Current reconstruction method, device and equipment of single-resistance sampling PWM inverter and medium

Abstract

The embodiment of the application provides a current reconstruction method, device and equipment of a single-resistance sampling PWM inverter and a medium, wherein the method comprises the following steps: obtaining an initial three-phase PWM waveform of a target sector of a PMW output voltage in a control period; determining the action time of a zero voltage vector, a first non-zero voltage vector and a second non-zero voltage vector in the target sector according to the initial three-phase PWM waveform; inserting three observation window times in the middle period of the initial three-phase PWM waveform, and reconstructing each initial three-phase PWM waveform by using the first non-zero voltage vector, the second non-zero voltage vector, a third non-zero voltage vector and a fourth non-zero voltage vector in the target sector; obtaining a first sampling current, a second sampling current and a third sampling current according to the reconstructed three-phase PWM waveform, and calculating a fourth sampling current according to the obtained sampling currents. In this way, the current sampling provides sufficient sampling window time, so that the single-resistance sampling method can realize phase current sampling and reconstruction in a non-observation area.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power electronic control, and particularly relates to a current reconstruction method, device, equipment and medium of a single-resistor sampling PWM inverter. BACKGROUND

[0002] In the prior art, a low-cost PWM inverter usually adopts a single-resistor sampling mode, however, the mode is a non-observation zone when the output space voltage vector is in a low modulation zone or near a non-zero voltage vector, and there is a problem that current sampling and current reconstruction cannot be achieved when in the non-observation zone. SUMMARY

[0003] In order to solve the above technical problems, the embodiments of the present application provide a current reconstruction method, device, equipment and medium of a single-resistor sampling PWM inverter.

[0004] In a first aspect, the embodiments of the present application provide a current reconstruction method of a single-resistor sampling PWM inverter, comprising:

[0005] obtaining an initial three-phase PWM waveform of a target sector of a PMW output voltage in a control period, the control period comprising at least two switching periods, and the target sector being any sector of a space voltage vector;

[0006] determining, according to the initial three-phase PWM waveform, an action time of a first zero voltage vector or a second zero voltage vector, an action time of a first non-zero voltage vector and an action time of a second non-zero voltage vector in the target sector;

[0007] inserting three observation window times in a middle period of the initial three-phase PWM waveform, reconstructing the initial three-phase PWM waveform by using a first non-zero voltage vector, a second non-zero voltage vector, a third non-zero voltage vector and a fourth non-zero voltage vector in the target sector to obtain a reconstructed three-phase PWM waveform, so that a duty cycle of the initial three-phase PWM waveform and the reconstructed three-phase PWM waveform remains consistent, wherein each observation window time is greater than or equal to a minimum sampling window time, the third non-zero voltage vector is a reverse voltage vector of the second non-zero voltage vector, and the fourth non-zero voltage vector is a reverse voltage vector of the first non-zero voltage vector;

[0008] collecting a first sampling current and a second sampling current corresponding to the second non-zero voltage vector at the first observation window time and the third observation window time of the reconstructed three-phase PWM waveform respectively, collecting a third sampling current corresponding to the first non-zero voltage vector at the second observation window time of the reconstructed three-phase PWM waveform, and determining a fourth sampling current corresponding to the second observation window of the reconstructed three-phase PWM waveform according to the first sampling current, the second sampling current and the third sampling current.

[0009] In an embodiment, the reconstructing the initial three-phase PWM waveform by using the first non-zero voltage vector, the second non-zero voltage vector, the third non-zero voltage vector and the fourth non-zero voltage vector in the target sector comprises:

[0010] determining the action time of the first non-zero voltage vector, the action time of the second non-zero voltage vector, the action time of the third non-zero voltage vector, the action time of the fourth non-zero voltage vector, the action time of the first zero voltage vector and the action time of the second zero voltage vector in the control period of the reconstructed PWM waveform according to the action time of the first zero voltage vector or the second zero voltage vector of the target sector, the action time of the first non-zero voltage vector, the action time of the second non-zero voltage vector and the observation window time;

[0011] setting the second observation window of the reconstructed PWM waveform as the second non-zero voltage vector of the target sector, and symmetrically setting the first non-zero voltage vector, the first zero voltage vector, the fourth non-zero voltage vector, the third non-zero voltage vector and the second zero voltage vector of the target sector with the second observation window of the reconstructed PWM waveform as the center.

[0012] In an embodiment, the determining the fourth sampling current corresponding to the second observation window of the reconstructed three-phase PWM waveform according to the first sampling current, the second sampling current and the third sampling current comprises:

[0013] calculating the fourth sampling current corresponding to the second observation window of the reconstructed three-phase PWM waveform according to the following formula:

[0014]

[0015] wherein, I4 represents the fourth sampling current, I1 represents the first phase sampling current, I2 represents the second sampling current, and I3 represents the third sampling current.

[0016] In an embodiment, the determining the action time of the first non-zero voltage vector, the action time of the second non-zero voltage vector, the action time of the third non-zero voltage vector, the action time of the fourth non-zero voltage vector, the action time of the first zero voltage vector and the action time of the second zero voltage vector in the control period of the reconstructed PWM waveform according to the action time of the first zero voltage vector or the second zero voltage vector of the target sector, the action time of the first non-zero voltage vector, the action time of the second non-zero voltage vector and the observation window time comprises:

[0017] The action time of the first non-zero voltage vector, the action time of the second non-zero voltage vector, the action time of the third non-zero voltage vector, the action time of the fourth non-zero voltage vector, the action time of the first zero voltage vector and the action time of the second zero voltage vector in the control period of the reconstructed PWM waveform are calculated according to the following formula:

[0018]

[0019]

[0020]

