A method, apparatus, and electrical equipment for detecting motor bus voltage.

Abstract

This invention discloses a method, device, and electrical equipment for detecting motor bus voltage. The method includes: determining the required first and second phases based on the sector where the inverter voltage vector is located; calculating the two current sampling times of the first and second phases within one PWM cycle and obtaining the sampling current; and determining the bus voltage based on the sampling current, sampling interval, motor winding inductance, and motor winding resistance. Based on the FOC single-resistor phase current sampling scheme, this invention utilizes the existing phase current sampling circuit and its AD port to calculate the bus voltage based on the inverter switching state and motor parameters. It eliminates the need for an additional bus voltage sampling circuit, thus avoiding additional hardware costs and the need to occupy an additional chip AD port, solving the problem of increased hardware costs and the requirement of occupying an AD port in existing technologies for bus voltage sampling.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and more specifically, to a method, apparatus, and electrical equipment for detecting motor bus voltage. Background Technology

[0002] The application of SVPWM (Space Vector Pulse Width Modulation) strategy in permanent magnet synchronous motor control is becoming increasingly widespread. It uses a three-phase inverter drive, and FOC (Field Oriented Control, also known as vector control) combined with SVPWM is a commonly used solution. This requires bus voltage detection to determine the actual turn-on and turn-off times of the switching transistors. Bus voltage detection typically involves connecting a large resistor in series between the buses and using a single chip's AD sampling port. This bus voltage detection scheme increases hardware costs and occupies an AD sampling port, thus consuming chip resources.

[0003] There is currently no effective solution to the problem that bus voltage sampling increases hardware costs and requires the use of a chip's AD port in existing technologies. Summary of the Invention

[0004] This invention provides a method, apparatus, and electrical equipment for detecting motor bus voltage, which at least solves the problem in the prior art that bus voltage sampling increases hardware costs and requires the use of a chip AD port.

[0005] To address the aforementioned technical problems, embodiments of the present invention provide a method for detecting motor bus voltage, comprising:

[0006] Determine the first and second phases to be used based on the sector where the inverter voltage vector is located;

[0007] Calculate the two current sampling times of the first phase and the two current sampling times of the second phase within one PWM cycle, and obtain the sampled current;

[0008] The bus voltage is determined based on the sampling current, sampling interval, motor winding inductance, and motor winding resistance.

[0009] Optionally, based on the sector where the inverter voltage vector is located, determine the first and second phases to be used, including:

[0010] Sort the turn-on times of the three-phase switch tubes corresponding to the sectors according to the length of time;

[0011] The phase with the longest activation time is selected as the first phase, the phase with the middle activation time is selected as the second phase, and the phase with the shortest activation time is selected as the third phase.

[0012] Optionally, the calculation of the two current sampling times of the first phase and the two current sampling times of the second phase within one PWM cycle includes:

[0013] The first current sampling time of the first phase is calculated based on the turn-on time of the first phase switch and the turn-on time of the second phase switch.

[0014] Calculate the difference between the PWM period and the first current sampling time of the first phase to obtain the second current sampling time of the first phase;

[0015] The first current sampling time of the second phase is calculated based on the turn-on time of the switch of the second phase and the turn-on time of the switch of the third phase.

[0016] The difference between the PWM period and the first current sampling time of the second phase is calculated to obtain the second current sampling time of the second phase.

[0017] Optionally, the first current sampling time of the first phase can be calculated using the following formula:

[0018]

[0019] Among them, T 11 T represents the first current sampling time of the first phase, T represents the PWM period, T1 represents the turn-on time of the first phase's switch, and T2 represents the turn-on time of the second phase's switch.

[0020] Optionally, the first current sampling time of the second phase can be calculated using the following formula:

[0021]

[0022] Among them, T 21 T represents the first current sampling time of the second phase, T represents the PWM period, T2 represents the turn-on time of the switch in the second phase, and T3 represents the turn-on time of the switch in the third phase.

[0023] Optionally, the bus voltage is determined based on the sampling current, sampling interval time, motor winding inductance, and motor winding resistance, including:

[0024] The inductor voltage divider is calculated based on the sampling current, the sampling interval time, and the motor winding inductance.

