Method and system for creating data maps to control motor flux weakening

Abstract

A method for creating a data map for controlling field weakening of a motor is provided. The method estimates a phase angle between a dq current vector and a d-axis based on a speed of the motor; estimates an input DC current; repeats the estimation of the phase angle and the DC current while reducing a magnitude of the dq current vector based on a difference between the estimated DC current and a preset DC current limit; and, when the DC current is equal to the preset DC current limit, interrupts the repetition of the estimation of the phase angle and the DC current, and, when the estimated DC current is equal to the preset DC current limit, stores a relationship between the speed of the motor, a DC voltage, the phase angle, and the magnitude of the dq current vector. The method realizes the control of the field weakening of the motor in a state where the motor current is limited to a desired magnitude, can limit the DC current of the motor according to the needs of a user, and can optimize the performance of the motor.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2021-0177627, filed on December 9, 2021, with the Korean Intellectual Property Office under 35 USC §119(a), the entire disclosure of which is incorporated herein by reference for all purposes. Technical Field

[0003] The following description relates to methods and systems for creating data maps for controlling the weak magnetic flux of motors. Background Technology

[0004] When driving a motor at high speed is advantageous, the motor torque must be increased to increase the motor speed. However, the amplitude of the voltage supplied to the motor is limited. To overcome this limitation, a flux weakening control method is employed, which reduces the motor's magnetic flux and thus increases the motor speed.

[0005] Typically, flux weakening control employs a method that uses data mapping to generate current commands for controlling the flux weakening. This involves pre-storing the stator current based on the motor speed and input voltage, as well as the phase angle for controlling the flux weakening. However, to implement this flux weakening control method, the operator must manually adjust the data mapping experimentally, one by one. Therefore, consistent motor control is difficult to achieve, and manual adjustments are time-consuming. Summary of the Invention

[0006] This summary is provided to introduce the selection of concepts in a simplified form, which are further described in the detailed embodiments below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to help determine the scope of the claimed subject matter.

[0007] In general, a method of creating a data map for controlling flux weakening of a motor is provided, the method including: estimating a phase angle between a dq current vector of the motor and a d-axis based on a speed of the motor; calculating a torque of the motor based on the estimated phase angle; estimating a direct current input to the motor based on an output of the motor, repeating the estimation of the phase angle and the estimation of the direct current while reducing a magnitude of the dq current vector based on a difference between the estimated direct current and a preset direct current limit value; interrupting the repetition of the estimation of the phase angle and the estimation of the direct current when the estimated direct current is equal to the preset direct current limit value; and storing a relationship between the speed of the motor, a direct current voltage input to the motor, the phase angle, and the magnitude of the dq current vector when the estimated direct current is equal to the preset direct current limit value.

[0008] The torque of the motor can be determined based on the estimated phase angle.

[0009] The output of the motor can be determined based on the determined torque, a resistance loss in the motor, and the direct current voltage input to the motor.

[0010] In the estimation of the phase angle, the phase angle is estimated based on the following equation:

[0011]

[0012] where γ is the estimated phase angle, R s is a resistance in the motor, L s is an inductance in the motor, ω r is a rotational speed of the motor, V dc = V batt -R c i b , V batt is a battery voltage storing a direct current power supplied to the motor, R c is a resistance of a wire from the battery to the motor, i b is the direct current having a preset initial value, I s is a magnitude of the dq current vector, and Φ is a magnetic flux of a magnetic field of the motor.

[0013] In the estimation of the direct current, the direct current can be estimated based on the following equation: where i b is the estimated direct current, i d = I ssin(γ), i q = I s cos(γ), γ is the phase angle estimated in the estimation of the phase angle, τ = k t × i q , k t is a predetermined torque constant of the motor determined based on characteristics of the motor, ω r is a rotational speed of the motor, R s is a resistance in the motor, and V dc is a direct current voltage input to the motor.

[0014] In repeating the estimation of the phase angle and the estimation of the direct current, for a motor speed range in which the magnitude of the direct current estimated in the estimation of the direct current is greater than a direct current limit value, an error value obtained by subtracting the direct current limit value from the estimated magnitude of the direct current is obtained, the magnitude of the dq current vector is reduced based on the error value, and the estimation of the phase angle and the estimation of the direct current are repeated by applying the reduced magnitude of the dq current vector.

[0015] In repeating the estimation of the phase angle and the estimation of the direct current, a value obtained by multiplying the error value by a predetermined constant is subtracted from the magnitude of the dq current vector, the magnitude of the dq current vector is reduced, and the estimation of the phase angle and the estimation of the direct current are repeated by applying the reduced magnitude of the dq current vector.

[0016] The method can include repeating the estimation of the phase angle and the estimation of the direct current until a radix of an electric power function of an Electronic Control Unit (ECU) is obtained by implementing a Newton-Raphson Method, to obtain a radix based on an entire electric power of a motor drive system, wherein the repeating of the estimation of the phase angle and the estimation of the direct current is implemented after the estimation of the direct current.

[0017] The electric power function of the ECU is determined based on the following equation: where P(i b ) is the electric power function of the ECU, V dc is a direct current voltage input to the motor, i b is an estimated direct current, i d = I s sin(γ), i q = I scos(y), y being a phase angle estimated in the estimation of the phase angle, R s R is the resistance in the motor, τ = k t x i q k t is a predetermined torque constant of the motor determined based on characteristics of the motor, ω r is a rotational speed of the motor, and R c is a resistance of a wire from a battery in which direct current power supplied to the motor is stored.