[0021] T p0 =(T ctrl -3T m -2T p1 -2T p2 -2T p3 ) / 2;

[0022] wherein T0 represents the action time of the first zero voltage vector or the second zero voltage vector in the switching period of the initial three-phase PWM waveform, T1 represents the action time of the first non-zero voltage vector in the switching period of the initial three-phase PWM waveform, T2 represents the action time of the second non-zero voltage vector in the switching period of the initial three-phase PWM waveform, T m represents the observation window time, T p1 represents the action time of the fourth non-zero voltage vector in the control period of the reconstructed PWM waveform, T p2 represents the action time of the third non-zero voltage vector in the control period of the reconstructed PWM waveform, T p0 represents the action time of the first zero voltage vector in the control period of the reconstructed PWM waveform, T p3 represents the action time of the second zero voltage vector in the control period of the reconstructed PWM waveform, T ctrl represents a control period.

[0023] In a second aspect, an embodiment of the present application provides a current reconstruction device of a single-resistor sampling PWM inverter, and the device comprises:

[0024] An acquisition module is configured to acquire an initial three-phase PWM waveform of a target sector of a PMW output voltage in a control period, the control period comprises at least two switching periods, and the target sector is any sector of a space voltage vector;

[0025] determining module, configured to determine, according to the initial three-phase PWM waveform, an action time of a first zero voltage vector or a second zero voltage vector of the target sector, an action time of a first non-zero voltage vector, and an action time of a second non-zero voltage vector;

[0026] reconstruction module, configured to insert three observation window times in a middle period of the initial three-phase PWM waveform, and reconstruct the initial three-phase PWM waveform by using a first non-zero voltage vector, a second non-zero voltage vector, a third non-zero voltage vector, and a fourth non-zero voltage vector in the target sector, to obtain a reconstructed three-phase PWM waveform, so that a duty cycle of the initial three-phase PWM waveform is consistent with that of the reconstructed three-phase PWM waveform, wherein each observation window time is greater than or equal to a minimum sampling window time, the third non-zero voltage vector is a reverse voltage vector of the second non-zero voltage vector, and the fourth non-zero voltage vector is a reverse voltage vector of the first non-zero voltage vector;

[0027] processing module, configured to collect a first sampling current corresponding to the second non-zero voltage vector at a first observation window time of the reconstructed three-phase PWM waveform and collect a second sampling current corresponding to the second non-zero voltage vector at a third observation window time of the reconstructed three-phase PWM waveform, collect a third sampling current corresponding to the first non-zero voltage vector at a second observation window time of the reconstructed three-phase PWM waveform, and determine a fourth sampling current corresponding to the second observation window of the reconstructed three-phase PWM waveform according to the first sampling current, the second sampling current, and the third sampling current.

[0028] In an embodiment, the reconstruction module includes:

[0029] determining sub-module, configured to determine, according to the action time of the first zero voltage vector or the second zero voltage vector of the target sector, the action time of the first non-zero voltage vector, the action time of the second non-zero voltage vector, and the observation window time, the action time of the first non-zero voltage vector, the action time of the second non-zero voltage vector, the action time of the third non-zero voltage vector, the action time of the fourth non-zero voltage vector, the action time of the first zero voltage vector, and the action time of the second zero voltage vector in a control period of the reconstructed PWM waveform;

[0030] setting sub-module, configured to set the second observation window of the reconstructed PWM waveform as the second non-zero voltage vector of the target sector, and symmetrically set, with the second observation window of the reconstructed PWM waveform as a center, the first non-zero voltage vector, the first zero voltage vector, the fourth non-zero voltage vector, the third non-zero voltage vector, and the second zero voltage vector of the target sector.

[0031] In an embodiment, the processing module is further configured to calculate the fourth sampling current corresponding to the second observation window of the reconstructed three-phase PWM waveform according to the following formula:

[0032]

[0033] wherein, wherein, I4 represents the fourth sampling current, I1 represents the first phase sampling current, I2 represents the second sampling current, and I3 represents the third sampling current.

[0034] In an embodiment, the determining sub-module is further configured to calculate the action time of the first non-zero voltage vector, the action time of the second non-zero voltage vector, the action time of the third non-zero voltage vector, the action time of the fourth non-zero voltage vector, the action time of the first zero voltage vector, and the action time of the second zero voltage vector in the control period of the reconstructed PWM waveform according to the following formula:

[0035]

[0036]

[0037]

[0038] T p0 = (T ctrl - 3T m - 2T p1 - 2T p2 - 2T p3 ) / 2.

[0039] wherein, T0 represents the action time of the first zero voltage vector or the second zero voltage vector in the switching period of the initial three-phase PWM waveform, T1 represents the action time of the first non-zero voltage vector in the switching period of the initial three-phase PWM waveform, T2 represents the action time of the second non-zero voltage vector in the switching period of the initial three-phase PWM waveform, T m represents the observation window time, T p1 represents the action time of the fourth non-zero voltage vector in the control period of the reconstructed PWM waveform, T p2 represents the action time of the third non-zero voltage vector in the control period of the reconstructed PWM waveform, T p0 represents the action time of the first zero voltage vector in the control period of the reconstructed PWM waveform, T p3 represents the action time of the second zero voltage vector in the control period of the reconstructed PWM waveform, T ctrl represents a control period.

[0040] In a third aspect, an electronic device is provided, comprising a memory and a processor, the memory is configured to store a computer program, and the computer program is configured to execute the current reconstruction method of the single-resistor sampling PWM inverter according to the first aspect when the processor runs.

[0041] In a fourth aspect, a computer readable storage medium is provided, which stores a computer program, and the computer program is configured to execute the current reconstruction method of the single-resistor sampling PWM inverter according to the first aspect when a processor runs.

