Single-resistor sampling method, device, medium, system, motor and electrical equipment

Abstract

The invention discloses a single-resistor sampling method, device and system, a medium, a motor and electrical equipment, and belongs to the field of motor control. The target switching time is different from the initial switching time, but the duty ratio of the whole switch is not changed, so that the synthesized reference voltage vector is not changed, and after the initial switching time is changed into the target switching time, the difference between the first conduction time of the switch of the second phase and the first conduction time of the switch of the first phase is the preset time. The difference between the first conduction time of the switch of the third phase and the first conduction time of the switch of the second phase is preset time, the preset time is greater than or equal to the minimum sampling time, and the preset time length is smaller than the minimum sampling time, so that the sampling point is set in the preset time length of the first conduction of the switch, and the sampling point can be ensured to be in an effective vector interval. At the moment, the switched-on switch is switched on for a period of time, and other switch states are not switched, so that the current is stable during sampling, and the sampling current error is small.

Description

Technical Field

[0001] The present application relates to the field of motor control, and in particular, to a single resistor sampling method, device, medium, system, motor and electrical equipment. Background Art

[0002] Permanent magnet synchronous motors are widely used in daily household appliances and electric vehicles. The current mainstream control method for permanent magnet synchronous motors is field vector control (FOC). This control method requires real-time rotor position and current feedback to implement control, and also needs to solve the rotor position of the motor through the current. Therefore, in motor control systems using sensorless control, such as household air conditioners, current sampling during motor operation is particularly important. High-precision current can greatly enhance the control accuracy of the motor. Current control is the core part of motor vector control. In traditional sampling control methods, multiple current sensors or multiple current sampling resistors are usually connected in series in the bridge arm of the inverter module for sampling. Although the sampling effect is good and the sampling accuracy is high, for products with sensitive component prices, the cost of multiple current sensors is high. In order to reduce costs, the method of single resistor time-sharing sampling phase current reconstruction can be considered, that is, current sampling is performed from the DC bus in combination with the switching state of the inverter module. This solution connects the sampling resistor in series in the bus, combines the switching state of the inverter module, measures the voltage on the resistor, converts it, and then reconstructs the phase current to obtain the complete motor phase current.

[0003] Compared with the traditional multi-current sensor sampling method, single resistor sampling saves costs, but it also has a series of technical difficulties. The most critical point is that single resistor sampling must ensure a minimum sampling time. The current value sampled less than the minimum sampling time may be distorted, resulting in undesirable current information. The traditional five-segment and seven-segment SVPWM modulation methods will have unobservable areas in the low, medium, and high modulation ratio stages. Sampling may occur during the current oscillation stage, resulting in large errors in the sampled current, or sampling during the zero vector stage and the inability to solve the third-phase current through Kirchhoff's current law, making it impossible to achieve motor control. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the present application provides a single-resistance sampling method, device, medium, system, motor and electrical equipment to solve the problem that the existing SVPWM control method has unobservable areas in the low, medium and high modulation ratio stages, resulting in a reconstruction dead zone in the current sampling reconstruction, and sampling may occur in the current oscillation stage, resulting in a large error in the sampled current, or it may cause sampling in the zero vector stage and fail to solve the third-phase current through Kirchhoff's current law, thereby failing to achieve motor control.

[0005] The technical solution adopted by this application to solve its technical problem is:

[0006] In a first aspect, a single resistor sampling method is provided, comprising:

[0007] Respectively obtain the initial switching time of the three-phase switch of the three-phase PWM wave obtained based on the seven-segment SVPMW modulation, the initial switching time is used to control the time of each state switching of the switch of the corresponding phase within one cycle, and the initial switching time includes a first initial switching time of the switch of the first phase, a second initial switching time of the switch of the second phase, and a third initial switching time of the switch of the third phase;

[0008] The target switching time of the three-phase switch of the three-phase PWM wave is determined by the initial switching information based on the minimum sampling time, the first target switching time of the switch of the first phase is the first initial switching time, the second target switching time of the switch of the second phase is the second initial switching time minus the first difference, and the third target switching time of the switch of the third phase is the third phase initial switching time minus the second difference, wherein the first difference=the first conduction time of the switch within the second initial switching time-the first conduction time of the switch within the first initial switching time+the preset time; the second difference=the first conduction time of the switch within the third initial switching time-the first conduction time of the switch within the second target switching time+the preset time, and the preset time is greater than or equal to the minimum sampling time;

[0009] The corresponding switches are controlled respectively according to the target switching time, and sampling is performed after each phase switch is first turned on for a preset time, and the preset time is less than the minimum sampling time.