[0025] Calculate the product of the second sampling current of the second phase and the resistance of the motor winding to obtain the resistive voltage divider;

[0026] The bus voltage is obtained by calculating the sum of the inductor voltage divider and the resistor voltage divider.

[0027] Optionally, the inductor voltage divider is calculated based on the sampling current, the sampling interval time, and the motor winding inductance, including:

[0028] The difference between the second sampling current of the first phase and the first sampling current of the first phase is calculated to obtain the current difference of the first phase. The derivative of the current difference of the first phase with respect to the sampling interval time of the first phase is obtained. Then, the product of the derivative and the inductance of the motor winding is calculated to obtain the inductance voltage of the first phase.

[0029] The difference between the second sampling current of the second phase and the first sampling current of the second phase is calculated to obtain the current difference of the second phase. The derivative of the current difference of the second phase with respect to the sampling interval time of the second phase is obtained. Then, the product of the derivative and the inductance of the motor winding is calculated to obtain the inductance voltage of the second phase.

[0030] This invention also provides a motor bus voltage detection device, comprising:

[0031] The first determining module is used to determine the first and second phases to be used based on the sector where the inverter voltage vector is located;

[0032] The calculation module is used to calculate the two current sampling times of the first phase and the two current sampling times of the second phase within one PWM cycle, and to obtain the sampled current;

[0033] The second determining module is used to determine the bus voltage based on the sampling current, sampling interval time, motor winding inductance, and motor winding resistance.

[0034] This invention also provides an electrical device, including: a motor and the motor bus voltage detection device described in this invention.

[0035] This invention also provides a computer device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method described in this invention.

[0036] This invention also provides a non-volatile computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the method described in this invention.

[0037] By applying the technical solution of this invention, the required first and second phases are determined based on the sector where the inverter voltage vector is located. The two current sampling times of the first and second phases within one PWM cycle are calculated, and the sampling current is obtained. Then, the bus voltage is determined based on the sampling current, sampling interval, motor winding inductance, and motor winding resistance. Based on the FOC single-resistor phase current sampling scheme, the existing phase current sampling circuit and its corresponding AD port are used to calculate the bus voltage based on the inverter switching state and motor parameters. This achieves bus voltage sampling without the need for an additional bus voltage sampling circuit, thus avoiding additional hardware costs and the occupation of an additional chip AD port, saving the chip an AD port and avoiding additional chip I / O resources. This solves the problem in existing technologies where bus voltage sampling increases hardware costs and requires the occupation of an additional chip AD port. Attached Figure Description

[0038] Figure 1 This is a flowchart of the motor bus voltage detection method provided in Embodiment 1 of the present invention;

[0039] Figure 2 This is a three-phase inverter circuit diagram provided in Embodiment 2 of the present invention;

[0040] Figure 3 This is a schematic diagram of a vector sector provided in Embodiment 2 of the present invention;

[0041] Figure 4 This is a schematic diagram of the 110 vector inverter switch provided in Embodiment 2 of the present invention;

[0042] Figure 5 This is a schematic diagram of a 100-vector inverter switch provided in Embodiment 2 of the present invention;

[0043] Figure 6 This is a schematic diagram of the 010 vector inverter switch provided in Embodiment 2 of the present invention;

[0044] Figure 7 This is a schematic diagram of the 011 vector inverter switch provided in Embodiment 2 of the present invention;

[0045] Figure 8 This is a schematic diagram of the 001 vector inverter switch provided in Embodiment 2 of the present invention;

[0046] Figure 9 This is a schematic diagram of the 101 vector inverter switch provided in Embodiment 2 of the present invention;

[0047] Figure 10A and 10B This is a schematic diagram of the switching sequence and waveforms of the inverter switches in each sector provided in Embodiment 2 of the present invention;

[0048] Figure 11This is a structural block diagram of the motor bus voltage detection device provided in Embodiment 3 of the present invention. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0050] It should be noted that the terms "first," "second," etc., used in the specification, claims, and drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0051] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0052] The optional embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0053] Example 1

[0054] This embodiment provides a method for detecting motor bus voltage. Figure 1 This is a flowchart of the motor bus voltage detection method provided in Embodiment 1 of the present invention, as follows: Figure 1 As shown, the method includes the following steps:

[0055] S101, determine the first and second phases to be used based on the sector where the inverter voltage vector is located.