[0042] The current reconstruction method of the single-resistor sampling PWM inverter, the device, the equipment and the medium provided by the present application provide sufficient sampling window time for current sampling, so that the single-resistor sampling method can realize phase current sampling and reconstruction in the non-observation area; the current sampling window inserted in the non-observation area is symmetrically designed, and the two-phase current time obtained by sampling is equivalent, so that the current reconstruction result meets the Kirchhoff's current law; the current reconstruction method of the single-resistor sampling PWM inverter provided by the present application reconstructs the PWM output space voltage vector in the non-observation area, does not increase the switching action and the switching loss, does not change the equivalent output space voltage vector amplitude and phase, and the PWM waveform in the control period is symmetric, which does not bring low-order harmonics. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope of protection of the present application. In each drawing, similar components are denoted by similar reference numerals.

[0044] Figure 1 A structure schematic diagram of the single-resistor sampling PWM inverter provided by the embodiments of the present application is shown;

[0045] Figure 2 A space voltage vector schematic diagram provided by the embodiments of the present application is shown;

[0046] Figure 3 A 4th sector PWM waveform and a single-resistor sampling schematic diagram provided by the embodiments of the present application are shown

[0047] Figure 4 A current reconstruction method of the single-resistor sampling PWM inverter provided by the embodiments of the present application is shown;

[0048] Figure 5 A PWM waveform schematic diagram before the space voltage vector reconstruction in the non-observation area provided by the embodiments of the present application is shown;

[0049] Figure 6A PWM waveform diagram after the reconstruction of the non-observation zone space voltage vector is shown.

[0050] Figure 7 A schematic diagram before the reconstruction of the PWM inverter output space voltage vector is shown.

[0051] Figure 8 A schematic diagram after the reconstruction of the PWM inverter output space voltage vector is shown.

[0052] Figure 9 A structure schematic diagram of the current reconstruction of the single-resistance sampling PWM inverter is shown. DETAILED DESCRIPTION

[0053] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application.

[0054] The components of the embodiments of the present application generally described and illustrated in the accompanying drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0055] Hereinafter, the terms "include", "have", and their conjugates used in various embodiments of the present application are only intended to denote a certain characteristic, number, step, operation, element, component, or combination of the foregoing, and should not be construed as excluding the presence or addition of one or more other characteristics, numbers, steps, operations, elements, components, or combinations thereof.

[0056] In addition, the terms "first", "second", "third", and the like are only used to distinguish descriptions, and cannot be understood as indicating or implying relative importance.

[0057] Unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which various embodiments of the present application belong. The terms (such as those defined in a generally used dictionary) will be interpreted as having the same meaning as the contextual meaning in the relevant technical field and will not be interpreted as having an idealized or overly formal meaning, unless clearly defined in various embodiments of the present application.

[0058] In the prior art, low-cost PWM inverters usually adopt a single-resistor sampling method. Referring to Figure 1 , Figure 1 is a main circuit topology diagram of a single-resistor sampling PWM inverter in the prior art; which includes a bus support capacitor Cp, a first power switching device S1, a second power switching device S2, a third power switching device S3, a fourth power switching device S4, a fifth power switching device S5, a sixth power switching device S6, and a sampling resistor Rs. The single-resistor sampling PWM inverter shown in Figure 1 requires that the duration of the non-zero voltage vector output by the inverter in a PWM switching period be greater than the minimum sampling window time, otherwise the bus current obtained by sampling is meaningless. When the output space voltage vector is in the low modulation region or near the non-zero voltage vector, the above requirement cannot be met. Therefore, the existing single-resistor sampling PWM inverter, when the output space voltage vector is in the low modulation region or near the non-zero voltage vector, is a non-observation region, and when in the non-observation region, there is a problem of being unable to realize current sampling and current reconstruction.

[0059] Embodiment 1

[0060] The embodiment of the present application provides a current reconstruction method of a single-resistor sampling PWM inverter, which is applied to Figure 1 the single-resistor sampling PWM inverter shown in the figure. Referring to Figure 2 , Figure 2 is a space voltage vector diagram, which can be divided into a first sector, a second sector, a third sector, a fourth sector, a fifth sector, and a sixth sector, V1-V6 represent six non-zero voltage vectors respectively, and V0 and V7 represent two zero voltage vectors respectively. The first sector includes two non-zero voltages V4 (100) and V6 (110), the second sector includes two non-zero voltages V6 (110) and V2 (010), the third sector includes two non-zero voltages V2 (010) and V3 (011), the fourth sector includes two non-zero voltages V3 (011) and V1 (001), the fifth sector includes two non-zero voltages V1 (001) and V5 (101), and the sixth sector includes two non-zero voltages V5 (101) and V1 (001). The first sector to the sixth sector also respectively include two zero voltage vectors V0 (000) and V7 (111). As shown in Figure 2 any sector of the space voltage vector can obtain a corresponding PWM waveform.

[0061] Referring to Figure 3 , Figure 3 is Figure 2 the fourth sector PWM waveform and the single-resistor sampling diagram shown in the figure, wherein T pwmis a switching period, Sa, Sb, Sc are three-phase PWM waveforms, Ia is the A-phase current, Ic is the C-phase current, T0 is the zero voltage vector action time, T1 is the non-zero voltage vector V1 action time, T2 is the non-zero voltage vector V3 action time. It should be noted that, in addition to the fourth sector, the PWM waveform and single-resistance sampling schematic diagram of other sectors can also be obtained, which is not described here.

[0062] Next, combined with Figures 1 to 3 The existing single-resistance sampling and current reconstruction scheme outside the unobserved area is described.

