:

[0179] The maximum corresponding first duty cycle is determined based on the sum of the squares of the current voltages of the three phases, the current voltage of the maximum phase, and the DC voltage.

[0180] In a possible implementation, the third determining module 830 is configured to:

[0181] A second duty cycle corresponding to the middle phase is determined based on the sum of the squares of the current voltages of the three phases, the current voltage of the middle phase, and the DC voltage.

[0182] In a possible implementation, the controllable switch device is any one of an IGBT, a Mosfet, and a combination of an IGBT and a diode connected in parallel in opposite directions.

[0183] It should be noted that the control device for a current source converter provided in the above embodiment only uses the division of the above functional modules as an example to illustrate the control of the current source converter. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. In addition, the control device for a current source converter provided in the above embodiment and the control method embodiment of a current source converter are based on the same concept. The specific implementation process is detailed in the method embodiment and will not be repeated here.

[0184] An embodiment of the present application provides a control circuit for a current source converter, the control circuit comprising a current source converter and a controller;

[0185] The controller is used to:

[0186] determining a maximum phase, a minimum phase, and an intermediate phase based on current voltages of the three phases of the three-phase alternating current;

[0187] Determining a first duty cycle corresponding to the maximum value based on the current voltage of the maximum phase;

[0188] Determining a second duty cycle corresponding to the middle phase based on a current voltage of the middle phase;

[0189] determining the minimum corresponding third duty cycle based on the intermediate corresponding second duty cycle, wherein the minimum phase is complementary to the intermediate phase;

[0190] Based on the current voltage of the three phases, the first duty cycle, the second duty cycle and the third duty cycle, a plurality of controllable switching devices in the current source converter are controlled to be turned on or off.

[0191] In a possible implementation, the controller is configured to:

[0192] In any switching cycle, when the controllable switching device corresponding to the middle is in the off state, the controllable switching device on the upper bridge arm corresponding to the minimum or the controllable switching device on the lower bridge arm corresponding to the minimum is controlled to be in the on state; when the controllable switching device corresponding to the middle is in the on state, the controllable switching device on the upper bridge arm corresponding to the minimum and the controllable switching device on the lower bridge arm corresponding to the minimum are both controlled to be in the off state.

[0193] In a possible implementation, the controller is configured to:

[0194] In any switching cycle, when the maximum corresponding controllable switching device and the middle corresponding controllable switching device are both in the off state, the controllable switching device on the upper bridge arm corresponding to the minimum and the controllable switching device on the lower bridge arm corresponding to the minimum are controlled to be in the on state; when the maximum corresponding controllable switching device is in the on state and the middle corresponding controllable switching device is in the off state, the controllable switching device on the upper bridge arm corresponding to the minimum or the controllable switching device on the lower bridge arm corresponding to the minimum is controlled to be in the on state.

[0195] In a possible implementation, the controller is configured to:

[0196] Controlling the controllable switch device on the upper bridge arm corresponding to the maximum and the controllable switch device on the lower bridge arm corresponding to the maximum to be turned on or turned off based on the first duty cycle;

[0197] Controlling the controllable switch device on the corresponding upper bridge arm and the controllable switch device on the corresponding lower bridge arm to be turned on or off based on the second duty cycle;

[0198] Based on the third duty cycle, the controllable switch device on the upper bridge arm corresponding to the minimum and the controllable switch device on the lower bridge arm corresponding to the minimum are controlled to be turned on or turned off.

[0199] In a possible implementation, the controller is configured to:

[0200] The maximum corresponding first duty cycle is determined based on the sum of the squares of the current voltages of the three phases, the current voltage of the maximum phase, and the DC voltage.

[0201] In a possible implementation, the controller is configured to:

[0202] A second duty cycle corresponding to the middle phase is determined based on the sum of the squares of the current voltages of the three phases, the current voltage of the middle phase, and the DC voltage.

[0203] In a possible implementation, the controllable switch device is any one of an IGBT, a Mosfet, and a combination of an IGBT and a diode connected in parallel in opposite directions.

[0204] FIG9 shows a block diagram of a terminal 900 according to an exemplary embodiment of the present application. The terminal may be the computer device described in the aforementioned embodiments. The terminal 900 may be 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 terminal 900 may also be referred to as a user device, a portable terminal, a laptop terminal, a desktop terminal, or other similar names.

[0205] Typically, the terminal 900 includes a processor 901 and a memory 902 .

[0206] The processor 901 may include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor 901 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 901 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 901 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 901 may also include an AI (artificial intelligence) processor, which is used to process computing operations related to machine learning.