[0056] S102, calculate the two current sampling times of the first phase and the two current sampling times of the second phase within one PWM cycle, and obtain the sampled current.

[0057] S103 determines the bus voltage based on the sampling current, sampling interval time, motor winding inductance, and motor winding resistance.

[0058] The inverter's operating cycle is divided into six sectors. The inverter's switching state (or switching action) can be determined based on the sector where the inverter voltage vector is located. Based on the inverter's switching state, the first and second phases in the current sector can be determined from the UVW three-phase configuration. The first and second phases may differ in different sectors. The sampled current is obtained by sampling the current at the current sampling time point through a phase current sampling circuit. Accordingly, two sampled currents for the first phase and two sampled currents for the second phase are acquired. Permanent magnet synchronous motor vector control (FOC) uses a phase current sampling circuit to collect the three-phase motor current through sampling resistors. Motor winding inductance and motor winding resistance are both motor parameters.

[0059] This embodiment determines the required first and second phases based on the sector where the inverter voltage vector is located. It calculates the two current sampling times for the first and second phases within one PWM cycle and obtains the sampled current. Then, it determines the bus voltage based on the sampled current, sampling interval, motor winding inductance, and motor winding resistance. Building upon the FOC single-resistor phase current sampling scheme, it utilizes the existing phase current sampling circuit and its corresponding AD port to calculate the bus voltage based on the inverter switching state and motor parameters. This achieves bus voltage sampling without requiring an additional bus voltage sampling circuit, thus avoiding additional hardware costs and saving an AD port on the chip. It also avoids additional chip I / O resources, solving the problem in existing technologies where bus voltage sampling increases hardware costs and requires an AD port.

[0060] In one implementation, determining the required first and second phases based on the sector where the inverter voltage vector is located includes: sorting the turn-on times of the three-phase switches corresponding to the sector according to their duration; selecting the phase with the longest turn-on time as the first phase, the phase with the middle turn-on time as the second phase, and the phase with the shortest turn-on time as the third phase. This implementation allows for the determination of the inverter's switching state based on the sector where the inverter voltage vector is located, thus providing the basis for subsequent calculations of the bus voltage.

[0061] In one implementation, calculating the two current sampling times of the first phase and the two current sampling times of the second phase within one PWM cycle includes: calculating the first current sampling time of the first phase based on the turn-on times of the first and second phase switches; calculating the difference between the PWM cycle and the first current sampling time of the first phase to obtain the second current sampling time of the first phase; calculating the first current sampling time of the second phase based on the turn-on times of the second and third phase switches; and calculating the difference between the PWM cycle and the first current sampling time of the second phase to obtain the second current sampling time of the second phase. This implementation can calculate the phase current sampling time based on the inverter switching status and obtain the sampled current at the corresponding sampling time points using an existing phase current sampling circuit.

[0062] Specifically, the first current sampling time of the first phase can be calculated using the following formula:

[0063]

[0064] Among them, T 11 T represents the first current sampling time of the first phase, T represents the PWM period, T1 represents the turn-on time of the first phase's switch, and T2 represents the turn-on time of the second phase's switch.

[0065] Specifically, the first current sampling time of the second phase can be calculated using the following formula:

[0066]

[0067] Among them, T 21 T represents the first current sampling time of the second phase, T represents the PWM period, T2 represents the turn-on time of the switch in the second phase, and T3 represents the turn-on time of the switch in the third phase.

[0068] In this embodiment, the motor is approximated as an inductive and resistive load, and the voltage divisions of the inductance and resistance are calculated separately to obtain the bus voltage, thus achieving bus voltage sampling. Specifically, the bus voltage is determined based on the sampling current, sampling interval time, motor winding inductance, and motor winding resistance, including: calculating the inductive voltage division based on the sampling current, sampling interval time, and motor winding inductance; calculating the product of the second sampling current of the second phase and the motor winding resistance to obtain the resistive voltage division; and calculating the sum of the inductive and resistive voltage divisions to obtain the bus voltage.