[0063] First, the PWM output voltage is expressed in the form of a space voltage vector. Taking the space voltage vector in the fourth sector as an example, the corresponding three-phase PWM waveform is as shown in Figure 3 During the voltage vector V1 action time, the current sampled by the sampling resistor Rs is Ic; during the voltage vector V3 action time, the current sampled by the sampling resistor Rs is -Ia, and the B-phase current is reconstructed as follows:

[0064] I b =-I C -I a ;

[0065] Where I b represents the B-phase current calculated by the existing reconstruction scheme.

[0066] It should be noted that the existing current reconstruction scheme in other sectors is the same, and is not described here. In the actual system, bus current sampling requires sufficient sampling window time, and the minimum sampling window is represented by Td, which is limited by the sampling circuit delay and the processor analog-to-digital conversion time. The action time of the zero voltage vector V1 is The action time of the zero voltage vector V3 is Figure 3 The non-zero voltage vector action time in the above formula needs to satisfy the following formula:

[0067]

[0068]

[0069] When the space voltage vector is in the unobserved area, the above conditions are not met.

[0070] The single-resistance sampling PWM inverter current reconstruction method provided by the embodiment can solve the problem of being unable to realize current sampling and current reconstruction when in the unobserved area. Details are described below.

[0071] Please refer to Figure 4The current reconstruction method of the single-resistance sampling PWM inverter provided in the embodiment comprises steps S401 to S404, and each step is described below.

[0072] In step S401, an initial three-phase PWM waveform of a target sector of a PMW output voltage in a control period is obtained, the control period comprises at least two switching periods, and the target sector is any sector of space voltage vectors.

[0073] In step S402, according to the initial three-phase PWM waveform, the action time of the first zero voltage vector or the second zero voltage vector, the action time of the first non-zero voltage vector, and the action time of the second non-zero voltage vector in the target sector are determined.

[0074] In step S403, three observation window times are inserted in the middle period of the initial three-phase PWM waveform, the initial three-phase PWM waveform is reconstructed by using the first non-zero voltage vector, the second non-zero voltage vector, the third non-zero voltage vector, and the fourth non-zero voltage vector in the target sector, to obtain a reconstructed three-phase PWM waveform, so that the duty cycles of the initial three-phase PWM waveform and the reconstructed three-phase PWM waveform remain consistent, wherein each observation window time is greater than or equal to a minimum sampling window time, the third non-zero voltage vector is a reverse voltage vector of the second non-zero voltage vector, and the fourth non-zero voltage vector is a reverse voltage vector of the first non-zero voltage vector.

[0075] The above steps are described below Figures 5-6 Taking the fourth sector as an example, the above steps are described below.

[0076] Taking the space voltage vector in the fourth sector as an example, Figure 5 The space voltage vector in the middle is in a non-observation area, wherein the action time of the non-zero voltage vector V1 in the control period Tctrl is 2T1, the action time of the non-zero voltage vector V3 is 2T2, and the following conditions are satisfied:

[0077]

[0078]

[0079] The reconstruction scheme provided in the embodiment is used to reconstruct the space voltage vector shown in FIG. 4, and the reconstructed three-phase PWM waveform is shown in FIG. 5. Figure 4 Figure 6 Tm is the inserted sampling window time, and the following conditions are satisfied:

[0080] T m ≥T d .

[0081] ​In an embodiment, the reconstructing the initial three-phase PWM waveform by using the first non-zero voltage vector, the second non-zero voltage vector, the third non-zero voltage vector and the fourth non-zero voltage vector in the target sector comprises:

[0082] determining the action time of the first non-zero voltage vector, the action time of the second non-zero voltage vector, the action time of the third non-zero voltage vector, the action time of the fourth non-zero voltage vector, the action time of the first zero voltage vector and the action time of the second zero voltage vector in the control period of the reconstructed PWM waveform according to the action time of the first zero voltage vector or the second zero voltage vector of the target sector, the action time of the first non-zero voltage vector, the action time of the second non-zero voltage vector and the observation window time;

[0083] setting the second observation window of the reconstructed PWM waveform as the second non-zero voltage vector of the target sector, and symmetrically setting the first non-zero voltage vector, the first zero voltage vector, the fourth non-zero voltage vector, the third non-zero voltage vector and the second zero voltage vector of the target sector with the second observation window of the reconstructed PWM waveform as the center.

[0084] In step S404, the first sampling current corresponding to the second non-zero voltage vector and the second sampling current are collected in the first observation window time and the third observation window time of the reconstructed three-phase PWM waveform respectively, the third sampling current corresponding to the first non-zero voltage vector is collected in the second observation window time of the reconstructed three-phase PWM waveform, and the fourth sampling current corresponding to the second observation window of the reconstructed three-phase PWM waveform is determined according to the first sampling current, the second sampling current and the third sampling current.

[0085] It should be noted that the target sector is any sector of the space voltage vector, that is, any one of the six sectors, and the sampling currents of the non-zero voltage vectors of different sectors are different. For example, refer to Table 1 below to read the sampling currents of each sector. Based on Table 1, the first sampling voltage, the second sampling voltage and the third sampling voltage of different sectors can be sampled.

[0086] Table 1, sampling current table

[0087]

[0088] In an embodiment, the determining the fourth sampling current corresponding to the second observation window of the reconstructed three-phase PWM waveform according to the first sampling current, the second sampling current and the third sampling current comprises:

[0089] The fourth sampling current corresponding to the second observation window of the reconstructed three-phase PWM waveform is calculated according to the following formula:

[0090]

[0091] wherein, I4 represents the fourth sampling current, I1 represents the first phase sampling current, I2 represents the second sampling current, and I3 represents the third sampling current.