[0010] Furthermore, it also includes:

[0011] The preset time is the minimum sampling time.

[0012] Furthermore, it also includes:

[0013] When in a high modulation ratio area or a low modulation ratio area, the preset time is the minimum sampling time;

[0014] When in the normal reconstruction area, the preset time is greater than the minimum sampling time.

[0015] Furthermore, it also includes:

[0016] determining a duty cycle of the three-phase switch based on the initial switching time;

[0017] The phase with the largest duty cycle is used as the first phase, the phase with the smallest duty cycle is used as the third phase, and the remaining phase is used as the second phase.

[0018] Furthermore, the preset duration is half of the minimum sampling time.

[0019] In a second aspect, a single resistor sampling device is provided, comprising:

[0020] An initial switching time acquisition module is used to respectively acquire the initial switching time of the three-phase switch of the three-phase PWM wave obtained based on the seven-segment SVPMW modulation, wherein the initial switching time is used to control the time of each state switching of the switch of the corresponding phase within one cycle, and the initial switching time includes a first initial switching time of the switch of the first phase, a second initial switching time of the switch of the second phase, and a third initial switching time of the switch of the third phase;

[0021] A target switching time determination module, used to determine the target switching time of the three-phase switch of the three-phase PWM wave based on the initial switching information based on the minimum sampling time, the first target switching time of the switch of the first phase is the first initial switching time, the second target switching time of the switch of the second phase is the second initial switching time minus the first difference, and the third target switching time of the switch of the third phase is the third phase initial switching time minus the second difference, wherein the first difference = the first conduction time of the switch within the second initial switching time - the first conduction time of the switch within the first initial switching time + the preset time; the second difference = the first conduction time of the switch within the third initial switching time - the first conduction time of the switch within the second target switching time + the preset time, and the preset time is greater than or equal to the minimum sampling time;

[0022] The switch control and sampling module is used to control the corresponding switches according to the target switching time, and perform sampling after each phase switch is first turned on for a preset time, and the preset time is less than the minimum sampling time.

[0023] In a third aspect, a computer-readable storage medium is provided, which stores a computer program. When the computer program is executed by a processor, the single resistor sampling method provided in the above embodiment can be implemented.

[0024] In a fourth aspect, a single resistor sampling system is provided, comprising:

[0025] at least one processor and at least one memory;

[0026] The memory stores executable instructions of the processor;

[0027] The processor is configured to execute the above-mentioned single resistor sampling method.

[0028] In a fifth aspect, a motor is provided, using the above-mentioned single resistor sampling method

[0029] In a sixth aspect, an electrical device is provided, comprising the above-mentioned motor.

[0030] Beneficial effects:

[0031] The technical solution of the present application provides a single-resistance sampling method, device, medium, system, motor and electrical equipment, which respectively obtain the initial switching time of the three-phase switch of the three-phase PWM wave obtained based on the seven-segment SVPMW modulation, and then determine the target switching time of the three-phase switch of the three-phase PWM wave based on the initial switching information based on the minimum sampling time; finally, the corresponding switches are controlled according to the target switching time, and sampling is performed after each phase switch is first turned on for a preset time. In the present application, the target switching time is different from the initial switching time, but the time interval between any two adjacent switching times remains unchanged, that is, the overall duty cycle of the switch remains unchanged, so the synthesized reference voltage vector remains unchanged. After the initial switching time is changed to the target switching time, the first turn-on time of the second phase switch differs from the first turn-on time of the first phase switch by a preset time, and the first turn-on time of the third phase switch differs from the first turn-on time of the second phase switch by a preset time. Since the preset time is greater than or equal to the minimum sampling time, and the preset duration is less than the minimum sampling time, the sampling point is set at the preset duration of the first turn-on of the switch to ensure that the sampling point is in the valid vector interval. At this time, since the turned-on switch has been turned on for an end time and other switch states have not yet switched, the current is stable during sampling and the sampling current error is small. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0033] Figure 1 is a motor control flow chart provided in an embodiment of the present application;

