ELECTROMECHANICAL BRAKING SYSTEM AND METHOD FOR SETTING A GEAR RATIO

Abstract

A method for setting a transmission ratio for an EMB system according to an exemplary embodiment of the present disclosure enables the filtering out of reduction ratios that are adverse for torque ripple or noise characteristics by excluding the same / similar sequences to a sequence of ripple that can be generated in the motor when a reduction ratio is set, facilitates root cause analysis when the EMB system has a (noise, vibration or roughness) NVH problem, since the motor and the reduction gear have their own unique sequence / frequency characteristics, and performs optimization of the reduction gear at an early design stage by selecting values ​​that are available and unavailable as the reduction gear ratio.

Description

TECHNICAL FIELD

[0001] The present invention relates to an EMB system and a method for adjusting a gear ratio thereof, in particular to a system and a method for adjusting a gear ratio of a reduction gear in an electromechanical braking system (EMB system). BACKGROUND

[0002] In an electromechanical braking (EMB) system that uses a motor and a reduction gear, when a sequence of torque ripple that can be generated in the motor and a sequence of ripple that can be generated in the reduction gear have similar overlap values, the noises overlap at the same sequence / frequency while the EMB system is operating, thereby deteriorating the noise, vibration, and harshness (NVH) characteristics of the EMB system. SUMMARY

[0003] An object to be achieved by the present disclosure is to provide an EMB system for adjusting a gear ratio of a reduction gear in an electromechanical braking (EMB) system taking into account an engine and the noise, vibration, and harshness (NVH) characteristics of the engine during operation, and a method for adjusting a gear ratio thereof.

[0004] Other unspecified objects of the present disclosure are additionally contemplated within the scope that can be easily derived from the following detailed description and the effects thereof.

[0005] An exemplary embodiment of the present disclosure provides an EMB system comprising: a motor; and a reduction gear for amplifying an output of the motor, wherein a gear ratio of the reduction gear is selected from a group of reduction gear gear ratio candidates by using reduction gear gear ratio candidates remaining after excluding a motor ripple generation order obtained based on specification information of the motor.

[0006] The motor may comprise a permanent magnet synchronous motor (PMSM), wherein the motor ripple generation order includes the number of poles and the number of slots in the PMSM.

[0007] The motor ripple generation order may include a basic generation order including a plurality of basic orders obtained based on the number of poles and the number of slots.

[0008] The basic generation order may include a plurality of basic orders obtained based on a plurality of mechanical orders representing an order of ripple generated due to mechanical characteristics of the motor and a plurality of electrical orders representing an order of ripple generated due to electrical characteristics of the motor.

[0009] The plurality of mechanical sequences may include a first mechanical sequence representing the number of poles, a second mechanical sequence representing the number of slots, a third mechanical sequence representing the lowest common multiple of the number of poles and the number of slots, and a fourth mechanical sequence representing twice as many as the third mechanical sequence, and the plurality of electrical sequences may include a first electrical sequence representing half the number of poles and a second electrical sequence representing the number of poles.

[0010] The basic generation sequence may include a plurality of basic sequences including the plurality of mechanical sequences and the plurality of electrical sequences as a whole.

[0011] The motor ripple generation order may further include an extended generation order obtained by extending the basic generation order to a preset extended range.

[0012] The extended generation order may include a plurality of extended orders obtained by extending each of the plurality of basic orders of the basic generation order using the extended range.

[0013] The extended range can represent ±1 and / or ±2.

[0014] When the motor is operated at a frequency of a preset reference value or above or the motor is operated at a varying speed, the motor ripple generation order may further include the extended generation order obtained by extending the basic generation order to the extended range.

[0015] The gear ratio of the reducer can be selected from a group of reducer gear ratio candidates consisting of gear ratios selectable for the reducer by using reducer gear ratio candidates remaining after excluding gear ratio candidates corresponding to all orders included in the motor ripple generation order.

[0016] Another exemplary embodiment of the present disclosure provides a method for adjusting a gear ratio of an electromechanical braking (EMB) system including a motor and a reduction gear for amplifying an output of the motor, the method comprising: obtaining a motor ripple generation order based on specification information of the motor; and selecting a gear ratio of the reduction gear from a group of reduction gear gear ratio candidates by using reduction gear gear ratio candidates remaining after excluding the obtained motor ripple generation order.