[0092] It should be noted that based on Table 1, the first sampling voltage, the second sampling voltage and the third sampling voltage of different sectors can be sampled, so that the first sampling voltage, the second sampling voltage and the third sampling voltage of each sector can be substituted into the above formula to calculate the fourth sampling current corresponding to the target sector.

[0093] Next, taking the 4th sector as an example, it is illustrated as follows. In the 4th sector, the first sampling voltage, the second sampling voltage and the third sampling voltage of different sectors can be sampled, so that the first sampling voltage, the second sampling voltage and the third sampling voltage of each sector can be substituted into the above formula to calculate the fourth sampling current corresponding to the target sector. Figure 6 The first observation window time and the third observation window time of the reconstructed three-phase PWM waveform shown in the figure respectively collect the first A-phase sampling current (-I a1 ) and the second A-phase sampling current (-I a2 ) corresponding to the non-zero voltage vector V3, and the second observation window time of the reconstructed three-phase PWM waveform collects the C-phase sampling current (I c ) corresponding to the non-zero voltage vector V1. a1 According to the first A-phase sampling current (-I a2 ), the second A-phase sampling current (-I c ) and the C-phase sampling current (I b ), the B-phase current (I b ) corresponding to the second observation window of the reconstructed three-phase PWM waveform is determined.

[0094] Exemplarily, taking the 4th sector as an example, the B-phase current corresponding to the second observation window of the reconstructed three-phase PWM waveform of the 4th sector can be calculated according to the following formula:

[0095]

[0096] wherein, I b represents the B-phase current, -I a1 represents the first A-phase sampling current, -I a2 represents the second A-phase sampling current, and I c represents the C-phase sampling current.

[0097] Please refer to Figure 6 again, taking the 4th sector as an example, the current I c is collected during the action time of the non-zero voltage vector V1, the currents -I a1 and -I a2 are collected during the action time of the non-zero voltage vector V3 twice. Due to the symmetry of the sampling window, the currents -I a1 and -I a2The current I can be equivalently obtained c The reconstruction calculation formula of the A-phase current and the corresponding B-phase current at the moment is It satisfies the Kirchhoff's law.

[0098] In an embodiment, the determination of the action time of the first non-zero voltage vector, the action time of the second non-zero voltage vector, the action time of the third non-zero voltage vector, the action time of the fourth non-zero voltage vector, the action time of the first zero voltage vector and the action time of the second zero voltage vector in the control period of the reconstructed PWM waveform according to the action time of the first zero voltage vector or the second zero voltage vector of the target sector, the action time of the first non-zero voltage vector, the action time of the second non-zero voltage vector and the observation window time comprises:

[0099] The action time of the first non-zero voltage vector, the action time of the second non-zero voltage vector, the action time of the third non-zero voltage vector, the action time of the fourth non-zero voltage vector, the action time of the first zero voltage vector and the action time of the second zero voltage vector in the control period of the reconstructed PWM waveform are calculated according to the following formula:

[0100]

[0101]

[0102]

[0103] T p0 = (T ctrl - 3T m - 2T p1 - 2T p2 - 2T p3 ) / 2

[0104] Wherein, T0 represents the action time of the first zero voltage vector or the second zero voltage vector in the switching period of the initial three-phase PWM waveform, T1 represents the action time of the first non-zero voltage vector in the switching period of the initial three-phase PWM waveform, T2 represents the action time of the second non-zero voltage vector in the switching period of the initial three-phase PWM waveform, T m represents the observation window time, T p1 represents the action time of the fourth non-zero voltage vector in the control period of the reconstructed PWM waveform, T p2 represents the action time of the third non-zero voltage vector in the control period of the reconstructed PWM waveform, T p0 represents the action time of the first zero voltage vector in the control period of the reconstructed PWM waveform, T p3denotes the action time of the second zero voltage vector in the control period of the reconstructed PWM waveform, T ctrl denotes the control period.

[0105] It should be noted that, taking the 4th sector as an example, the reconstructed non-zero voltage vectors are V1, V3, V4 and V6. In order to ensure that the duty cycle of the three-phase PWM remains unchanged before and after reconstruction, the following can be combined Figure 5 and Figure 6 The following formula is derived:

[0106]

[0107]

[0108]

[0109] The action time of the non-zero voltage vectors V1, V3, V4 and V6 in the control period T ctrl is respectively: V1: T m ; V3: 2T m ; V4: 2T p1 = 2T m - 2T2; V6: 2T p2 = T m - 2T1.

[0110] It can be known from Figure 2 that the relationship between the non-zero voltage vectors V1, V3 and V4, V6 is:

[0111] V4 = -V3, V6 = -V1;

[0112] Substituting the above formula, the equivalent non-zero voltage vectors in the control period T Figure 6 after reconstruction are V1 and V3, and the action time thereof is respectively: V1: 2T1; V3: 2T2; in this way, the non-zero voltage vectors in the control period T Figure 5 after reconstruction are the same as the action time of the non-zero voltage vectors V1 and V3 in the control period T before space vector reconstruction. It should be further noted that, except for the 4th sector, the derivation process and conclusion of other sectors are the same and will not be repeated.

[0113] Figure 7 In this embodiment, the output space voltage vector is reconstructed by inserting an observation window, which realizes the sampling and reconstruction of the non-observation area phase current while ensuring that the equivalent output space voltage vector in the control period is unchanged. The vector relationship of the space voltage vector before and after reconstruction is represented by Figure 8 and Figure 7 , Figure 8 denotes the space voltage vector before reconstruction, Figure 7 denotes the space voltage vector after reconstruction, Figure 8 andVs in the formula respectively represent a target space voltage vector before reconstruction and a target space voltage vector after reconstruction.