[0034] Figure 2 This is a single resistor sampling principle diagram provided in an embodiment of the present application;

[0035] Figure 3 This is a schematic diagram of a minimum sampling time of a single resistor current provided in an embodiment of the present application;

[0036] Figure 4 This is a single resistor sampling time schematic diagram provided in an embodiment of the present application;

[0037] Figure 5 This is a schematic diagram of a current-only reconstruction area provided in an embodiment of the present application;

[0038] Figure 6This is a schematic diagram of a switch state of an existing non-observation area provided in an embodiment of the present application;

[0039] Figure 7 This is a flow chart of a single resistor sampling method provided in an embodiment of the present application;

[0040] Figure 8 The sample provided in the embodiment of the present application Figure 7 Schematic diagram of the switch state after the method shown;

[0041] Fig. 9 It is a schematic diagram of PWM phase shift and sampling trigger simulation provided by an embodiment of the present application;

[0042] Fig.10 It is a schematic diagram of bus current and bus sampling current provided in an embodiment of the present application;

[0043] Fig.11 It is a schematic diagram comparing the current sampling current of the current sensor and the current reconstructed by single resistor sampling provided in the embodiment of the present application;

[0044] Fig.12 It is a schematic diagram comparing the local details of the current sampled by the current sensor and the local details of the current reconstructed by single resistor sampling provided in the embodiment of the present application;

[0045] Fig.13 It is a schematic diagram of the structure of a single resistor sampling device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme of the present application is described in detail below in conjunction with the accompanying drawings and embodiments. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other implementation methods obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0047] The motor control flow chart using seven-segment SVPWM modulation is as follows Figure 1 As shown in Figure 1, the current sampling resistor is connected in series in the DC bus to sample the phase current of the motor. Figure 2 As shown. In an ideal current sampling situation, current sampling only takes a moment, but the actual situation is that the control system has a dead time T dead , Component conduction time T on , Current sampling analog-to-digital conversion processing time T trans and current stabilization time T stable , so there is a minimum sampling T for current sampling min , the distribution of each period is as follows Figure 3As shown, the minimum sampling time consists of:

[0048] T min =T dead +T on +T stable +T trans (1.1)

[0049] When the sampling time is less than the effective vector action time, sampling may occur during the current oscillation phase, resulting in a large error in the sampled current, or sampling may occur during the zero vector phase and the third-phase current cannot be solved through Kirchhoff's current law, thereby making it impossible to achieve motor control.

[0050] like Figure 4 As shown in the figure, in the traditional seven-segment SVPWM modulation scheme, the switch states are symmetrically distributed and sampled in the effective sampling vector interval. Due to the existence of the minimum current sampling time, the effective vector will be less than 2 in both high and low modulation ratios and sector boundary areas, resulting in a reconstruction dead zone for current sampling reconstruction, such as Figure 5 So no matter which sector the motor is in, as long as sector switching and high or low modulation ratios occur, there will inevitably be areas where reconstruction cannot be observed. Figure 6 It is the switch state of the non-observation area.

[0051] To solve this problem, refer to Figure 7 , the embodiment of the present application provides a single resistor sampling method, comprising:

[0052] S11: respectively obtaining initial switching time of three-phase switches of three-phase PWM waves obtained based on seven-segment SVPMW modulation, wherein the initial switching time is used to control the time of each state switching of the switch of the corresponding phase within one cycle, and the initial switching time includes a first initial switching time of the switch of the first phase, a second initial switching time of the switch of the second phase, and a third initial switching time of the switch of the third phase;

[0053] Among them, the first phase, the second phase and the third phase are determined based on the duty cycle. Specifically, the duty cycle of the three-phase switch is determined based on the initial switching time; the phase with the largest duty cycle is used as the first phase, the phase with the smallest duty cycle is used as the third phase, and the remaining phase is used as the second phase.