[0017] The motor may comprise a permanent magnet synchronous motor (PMSM), wherein obtaining a motor ripple generation order may comprise obtaining the motor ripple generation order based on the specification information including the number of poles and the number of slots in the PMSM.

[0018] The motor ripple generation order may include a basic generation order including a plurality of basic orders obtained based on the number of poles and the number of slots.

[0019] The basic generation order may include a plurality of basic orders obtained based on a plurality of mechanical orders representing an order of ripple generated due to mechanical characteristics of the motor and a plurality of electrical orders representing an order of ripple generated due to electrical characteristics of the motor.

[0020] The plurality of mechanical sequences may include a first mechanical sequence representing the number of poles, a second mechanical sequence representing the number of slots, a third mechanical sequence representing the lowest common multiple of the number of poles and the number of slots, and a fourth mechanical sequence representing twice as many as the third mechanical sequence, and the plurality of electrical sequences includes a first electrical sequence representing half the number of poles and a second electrical sequence representing the number of poles.

[0021] The basic generation sequence may include a plurality of basic sequences including the plurality of mechanical sequences and the plurality of electrical sequences as a whole.

[0022] The motor ripple generation order may further include an extended generation order obtained by extending the basic generation order to a preset extended range.

[0023] The extended generation order may include a plurality of extended orders obtained by extending each of the plurality of basic orders of the basic generation order using the extended range.

[0024] When the motor is operated at a frequency of a preset reference value or above or the motor is operated at a varying speed, the motor ripple generation order may further include the extended generation order obtained by extending the basic generation order to the extended range.

[0025] An EMB system and a method for adjusting a gear ratio thereof according to an exemplary embodiment of the present disclosure enables filtering out gear ratios of a reduction gear that are detrimental to torque ripple or noise characteristics by excluding the same / similar sequences to a sequence of ripple that may be generated in the motor when adjusting a gear ratio of the reduction gear, performs root cause analysis more easily when the EMB system has an NVH (noise, vibration, or harshness) problem because the motor and the reduction gear have their own unique sequence / frequency characteristics, and performs optimization of the reduction gear at an early design stage by selecting values ​​that are available and unavailable as the gear ratio of the reduction gear.

[0026] The effects of the present disclosure are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram for explaining an EMB system according to an exemplary embodiment of the present disclosure. Fig. 2 is a view for explaining an example of ripple generation in a motor according to an exemplary embodiment of the present disclosure. Fig. 3 is a view showing an ideal operation in the Fig. 2 shows the engine shown. Fig. 4 is a view showing a farm in the Fig. 2 shows when a magnetic surface and an MPS are horizontally misaligned. Fig. 5 is a view showing an operation in the Fig. 2 in the case of concentric misalignment on one axis. Fig. 6 is a view showing an operation in the Fig. 2 in the case of concentric misalignment on both the X and Y axes. Fig. 7 is a view showing ripple components occurring in the Fig. 2 shown engine can be generated. Fig. 8 is a flowchart for explaining a method for setting a gear ratio for an EMB system according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0027] Advantages and features of the present disclosure, and methods for achieving them, will become apparent from the embodiments described in detail below with reference to the accompanying drawings. This disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art. This disclosure is defined only by the scope of the claims. Like reference characters refer to like elements throughout this specification.

[0028] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meanings as those commonly understood by one of ordinary skill in the art. It is further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having meanings consistent with their meanings in the context of the relevant art and the present disclosure, and should not be interpreted in an idealized or overly formal sense unless expressly so defined.

[0029] Terms such as "first," "second," etc., are intended to distinguish one element from another, and the scope of the right should not be limited by these terms. For example, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

[0030] Identification codes (e.g., a, b, and c) of each step are used solely for clarity and ease of description. No specific order of steps is indicated. The steps may be performed in a different order than described unless clearly limited otherwise. Specifically, the steps may be performed in the same order as described, may be performed substantially concurrently, or may be performed in the reverse order.

[0031] The terms “have,” “may have,” “include,” and “may include,” as used herein, indicate the presence of corresponding features (e.g., elements such as numeric values, functions, operations, or parts) and do not preclude the presence of additional features.