[0114] The current reconstruction method of the single-resistance sampling PWM inverter provided in the embodiments of the present application provides sufficient sampling window time for current sampling, so that the single-resistance sampling method can realize phase current sampling and reconstruction in the non-observation zone; the current sampling window inserted in the non-observation zone is symmetrically designed, and the two-phase current times obtained by sampling are equivalent and consistent, so that the current reconstruction result satisfies the Kirchhoff's current law; the current reconstruction method of the single-resistance sampling PWM inverter provided in the present application reconstructs the PWM output space voltage vector in the non-observation zone, does not increase switching action and switching loss, does not change the equivalent output space voltage vector amplitude and phase, and simultaneously controls the symmetry of the PWM waveform in the control period, and does not bring low-order harmonics.

[0115] Embodiment 2

[0116] The embodiments of the present application also provide a current reconstruction device of a single-resistance sampling PWM inverter.

[0117] Referring to Figure 9 , the current reconstruction device 900 of the single-resistance sampling PWM inverter comprises:

[0118] An acquisition module 901 is configured to acquire an initial three-phase PWM waveform of a target sector of a PMW output voltage in a control period, the control period comprising at least two switching periods, and the target sector being any sector of a space voltage vector;

[0119] A determination module 902 is configured to determine, according to the initial three-phase PWM waveform, an action time of a first zero voltage vector or a second zero voltage vector, an action time of a first non-zero voltage vector, and an action time of a second non-zero voltage vector in the target sector;

[0120] A reconstruction module 903 is configured to insert 3 observation window times in a middle period of the initial three-phase PWM waveform, reconstruct the initial three-phase PWM waveform by using a first non-zero voltage vector, a second non-zero voltage vector, a third non-zero voltage vector, and a fourth non-zero voltage vector in the target sector, to obtain a reconstructed three-phase PWM waveform, so that the duty cycles of the initial three-phase PWM waveform and the reconstructed three-phase PWM waveform remain consistent, wherein each observation window time is greater than or equal to a minimum sampling window time, the third non-zero voltage vector is a reverse voltage vector of the second non-zero voltage vector, and the fourth non-zero voltage vector is a reverse voltage vector of the first non-zero voltage vector;

[0121] The processing module 904 is configured to collect a first sampling current corresponding to a second non-zero voltage vector at a first observation window time and a third observation window time of the reconstructed three-phase PWM waveform, collect a third sampling current corresponding to the first non-zero voltage vector at a second observation window time of the reconstructed three-phase PWM waveform, and determine a fourth sampling current corresponding to the second observation window of the reconstructed three-phase PWM waveform according to the first sampling current, the second sampling current and the third sampling current.

[0122] In an embodiment, the reconstruction module 903 includes:

[0123] The determination sub-module is configured to determine the action time of the first non-zero voltage vector, the action time of the second non-zero voltage vector, the action time of the third non-zero voltage vector, the action time of the fourth non-zero voltage vector, the action time of the first zero voltage vector and the action time of the second zero voltage vector in the control period of the reconstructed PWM waveform according to the action time of the first zero voltage vector or the second zero voltage vector of the target sector, the action time of the first non-zero voltage vector, the action time of the second non-zero voltage vector and the observation window time.

[0124] The setting sub-module is configured to set the second observation window of the reconstructed PWM waveform as the second non-zero voltage vector of the target sector, and symmetrically set the first non-zero voltage vector, the first zero voltage vector, the fourth non-zero voltage vector, the third non-zero voltage vector and the second zero voltage vector of the target sector with the second observation window of the reconstructed PWM waveform as the center.

[0125] In an embodiment, the processing module 404 is further configured to calculate the fourth sampling current corresponding to the second observation window of the reconstructed three-phase PWM waveform according to the following formula:

[0126]

[0127] Wherein, I4 represents the fourth sampling current, I1 represents the first phase sampling current, I2 represents the second sampling current, and I3 represents the third sampling current.

[0128] In an embodiment, the determination sub-module is further configured to calculate the action time of the first non-zero voltage vector, the action time of the second non-zero voltage vector, the action time of the third non-zero voltage vector, the action time of the fourth non-zero voltage vector, the action time of the first zero voltage vector and the action time of the second zero voltage vector in the control period of the reconstructed PWM waveform according to the following formula:

[0129]

[0130]

[0131]

[0132] T p0 = (T ctrl - 3T m - 2T p1 - 2T p2 - 2T p3 ) / 2.

[0133] wherein, T0 represents the action time of the first zero voltage vector or the second zero voltage vector in the switching period of the initial three-phase PWM waveform, T1 represents the action time of the first non-zero voltage vector in the switching period of the initial three-phase PWM waveform, T2 represents the action time of the second non-zero voltage vector in the switching period of the initial three-phase PWM waveform, T m represents the observation window time, T p1 represents the action time of the fourth non-zero voltage vector in the control period of the reconstructed PWM waveform, T p2 represents the action time of the third non-zero voltage vector in the control period of the reconstructed PWM waveform, T p0 represents the action time of the first zero voltage vector in the control period of the reconstructed PWM waveform, T p3 represents the action time of the second zero voltage vector in the control period of the reconstructed PWM waveform, T ctrl represents the control period.

[0134] The current reconstruction device of the single-resistance sampling PWM inverter provided by the embodiment of the application provides sufficient sampling window time for current sampling, so that the single-resistance sampling method can realize phase current sampling and reconstruction in the non-observation area; the current sampling window inserted in the non-observation area is symmetrically designed, and the two-phase current times obtained by sampling are equivalent, so that the current reconstruction result meets the Kirchhoff's current law; the current reconstruction method of the single-resistance sampling PWM inverter provided by the application reconstructs the PWM output space voltage vector in the non-observation area, does not increase switching action and switching loss, does not change the equivalent output space voltage vector amplitude and phase, and the PWM waveform in the control period is symmetric, which does not bring low-order harmonics.