[0054] Exemplarily, according to the vector synthesis principle, the reference voltage vector and the basic voltage vector have the following relationship:

[0055]

[0056] Among them, T (xxx) Represents the duration of action of the basic voltage vector xxx, T sis the carrier frequency period, U 0 and U 7 is the zero vector, U 1 -U 6 are the basic voltage vectors respectively. From the synthesis principle, we know that U 1 , U 2 and U 4 The relationship between it and the other five vectors is as follows:

[0057] U 6 =U 2 +U 4

[0058] U 3 =U 1 +U 2

[0059] U 5 =U 1 +U 4

[0060] U 7 =U 1 +U 2 +U 4 (1.3)

[0061] Then the relationship between the reference voltage vector and the basic vector can be rewritten as:

[0062]

[0063] Then there is

[0064]

[0065] Obviously, after equivalent replacement, the reference voltage can be U 1 , U 2 , U 4 The three basic voltage vectors are synthesized; similarly, the reference voltage vector can also be synthesized by U 3 , U 5 , U 6 The three basic voltage vectors are represented. The action time of each basic voltage vector is composed of the time of four switching states, and these four parts represent the total opening time of each phase upper bridge. 1 For example, (T (100) +T (101) +T (110) +T (111) ) represents the total opening time of the bridge on phase A.

[0066] T a =T (001) +T (011) +T (101) +T(111)

[0067] T b =T (010) +T (011) +T (110) +T (111)

[0068] T c =T (100) +T (101) +T (110) +T (111) (1.6)

[0069] The above basic voltage vector time T a 、T b 、T c Substituting into the reference voltage vector synthesis formula (1.5), we can get

[0070]

[0071] Because U 1 , U 2 , U 4 The amplitude and phase of the resultant vector are independent of the modulation mode, so the size of the resultant vector is only related to the on-time. Therefore, it is only necessary to ensure that the on-time of the three-phase bridge arm is consistent with the duty cycle of the original SVPWM modulation to ensure that the generated reference voltage vector remains unchanged. To achieve real-time modulation of the SVPWM signal, it is necessary to know the reference voltage vector U ref The sector where the reference voltage vector is located is then synthesized using the adjacent basic voltage vector and zero vector of the sector. Here we still take sector 1 as an example to calculate the basic voltage vector and zero vector action time required to synthesize any reference voltage vector in the sector:

[0072]

[0073] T 0 =T s -T 4 -T 6 (1.8)

[0074] Where U dc is the DC bus voltage, u α 、u β They are the reference voltage vector U ref The components on the α and β axes, T 4 、T 6 Corresponding to U 4 and U 6 Duration of action, T 0 The zero vector U 0 (U 7 ) duration of action.

[0075] Therefore, it is easy to know that the vector switching time of sector 1 is as follows:

[0076] T x =(T s -T 4 -T 6 ) / 4=T 0 / 4

[0077] T y =T x +T 4 / 6=T 0 / 4+T 4 / 6

[0078] T z =T y +T 6 / 2=T 0 / 4+T 4 / 6+T 6 / 2(1.9)

[0079] In the above formula, Tx, Ty, and Tz are the emission moments of the three PWM waves after phase shifting, i.e. the first conduction time in the initial switching time.

[0080] S12: Determine the target switching time of the three-phase switch of the three-phase PWM wave based on the initial switching information based on the minimum sampling time, the first target switching time of the switch of the first phase is the first initial switching time, the second target switching time of the switch of the second phase is the second initial switching time minus the first difference, and the third target switching time of the switch of the third phase is the third phase initial switching time minus the second difference, wherein the first difference = the first conduction time of the switch within the second initial switching time - the first conduction time of the switch within the first initial switching time + the preset time; the second difference = the first conduction time of the switch within the third initial switching time - the first conduction time of the switch within the second target switching time + the preset time, and the preset time is greater than or equal to the minimum sampling time.