[0018] In repeating the estimation of the phase angle and the estimation of the direct current until a base number of the electric power function of the ECU is obtained, the estimation of the phase angle and the estimation of the direct current are repeated until a base number satisfying P(i b ) = 0 is obtained. becomes less than a preset reference value in the following equation: where P'(i b ) is a differential of P(i b ).

[0019] In one general aspect, a system for creating a data map for controlling field weakening of a motor includes one or more processors configured to: estimate a phase angle between a dq current vector of the motor and a d-axis based on a speed of the motor; calculate a torque of the motor based on the estimated phase angle; estimate a direct current input to the motor based on an output of the motor; repeat the estimation of the phase angle and the estimation of the direct current while reducing a magnitude of the dq current vector based on a difference between the estimated direct current and a preset direct current limit value; interrupt the repeating of the estimation of the phase angle and the estimation of the direct current when the estimated direct current is equal to the preset direct current limit value in the repeating of the estimation of the phase angle and the estimation of the direct current; and store a relationship between the speed of the motor, a direct current voltage input to the motor, the phase angle, and the magnitude of the dq current vector when the estimated direct current is equal to the preset direct current limit value.

[0020] The torque of the motor can be determined based on the estimated phase angle.

[0021] The output of the motor can be determined based on the determined torque, a resistance loss in the motor, and a direct current voltage input to the motor.

[0022] Other features and aspects will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the application. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1To show a circuit diagram of an embodiment of a motor driving system that drives by applying a data map created by a method of creating a data map for controlling flux weakening of a motor according to one or more embodiments.

[0024] Figure 2 To show a block diagram of a configuration of a flux weakening controller that uses a data map created by a method of creating a data map for controlling flux weakening of a motor according to one or more embodiments.

[0025] Figure 3 To show a block diagram of a configuration of a system for implementing a method of creating a data map for controlling flux weakening of a motor according to one or more embodiments.

[0026] Figure 4 To show a flowchart of a method of creating a data map for controlling flux weakening of a motor according to one or more embodiments.

[0027] Figure 5 To show a view of a circle representing a current limit of a motor and a circle representing a voltage limit of a motor according to a rotational speed of the motor according to one or more embodiments, the two circles being represented on a coordinate plane, where a d-axis represents a d-axis current, and where a q-axis represents a q-axis current.

[0028] Figure 6 To show a graph of a relationship between speed and torque of a motor and a relationship between speed and direct current according to one or more embodiments.

[0029] Figure 7 To show a view of an example of a direct current limit applied in a method of creating a data map for controlling flux weakening of a motor according to one or more embodiments.

[0030] Figure 8 and Figure 9 are views showing a change in a dq current vector and a change in a direct current of a motor caused by a method of creating a data map for controlling flux weakening of a motor according to one or more embodiments, respectively.

[0031] Throughout the drawings and detailed description, identical reference labels can indicate the same elements throughout the specified drawings. The drawings can not be to scale, and the relative dimensions, proportions, and depiction of elements in the drawings can be exaggerated for clarity, illustration, and convenience. DETAILED DESCRIPTION

[0032] The following detailed description is presented to aid the reader in gaining a comprehensive understanding of the methods, apparatuses, and / or systems described herein. However, various changes, modifications, and equivalents can be used, and thus particular embodiments described herein are not intended as being limiting as there are many different ways to implement the methods, apparatuses, and / or systems described herein. For example, the order in which operations are described is not intended to be limiting unless otherwise specified, and the operations can be changed, modified, and / or combined in various ways, as will be apparent to one of ordinary skill in the art having the benefit of this disclosure. Additionally, features described herein as being implemented in one manner can be implemented in a different manner, as will be apparent to one of ordinary skill in the art having the benefit of this disclosure. Also, the description is not intended to be limited to the embodiments described herein, unless otherwise specified, as the description is intended to be illustrative of the methods, apparatuses, and / or systems described herein.

[0033] The features described herein can be implemented in different forms and are not to be construed as limited to the embodiments described herein. Rather, the embodiments described herein have been provided merely for the purposes of illustration so as to enable those with ordinary skill in the art to make and use embodiments of the methods, apparatuses, and / or systems described herein.

[0034] While terms such as “first,” “second,” and “third” can be used herein to describe various components, assemblies, regions, layers or sections, these components, assemblies, regions, layers or sections should not be limited by these terms. Rather, these terms are merely used to distinguish one component, assembly, region, layer or section from another. Thus, a component, assembly, region, layer or section referred to as a first component, assembly, region, layer or section in the embodiments described herein can also be referred to as a second component, assembly, region, layer or section without departing from the teachings of the embodiments.

[0035] The terminology used herein is for the purpose of describing particular examples only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. As used herein, the terms “include,” “comprise,” and “have” indicate the presence of the stated feature, number, operation, element, component, and / or combination, but do not preclude the presence or addition of one or more other features, numbers, operations, elements, components, and / or combinations.

[0036] Also, terms such as first, second, A, B, (a), (b) can be used herein to describe components. Each of these terms does not define the nature, order or sequence of the corresponding components, but only serves to distinguish the corresponding components from other components.