[0135] Embodiment 3

[0136] In addition, the embodiment of the application provides an electronic device, including a memory and a processor, the memory stores a computer program, and the computer program executes the current reconstruction method of the single-resistance sampling PWM inverter provided by the above method embodiment when the processor runs.

[0137] The electronic device of the embodiment can correspondingly perform the content in the above embodiment 1, and the part not described in detail in the embodiment is referred to the content recorded in the embodiment 1, which will not be repeated here.

[0138] Embodiment 4

[0139] In addition, the embodiment of the present application provides a computer readable storage medium, which stores a computer program, the computer program executes the current reconstruction method of the single-resistance sampling PWM inverter provided by the embodiment 1 when running on the processor.

[0140] The computer readable storage medium of the embodiment can correspondingly perform the content in the above embodiment 1, and the part not described in detail in the embodiment is referred to the content recorded in the embodiment 1, which will not be repeated here.

[0141] In several embodiments provided in the present application, it should be understood that the disclosed apparatus and method can also be implemented by other means. The apparatus embodiment described above is only schematic, for example, the flow chart and structure chart in the drawings show the possible implementation architecture, function and operation of the apparatus, method and computer program product according to the embodiments of the present application. In this regard, each block in the flow chart or structure chart can represent a module, a program segment or a part of code, which contains one or more executable instructions for implementing the specified logical function. It should also be noted that in alternative implementation, the functions noted in the block can occur in different order than that noted in the drawings. For example, two consecutive blocks can actually be executed substantially in parallel, and sometimes they can be executed in reverse order, depending on the function involved. It should also be noted that each block in the structure chart and / or flow chart, and the combination of blocks in the structure chart and / or flow chart, can be implemented by a dedicated hardware-based system for implementing the specified function or action, or can be implemented by a combination of dedicated hardware and computer instructions.

[0142] In addition, each functional module or unit in each embodiment of the present application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0143] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application or the parts of the present application that essentially contribute to the prior art or the parts of the technical solutions can be embodied in the form of software products. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a smart phone, a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in the various embodiments of the present application. The aforementioned storage medium includes a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various media that can store program codes.

[0144] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A current reconstruction method for single-resistor sampling PWM inverters, characterized in that, The method comprises the following steps: acquiring an initial three-phase PWM waveform of a target sector of a PMW output voltage in a control period, the control period comprising at least two switching periods, and the target sector being any sector of a space voltage vector; determining an action time of a first zero voltage vector or a second zero voltage vector, an action time of a first non-zero voltage vector, and an action time of a second non-zero voltage vector in the target sector according to the initial three-phase PWM waveform; inserting three observation window times in a middle period of the initial three-phase PWM waveform, and reconstructing the initial three-phase PWM waveform by using a first non-zero voltage vector, a second non-zero voltage vector, a third non-zero voltage vector, and a fourth non-zero voltage vector in the target sector to obtain a reconstructed three-phase PWM waveform, so that a duty cycle of the initial three-phase PWM waveform is consistent with that of the reconstructed three-phase PWM waveform, wherein each observation window time is greater than or equal to a minimum sampling window time, the third non-zero voltage vector is a reverse voltage vector of the second non-zero voltage vector, and the fourth non-zero voltage vector is a reverse voltage vector of the first non-zero voltage vector; collecting a first sampling current corresponding to the second non-zero voltage vector and a second sampling current in the first observation window time and the third observation window time of the reconstructed three-phase PWM waveform respectively, collecting a third sampling current corresponding to the first non-zero voltage vector in the second observation window time of the reconstructed three-phase PWM waveform, and determining a fourth sampling current corresponding to the second observation window of the reconstructed three-phase PWM waveform according to the first sampling current, the second sampling current, and the third sampling current; the determination of the fourth sampling current corresponding to the second observation window of the reconstructed three-phase PWM waveform according to the first sampling current, the second sampling current, and the third sampling current comprises: calculating the fourth sampling current corresponding to the second observation window of the reconstructed three-phase PWM waveform according to the following formula: ； wherein I4 represents the fourth sampling current, I1 represents the first sampling current, I2 represents the second sampling current, and I3 represents the third sampling current.

2. The method of claim 1, wherein, the reconstruction of the initial three-phase PWM waveform by using the first non-zero voltage vector, the second non-zero voltage vector, the third non-zero voltage vector, and the fourth non-zero voltage vector in the target sector comprises: determining the action time of the first non-zero voltage vector, the action time of the second non-zero voltage vector, the action time of the third non-zero voltage vector, the action time of the fourth non-zero voltage vector, the action time of the first zero voltage vector, and the action time of the second zero voltage vector in the control period of the reconstructed PWM waveform according to the action time of the first zero voltage vector or the second zero voltage vector, the action time of the first non-zero voltage vector, the action time of the second non-zero voltage vector, and the observation window time. The second observation window of the reconstructed PWM waveform is set as a second non-zero voltage vector of the target sector, and the first non-zero voltage vector, the first zero voltage vector, the fourth non-zero voltage vector, the third non-zero voltage vector and the second zero voltage vector of the target sector are symmetrically arranged around the second observation window of the reconstructed PWM waveform.