[0081] In one embodiment, the preset time is the minimum sampling time. Figure 8 As shown in the figure, the switch on time node of the PWM wave with the largest duty cycle remains unchanged, and the sampling point is set in the first half cycle. The switch on time of the other two phases is adjusted according to the sampling needs. The on time of the other two phases in the first half cycle after adjustment is:

[0082] T x =T 0 / 4

[0083] T y =T x +T min =T 0 / 4+T min

[0084] T z =T y +T min =T 0 / 4+2T min (1.10)

[0085] Phase shifting method Figure 8 As shown, accordingly, the second half cycle should also be shifted right by the corresponding time. Before the modification, the timing of the seven-segment SVPWM modulation is:

[0086] t=[T 0 / 4 T 4 / 2 T 6 / 2 T 0 / 2 T 6 / 2 T 4 / 2 T 0 / 4] (1.11)

[0087] The modified modulation signal changes from seven segments to three segments, and the new switching timing of each phase is as follows:

[0088] t 1 =[T 0 / 4T s -T 0 / 2T 0 / 4]

[0089] t 2 =[T 0 / 4+T min T 6 +T 0 / 2T s -3T 0 / 4-T min ]

[0090] t 3 =[T 0 / 4+2T min T 0 / 2T s -3T 0 / 4-2T min ](1.12)

[0091] The timing is no longer strictly symmetrical, but the advantage of this method is that it does not require the effective vector T 4 / 2, T 6 / 2 Action time length and T min In comparison, the SVPWM modulation signal is directly modified by phase shifting to ensure that sufficient current sampling time is given without requiring additional computing time and computing resources.

[0092] In the above embodiment, the preset time is the minimum sampling time, which ensures that accurate sampling can be performed once in any case. However, if multiple sampling is required, the preset time can be greater than the minimum sampling time. However, this situation must be in the normal reconstruction area. If the preset time is greater than the minimum sampling time in the high modulation ratio and low modulation ratio areas, the final collected current is also inaccurate.

[0093] Therefore, in another embodiment, when in a high modulation ratio area or a low modulation ratio area, the preset time is the minimum sampling time; when in a normal reconstruction area, the preset time is greater than the minimum sampling time.

[0094] Among them, the high modulation ratio area, the low modulation ratio area and the normal reconstruction area are referenced Figure 5 's annotation.

[0095] S13: Control the corresponding switches according to the target switching time, and perform sampling after each phase switch is first turned on for a preset time, wherein the preset time is less than the minimum sampling time, that is, the sampling point mentioned in the above embodiment is in the first half cycle.

[0096] As a preferred implementation method of the embodiment of the present application, the preset duration is half of the minimum sampling time. It should be noted that when the sampling point is when each phase switch is turned on for the first time for the preset duration, the phase switch has been turned on for a period of time, and other phase switches do not need to be switched, so the current is in a stable period at this time, and because the phase switch is turned on for the first time, it is in an effective vector stage, not a zero vector, and the sampled current can be accurately measured at this time.

[0097] Fig. 9 This is a simulation diagram of phase-shift sampling. The minimum sampling effective vector time is set to 6μs. The sampling trigger fully considers the dead time + current oscillation time of 3μs in total. The sampling trigger moment is in the middle part of the effective sampling vector to ensure that stable current information can be sampled. Fig.10 To compare the sampled current obtained by bus sampling with the bus current, Fig.10 The upper part is the bus current, and the lower part is the bus sampling current. The sampled current is then reconstructed. Fig.11 It is the comparison between the three-phase current sampled by the current sensor and the current reconstructed by single resistor sampling, where Fig.11 The upper part is the three-phase current sampled by the current sensor, and the lower part is the current reconstructed by single resistor sampling. The two-phase current is obtained by sampling and the third-phase current is solved by Kirchhoff's current law:

[0098] i a +i b +i c =0(1.13)

[0099] Fig.12 It can be clearly seen that compared with the sampling and reconstruction current ( Fig.12 The upper part is the local details of the current sampled by the current sensor, and the lower part is the local details of the current sampled and reconstructed by a single resistor). There is high-frequency ripple in the current sampled by the current sensor. This ripple will exist regardless of whether it is symmetrical PWM modulation or asymmetrical PWM modulation, but the error range of the ripple is still within the controllable range. The method proposed in the embodiment of the present application combined with the current reconstruction method greatly reduces the ripple, which shows that this method is extremely superior.