[0037] Throughout the specification, when an element (such as a layer, region, or substrate) is referred to as being "on" another element, "connected to" or "coupled to" another element, it can be directly on, connected, or coupled to the other element, or one or more other elements can be interposed therebetween. In contrast, when an element is referred to as being "directly on," "directly connected to," or "directly coupled to" another element, there are no other elements interposed therebetween. Also, the terms such as "between" and "directly between" and "adjacent" and "directly adjacent" can be interpreted in the same manner as described above.

[0038] Unless otherwise defined, all terms used in disclosing embodiments, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and this disclosure and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0039] In addition, in the description of the exemplary embodiments, a detailed description of structures or functions known to those skilled in the art after understanding the disclosure of the present application will be omitted.

[0040] Hereinafter, examples will be described in detail with reference to the accompanying drawings, and the same reference numerals denote the same elements throughout the drawings.

[0041] One or more examples can implement control of motor flux weakening in a state in which motor current is limited to a desired magnitude.

[0042] Using the exemplary method of creating a data map for controlling motor flux weakening, direct current of the motor can be limited according to the user's needs.

[0043] In particular, using the exemplary method of creating a data map for controlling motor flux weakening, the map can be created by implementing a computer system to which a suitable algorithm is applied, without implementing manual adjustment. Thus, performance of the motor can be optimized.

[0044] Figure 1 To show a circuit diagram of an example of a motor driving system that is driven by a data map created by applying a method of creating a data map for controlling motor flux weakening according to one or more embodiments.

[0045] Reference Figure 1According to an exemplary embodiment, a motor drive system driven by a data map created by applying a creation method of a data map for controlling a motor flux can be configured to include an energy storage device 10, an inverter 20, a motor 30, a rotational angle sensor 31, and a controller 100.

[0046] The energy storage device 10 functions as a constituent element such as a battery in which electric energy for driving the motor 30 is stored in a manner to provide a direct current. The energy storage device 10 can provide a direct current power to an input terminal of the inverter 20.

[0047] The inverter 20 functions as a constituent element for converting a direct current power stored as electric energy in the energy storage device 10 and provided from the energy storage device 10 into an alternating current power for motor driving. The inverter 20 can include a plurality of switching elements S1 to S6 whose ON and OFF states are controlled by a pulse-width modulation signal provided from the controller 100.

[0048] The motor 30 functions as a constituent element that is supplied with a three-phase alternating current power from the inverter 20 and generates a rotational force. Various types of motors known in the art to which one or more embodiments belong can be used as the motor 30. For example, the motor 30 can be used as a steering drive motor for a motor driven power steering (MDPS) system within a vehicle, a motor that provides a rotational force to a driving wheel of an eco-friendly vehicle, or other motors.

[0049] The rotational angle sensor 31 functions as a constituent element that measures a position of a motor rotor, i.e., a rotational angle of the motor rotor. The rotational angle sensor 31 can measure a rotational angle of a rotor of the motor 30 and can continuously output rotational angle measurement signals each including information about a measured rotor rotational angle. For example, the rotational angle sensor 31 can be implemented as a resolver or the like.

[0050] The controller 100 can implement control according to a pulse-width modulation scheme to fundamentally implement control to set a torque of the motor 30 to a desired value. The control according to the pulse-width modulation scheme appropriately adjusts duty cycles (duty ratios) of the switching elements S1 to S6 of the inverter 20. For this control, at a certain time point, the controller 100 implements sampling on values lu and lv detected from a signal provided from the rotational angle sensor 31 and detected from a current provided to the motor 30. Then, based on the sampled values, the controller 100 derives information associated with a torque of the motor 30 currently driven.

[0051] Furthermore, the controller 100 compares information associated with the torque of the currently driven motor 30 (derived from sampled values) with a torque command value for the motor 30 (a target torque value expected to be obtained by the motor 30), which is input from an external source. Then, based on the comparison result, the controller 100 controls the switching elements S1 to S6 of the inverter 20 such that the motor 30 outputs a value corresponding to the torque command value.

[0052] In particular, according to one or more embodiments, using a data mapping created by a method for creating a data mapping for controlling motor flux weakening, the controller 100 can implement flux weakening control of the motor in the range where the motor is driven at high speed.

[0053] Figure 2 To illustrate the configuration of a flux weakening controller according to one or more embodiments, the flux weakening controller uses a data mapping created by a method for creating data mappings for controlling the flux weakening of a motor.

[0054] Figure 2 The flux weakening controller shown can be Figure 1 The controller 100 is provided in the field. The flux weakening controller includes data maps 110 and 120. Data map 110 receives the motor speed ω. r The phase angle γ is used as input and outputs the phase angle corresponding to the received value. Data map 120 receives DC voltage (which corresponds to...). Figure 1 Inverter input voltage (V) dc It is provided as input to the motor, and the output is the magnitude I of the dq current vector corresponding to the received value. s .

[0055] The data stored in data map 110 is the motor speed ω r The changing phase angle γ. Stored in data map 120 is the phase angle that varies with the DC voltage V. dc The magnitude I of the changing dq current vector s In actual motor driving, under the condition of implementing flux weakening control, the data map 110 can receive the measured motor speed ω. r As input, it can search for and output its corresponding phase angle γ. The data map 120 can receive the measured DC voltage V. dc As input, it can search for and output the magnitude I of the corresponding dq current vector. s .