[0032] The term "unit," as used herein, refers to a software component or a hardware component, such as a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC), and a unit performs specific tasks. However, the meaning of "unit" is not limited to software or hardware. A unit may be configured to reside on an addressable storage medium and may be configured to execute on one or more processors. For example, a unit may include components such as software components, object-oriented software components, class components and task components, processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables.The functions provided in the components and units can be combined into fewer components and units or further separated into additional components and units.

[0033] Hereinafter, an EMB system and a gear ratio adjusting method thereof according to an exemplary embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.

[0034] First, an EMB system according to an exemplary embodiment of the present disclosure will be described with reference to the Fig. 1 to Fig. 7 described.

[0035] Fig. 1 is a block diagram for explaining an EMB system according to an exemplary embodiment of the present disclosure. Fig.2 is a view for explaining an example of ripple generation in a motor according to an exemplary embodiment of the present disclosure. Fig. 3 is a view showing an ideal operation in the Fig. 2 shows the engine shown. Fig. 4 is a view showing a farm in the Fig. 2 shows when a magnetic surface and an MPS are horizontally misaligned. Fig. 5 is a view showing an operation in the Fig. 2 in the case of concentric misalignment on one axis. Fig. 6 is a view showing an operation in the Fig. 2 in the case of concentric misalignment on both the X and Y axes. Fig. 7 is a view showing ripple components occurring in the Fig. 2 shown engine can be generated.

[0036] With reference to Fig.1, an electromechanical braking (EMB) system according to an exemplary embodiment of the present disclosure includes a motor 110 and a reduction gear 120 for amplifying an output of the motor 110, and can adjust a gear ratio of the reduction gear 120 in consideration of the motor 110 and the noise, vibration, and harshness (NVH) characteristics of the motor 110 during operation.

[0037] Accordingly, the present disclosure may enable filtering out gear ratios of the reduction gear 120 that are detrimental to torque ripple or noise characteristics by excluding the same / similar sequences to a sequence of ripple that may be generated in the motor when adjusting a gear ratio of the reduction gear 120, may more easily perform root cause analysis when the EMB system has an NVH problem because the motor 110 and the reduction gear 120 have their own unique sequence / frequency characteristics, and may perform optimization of the reduction gear 120 at an early design stage by selecting values ​​that are available and unavailable as the gear ratio of the reduction gear 120.

[0038] That is, the motor 110 may comprise a permanent magnet synchronous motor (PMSM).

[0039] In addition, the reduction gear 120 is used as a medium for amplifying / transmitting an output of the motor 110 and may be in various types such as a pulley, a worm-worm gear, a planetary gear, a ball nut, and so on.

[0040] In this case, the gear ratio of the reduction gear 120 can be selected from a group of reduction gear ratio candidates by using reduction gear ratio candidates remaining after excluding a motor ripple generation order obtained based on specification information of the motor 110. That is, the gear ratio of the reduction gear 120 can be selected from a group of reduction gear ratio candidates consisting of gear ratios selectable for the reduction gear 120 by using reduction gear ratio candidates remaining after excluding gear ratio candidates corresponding to all orders included in the motor ripple generation order.

[0041] Specifically, the motor ripple generation order may be obtained based on specification information including the number of poles and the number of slots in the permanent magnet synchronous motor (PMSM). For example, a ripple order represents a value into which a characteristic of the ripple generated when the motor 110 mechanically rotates with respect to a shaft is converted. When one ripple is generated per revolution, the ripple order may be defined as the first, and when two ripples are generated per revolution, the ripple order may be defined as the second. In this case, a mechanical order refers to a order generated when the shaft of the motor 110 mechanically rotates 360 degrees, that is, one revolution.An electrical sequence refers to a sequence produced when, in the case of a three-phase motor, a sine wave completes a cycle with respect to a counter electromotive voltage or counter electromotive current.