[0100] The single-resistance sampling method provided in the embodiment of the present application obtains the initial switching time of the three-phase switch of the three-phase PWM wave obtained based on the seven-segment SVPMW modulation, and then determines the target switching time of the three-phase switch of the three-phase PWM wave based on the initial switching information based on the minimum sampling time; finally, the corresponding switches are controlled according to the target switching time, and sampling is performed after each phase switch is first turned on for a preset time. In the present application, the target switching time is different from the initial switching time, but the switching time interval between any two adjacent switching times remains unchanged, that is, the overall duty cycle of the switch remains unchanged, so the synthesized reference voltage vector remains unchanged. After the initial switching time is changed to the target switching time, the first turn-on time of the second phase switch differs from the first turn-on time of the first phase switch by a preset time, and the first turn-on time of the third phase switch differs from the first turn-on time of the second phase switch by a preset time. Since the preset time is greater than or equal to the minimum sampling time, and the preset duration is less than the minimum sampling time, the sampling point is set at the preset duration of the first turn-on of the switch, so that the sampling point can be ensured to be in the valid vector interval. At this time, since the turned-on switch has been turned on for one end of the time, and the other switch states have not been switched, the current is stable during sampling and the sampling current error is small. It is ensured that single-resistance sampling can have sufficient sampling time regardless of the low, medium or high modulation ratio, and the code amount is small, the calculation is simple, the sampling current is accurate, and the reconstructed current has a small high-frequency ripple compared with the multi-sensor sampling current.

[0101] Based on the same inventive concept, Fig.13 As shown, the present application also provides a single resistor sampling device 130, comprising:

[0102] An initial switching time acquisition module 131 is used to respectively acquire the initial switching time of the three-phase switch of the three-phase PWM wave obtained based on the seven-segment SVPMW modulation, wherein the initial switching time is used to control the time of each state switching of the switch of the corresponding phase within one cycle, and the initial switching time includes a first initial switching time of the switch of the first phase, a second initial switching time of the switch of the second phase, and a third initial switching time of the switch of the third phase;

[0103] Wherein, the duty cycle of the three-phase switch is determined based on the initial switching time; the phase with the largest duty cycle is used as the first phase, the phase with the smallest duty cycle is used as the third phase, and the remaining phase is used as the second phase.

[0104] The target switching time determination module 132 is used to determine the target switching time of the three-phase switch of the three-phase PWM wave based on the initial switching information based on the minimum sampling time, the first target switching time of the switch of the first phase is the first initial switching time, the second target switching time of the switch of the second phase is the second initial switching time minus the first difference, and the third target switching time of the switch of the third phase is the third phase initial switching time minus the second difference, wherein the first difference = the first conduction time of the switch within the second initial switching time - the first conduction time of the switch within the first initial switching time + the preset time; the second difference = the first conduction time of the switch within the third initial switching time - the first conduction time of the switch within the second target switching time + the preset time, and the preset time is greater than or equal to the minimum sampling time;

[0105] In one embodiment, the preset time is the minimum sampling time.

[0106] In another embodiment, when in a high modulation ratio region or a low modulation ratio region, the preset time is the minimum sampling time;

[0107] When in the normal reconstruction area, the preset time is greater than the minimum sampling time.

[0108] The switch control and sampling module 133 is used to control the corresponding switches according to the target switching time, and perform sampling after each phase switch is first turned on for a preset time, and the preset time is less than the minimum sampling time.

[0109] As a preferred implementation method of the embodiment of the present application, the preset duration is half of the minimum sampling time.

[0110] The single-resistance sampling device provided in the embodiment of the present application obtains the initial switching time of the three-phase switch of the three-phase PWM wave obtained based on the seven-segment SVPMW modulation, and then determines the target switching time of the three-phase switch of the three-phase PWM wave based on the initial switching information based on the minimum sampling time; finally, the corresponding switches are controlled according to the target switching time, and sampling is performed after each phase switch is first turned on for a preset period of time. In the present application, the target switching time is different from the initial switching time, but the time interval between any two adjacent switching times remains unchanged, that is, the overall duty cycle of the switch remains unchanged, so the synthesized reference voltage vector remains unchanged. After the initial switching time is changed to the target switching time, the first turn-on time of the second phase switch differs from the first turn-on time of the first phase switch by a preset time, and the first turn-on time of the third phase switch differs from the first turn-on time of the second phase switch by a preset time. Since the preset time is greater than or equal to the minimum sampling time, and the preset duration is less than the minimum sampling time, the sampling point is set at the preset duration of the first turn-on of the switch to ensure that the sampling point is in the valid vector interval. At this time, since the turned-on switch has been turned on for an end time and other switch states have not yet switched, the current is stable during sampling and the sampling current error is small.