[0056] Stored in the data maps 110 and 120 are a plurality of discrete data. Thus, each of the data maps 110 and 120 does not output a value that exactly corresponds to the input voltage. Thus, the data map 110 can output two phase angles γ that respectively correspond to the indices of the upper and lower limit values closest to the input voltage. The data map 120 can output two dq current vector magnitudes I s that respectively correspond to the indices of the upper and lower limit values closest to the input voltage. s Linear interpolation is implemented (120). Thus, the phase angles γ and the dq current vector magnitudes I r that respectively correspond to the motor speed ω dc and the DC voltage V s are determined. The maximum value of the q-axis current command

[0057] Further, the field-weakening controller limits the q-axis current command determined based on the torque command of the motor to the maximum value of the calculated q-axis current command and outputs the final q-axis current command (140). Then, the field-weakening controller applies the phase angle to the finally determined q-axis current command, so that the d-axis current command

[0058] The method of creating data maps for controlling field weakening of a motor according to one or more embodiments can serve the purpose of creating the data maps 110 and 120 for controlling field weakening.

[0059] Figure 3 A block diagram showing the configuration of a system for implementing the method of creating data maps for controlling field weakening of a motor according to one or more embodiments.

[0060] Referring to Figure 3 , the system for implementing the method of creating data maps for controlling field weakening of a motor can be configured to include a processor 200 and a memory 300. The processor 200 implements various calculation and determination operations necessary to create the data maps. Various data segments necessary for the processor 200 to implement the calculation and determination operations are stored in the memory 300.

[0061] In order to implement the calculation and determination operations necessary to create the data maps, the processor 200 can be provided with various parameters of the motor for which field weakening control is performed in advance, and as necessary, the processor 200 can store these parameters in the memory 300 or can read the stored parameters therefrom.

[0062] Further, the processor 200 can store in the memory 300 a data segment resulting from the calculation and determination operation, which is required to create the data map, and the processor 200 can finally store the created data map in the memory 300.

[0063] Figure 4 A flowchart of a method of creating a data map for flux-weakening control of an electric motor according to one or more embodiments.

[0064] Referring to Figure 4 , according to one or more embodiments, in the method of creating a data map for flux-weakening control of an electric motor, first, the step S11 of estimating a phase angle applied to control the flux weakening can be a step in which a processor 10 derives a phase angle applied to control the flux weakening using inputted parameters of the electric motor.

[0065] Figure 5 To show a view of a circle representing a current limit of an electric motor and a circle representing a voltage limit according to a rotational speed of the electric motor, the two circles are represented on a coordinate plane, where a d-axis represents a d-axis current, and where a q-axis represents a q-axis current.

[0066] As shown in Figure 5 , a current of a stator of an electric motor, i.e. a vector current I s , has a limit represented by a circle C on a coordinate plane of the vector current in the d-axis and the q-axis. A voltage of the electric motor has a limit represented by circles O1 and O2. In particular, for the voltage of the electric motor, the higher the rotational speed of the electric motor, the smaller the circle representing the voltage limit has in size.

[0067] Generally, torque control of an electric motor is implemented by a scheme of estimating an electric motor current on a curve called maximum torque per ampere (MTPA). In a case where the rotational speed of the electric motor is low, because the circle representing the voltage limit has a sufficiently large size, the MTPA curve is formed within the circle representing the voltage limit. Thus, torque control is possible. However, an increase in the rotational speed of the electric motor decreases the size of the circle representing the voltage limit. Thus, when the MTPA curve is located outside the circle representing the voltage limit, it is not possible to control the electric motor in such a way that a required speed is output at a required torque. Flux-weakening control is started.

[0068] In a case where the flux-weakening control is implemented, a current command can be estimated at a point where the circle C representing the current limit intersects with the circles O1 and O2 each representing the voltage limit. It can be checked that the effective flux is further reduced because the higher the rotational speed of the electric motor, the more the d-axis current increases in the negative direction.

[0069] The phase angle γ refers to an angle that a straight line in a dq coordinate plane in which a vector current is plotted makes with respect to a q axis. The straight line connects an origin with a point at which a circle representing a current limit and a circle representing a voltage limit intersect.

[0070] In step Sll, the phase angle γ can be theoretically estimated as follows.

[0071] The voltage equation of the motor can be expressed as the following Equation 1 and Equation 2.

[0072] Equation 1:

[0073]

[0074] Equation 2:

[0075]

[0076] where v d is a d-axis voltage of the motor, v q is a q-axis voltage of the motor, R s is a resistance in the motor, L s is an inductance in the motor, ω r is a rotational speed of the motor, i d is a d-axis current of the motor, i q is a q-axis current of the motor, and Φ is a magnetic flux of a magnetic field of the motor.

[0077] In Equations 1 and 2, in a case where the motor is in a normal state (in a state where a constant output is generated), and terms are 0 (zero) because the current does not change. Accordingly, Equations 1 and 2 can be rewritten as the following Equations 3 and 4, respectively.

[0078] Equation 3:

[0079] v d = R s i d - ω r L s i q

[0080] Equation 4:

[0081] v q = R s i q + ω r L s i d + ω r Φ

[0082] The dq voltage of the motor and the input voltage V LThe relationship between them is shown in Equation 5 below. Thus, substituting Equations 3 and 4 into Equation 5 gives Equation 6.