[0069] Inductive voltage division includes: the inductive voltage division of the first phase and the inductive voltage division of the second phase. Specifically, the inductive voltage division is calculated based on the sampling current, sampling interval time, and motor winding inductance, including:

[0070] The difference between the second sampling current of the first phase and the first sampling current of the first phase is calculated to obtain the current difference of the first phase. The derivative of the current difference of the first phase with respect to the sampling interval time of the first phase is obtained. Then, the product of the derivative and the inductance of the motor winding is calculated to obtain the inductance voltage of the first phase.

[0071] The difference between the second sampling current of the second phase and the first sampling current of the second phase is calculated to obtain the current difference of the second phase. The derivative of the current difference of the second phase with respect to the sampling interval time of the second phase is obtained. Then, the product of this derivative and the inductance of the motor winding is calculated to obtain the inductive voltage division of the second phase.

[0072] By following the steps above, the inductor voltage division can be calculated relatively accurately and reliably. By adding the inductor voltage division of the first phase, the inductor voltage division of the second phase, and the resistor voltage division, the bus voltage can be obtained.

[0073] Example 2

[0074] The above-described motor bus voltage detection method will be described below with reference to a specific embodiment. However, it is worth noting that this specific embodiment is only for better illustration of this application and does not constitute an improper limitation of this application. The same or corresponding terminology as in the above embodiment will not be repeated in this embodiment.

[0075] like Figure 2 The diagram shows a three-phase inverter circuit, including: bus 10, inverter 20, and motor 30. Capacitor C stores energy to maintain stable bus voltage, and Udc represents the bus voltage. Inverter 20 includes three pairs of upper and lower bridge switches Q1 to Q6, which convert the DC power from the bus to AC power to supply the motor windings. Sampling resistor R1 is used to detect the motor current and bus voltage. Motor 30 is driven by variable AC power provided by inverter 20.

[0076] like Figure 3 The diagram shows a vector sector diagram. One operating cycle of the inverter is divided into six sectors. The composite vector Uout of the inverter output voltage (referred to as the voltage vector) rotates within this hexagon. The inverter switching action is determined by identifying which sector the voltage vector is in. The inverter switching state is used to determine the phase line to which the current flowing through the sampling resistor belongs.

[0077] Taking the voltage vector falling in sector 1 as an example, it is composed of its adjacent switching actions 100(4), 110(6) and zero vectors 000(0), 111(7). Figure 4 and Figure 5 The circuit operation states of the inverter in sector 1 are shown in two switching states, 110 and 100, respectively. Figure 4 As shown, when the inverter switch state is 110, the current flows from phases U and V to phase W. Therefore, the current flowing through the sampling resistor R at this time is the phase W current. Figure 5 As shown, when the inverter switch state is 100, the current flows from phase U to phase V and phase W, so the current flowing through the sampling resistor R at this time is the phase U current.

[0078] like Figure 6 As shown, when the inverter switch state is 010, current flows from phase V to phases U and W, so the current flowing through the sampling resistor R at this time is the phase V current. Figure 7 As shown, when the inverter switch state is 011, the current flows from phase V and phase W to phase U, so the current flowing through the sampling resistor R at this time is the phase U current. Figure 8 As shown, when the inverter switch state is 001, current flows from phase W to phases U and V. Therefore, the current flowing through the sampling resistor R at this time is the phase W current. Figure 9 As shown, when the inverter is in state 101, the current is collected from phases U and W to phase V. Therefore, the current flowing through the sampling resistor R at this time is the phase V current.

[0079] like Figure 10A and Figure 10B The diagram shows the switching sequence of each sector and the waveforms driving the inverter. θ represents the electrical angle of the motor rotor. In the three-phase waveform diagram, from top to bottom, the waveforms are U-phase, V-phase, and W-phase. Taking sector 1 as an example, within one PWM cycle, samples are taken twice at 110° and 100° respectively. The phase inductance voltage is calculated by combining the time interval between the two samples, thus obtaining the bus voltage.

[0080] The relationship between the turn-on times of the three-phase switching transistors in each sector and the first, second, and third phases in each sector are shown in Table 1 below.