[0111] Based on the same inventive concept, the present application also provides a computer-readable storage medium storing a computer program, which can implement the single resistor sampling method provided in the above embodiment when executed by a processor.

[0112] The computer-readable storage medium provided in the embodiment of the present application can respectively obtain the initial switching time of the three-phase switch of the three-phase PWM wave obtained based on the seven-segment SVPMW modulation, and then determine the target switching time of the three-phase switch of the three-phase PWM wave based on the initial switching information based on the minimum sampling time; finally, the corresponding switches are controlled respectively according to the target switching time, and sampling is performed after each phase switch is first turned on for a preset time. In the present application, the target switching time is different from the initial switching time, but the time interval between any two adjacent switching times remains unchanged, that is, the overall duty cycle of the switch remains unchanged, so the synthesized reference voltage vector remains unchanged. After the initial switching time is changed to the target switching time, the first turn-on time of the second phase switch differs from the first turn-on time of the first phase switch by a preset time, and the first turn-on time of the third phase switch differs from the first turn-on time of the second phase switch by a preset time. Since the preset time is greater than or equal to the minimum sampling time, and the preset duration is less than the minimum sampling time, the sampling point is set at the preset duration of the first turn-on of the switch to ensure that the sampling point is in the valid vector interval. At this time, since the turned-on switch has been turned on for an end time and other switch states have not yet switched, the current is stable during sampling and the sampling current error is small.

[0113] Based on the same inventive concept, the present application also provides a single resistor sampling system, comprising:

[0114] at least one processor and at least one memory;

[0115] The memory stores executable instructions of the processor;

[0116] The processor is configured to execute the single resistor sampling method provided in the above embodiment.

[0117] The single-resistance sampling system provided in the embodiment of the present application stores executable instructions of the processor in a memory. When the executable instructions are executed, the processor can respectively obtain the initial switching time of the three-phase switch of the three-phase PWM wave obtained based on the seven-segment SVPMW modulation, and then determine the target switching time of the three-phase switch of the three-phase PWM wave based on the initial switching information based on the minimum sampling time; finally, the corresponding switches are controlled respectively according to the target switching time, and sampling is performed after each phase switch is first turned on for a preset period of time. In the present application, the target switching time is different from the initial switching time, but the time interval between any two adjacent switching times remains unchanged, that is, the overall duty cycle of the switch remains unchanged, so the synthesized reference voltage vector remains unchanged. After the initial switching time is changed to the target switching time, the first turn-on time of the second phase switch differs from the first turn-on time of the first phase switch by a preset time, and the first turn-on time of the third phase switch differs from the first turn-on time of the second phase switch by a preset time. Since the preset time is greater than or equal to the minimum sampling time, and the preset duration is less than the minimum sampling time, the sampling point is set at the preset duration of the first turn-on of the switch to ensure that the sampling point is in the valid vector interval. At this time, since the turned-on switch has been turned on for an end time and other switch states have not yet switched, the current is stable during sampling and the sampling current error is small.

[0118] Based on the same inventive concept, the present application also provides a motor, applying the single resistor sampling method provided in the above embodiment.

[0119] The motor provided in the embodiment of the present application can obtain the initial switching time of the three-phase switch of the three-phase PWM wave obtained based on the seven-segment SVPMW modulation by applying the single-resistance sampling method provided in the above embodiment, and then determine the target switching time of the three-phase switch of the three-phase PWM wave based on the initial switching information based on the minimum sampling time; finally, the corresponding switches are controlled respectively according to the target switching time, and sampling is performed after each phase switch is first turned on for a preset period of time. In the present application, the target switching time is different from the initial switching time, but the time interval between any two adjacent switching times remains unchanged, that is, the overall duty cycle of the switch remains unchanged, so the synthesized reference voltage vector remains unchanged. After the initial switching time is changed to the target switching time, the first turn-on time of the second phase switch differs from the first turn-on time of the first phase switch by a preset time, and the first turn-on time of the third phase switch differs from the first turn-on time of the second phase switch by a preset time. Since the preset time is greater than or equal to the minimum sampling time, and the preset duration is less than the minimum sampling time, the sampling point is set at the preset duration of the first turn-on of the switch to ensure that the sampling point is in the valid vector interval. At this time, since the turned-on switch has been turned on for an end of time and other switch states have not yet switched, the current is stable during sampling and the sampling current error is small.