[0083] Equation 5:

[0084]

[0085] wherein, and V dc is the direct current supplied to the motor. Normally, V dc may be determined as a value obtained by subtracting the product of the direct current i batt supplied to the motor and the resistance R b of a wire from the battery voltage V c , which is stored at the battery voltage V batt under which the direct current (V dc = V batt - R c i b , where the initial value of i b may be set in advance) to be supplied to the motor.

[0086] Substituting Equations 3 and 4 into Equation 5 gives the following Equation 6.

[0087] Equation 6:

[0088]

[0089] The d-axis current and the q-axis current correspond to the d-axis component and the q-axis component of the current I s of the stator of the motor, respectively, and thus can be expressed as i d = -I s sin γ and i q = I s cos(γ), respectively. Substituting i d = -I s sin γ and i q = I s cos(γ) into Equation 6 gives the following Equation 7. Rewriting Equation 7 in terms of the phase angle φ eventually gives Equation 8. In Equation 7, I s is the magnitude of the dq current vector, and the maximum value of I s is determined in the process of designing the motor.

[0090] Equation 7:

[0091]

[0092] Equation 8:

[0093]

[0094] As in Equation 8, where the phase angle γ is expressed as a function of the motor speed ω r The phase angle can be estimated in the step S11 of estimating the phase angle based on the motor speed.

[0095] Subsequently, when the step S11 of estimating the phase angle ends, the processor 10 can implement the step S12 of estimating the direct current.

[0096] Figure 6 A graph showing the relationship between the speed of the motor and the torque and the relationship between the speed and the direct current.

[0097] As Figure 6 indicated in the above description, in the case where the motor speed is lower than the motor speed at the inflection point where the motor speed is constant, the motor drive is implemented as described above, and during the motor drive, the current of the motor is determined on a curve called maximum torque per ampere (MTPA). In the case where the motor speed is equal to or higher than the speed at the inflection point, it is not possible to control the motor in such a way that the required speed is output at the required torque. Therefore, the field weakening control is implemented. In this interval, the input direct current i b remains uniform.

[0098] In the interval where the rotational speed of the motor is lower than the rotational speed at the inflection point, the d-axis current of the motor is 0, and its q-axis current has a value equal to I s . In the interval where the rotational speed of the motor is equal to or higher than the rotational speed at the inflection point (field weakening control interval), the d-axis current of the motor and the q-axis current of the motor can be determined in accordance with the following Equation 9.

[0099] Equation 9:

[0100] i d = I s sin(γ)

[0101] i q = I s cos(γ)

[0102] As the phase angle γ in Equation 9, the phase angle estimated in the step S11 can be used.

[0103] The torque τ of the motor can be calculated in accordance with the following Equation 10, where the q-axis current calculated with Equation 9 in the interval where the rotational speed of the motor is higher than the rotational speed at the inflection point is used.

[0104] Equation 10:

[0105] τ = k t × i q

[0106] where k tis a constant of the torque of the motor, and can be a value determined in advance based on characteristics of the motor.

[0107] The electric power of the motor can be expressed as a product of the direct current and the direct voltage. Therefore, the direct current is equal to the total electric power of the motor divided by the direct voltage. At this point, the electric power of the motor is equal to the sum of the output of the motor and the loss in the motor. Therefore, the direct current can be estimated in accordance with the following Equation 11.

[0108] Equation 11:

[0109]

[0110] where P output is the output of the motor, and P ml is the loss in the motor. The output of the motor is equal to a value obtained by multiplying the torque by the motor speed. The loss in the motor can be expressed as

[0111] The phase angle γ for the flux-weakening control and the direct current i b may not be accurate. In order to improve the accuracy of the estimated values, according to an embodiment, step S13 can be implemented. In step S13, the accuracy of the estimated values is improved to a predetermined level or higher by obtaining the base of the electric power function P(i b ) of the electronic control unit (ECU) using the Newton-Raphson method, and then the estimation is ended.

[0112] The electric power function P(i b ) of the ECU can be obtained as follows.

[0113] Equation 12:

[0114] P total = P ECU + P cable + P ml + P output

[0115] The total electric power P total of the motor drive system is as shown in Equation 12, where P ECU is the electric power function of the ECU of the motor drive system, P cable corresponds to the loss of electric power occurring in the electric cables within the motor drive system, P ml corresponds to the loss of the motor itself, and P output corresponds to the output of the motor. Each term can be expressed with the following Equation 13.

[0116] Equation 13:

[0117]

[0118] Equation 13 is expressed in terms of the ECU's power function P(i b Rewritten, we get the following equation 14.

[0119] Equation 14:

[0120]

[0121] The P(i) condition can be obtained by applying the Newton-Raphson method to Equation 14 according to Equation 15. b The base of 0.

[0122] Equation 15:

[0123]

[0124] Where, P'(i b ) represents P(i b The differential of ).

[0125] Repeat steps S11 to S13 until the error is represented in Equation 15. By sufficiently reducing (to a value below a preset reference value), the estimation accuracy of the phase value used for weak flux control and the estimation accuracy of the DC current can be improved.

[0126] In step S13, in equation 15 When the value decreases to a value lower than the preset reference value, the estimation of phase angle and DC current ends, and step S14 of applying a limit value for DC current can be implemented.