[0081] Table 1. Correspondence between sector and three-phase switch turn-on time

[0082]

[0083] In the table above, Tu represents the turn-on time of the U-phase switch, Tv represents the turn-on time of the V-phase switch, Tw represents the turn-on time of the W-phase switch, and T1, T2, and T3 are generalized representations, with T1 > T2 > T3. T1 represents the turn-on time of the first phase switch, T2 represents the turn-on time of the second phase switch, and T3 represents the turn-on time of the third phase switch.

[0084] The current sampling time is calculated as follows:

[0085]

[0086]

[0087] Among them, T 11T represents the time of the first current sampling of the first phase. 12 T represents the second current sampling time of the first phase, T represents the PWM period, T1 represents the turn-on time of the switch in the first phase, and T2 represents the turn-on time of the switch in the second phase. 21 T represents the first current sampling time of the second phase. 22 T3 represents the second current sampling time of the second phase, and T3 represents the turn-on time of the switch in the third phase.

[0088] The calculations for inductive voltage division, resistive voltage division, and bus voltage are as follows:

[0089]

[0090]

[0091] V3 = I 22 ×R,

[0092] U dc =V1+V2+V3,

[0093] Where V1 represents the inductor voltage divider of the first phase, V2 represents the inductor voltage divider of the second phase, V3 represents the resistor voltage divider, and I... 11 This represents the first sampled current of the first phase (i.e., the first phase at time T). 11 The sampling current at time (I) 12 This represents the second sampling current of the first phase (i.e., the first phase at T). 12 The sampling current at time t represents the sampling interval time, I 21 This represents the first sampling current of the second phase (i.e., the second phase at T). 21 The sampling current at time (I) 22 This represents the second sampling current of the second phase (i.e., the second phase at T). 22 (Sampling current at time), L represents the motor winding inductance, R represents the motor winding resistance, U dc This indicates the bus voltage.

[0094] In this embodiment of the invention, the motor is approximated as an inductive load and a resistive load, and the voltage division of the inductor and the resistor is calculated respectively to obtain the bus voltage.

[0095] Taking the voltage vector falling in sector 1 as an example, Tu>Tv>Tw, the first phase is determined to be phase U, the second phase to be phase V, and the third phase to be phase W, that is, T1=Tu, T2=Tv, T3=Tw, Tu represents the turn-on time of phase U switch calculated in FOC, Tv represents the turn-on time of phase V switch calculated in FOC, and Tw represents the turn-on time of phase W switch calculated in FOC.

[0096] (1) Calculate the current sampling time and obtain the sampling current.

[0097] First U-phase current sampling time The first U-phase sampling current is denoted as I. u1 .

[0098] Second U-phase current sampling time T u2 =TT u1 The second U-phase sampling current is denoted as I. u2 .

[0099] First V-phase current sampling time The first V-phase sampling current is denoted as I. v1 .

[0100] Second phase V current sampling time T v2 =TT v1 The second phase V sampling current is denoted as I. v2 .

[0101] (2) Calculate the inductive voltage division and resistive voltage division of the motor windings.

[0102] U-phase winding inductance voltage divider

[0103] Voltage division by the V-phase winding inductance

[0104] Voltage divider V3 = I v2 ×R.

[0105] (3) Calculate the bus voltage U dc =V u +V v +V3.

[0106] Example 3

[0107] Based on the same inventive concept, this embodiment provides a motor bus voltage detection device, which can be used to implement the motor bus voltage detection method described in the above embodiments. This device can be implemented through software and / or hardware.

[0108] Figure 11 This is a structural block diagram of the motor bus voltage detection device provided in Embodiment 3 of the present invention, as shown below. Figure 11 As shown, the device includes:

[0109] The first determining module 1101 is used to determine the first and second phases to be used based on the sector where the inverter voltage vector is located.

[0110] The calculation module 1102 is used to calculate the two current sampling times of the first phase and the two current sampling times of the second phase within one PWM cycle, and to obtain the sampled current;

[0111] The second determining module 1103 is used to determine the bus voltage based on the sampling current, sampling interval time, motor winding inductance, and motor winding resistance.