[0042] That is, the motor ripple generation order may include a basic generation order including a plurality of basic orders obtained based on the number of poles and the number of slots. Here, the basic generation order may include a plurality of basic orders obtained based on a plurality of mechanical orders representing an order of ripple generated due to mechanical characteristics of the motor 110 and a plurality of electrical orders representing an order of ripple generated due to electrical characteristics of the motor 110. The plurality of mechanical orders may include a first mechanical order, a second mechanical order, a third mechanical order, and a fourth mechanical order.The first mechanical order is a ripple order generated due to a slot manufacturing problem or manufacturing variation, and may represent the number of poles. The second mechanical order is a ripple order generated due to a rotor manufacturing problem or manufacturing variation, and may represent the number of slots. The third mechanical order is a order where the highest torque ripple is generated relative to the electromagnetic system design and may represent the lowest common multiple of the number of poles and the number of slots. The fourth mechanical order is a ripple order generated due to back electromotive voltage characteristics of the motor 110 and may represent twice as many as the third mechanical order.Furthermore, the plurality of electrical sequences may include a first electrical sequence and a second electrical sequence. The first electrical sequence is a ripple sequence generated due to a current sensor offset error or device leakage, and may represent half the number of poles. The second electrical sequence is a ripple sequence generated due to a current sensor gain error or device leakage, and may represent the number of poles. In other words, the basic generation sequence may include a plurality of basic sequences that include the plurality of mechanical sequences and the plurality of electrical sequences in total.

[0043] For example, if the number of poles is “N” and the number of slots is “M”, the motor ripple generation order may include such a basic generation order as in [Table 1]. [Table 1] N=6&M=9 N=8&M=12 N=10&M=12 first electrical sequence 1*N / 2 3 4 5 second electrical sequence 2*N / 2 6 8 10 first mechanical sequence N 6 8 10 second mechanical sequence M 9 12 12 third mechanical sequence lowest common multiple of N and M 18 24 60 fourth mechanical order 2*(third mechanical order) 36 48 120 Basic generation sequence 3, 6, 9, 18, 36 4, 8, 12, 24, 48 5, 10, 12, 60, 120

[0044] Furthermore, the motor ripple generation order may further include an extended generation order obtained by expanding the basic generation order to a preset extended range. Here, the extended generation order may include a plurality of extended orders obtained by expanding each of the plurality of basic orders of the basic generation order using the extended range. In this case, the extended range may represent ±1 and / or ±2. That is, the extended range may cover each basic order and -2 to +2 of this order.

[0045] In this case, when the motor 110 is operated at a frequency of a preset reference value (1,000 rpm or the like) or higher, or the motor 110 is operated at a varying speed rather than a constant speed, the motor ripple generation order may further include the extended generation order obtained by expanding the basic generation order to the extended range. For example, when the motor 110 is primarily operated at a speed of 1,000 rpm, the twelfth order corresponds to 2,000 Hz.This means that the tenth order, which is the twelfth order minus 2, corresponds to 167 Hz, the fourteenth order, which is the twelfth order plus 2, corresponds to 233 Hz, the twenty-fourth order corresponds to 400 Hz, the twenty-second order, which is the twenty-fourth order minus 2, corresponds to 367 Hz, and the twenty-sixth order, which is the twenty-fourth order plus 2, corresponds to 433 Hz. Therefore, the intervals between the orders are narrow compared to the frequencies to be analyzed, which makes NVH analysis difficult. In addition, a large amount of input data is required for precise analysis. However, in a system with varying speed, it is not easy to obtain sufficient data required for analysis within the same speed. In addition, frequencies that a human ear hears merge into a single frequency at higher frequencies.Therefore, it is necessary to eliminate only precise multiples of sequences in a system operating at a low constant speed and to exclude sequences to an extended range in a system operating at varying speeds. For example, if the engine 110 operates primarily at a speed of 500 rpm, the twelfth sequence corresponds to 1,000 Hz. This means that the tenth sequence, which is the twelfth sequence minus 2, corresponds to 83 Hz, the fourteenth sequence, which is the twelfth sequence plus 2, corresponds to 117 Hz, the twenty-fourth sequence corresponds to 200 Hz, the twenty-second sequence, which is the twenty-fourth sequence minus 2, corresponds to 183 Hz, and the twenty-sixth sequence, which is the twenty-fourth sequence plus 2, corresponds to 217 Hz.These frequencies correspond to a low frequency range in which humans or NVH devices can detect frequencies relatively easily.