[0127] Figure 7 This is a view illustrating an embodiment of a DC current limit applied in a method for creating a data map for controlling the weak magnetic flux of an electric motor, according to one or more embodiments.

[0128] Reference Figure 7 This requires optimizing the vehicle's power consumption during the motor's flux weakening control process and limiting the DC current according to the user's design references. In other words, such as Figure 7 As shown, the DC current of the motor needs to be limited in such a way that the DC current i blimit The value is lower than the DC current i that can be supplied to the motor. b The amplitude.

[0129] In step S14, based on the estimated DC current i b With DC current limit value i blimit The difference between them can reduce the magnitude I of the dq current vector. s Steps S11 and S13 are performed simultaneously.

[0130] More specifically, in step S14, for the motor speed range in which the magnitude of the direct current i b estimated by steps Sll and S13 is higher than the value of the direct current limit value i blimit , the difference Δi b between these two values can be obtained according to the following equation 16.

[0131] Equation 16:

[0132] Δi b = i b - i blimit (@ i b > i blimit )

[0133] In this range, Δi b is multiplied by a constant k (the constant k is set to a value low enough to apply to the dq current vector) and the result of the multiplication is applied to I s according to the following equation 17.

[0134] Equation 17:

[0135] I s = I s_old - Δi b × k (@ i b > i blimit )

[0136] where I s_old represents the magnitude of the dq current vector determined in the cycle immediately before the calculation is repeated.

[0137] Steps Sll to S13 can be implemented by applying the magnitude of the dq current determined using equation 17 (S15). The current value of the motor estimated by repeating steps Sll to S13 gradually approaches the current limit value i blimit , and eventually can be approximately the same as the direct current limit value i blimit .

[0138] When the estimated value of the direct current falls at or below the direct current limit value i blimit by implementing steps S14 and S15, the repetition of steps Sll to S13 for applying the current limit is interrupted (S15). Then, a relationship between the motor speed ω r at the point in time at which the interruption occurred and the magnitude I s of the current vector that changes the direct voltage V dc of the motor, and the motor speed ω r at the point in time at which the interruption occurred, the direct voltage V dc of the motor that changes, can be created.the magnitude of the current vector I s a relationship between the phase angle estimate γ and the magnitude of the current vector I

[0139] Figure 8 and Figure 9 are views showing changes in the dq current vector and changes in the direct current of the motor caused by the method for creating a data map for controlling the motor flux of the motor according to one or more embodiments.

[0140] As shown in Figure 8 , according to one or more embodiments, the magnitude of the dq current vector can be determined in a manner that gradually decreases according to the direct current limit value of the motor by the method for creating a data map for controlling the motor flux of the motor. Therefore, as shown in Figure 9 , the magnitude of the direct current i b of the motor can be limited to a given current limit value i blimit .

[0141] As described above, according to one or more embodiments, the direct current of the motor can be limited according to the user's needs by the method for creating a data map for controlling the motor flux of the motor. In particular, according to one or more embodiments, by the method for creating a data map for controlling the motor flux of the motor without implementing manual adjustment, a computer system applying a suitable algorithm can create a map. Therefore, the performance of the motor can be optimized.

[0142] The devices, apparatuses, units, modules, and components described herein are implemented by hardware components. Examples of hardware components that can be used to implement the operations described in this application, when appropriate, include controllers, sensors, generators, drivers, memories, comparators, arithmetic logic units, adders, subtractors, multipliers, dividers, integrators, and any other electronic components configured to implement the operations described in this application. In other examples, one or more hardware components implementing the operations described in this application are implemented by computing hardware, for example, by one or more processors or computers. The processor or computer can be implemented by one or more processing elements, such as logic gates arrays, controllers and arithmetic logic units, digital signal processors, microcomputers, programmable logic controllers, field programmable gate arrays, programmable logic arrays, microprocessors, or any other device or combination of devices configured to respond to and implement instructions in a defined manner to achieve a desired result. In one embodiment, the processor or computer includes or is connected to one or more memories that store instructions or software for execution by the processor or computer. The hardware components implemented by the processor or computer can execute instructions or software, such as an operating system (OS) and one or more software applications running on the OS, to implement the operations described in this application. The hardware components can also access, manipulate, process, create, and store data in response to the execution of the instructions or software. For simplicity, the singular term "processor" or "computer" can be used in this application to describe an example, but in other examples, multiple processors or computers can be used, or a processor or computer can include multiple processing elements and / or multiple types of processing elements. For example, a single hardware component or two or more hardware components can be implemented by a single processor, or two or more processors, or a processor and a controller. One or more hardware components can be implemented by one or more processors, or a processor and a controller, and one or more other hardware components can be implemented by one or more other processors, or another processor and another controller. The one or more processors, or a processor and a controller, can implement a single hardware component, or two or more hardware components.The hardware components can have any one or more of various different processing configurations, examples of which include: a single processor, independent processors, parallel processors, single-instruction single-data (SISD) multiprocessors, single-instruction multiple-data (SIMD) multiprocessors, multiple-instruction single-data (MISD) multiprocessors, multiple-instruction multiple-data (MIMD) multiprocessors, controllers and arithmetic logic units (ALUs), DSPs, microcontrollers, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), programmable logic units (PLUs), central processing units (CPUs), graphics processing units (GPUs), neural processing units (NPUs), or any other devices capable of responding to and executing instructions in a defined manner.