[0207] The memory 902 may include one or more computer-readable storage media, which may be non-transitory. The memory 902 may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices and flash memory storage devices. In some embodiments, the non-transitory computer-readable storage medium in the memory 902 is used to store at least one instruction, which is executed by the processor 901 to implement the control method of the current source converter provided in the method embodiment of the present application.

[0208] In some embodiments, terminal 900 may optionally include a peripheral device interface 903 and at least one peripheral device. The processor 901, memory 902, and peripheral device interface 903 may be connected via a bus or signal lines. Each peripheral device may be connected to peripheral device interface 903 via a bus, signal lines, or circuit boards. Specifically, the peripheral device may include at least one of a radio frequency circuit 904, a display screen 905, a camera 906, an audio circuit 907, a positioning component 908, and a power supply 909.

[0209] The peripheral device interface 903 can be used to connect at least one I / O (input / output)-related peripheral device to the processor 901 and the memory 902. In some embodiments, the processor 901, the memory 902, and the peripheral device interface 903 are integrated on the same chip or circuit board; in some other embodiments, any one or two of the processor 901, the memory 902, and the peripheral device interface 903 can be implemented on separate chips or circuit boards, which is not limited in this embodiment.

[0210] The radio frequency circuit 904 is used to receive and transmit RF (radio frequency) signals, also known as electromagnetic signals. The radio frequency circuit 904 communicates with communication networks and other communication devices via electromagnetic signals. The radio frequency circuit 904 converts electrical signals into electromagnetic signals for transmission, or converts received electromagnetic signals into electrical signals. Optionally, the radio frequency circuit 904 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, etc. The radio frequency circuit 904 can communicate with other terminals via at least one wireless communication protocol. Such wireless communication protocols include, but are not limited to, metropolitan area networks, various generations of mobile communication networks (2G, 3G, 4G, and 5G), wireless local area networks, and / or WiFi (wireless fidelity) networks. In some embodiments, the radio frequency circuit 904 may also include circuits related to NFC (near field communication), which is not limited in this application.

[0211] Display screen 905 is used to display a user interface (UI). This UI can include graphics, text, icons, videos, or any combination thereof. If display screen 905 is a touchscreen display, it can also capture touch signals on or above the surface of display screen 905. These touch signals can be input as control signals to processor 901 for processing. Display screen 905 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 905, located on the front panel of terminal 900. In other embodiments, there can be at least two display screens 905, located on different surfaces of terminal 900 or in a foldable design. In still other embodiments, display screen 905 can be a flexible display, located on a curved or foldable surface of terminal 900. Display screen 905 can also be configured as a non-rectangular, irregular shape, also known as a special-shaped screen. Display screen 905 can be made of materials such as LCD (liquid crystal display) and OLED (organic light-emitting diode).

[0212] The camera assembly 906 is used to capture images or videos. Optionally, the camera assembly 906 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 906 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.

[0213] The audio circuit 907 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 901 for processing, or input into the radio frequency circuit 904 to achieve voice communication. For the purpose of stereo sound collection or noise reduction, there may be multiple microphones, each located in different parts of the terminal 900. The microphone may also be an array microphone or an omnidirectional collection microphone. The speaker is used to convert electrical signals from the processor 901 or the radio frequency circuit 904 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 ranging. In some embodiments, the audio circuit 907 may also include a headphone jack.

[0214] The positioning component 908 is used to locate the current geographic location of the terminal 900 to implement navigation or LBS (location based service). The positioning component 908 can be a positioning component based on the GPS (global positioning system), Beidou system, Greninja system or Galileo system.

[0215] Power supply 909 is used to power various components in terminal 900. Power supply 909 can be AC ​​power, DC power, disposable batteries, or rechargeable batteries. When power supply 909 includes a rechargeable battery, the rechargeable battery can support wired charging or wireless charging. The rechargeable battery can also be used to support fast charging technology.

[0216] In some embodiments, the terminal 900 further includes one or more sensors 910 , including but not limited to: an acceleration sensor 911 , a gyroscope sensor 912 , a pressure sensor 913 , a fingerprint sensor 914 , an optical sensor 915 , and a proximity sensor 916 .

[0217] The accelerometer 911 can detect the magnitude of acceleration along the three coordinate axes of the coordinate system established by the terminal 900. For example, the accelerometer 911 can be used to detect the components of gravity acceleration along the three coordinate axes. The processor 901 can control the display screen 905 to display the user interface in a landscape or portrait view based on the gravity acceleration signal collected by the accelerometer 911. The accelerometer 911 can also be used to collect game or user motion data.