[0112] Optionally, the first determining module 1101 is specifically used to: sort the turn-on times of the three-phase switch tubes corresponding to the sector according to the length of time; select the one with the longest turn-on time as the first phase, select the one with the middle turn-on time as the second phase, and select the one with the shortest turn-on time as the third phase.

[0113] Optionally, the computing module 1102 includes:

[0114] The first calculation unit is used to calculate the first current sampling time of the first phase based on the turn-on time of the switch of the first phase and the turn-on time of the switch of the second phase.

[0115] The second calculation unit is used to calculate the difference between the PWM period and the first current sampling time of the first phase, so as to obtain the second current sampling time of the first phase.

[0116] The third calculation unit is used to calculate the first current sampling time of the second phase based on the turn-on time of the switch of the second phase and the turn-on time of the switch of the third phase.

[0117] The fourth calculation unit is used to calculate the difference between the PWM period and the first current sampling time of the second phase, so as to obtain the second current sampling time of the second phase.

[0118] Optionally, the first calculation unit uses the following formula to calculate the first current sampling time of the first phase:

[0119]

[0120] Among them, T 11 T represents the first current sampling time of the first phase, T represents the PWM period, T1 represents the turn-on time of the first phase's switch, and T2 represents the turn-on time of the second phase's switch.

[0121] Optionally, the third calculation unit uses the following formula to calculate the first current sampling time of the second phase:

[0122]

[0123] Among them, T 21 T represents the first current sampling time of the second phase, T represents the PWM period, T2 represents the turn-on time of the switch in the second phase, and T3 represents the turn-on time of the switch in the third phase.

[0124] Optionally, the second determining module 1103 includes:

[0125] The fifth calculation unit is used to calculate the inductor voltage divider based on the sampling current, the sampling interval time, and the motor winding inductance.

[0126] The sixth calculation unit is used to calculate the product of the second sampling current of the second phase and the resistance of the motor winding to obtain the resistive voltage division;

[0127] The seventh calculation unit is used to calculate the sum of the inductor voltage divider and the resistor voltage divider to obtain the bus voltage.

[0128] Optionally, the fifth computing unit is specifically used for:

[0129] The difference between the second sampling current of the first phase and the first sampling current of the first phase is calculated to obtain the current difference of the first phase. The derivative of the current difference of the first phase with respect to the sampling interval time of the first phase is obtained. Then, the product of the derivative and the inductance of the motor winding is calculated to obtain the inductance voltage of the first phase.

[0130] The difference between the second sampling current of the second phase and the first sampling current of the second phase is calculated to obtain the current difference of the second phase. The derivative of the current difference of the second phase with respect to the sampling interval time of the second phase is obtained. Then, the product of the derivative and the inductance of the motor winding is calculated to obtain the inductance voltage of the second phase.

[0131] The aforementioned motor bus voltage detection device can execute the motor bus voltage detection method provided in the embodiments of the present invention, and has the corresponding functional modules and beneficial effects for executing the method. Technical details not described in detail in this embodiment can be found in the method provided in the embodiments of the present invention.

[0132] Example 4

[0133] This embodiment provides an electrical device, including: a motor and the motor bus voltage detection device described in the above embodiment.

[0134] Example 5

[0135] This embodiment provides a computer device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the method described in the above embodiment.

[0136] Example 6

[0137] This embodiment provides a non-volatile computer-readable storage medium on which a computer program is stored, which, when executed by a processor, implements the steps of the method described in the above embodiment.