[0143] Software can include one or more computer programs, code, instructions, or some combination thereof, for independently or collectively instructing or configuring a processing device to operate as desired. Software and data can be embodied permanently or temporarily in any type of machine, component, physical or virtual equipment, computer storage medium or device, or spread across multiple entities. Software can be distributed over the Internet on a via of different types of media including, but not limited to, wireline, wireless, or over-the-air methods. Software and data can be stored and executed, or interpreted and run, on one or more computer processors, and the execution produce a computer-implemented process. Software and data can also be distributed electronically via any real or virtual type of wired or wireless connection, including advanced distribution networks when other information carriers are available.

[0144] The methods implementing the operations described in this application can be implemented by a computing hardware, such as by one or more processors or computers, executing instructions or software to perform the operations described in this application as implemented by the methods. For example, a single operation or two or more operations can be performed by a single processor, or two or more processors, or a processor and a controller. One or more operations can be performed by one or more processors, or a processor and a controller, and one or more other operations can be performed by one or more other processors, or another processor and another controller. The one or more processors, or a processor and a controller, can perform a single operation, or two or more operations.

[0145] The instructions or software to control a processor or computer to implement the hardware components and perform the operations described above as implemented by the methods are written as a computer program, code segment, instructions, or any combination thereof, for individually or collectively instructing or configuring a processor or computer to operate as a machine or special-purpose computer to perform the operations described above as implemented by the hardware components and methods. In one embodiment, the instructions or software include machine code that is directly executed by a processor or computer, such as machine code produced by a compiler. In one embodiment, the instructions or software include at least one of a script, a macro, a dynamic link library (DLL), middleware, firmware, a device driver, an application program that stores a storage lane recognition method. In another embodiment, the instructions or software include high-level code that is executed by a processor or computer using an interpreter. Programmers of ordinary skill in the art with access to the block diagrams and flowcharts shown in the drawings and the corresponding descriptions in the specification, which disclose algorithms and methods as described above for implementing the operations implemented by the hardware components, can easily write the instructions or software based on the block diagrams and flowcharts and the corresponding descriptions in the specification.

[0146] Instructions or software for controlling a processor or computer to implement the hardware components and carry out the above-described methods, as well as any associated data, data files, and data structures, are recorded, stored, or fixed in one or more non-transitory computer-readable storage media or on the media. Examples of non-transitory computer-readable storage media include read-only memory (ROM), random-access programmable read only memory (PROM), electrically erasable programmable read only memory (EEPROM), random-access memory (RAM), magnetic RAM (MRAM), spin-transfer torque (STT)-MRAM, static random-access memory (SRAM), thyristor RAM (T-RAM), zero capacitor RAM (Z-RAM), twin transistor RAM (TTRAM), conductive bridging RAM (CBRAM), ferroelectric RAM (FeRAM), phase change RAM (PRAM), resistive RAM (RRAM), nanotube RRAM, polymer RAM (PoRAM), nano floating gate Memory (NFGM), holographic memory, molecular electronic memory devices, insulator resistance change memory, dynamic random access memory (DRAM), static random access memory (SRAM), flash memory, nonvolatile memory, CD-ROM, CD-R, CD+R, CD-RW, CD+RW, DVD-ROM, DVD-R, DVD+R, DVD-RW, DVD+RW, DVD-RAM, BD-ROM, BD-R, BD-R LTH, BD-RE, Blu-ray or optical disc memory, hard disk drive (HDD), solid state drive (SSD), flash drive, compact flash, smart media, smart media card, memory stick, multimedia card, multimedia card micro, xD picture card, and any other suitable type of memory.SSDs), card-type memories (such as multimedia micro cards or cards, e.g., secure digital (SD) or extreme digital (XD)), magnetic tapes, floppy disks, magneto-optical data storage devices, optical data storage devices, hard disks, solid state disks, and any other devices configured to store instructions or software and any related data, data files, and data structures in a non-transitory manner and to provide the instructions or software and any related data, data files, and data structures to a processor or computer so that the processor or computer can execute the instructions. In one embodiment, the instructions or software and any related data, data files, and data structures are distributed across a network-coupled computer system so that the instructions and software and any related data, data files, and data structures are stored, accessed, and executed by one or more processors or computers in a distributed manner.

[0147] Although the present disclosure includes specific embodiments, it will be apparent after an understanding of the present disclosure that various changes in form and details can be made in these embodiments without departing from the spirit and scope of the claims and their equivalents. The embodiments described herein are to be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment are to be considered to apply to similar features or aspects within other embodiments. Suitable results can be achieved if the described techniques are performed in a different order, and / or if the components of the described systems, architectures, devices, or circuits are combined in a different manner, and / or replaced or supplemented by other components or equivalents thereof. Accordingly, the scope of the present disclosure is not limited to the detailed description provided herein, but is only limited by the claims and their equivalents, and all changes that come within the meaning and range of equivalents are intended to be embraced by the claims.