3. The method of claim 2, wherein, The determination of the action time of the first non-zero voltage vector, the action time of the second non-zero voltage vector, the action time of the third non-zero voltage vector, the action time of the fourth non-zero voltage vector, the action time of the first zero voltage vector and the action time of the second zero voltage vector in the control period of the reconstructed PWM waveform according to the action time of the first zero voltage vector or the second zero voltage vector, the action time of the first non-zero voltage vector, the action time of the second non-zero voltage vector and the observation window time of the target sector comprises: The action time of the first non-zero voltage vector, the action time of the second non-zero voltage vector, the action time of the third non-zero voltage vector, the action time of the fourth non-zero voltage vector, the action time of the first zero voltage vector and the action time of the second zero voltage vector in the control period of the reconstructed PWM waveform are calculated according to the following formula: ； ； ； ； wherein T0 represents the time of action of the first or second zero voltage vector within the switching period of the initial three-phase PWM waveform, T1 represents the time of action of the first non-zero voltage vector within the switching period of the initial three-phase PWM waveform, T2 represents the time of action of the second non-zero voltage vector within the switching period of the initial three-phase PWM waveform, T m represents the observation window time, T p1 represents the time of action of the fourth non-zero voltage vector within the control period of the reconstructed PWM waveform, T p2 represents the time of action of the third non-zero voltage vector within the control period of the reconstructed PWM waveform, T p0 represents the time of action of the first zero voltage vector within the control period of the reconstructed PWM waveform, T p3 represents the time of action of the second zero voltage vector within the control period of the reconstructed PWM waveform, T ctrl represents the control period.

4. A current reconstruction apparatus for a single-resistor sampling PWM inverter, characterized by comprising: Comprise: The acquisition module is used to acquire an initial three-phase PWM waveform of a target sector of a PMW output voltage in a control period, the control period comprises at least two switching periods, and the target sector is any sector of a space voltage vector. The determination module is used to determine the action time of the first zero voltage vector or the second zero voltage vector, the action time of the first non-zero voltage vector and the action time of the second non-zero voltage vector of the target sector according to the initial three-phase PWM waveform. The reconstruction module is used to insert three observation window times in a middle period of the initial three-phase PWM waveform, reconstruct the initial three-phase PWM waveform by using the first non-zero voltage vector, the second non-zero voltage vector, the third non-zero voltage vector and the fourth non-zero voltage vector in the target sector, and obtain a reconstructed three-phase PWM waveform, so that the duty cycles of the initial three-phase PWM waveform and the reconstructed three-phase PWM waveform remain consistent, wherein each observation window time is greater than or equal to a minimum sampling window time, the third non-zero voltage vector is a reverse voltage vector of the second non-zero voltage vector, and the fourth non-zero voltage vector is a reverse voltage vector of the first non-zero voltage vector. The processing module is used to collect a first sampling current corresponding to the second non-zero voltage vector and a second sampling current in the first observation window time and the third observation window time of the reconstructed three-phase PWM waveform respectively, collect a third sampling current corresponding to the first non-zero voltage vector in the second observation window time of the reconstructed three-phase PWM waveform, and determine a fourth sampling current corresponding to the second observation window of the reconstructed three-phase PWM waveform according to the first sampling current, the second sampling current and the third sampling current. The processing module is further used to calculate the fourth sampling current corresponding to the second observation window of the reconstructed three-phase PWM waveform according to the following formula: ； I4= I1+ I2+ I3+ I4, wherein, I4 represents the fourth sampling current, I1 represents the first sampling current, I2 represents the second sampling current, and I3 represents the third sampling current.

5. The apparatus of claim 4, wherein, The reconstruction module comprises: The determining sub-module is configured to determine, according to the action time of the first zero voltage vector or the second zero voltage vector of the target sector, the action time of the first non-zero voltage vector, the action time of the second non-zero voltage vector, and the observation window time, the action time of the first non-zero voltage vector, the action time of the second non-zero voltage vector, the action time of the third non-zero voltage vector, the action time of the fourth non-zero voltage vector, the action time of the first zero voltage vector, and the action time of the second zero voltage vector in a control period of the reconstructed PWM waveform. The setting sub-module is configured to set a second observation window of the reconstructed PWM waveform as the second non-zero voltage vector of the target sector, and symmetrically set the first non-zero voltage vector, the first zero voltage vector, the fourth non-zero voltage vector, the third non-zero voltage vector, and the second zero voltage vector of the target sector with the second observation window of the reconstructed PWM waveform as the center.

6. The apparatus of claim 5, wherein, The determining sub-module is further configured to calculate the action time of the first non-zero voltage vector, the action time of the second non-zero voltage vector, the action time of the third non-zero voltage vector, the action time of the fourth non-zero voltage vector, the action time of the first zero voltage vector, and the action time of the second zero voltage vector in a control period of the reconstructed PWM waveform according to the following formula: ； ； ； ； wherein T0 represents the time of action of the first or second zero voltage vector within the switching period of the initial three-phase PWM waveform, T1 represents the time of action of the first non-zero voltage vector within the switching period of the initial three-phase PWM waveform, T2 represents the time of action of the second non-zero voltage vector within the switching period of the initial three-phase PWM waveform, T m represents the observation window time, T p1 represents the time of action of the fourth non-zero voltage vector within the control period of the reconstructed PWM waveform, T p2 represents the time of action of the third non-zero voltage vector within the control period of the reconstructed PWM waveform, T p0 represents the time of action of the first zero voltage vector within the control period of the reconstructed PWM waveform, T p3 represents the time of action of the second zero voltage vector within the control period of the reconstructed PWM waveform, T ctrl represents the control period.

7. An electronic device, comprising: The memory is configured to store a computer program, and the computer program is configured to execute the current reconstruction method of the single-resistance sampling PWM inverter according to any one of claims 1 to 3 when the processor runs.

8. A computer-readable storage medium, characterized in that, The memory is configured to store a computer program, and the computer program is configured to execute the current reconstruction method of the single-resistance sampling PWM inverter according to any one of claims 1 to 3 when the processor runs.

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