[0046] For example, if the number of poles is “N”, the number of slots is “M”, and the extended range is “±1 and ±2”, the motor ripple generation order may include such a basic generation order as in [Table 2]. [Table 2] N=6&M=9 Basic generation sequence Extended generation order (±1) Extended generation order (±2) Motor ripple generation sequence 3 2, 4 1,5 1, 2, 3, 4, 5 6 5, 7 4, 8 4, 5, 6, 7, 8 9 8, 10 7, 11 7, 8, 9, 10, 11 18 17, 19 16, 20 16, 17, 18, 19, 20 36 35, 37 34, 38 34, 35, 36, 37, 38 N=8 & M=12 Basic generation sequence Extended generation order (±1) Extended generation order (±2) Motor ripple generation sequence 4 3, 5 2, 6 2, 3, 4, 5, 6 8 7, 9 6, 10 6, 7, 8, 9, 10 12 11, 13 10, 14 10, 11, 12, 13, 14 24 23, 25 22, 26 22, 23, 24, 25, 26 48 47, 49 46, 50 46, 47, 48, 49, 50 N=10 & M=12 Basic generation sequence Extended generation order (±1) Extended generation order (±2) Motor ripple generation sequence 5 4, 6 3, 7 3, 4, 5, 6, 7 10 9, 11 8, 12 8, 9, 10, 11, 12 12 11, 13 10, 14 10, 11, 12, 13, 14 60 59, 61 58, 62 58, 59, 60, 61, 62 120 119, 121 118, 122 118, 119, 120, 121, 122

[0047] The reason why the extended generation order (±1, ±2 or ±1 and ±2) obtained by extending the basic generation order to a preset extended range is considered will be explained with reference to the Fig. 2 to Fig. 7 described.

[0048] In the case of MPS (Motor Position Sensor), as in Fig.2, a puck magnet for detecting is attached to one end of a rotor of the motor, and a sensor for measuring the magnetic flux of the magnet, i.e., MPS, is mounted on a PCB.

[0049] Under an ideal condition where all requirements are correctly met, such as when the centers of the magnet and the MPS are correctly aligned and the magnet and the MPS are perfectly horizontal, no harmonics are generated. However, errors are unavoidable in manufacturing processes. These errors are generated because in the MPS, the sine and cosine of each flux are 90 degrees out of phase, depending on the structural conditions of the MPS, and the rotor angle is calculated using the arctangent.

[0050] Under ideal conditions, angles are calculated without problems. On the other hand, as in Fig.3, when one side of the magnet and one side of the MPS are not horizontal to each other (the magnet is mounted at a slight incline, or the PCB or the MPS is horizontally misaligned), or when a horizontal misalignment is caused when the magnet is magnetized, a primary ripple component is integrated into the angle information, as shown in Fig. 4. Also, if the magnet and the MPS are concentrically misaligned due to a deviation on either the X-axis or the Y-axis, a primary ripple component is generated, as shown in Fig. 5. Furthermore, if they are concentrically misaligned on both the X-axis and the Y-axis, a primary waviness component is generated, as shown in Fig.6. In summary, in the case of a product using MPS, a primary ripple component and a secondary ripple component can potentially be included, as shown in Fig. 7. Since the generated ripple components are integrated into the control input and generate current and voltage, ±1 orders and ±2 orders are additionally generated. Accordingly, the present disclosure is capable of obtaining a motor ripple generation order taking into account an extended generation order obtained by expanding a basic generation order to a preset extended range.

[0051] Thereafter, the gear ratio of the reduction gear 120 may be selected from a group of reduction gear gear ratio candidates consisting of gear ratios selectable for the reduction gear 120 by using reduction gear gear ratio candidates remaining after excluding gear ratio candidates corresponding to all orders included in the motor ripple generation order.For example, in the case of an 8-pole, 12-slot permanent magnet synchronous motor (PMSM), the gear ratio of the reducer 120 can be selected from a group of reducer gear ratio candidates by using reducer gear ratio candidates remaining after excluding gear ratio candidates corresponding to all orders included in the ripple generation order of the motor 110, including 2nd, 3rd, 4th, 5th, and 6th orders / 6th, 7th, 8th, 9th, and 10th orders / 10th, 11th, 12th, 13th, and 14th orders / 22nd, 23rd, 24th, 25th, and 26th orders / 46th, 47th, 48th, 49th, and 50th orders.

[0052] Next, a method for setting a gear ratio for an EMB system according to an exemplary embodiment of the present disclosure will be described with reference to Fig. 8 described.

[0053] Fig.8 is a flowchart for explaining a method for setting a gear ratio for an EMB system according to an exemplary embodiment of the present disclosure.