Claims

1. A method of creating a data map for controlling flux weakening of an electric machine, the method comprising: estimating a phase angle between a dq current vector of the electric machine and a d-axis based on a speed of the electric machine; calculating a torque of the electric machine based on the estimated phase angle; estimating a direct current input into the electric machine based on an output of the electric machine; repeating the estimation of the phase angle and the estimation of the direct current while reducing a magnitude of the dq current vector based on a difference between the estimated direct current and a preset direct current limit value; interrupting the repetition of the estimation of the phase angle and the estimation of the direct current when the estimated direct current is equal to the preset direct current limit value; and storing a relationship between the speed of the electric machine, a direct current voltage input into the electric machine, the phase angle, and the magnitude of the dq current vector when the estimated direct current is equal to the preset direct current limit value. wherein, in the estimation of the phase angle, the phase angle is estimated based on the following equation: the output of the electric machine is determined based on the determined torque, a resistance loss in the electric machine, and the direct current voltage input into the electric machine. where γ is the estimated phase angle, R s is the resistance in the motor, L s is the inductance in the motor, ω r is the rotational speed of the motor, , , V batt is the battery voltage storing the DC power supplied to the motor, R c is the resistance of the wire from the battery to the motor, i b is the DC current with a preset initial value, I s is the amplitude of the dq current vector, and Φ is the magnetic flux of the magnetic field of the motor.

2. The method of claim 1, wherein, in the estimation of the direct current, the direct current is estimated based on the following equation:

3. The method of claim 1, wherein, in the repeating of the estimation of the phase angle and the estimation of the direct current, for an electric machine speed interval in which the magnitude of the direct current estimated in the estimation of the direct current is greater than the direct current limit value, an error value obtained by subtracting the direct current limit value from the magnitude of the estimated direct current is obtained, the magnitude of the dq current vector is reduced based on the error value, and the estimation of the phase angle and the estimation of the direct current are repeated by applying the reduced magnitude of the dq current vector. wherein i b is the estimated direct current, i d = I s sin (γ), i q = I s cos (γ), γ is the phase angle estimated in the estimation of the phase angle, τ = k t × i q , k t is a predetermined torque constant of the electric machine determined on the basis of a characteristic of the electric machine, ω r is a rotational speed of the electric machine, R s is an electrical resistance in the electric machine, and V dc is a direct voltage input to the electric machine; wherein I s is a magnitude of the dq current vector, P output is an output of the electric machine, and P ml is a loss in the electric machine.

4. The method of claim 1, wherein, in the repeating of the estimation of the phase angle and the estimation of the direct current, 5. The method of claim 4, wherein, the magnitude of the dq current vector is reduced by subtracting a value obtained by multiplying the error value by a preset constant from the magnitude of the dq current vector, and the estimation of the phase angle and the estimation of the direct current are repeated by applying the reduced magnitude of the dq current vector. 6.The method of claim 1, further comprising: repeating the estimation of the phase angle and the estimation of the direct current until a base of an electrical power function of an electronic control unit (ECU) is obtained by implementing a Newton-Raphson method to obtain a base based on a total electrical power of an electric machine drive system, wherein, after the estimation of the direct current, the repeating of the estimation of the phase angle and the estimation of the direct current is implemented. the electrical power function of the ECU is determined based on the following equation:

7. The method of claim 6, wherein, 9.A system of creating a data map for controlling flux weakening of an electric machine, comprising: where P(i b ) is an electrical power function of the ECU, V dc is the DC voltage input to the motor, i b is an estimated DC current, i d = I s sin (γ), i q = I s cos (γ), γ is a phase angle estimated in estimation of the phase angle, R s is an electrical resistance in the motor, τ = k t x i q , k t is a predetermined torque constant of the motor determined based on characteristics of the motor, ω r is a rotational speed of the motor, and R c is an electrical resistance of a wire from a battery in which DC power supplied to the motor is stored.

8. The method of claim 7, wherein, In the repetition of the estimation of the phase angle and of the direct current until the base of the electrical power function of the ECU is obtained, to obtain the base that satisfies P(i b ) = 0, the estimation of the phase angle and of the direct current is repeated until is less than a preset reference value in the following equation: where P'(i b ) is the derivative of P(i b ). one or more processors configured to: estimate a phase angle between a dq current vector of the electric machine and a d-axis based on a speed of the electric machine; calculate a torque of the electric machine based on the estimated phase angle; estimate a direct current input into the electric machine based on an output of the electric machine; ​ the estimation of the phase angle and the estimation of the direct current are repeated while reducing the amplitude of the dq current vector based on a difference between the estimated direct current and a preset direct current limit value; the repetition of the estimation of the phase angle and the estimation of the direct current is interrupted when the estimated direct current in the repetition of the estimation of the phase angle and the estimation of the direct current is equal to the preset direct current limit value; and when the estimated direct current is equal to the preset direct current limit value, a relationship between a speed of the motor, a direct current voltage input to the motor, the phase angle and the amplitude of the dq current vector is stored; wherein, in the estimation of the phase angle, the phase angle is estimated based on the following equation: where γ is the estimated phase angle, R s is the resistance in the electric machine, L s is the inductance in the electric machine, ω r is the rotational speed of the electric machine, , , V batt is the battery voltage storing the direct current power supplied to the electric machine, R c is the resistance of the wire from the battery to the electric machine, i b is the direct current with a preset initial value, I s is the amplitude of the dq current vector, and Φ is the magnetic flux of the magnetic field of the electric machine.

10. The system of claim 9, wherein, the output of the motor is determined based on the determined torque, a resistance loss in the motor and a direct current voltage input to the motor.

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