[0218] The gyroscope sensor 912 can detect the orientation and rotation angle of the terminal 900. It can work with the accelerometer 911 to collect the user's 3D movements on the terminal 900. Based on the data collected by the gyroscope sensor 912, the processor 901 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.

[0219] The pressure sensor 913 can be set on the side frame of the terminal 900 and / or the lower layer of the display screen 905. When the pressure sensor 913 is set on the side frame of the terminal 900, it can detect the user's grip signal of the terminal 900, and the processor 901 performs left and right hand recognition or shortcut operations based on the grip signal collected by the pressure sensor 913. When the pressure sensor 913 is set on the lower layer of the display screen 905, the processor 901 controls the operable controls on the UI interface based on the user's pressure operation on the display screen 905. The operable controls include at least one of button controls, scroll bar controls, icon controls, and menu controls.

[0220] The fingerprint sensor 914 is used to collect the user's fingerprint. The processor 901 identifies the user's identity based on the fingerprint collected by the fingerprint sensor 914, or the fingerprint sensor 914 identifies the user's identity based on the collected fingerprint. When the user's identity is identified as a trusted identity, the processor 901 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 914 can be set on the front, back, or side of the terminal 900. When a physical button or manufacturer logo is set on the terminal 900, the fingerprint sensor 914 can be integrated with the physical button or manufacturer logo.

[0221] The optical sensor 915 is used to detect ambient light intensity. In one embodiment, the processor 901 can control the display brightness of the display screen 905 based on the ambient light intensity detected by the optical sensor 915. Specifically, when the ambient light intensity is high, the display brightness of the display screen 905 is increased; when the ambient light intensity is low, the display brightness of the display screen 905 is decreased. In another embodiment, the processor 901 can also dynamically adjust the shooting parameters of the camera assembly 906 based on the ambient light intensity detected by the optical sensor 915.

[0222] Proximity sensor 916, also known as a distance sensor, is typically located on the front panel of terminal 900. Proximity sensor 916 is used to detect the distance between the user and the front of terminal 900. In one embodiment, when proximity sensor 916 detects that the distance between the user and the front of terminal 900 is gradually decreasing, processor 901 controls display screen 905 to switch from the screen-on state to the screen-off state. When proximity sensor 916 detects that the distance between the user and the front of terminal 900 is gradually increasing, processor 901 controls display screen 905 to switch from the screen-off state to the screen-on state.

[0223] Those skilled in the art will appreciate that the structure shown in FIG9 does not limit the terminal 900 and may include more or fewer components than shown, or combine certain components, or adopt a different component arrangement.

[0224] FIG10 is a schematic diagram of the structure of a server provided in an embodiment of the present application. The server 1000 may vary significantly due to different configurations or performance, and may include one or more processors (central processing units, CPUs) 1001 and one or more memories 1002. The memories 1002 store at least one instruction, which is loaded and executed by the processors 1001 to implement the methods provided in the above-mentioned various method embodiments. Of course, the server may also have components such as a wired or wireless network interface, a keyboard, and input / output interfaces for input and output. The server may also include other components for implementing device functions, which are not described in detail here.

[0225] In an exemplary embodiment, a computer-readable storage medium is also provided, such as a memory including instructions. The instructions can be executed by a processor in a terminal to implement the control method of the current source 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, etc.

[0226] 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.

[0227] It should be noted that the information (including but not limited to user device information, user personal information, etc.), data (including but not limited to data used for analysis, stored data, displayed data, etc.) and signals (including but not limited to signals transmitted between user terminals and other devices, etc.) involved in this application are all authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with the relevant laws, regulations and standards of the relevant countries and regions. For example, the "three-phase current voltage" involved in this application is obtained with full authorization.

[0228] The above description is merely an optional 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 shall be included in the scope of protection of the present application.

Claims

1. A control method for a current source type converter, characterized in that The method includes: Determining a maximum phase, a minimum phase, and an intermediate phase based on the current voltages of the three phases in the three-phase alternating current; Determining a first duty cycle corresponding to the maximum phase based on the current voltage of the maximum phase; Determining a second duty cycle corresponding to the intermediate phase based on the current voltage of the intermediate phase; Determining a third duty cycle corresponding to the minimum phase based on the second duty cycle corresponding to the intermediate phase, where the minimum phase is complementary to the intermediate phase; Controlling the conduction or disconnection of a plurality of controllable switch devices in a current source type converter based on the first duty cycle, the second duty cycle, and the third duty cycle.