[0054] With reference to Fig. 8, the EMB system 100 may obtain a motor ripple generation order based on specification information of the motor 110 (S110).

[0055] That is, the EMB system 100 may obtain a motor ripple generation order based on specification information including the number of poles and the number of slots in the permanent magnet synchronous motor (PMSM).

[0056] That is, the motor ripple generation order may include a basic generation order including a plurality of basic orders obtained based on the number of poles and the number of slots. Here, the basic generation order may include a plurality of basic orders obtained based on a plurality of mechanical orders representing an order of ripple generated due to mechanical characteristics of the motor and a plurality of electrical orders representing an order of ripple generated due to electrical characteristics of the motor 110. The plurality of mechanical orders may include a first mechanical order, a second mechanical order, a third mechanical order, and a fourth mechanical order. The first mechanical order may represent the number of poles.The second mechanical sequence may represent the number of slots. The third mechanical sequence may represent the lowest common multiple of the number of poles and the number of slots. The fourth mechanical sequence may represent twice as many as the third mechanical sequence. Furthermore, the plurality of electrical sequences may include a first electrical sequence and a second electrical sequence. The first electrical sequence may represent half the number of poles. The second electrical sequence may represent the number of poles. In other words, the basic generation sequence may include a plurality of basic sequences that include the plurality of mechanical sequences and the plurality of electrical sequences in total.

[0057] Furthermore, the motor ripple generation order may further include an extended generation order obtained by expanding the basic generation order to a preset extended range. Here, the extended generation order may include a plurality of extended orders obtained by expanding each of the plurality of basic orders of the basic generation order using the extended range. In this case, the extended range may represent ±1 and / or ±2.

[0058] In this case, when the motor 110 is operated at a frequency of a preset reference value (1,000 rpm or the like) or above, or the motor 110 is operated at a varying speed rather than a constant speed, the motor ripple generation order may further include the extended generation order obtained by expanding the basic generation order to the extended range.

[0059] Thereafter, the EMB system 100 may set a gear ratio of the reduction gear 120 using the obtained motor ripple generation order (S120).

[0060] That is, the EMB system 100 can select the gear ratio of the reduction gear 120 from a group of reduction gear ratio candidates by using the reduction gear ratio candidates remaining after excluding the obtained motor ripple generation order. In other words, the EMB system 100 can select the gear ratio of the reduction gear 120 from a group of reduction gear ratio candidates consisting of gear ratios selectable for the reduction gear 120 by using the reduction gear ratio candidates remaining after excluding the gear ratio candidates corresponding to all orders included in the motor ripple generation order.

[0061] Although it is described above that all the elements constituting the embodiment of the present disclosure are combined or operated in combination, the present disclosure is not necessarily limited to what has been described here. That is, two or more of the elements constituting the embodiment of the present disclosure may be selectively combined with each other or operated in combination with each other, as long as such a combination is within the scope of the present invention. Furthermore, although it is possible for each element to be implemented as its own individual hardware, it is also possible for some or all of the elements to be selectively combined with each other to be implemented as a computer program having a program module that performs the combined some or all of the functions in one or more pieces of hardware.Furthermore, the embodiment of the present invention can be realized by storing the computer program in computer-readable media, such as USB memory, CD-ROM, flash memory, etc., and reading and executing it by a computer. The computer-readable media may also include magnetic recording media, optical recording media, etc.

[0062] The above description is merely illustrative of the technical idea of ​​the present disclosure, and those skilled in the art to which the present disclosure refers may make various modifications, changes, and substitutions without departing from the essential features of the present disclosure. Therefore, the embodiments disclosed in the present disclosure and the accompanying drawings are not intended to limit the technical spirit of the present disclosure, but to explain the scope of the technical spirit of the present disclosure. The scope of the present disclosure should be interpreted by the following claims, and all technical teachings within the equivalent scope thereto should be construed as being included within the scope of the present disclosure.

