阅读说明：本技术 电动马达的驱动装置以及电动泵装置 (Electric motor drive device and electric pump device ) 是由 宫本裕章 相泽浩一 于 2019-07-29 设计创作，主要内容包括：本发明提供能够在抑制结构变复杂的同时,在多个转速的区域检测失步的电动马达的驱动装置以及电动泵装置。所述电动马达(110)的驱动装置(100)为不具有位置检测传感器的电动马达(110)的驱动装置(100),具备：驱动部(20),其根据从外部输入的指令值驱动电动马达(110)；转速检测部(13),其检测由驱动部(20)驱动的电动马达(110)的转速；以及失步判断部(15),其在通过转速检测部(13)检测出的转速小于规定的阈值的情况下,判断为电动马达(110)正在失步。并且,构成为规定的阈值根据从外部输入的指令值被变更。(The invention provides a drive device of an electric motor and an electric pump device capable of detecting step-out in a plurality of rotating speed areas while inhibiting the structure from becoming complicated. The drive device (100) for the electric motor (110) is a drive device (100) for an electric motor (110) that does not have a position detection sensor, and is provided with: a drive unit (20) that drives the electric motor (110) according to a command value input from the outside; a rotation speed detection unit (13) that detects the rotation speed of an electric motor (110) driven by a drive unit (20); and a step-out determination unit (15) that determines that the electric motor (110) is stepping out when the rotation speed detected by the rotation speed detection unit (13) is less than a predetermined threshold value. The predetermined threshold value is changed in accordance with a command value input from the outside.)

1. A drive device for an electric motor, which does not have a position detection sensor, is provided with:

a drive unit that drives the electric motor in accordance with a command value input from the outside;

a rotation speed detection unit that detects a rotation speed of the electric motor driven by the drive unit; and

a step-out determination unit that determines that the electric motor is stepping out when the rotation speed detected by the rotation speed detection unit is less than a predetermined threshold value,

the predetermined threshold value is configured to be changed in accordance with the command value input from the outside.

2. The drive device of an electric motor according to claim 1,

the predetermined threshold includes: a 1 st threshold value when the command value inputted from the outside is equal to or more than a predetermined value, and a 2 nd threshold value smaller than the 1 st threshold value when the command value inputted from the outside is smaller than the predetermined value,

the predetermined threshold value is configured to be selected from either the 1 st threshold value or the 2 nd threshold value in accordance with the command value input from the outside.

3. The drive device of an electric motor according to claim 1 or 2,

the step-out determining unit is configured to stop the voltage command to the electric motor and stop the electric motor when the step-out determining unit determines that the electric motor is being stepped out.

4. The drive device of an electric motor according to claim 3,

the step-out determining unit is configured to restart the stopped electric motor when the step-out determining unit determines that the electric motor is being stepped out.

5. The drive device of an electric motor according to claim 2,

the step-out determining unit is configured to stop the voltage command to the electric motor and stop the electric motor when the step-out determining unit determines that the electric motor is being stepped out.

6. The drive device of an electric motor according to any one of claims 1 to 7,

the command value input from the outside is a duty ratio corresponding to a target rotation speed of the electric motor.

7. An electric pump device is provided with:

an electric pump driven by an electric motor without a position detection sensor; and

a drive device for the electric motor, wherein the drive device comprises a motor,

the driving device of the electric motor includes:

a drive unit that drives the electric motor in accordance with a command value input from the outside;

a rotation speed detection unit that detects a rotation speed of the electric motor driven by the drive unit; and

a step-out determination unit that determines that the electric motor is stepping out when the rotation speed detected by the rotation speed detection unit is less than a predetermined threshold value,

the predetermined threshold value is configured to be changed in accordance with the command value input from the outside.

Technical Field

The present invention relates to a drive device for an electric motor and an electric pump device without a position detection sensor, and more particularly to a drive device for an electric motor and an electric pump device provided with a step-out determination unit that determines that the electric motor is being stepped out.