2. The method according to claim 1, wherein The controlling the conduction or disconnection of a plurality of controllable switch devices in a current source type converter based on the first duty cycle, the second duty cycle, and the third duty cycle includes: During any switching period, when the controllable switch device corresponding to the intermediate phase is in the off state, controlling the controllable switch device on the upper bridge arm corresponding to the minimum phase or the controllable switch device on the lower bridge arm corresponding to the minimum phase to be in the on state, and when the controllable switch device corresponding to the intermediate phase is in the on state, controlling both the controllable switch device on the upper bridge arm corresponding to the minimum phase and the controllable switch device on the lower bridge arm corresponding to the minimum phase to be in the off state.

3. The method according to claim 1, wherein The controlling the conduction or disconnection of a plurality of controllable switch devices in a current source type converter based on the first duty cycle, the second duty cycle, and the third duty cycle includes: During any switching period, when both the controllable switch device corresponding to the maximum phase and the controllable switch device corresponding to the intermediate phase are in the off state, controlling both the controllable switch device on the upper bridge arm corresponding to the minimum phase and the controllable switch device on the lower bridge arm corresponding to the minimum phase to be in the on state, and when the controllable switch device corresponding to the maximum phase is in the on state and the controllable switch device corresponding to the intermediate phase is in the off state, controlling the controllable switch device on the upper bridge arm corresponding to the minimum phase or the controllable switch device on the lower bridge arm corresponding to the minimum phase to be in the on state.

4. The method according to claim 1, wherein The controlling the conduction or disconnection of a plurality of controllable switch devices in a current source type converter based on the first duty cycle, the second duty cycle, and the third duty cycle includes: During any switching period, controlling both the controllable switch device on the upper bridge arm corresponding to the maximum phase and the controllable switch device on the lower bridge arm corresponding to the maximum phase to be in the on state or both to be in the off state based on the first duty cycle; Controlling both the controllable switch device on the upper bridge arm corresponding to the intermediate phase and the controllable switch device on the lower bridge arm corresponding to the intermediate phase to be in the on state or both to be in the off state based on the second duty cycle; Controlling both the controllable switch device on the upper bridge arm corresponding to the minimum phase and the controllable switch device on the lower bridge arm corresponding to the minimum phase to be in the on state or both to be in the off state based on the third duty cycle.

5. The method according to claim 1, characterized in that, The determining the first duty cycle corresponding to the maximum phase based on the current voltage of the maximum phase includes: Determining the first duty cycle corresponding to the maximum phase based on the sum of the squares of the current voltages of the three phases, the current voltage of the maximum phase, and the DC voltage.

6. The method according to claim 1, wherein Determining the second duty ratio corresponding to the intermediate phase based on the current voltage of the intermediate phase includes: Determining the second duty ratio corresponding to the intermediate phase based on the sum of the squares of the current voltages of the three phases, the current voltage of the intermediate phase, and the DC voltage.

7. A control device for a current source type converter, characterized in that, The device includes: A first determination module, configured to determine a maximum phase, a minimum phase, and an intermediate phase based on the current voltages of the three phases in the three-phase alternating current; A second determination module, configured to determine the first duty ratio corresponding to the maximum phase based on the current voltage of the maximum phase; A third determination module, configured to determine the second duty ratio corresponding to the intermediate phase based on the current voltage of the intermediate phase; A fourth determination module, configured to determine the third duty ratio corresponding to the minimum phase based on the second duty ratio corresponding to the intermediate phase, where the minimum phase is complementary to the intermediate phase; A control module, configured to control multiple controllable switch devices in the current source type converter to conduct or disconnect based on the current voltages of the three phases, the first duty ratio, the second duty ratio, and the third duty ratio.

8. A control circuit for a current source type converter, characterized in that, The control circuit includes a current source type converter and a controller; The controller is configured to: Determine a maximum phase, a minimum phase, and an intermediate phase based on the current voltages of the three phases in the three-phase alternating current; Determine the first duty ratio corresponding to the maximum phase based on the current voltage of the maximum phase; Determine the second duty ratio corresponding to the intermediate phase based on the current voltage of the intermediate phase; Determine the third duty ratio corresponding to the minimum phase based on the second duty ratio corresponding to the intermediate phase, where the minimum phase is complementary to the intermediate phase; Control multiple controllable switch devices in the current source type converter to conduct or disconnect based on the current voltages of the three phases, the first duty ratio, the second duty ratio, and the third duty ratio.

9. A computer device, characterized in that, The computer device includes a processor and a memory, and at least one instruction is stored in the memory, and the at least one instruction is loaded and executed by the processor to implement the operations performed by the control method of the current source type converter according to any one of claims 1 to 6.

10. A computer-readable storage medium, characterized in that, At least one instruction is stored in the storage medium, and the at least one instruction is loaded and executed by a processor to implement the operations performed by the control method of the current source type converter according to any one of claims 1 to 6.

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