[0138] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0139] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0140] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method of detecting a voltage of a bus bar of an electric machine, characterized by, The method comprises the following steps: determining the first phase and the second phase to be used according to the sector in which the inverter voltage vector is located; calculating the current sampling time of the first phase and the current sampling time of the second phase in a PWM cycle, and obtaining the sampling current; determining the bus voltage according to the sampling current, the sampling interval time, the motor winding inductance and the motor winding resistance; determining the first phase and the second phase to be used according to the sector in which the inverter voltage vector is located, which comprises the following steps: sorting the on time of the three-phase switch tube corresponding to the sector according to the length of time; selecting the on time of the longest as the first phase, the on time of the middle as the second phase, and the on time of the shortest as the third phase; calculating the current sampling time of the first phase and the current sampling time of the second phase in a PWM cycle, which comprises the following steps: calculating the first current sampling time of the first phase according to the on time of the switch tube of the first phase and the on time of the switch tube of the second phase; calculating the difference between the PWM cycle and the first current sampling time of the first phase to obtain the second current sampling time of the first phase; calculating the first current sampling time of the second phase according to the on time of the switch tube of the second phase and the on time of the switch tube of the third phase; calculating the difference between the PWM cycle and the first current sampling time of the second phase to obtain the second current sampling time of the second phase; determining the bus voltage according to the sampling current, the sampling interval time, the motor winding inductance and the motor winding resistance, which comprises the following steps: calculating the inductance voltage drop according to the sampling current, the sampling interval time and the motor winding inductance; calculating the product of the second sampling current of the second phase and the motor winding resistance to obtain the resistance voltage drop; calculating the sum of the inductance voltage drop and the resistance voltage drop to obtain the bus voltage.

2. The method of claim 1, wherein, The following formula is used to calculate the first current sampling time of the first phase: ， wherein, denotes a first current sampling time of the first phase, denotes a PWM period, denotes a switch on time of the first phase, denotes a switch on time of the second phase.

3. The method of claim 1, wherein, The following formula is used to calculate the first current sampling time of the second phase: ， wherein, denotes the first current sampling time of the second phase, denotes the PWM period, denotes the switch-on time of the switch of the second phase, denotes the switch-on time of the switch of the third phase.

4. The method of claim 1, wherein, calculating the inductance voltage drop according to the sampling current, the sampling interval time and the motor winding inductance, which comprises the following steps: calculating the current difference of the first phase by calculating the difference between the second sampling current of the first phase and the first sampling current of the first phase, calculating the derivative of the current difference of the first phase with respect to the sampling interval time of the first phase, and then calculating the product of the derivative and the motor winding inductance to obtain the inductance voltage drop of the first phase; calculating the current difference of the second phase by calculating the difference between the second sampling current of the second phase and the first sampling current of the second phase, calculating the derivative of the current difference of the second phase with respect to the sampling interval time of the second phase, and then calculating the product of the derivative and the motor winding inductance to obtain the inductance voltage drop of the second phase.

5. An electric machine bus voltage detection device, characterized by, The method comprises the following steps: a first determination module for determining the first phase and the second phase to be used according to the sector in which the inverter voltage vector is located; a calculation module for calculating the current sampling time of the first phase and the current sampling time of the second phase in a PWM cycle, and obtaining the sampling current; The second determining module is configured to determine the bus voltage according to the sampling current, the sampling interval time, the motor winding inductance, and the motor winding resistance. The first determining module is configured to sort the on time of the three-phase switch tubes corresponding to the sectors according to the length of time; The longest on time is selected as the first phase, the on time in the middle is selected as the second phase, and the shortest on time is selected as the third phase; The calculation module comprises: The first calculation unit is configured to calculate the first current sampling time of the first phase according to the on time of the switch tube of the first phase and the on time of the switch tube of the second phase; The second calculation unit is configured to calculate the second current sampling time of the first phase by calculating the difference between the PWM period and the first current sampling time of the first phase; The third calculation unit is configured to calculate the first current sampling time of the second phase according to the on time of the switch tube of the second phase and the on time of the switch tube of the third phase; The fourth calculation unit is configured to calculate the second current sampling time of the second phase by calculating the difference between the PWM period and the first current sampling time of the second phase; The second determining module comprises: The fifth calculation unit is configured to calculate the inductance voltage drop according to the sampling current, the sampling interval time, and the motor winding inductance; The sixth calculation unit is configured to calculate the product of the second sampling current of the second phase and the motor winding resistance to obtain the resistance voltage drop; The seventh calculation unit is configured to calculate the sum of the inductance voltage drop and the resistance voltage drop to obtain the bus voltage.

6. An electric device, characterized by The motor and the bus voltage detection device of the motor according to claim 5. A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method according to any one of claims 1 to 4 when executing the computer program.

7. A computer device comprising: The computer program is executed by the processor to implement the steps of the method according to any one of claims 1 to 4.

8. A non-transitory computer readable storage medium having stored thereon a computer program, characterized in that, ​

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