Background

Conventionally, there is known a brushless motor control device which includes a step-out determining unit for determining that an electric motor is being stepped out and which does not include a position detection sensor (see, for example, patent document 1).

The brushless motor control device described in patent document 1 includes an abnormality detection means (step-out determination unit) for determining that the brushless motor is abnormal in response to a situation in which the shaft error exceeds a predetermined reference value. Here, the "axis error" refers to an axis offset angle between a d-q axis as a rotation coordinate axis and a virtual d-q axis in control when a magnetic flux axis of the brushless motor is a d axis and an axis orthogonal to the d axis is a q axis. Specifically, in patent document 1, the shaft error is calculated from the voltage command value, the current value, the rotation speed, and the brushless motor constant by using a predetermined equation. Then, based on the fact that the shaft error exceeds a preset reference value, it is determined that the brushless motor is abnormal.

In addition, in the case of the brushless motor, if the shaft error is within a range of ± 90 degrees, the brushless motor is stable. In addition, when the field weakening control is performed, the axis error is controlled within a range of ± 60 degrees. Therefore, in patent document 1, when the axis error exceeds ± 60 degrees, it is determined that the error is abnormal.

In addition, in a brushless motor without a position detection sensor, the position of the rotor is detected based on an induced voltage generated in the brushless motor. However, in a region where the rotation speed of the brushless motor is relatively low, no induced voltage (or weak induced voltage) of the brushless motor is generated, and therefore, the position of the brushless motor (rotor) cannot be detected. Therefore, in a region where the rotation speed of the brushless motor is relatively low, there is a possibility of step-out (the rotor rotates in a state of being out of synchronization with the input command value). Further, even in a region where the rotation speed of the brushless motor is relatively high, there is a possibility that step-out may occur due to a rapid change in the rotation speed of the rotor. In patent document 1, the axis error is calculated from the voltage command value. Therefore, it is considered that step-out is detected not only in a region where the rotation speed of the brushless motor is relatively low (a region where the duty ratio of the voltage command value is small) but also in a region where the rotation speed of the brushless motor is relatively high (a region where the duty ratio of the voltage command value is large). That is, it is considered that patent document 1 is configured to be able to detect step-out in a region of the rotation speeds of a plurality of brushless motors.

Patent document 1: japanese patent laid-open No. 2012 and 60781

However, the brushless motor control device described in patent document 1 determines an abnormality (step-out or the like) of the brushless motor in a plurality of rotation speed regions, and therefore, it is necessary to calculate a shaft error by a predetermined equation based on a voltage command value, a current value, a rotation speed, and a brushless motor constant. Here, in general, in order to detect a current value, an amplifier for amplifying a signal of the detected current is required. Therefore, the structure described in patent document 1 has a problem that a structure for detecting an abnormality of the brushless motor becomes relatively complicated.

Disclosure of Invention

The present invention has been made to solve the above-described problems, and an object of 1 of the present invention is to provide a drive device for an electric motor and an electric pump device capable of detecting step-out in a plurality of rotation speed regions while suppressing the complexity of the configuration.

In order to achieve the above object, a drive device for an electric motor according to claim 1 of the present invention is a drive device for an electric motor without a position detection sensor, comprising: a drive unit that drives the electric motor according to a command value input from the outside; a rotation speed detection unit that detects a rotation speed of an electric motor driven by the drive unit; and a step-out determining unit configured to determine that the electric motor is stepping out when the rotation speed detected by the rotation speed detecting unit is less than a predetermined threshold value, and the predetermined threshold value is changed in accordance with a command value input from the outside.