Claims

[1] EMB system, comprising: an engine; and a reduction gear for amplifying an output of the motor, wherein a gear ratio of the reduction gear is selected from a group of reduction gear gear ratio candidates by using reduction gear gear ratio candidates remaining after excluding a motor ripple generation order obtained based on specification information of the motor. [2] The EMB system of claim 1, wherein the motor comprises a permanent magnet synchronous motor (PMSM), wherein the motor ripple generation order includes the number of poles and the number of slots in the PMSM. [3] The EMB system according to claim 2, wherein the motor ripple generation order comprises a basic generation order including a plurality of basic orders obtained based on the number of poles and the number of slots. [4] The EMB system according to claim 3, wherein the basic generation order comprises a plurality of basic orders obtained based on a plurality of mechanical orders representing an order of ripple generated due to mechanical characteristics of the motor and a plurality of electrical orders representing an order of ripple generated due to electrical characteristics of the motor. [5] The EMB system of claim 4, wherein the plurality of mechanical sequences comprises a first mechanical sequence representing the number of poles, a second mechanical sequence representing the number of slots, a third mechanical sequence representing the lowest common multiple of the number of poles and the number of slots, and a fourth mechanical sequence representing twice as many as the third mechanical sequence, and the plurality of electrical sequences comprises a first electrical sequence representing half the number of poles and a second electrical sequence representing the number of poles. [6] The EMB system of claim 5, wherein the basic generation sequence comprises a plurality of basic sequences comprising the plurality of mechanical sequences and the plurality of electrical sequences in total. [7] The EMB system according to any one of claims 3 to 6, wherein the motor ripple generation order further comprises an extended generation order obtained by extending the basic generation order to a preset extended range. [8] The EMB system according to claim 7, wherein the extended generation order comprises a plurality of extended orders obtained by extending each of the plurality of basic orders of the basic generation order using the extended range. [9] The EMB system of claim 8, wherein the extended range is ±1 and / or ±2. [10] The EMB system according to any one of claims 7 to 9, wherein, when the motor is operated at a frequency of a preset reference value or above or the motor is operated at a varying speed, the motor ripple generation order further comprises the extended generation order obtained by extending the basic generation order to the extended range. [11] An EMB system according to any preceding claim, wherein the gear ratio of the reduction gear is selected from a group of reduction gear gear ratio candidates consisting of gear ratios selectable for the reduction gear by using reduction gear gear ratio candidates remaining after excluding gear ratio candidates corresponding to all orders included in the motor ripple generation order. [12] A method for adjusting a gear ratio of an electromechanical braking (EMB) system comprising a motor and a reduction gear for amplifying an output of the motor, the method comprising: Obtaining a motor ripple generation order based on motor specification information; and Selecting a gear ratio of the reducer from a group of reducer gear ratio candidates by using reducer gear ratio candidates remaining after excluding the obtained motor ripple generation order. [13] The method of claim 12, wherein the motor comprises a permanent magnet synchronous motor (PMSM), wherein obtaining a motor ripple generation order comprises obtaining the motor ripple generation order based on the specification information including the number of poles and the number of slots in the PMSM. [14] The method according to claim 13, wherein the motor ripple generation order comprises a basic generation order including a plurality of basic orders obtained based on the number of poles and the number of slots. [15] The method according to claim 14, wherein the basic generation order comprises a plurality of basic orders obtained based on a plurality of mechanical orders representing an order of ripple generated due to mechanical characteristics of the motor and a plurality of electrical orders representing an order of ripple generated due to electrical characteristics of the motor. [16] The method of claim 15, wherein the plurality of mechanical sequences comprises a first mechanical sequence representing the number of poles, a second mechanical sequence representing the number of slots, a third mechanical sequence representing the lowest common multiple of the number of poles and the number of slots, and a fourth mechanical sequence representing twice as many as the third mechanical sequence, and the plurality of electrical sequences comprises a first electrical sequence representing half the number of poles and a second electrical sequence representing the number of poles. [17] The method of claim 16, wherein the basic generation sequence comprises a plurality of basic sequences comprising the plurality of mechanical sequences and the plurality of electrical sequences in total. [18] The method according to any one of claims 14 to 17, wherein the motor ripple generation order further comprises an extended generation order obtained by extending the basic generation order to a preset extended range. [19] The method of claim 18, wherein the extended generation order comprises a plurality of extended orders obtained by extending each of the plurality of basic orders of the basic generation order using the extended range. [20] The method according to claim 18 or 19, wherein, when the motor is operated at a frequency of a preset reference value or above or the motor is operated at a varying speed, the motor ripple generation order further comprises the extended generation order obtained by extending the basic generation order to the extended range.

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