[0120] Based on the same inventive concept, the present application also provides an electrical device, including the motor provided in the above embodiment.

[0121] It should be noted that, in the description of this application, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of this application, unless otherwise specified, the meaning of "plurality" refers to at least two.

[0122] It can be understood that the same or similar parts of the above embodiments can be referenced to each other, and the contents not described in detail in some embodiments can refer to the same or similar contents in other embodiments.

Claims

1. A single resistor sampling method, characterized in that: include: Respectively obtain the initial switching time of the three-phase switch of the three-phase PWM wave obtained based on the seven-segment SVPMW modulation, the initial switching time is used to control the time of each state switching of the switch of the corresponding phase within one cycle, and the initial switching time includes a first initial switching time of the switch of the first phase, a second initial switching time of the switch of the second phase, and a third initial switching time of the switch of the third phase; The target switching time of the three-phase switch of the three-phase PWM wave is determined by the initial switching information based on the minimum sampling time, the first target switching time of the switch of the first phase is the first initial switching time, the second target switching time of the switch of the second phase is the second initial switching time minus the first difference, and the third target switching time of the switch of the third phase is the third phase initial switching time minus the second difference, wherein the first difference=the first conduction time of the switch within the second initial switching time-the first conduction time of the switch within the first initial switching time+the preset time; the second difference=the first conduction time of the switch within the third initial switching time-the first conduction time of the switch within the second target switching time+the preset time, and the preset time is greater than or equal to the minimum sampling time; The corresponding switches are controlled respectively according to the target switching time, and sampling is performed after each phase switch is first turned on for a preset time, and the preset time is less than the minimum sampling time.

2. The method according to claim 1, characterized in that , also includes: The preset time is the minimum sampling time.

3. The method according to claim 1, characterized in that Also includes: When in a high modulation ratio area or a low modulation ratio area, the preset time is the minimum sampling time; When in the normal reconstruction area, the preset time is greater than the minimum sampling time.

4. The method according to claim 1, characterized in that Also includes: determining a duty cycle of the three-phase switch based on the initial switching time; The phase with the largest duty cycle is used as the first phase, the phase with the smallest duty cycle is used as the third phase, and the remaining phase is used as the second phase.

5. The method according to claim 1, characterized in that: The preset duration is half of the minimum sampling time.

6. A single resistor sampling device, characterized in that: include: An initial switching time acquisition module is used to respectively acquire the initial switching time of the three-phase switch of the three-phase PWM wave obtained based on the seven-segment SVPMW modulation, wherein the initial switching time is used to control the time of each state switching of the switch of the corresponding phase within one cycle, and the initial switching time includes a first initial switching time of the switch of the first phase, a second initial switching time of the switch of the second phase, and a third initial switching time of the switch of the third phase; A target switching time determination module, used to determine the target switching time of the three-phase switch of the three-phase PWM wave from the initial switching information based on the minimum sampling time, the first target switching time of the switch of the first phase is the first initial switching time, the second target switching time of the switch of the second phase is the second initial switching time minus the first difference, and the third target switching time of the switch of the third phase is the third phase initial switching time minus the second difference, wherein the first difference = the first conduction time of the switch within the second initial switching time - the first conduction time of the switch within the first initial switching time + the preset time; the second difference = the first conduction time of the switch within the third initial switching time - the first conduction time of the switch within the second target switching time + the preset time, and the preset time is greater than or equal to the minimum sampling time; The switch control and sampling module is used to control the corresponding switches according to the target switching time, and perform sampling after each phase switch is first turned on for a preset time, and the preset time is less than the minimum sampling time.

7. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed by a processor, the method described in any one of claims 1 to 5 can be implemented.

8. A single resistor sampling system, characterized in that: include: at least one processor and at least one memory; The memory stores executable instructions of the processor; The processor is configured to execute the method according to any one of claims 1 to 5.

9. A motor, characterized in that: The method according to any one of claims 1 to 5 is used.

10. An electrical device, characterized in that: A motor comprising the motor described in claim 9.

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