In the electric motor driving device according to claim 1 of the present invention, as described above, the step-out determining unit is provided for determining that the electric motor is stepping out when the rotation speed detected by the rotation speed detecting unit is less than a predetermined threshold value, and the predetermined threshold value is changed in accordance with an instruction value input from the outside. Since the predetermined threshold value is changed in accordance with the command value inputted from the outside in this way, it is possible to detect step-out from the predetermined threshold value corresponding to the command value in the range of a plurality of command values (i.e., the number of revolutions). Since step-out is determined only based on the rotation speed (whether or not the rotation speed is less than a predetermined threshold), it is not necessary to provide an amplifier or the like for detecting the current value, unlike the case where a current value or the like is used in addition to the rotation speed in determining step-out. Therefore, it is possible to detect step-out in a region of a plurality of rotation speeds while suppressing the structure from becoming complicated. Further, since whether or not step-out is determined by comparing the rotation speed detected by the rotation speed detecting unit with a predetermined threshold value (whether or not the rotation speed is smaller than the predetermined threshold value), it is not necessary to perform calculation by a relatively complicated equation. Therefore, the load on the drive device can be suppressed from increasing.

In the electric motor driving device according to claim 1, it is preferable that the predetermined threshold value includes a 1 st threshold value when the command value inputted from the outside is equal to or greater than the predetermined value, and a 2 nd threshold value smaller than the 1 st threshold value when the command value inputted from the outside is smaller than the predetermined value, and that one of the 1 st threshold value and the 2 nd threshold value is selected in accordance with the command value inputted from the outside.

With this configuration, when the command value input from the outside is equal to or greater than the predetermined value (in a region where the rotation speed is relatively high), it is possible to easily determine whether or not the electric motor is out of step based on the comparison between the rotation speed detected by the rotation speed detection unit and the 1 st threshold value. In addition, when the command value inputted from the outside is smaller than a predetermined value (a region in which the rotation speed is relatively low), whether or not the electric motor is out of step can be easily determined based on the comparison between the rotation speed detected by the rotation speed detecting unit and the 2 nd threshold value.

In the electric motor driving device according to claim 1, it is preferable that the step-out determining unit stops the voltage command to the electric motor and stops the electric motor when determining that the electric motor is being stepped out.

In this configuration, since the electric motor is stopped when it is determined that the electric motor is out of step, continuation of driving of the electric motor can be suppressed in a state where the electric motor is out of step.

In this case, it is preferable that the step-out determining unit be configured to restart the stopped electric motor when the step-out determining unit determines that the electric motor is being stepped out.

Here, generally, when the electric motor is stopped, the rotor is configured to be stopped at a predetermined position determined in advance by the magnetic field of the permanent magnet. Further, by restarting the electric motor in a state where the rotor is stopped at a predetermined position, the electric motor can be started while suppressing step-out.

The electric pump device according to claim 2 of the present invention includes: an electric pump driven by an electric motor without a position detection sensor; and a drive device for the electric motor, the drive device for the electric motor comprising: a drive unit that drives the electric motor according to a command value input from the outside; a rotation speed detection unit that detects a rotation speed of an electric motor driven by the drive unit; and a step-out determining unit configured to determine that the electric motor is stepping out when the rotation speed detected by the rotation speed detecting unit is less than a predetermined threshold value, and the predetermined threshold value is changed in accordance with a command value input from the outside.

In the electric pump device according to claim 2 of the present invention, as described above, the drive device for driving the electric motor of the electric pump includes the step-out determining unit that determines that the electric motor is being stepped out when the rotation speed detected by the rotation speed detecting unit is less than the predetermined threshold value, and the predetermined threshold value is changed in accordance with the command value input from the outside. Since the predetermined threshold value is changed in accordance with the command value inputted from the outside in this way, it is possible to detect step-out from the predetermined threshold value corresponding to the command value in the range of a plurality of command values (i.e., the number of revolutions). Since step-out is determined only based on the rotation speed (whether or not the rotation speed is less than a predetermined threshold), it is not necessary to provide an amplifier or the like for detecting the current value, unlike the case where a current value or the like is used in addition to the rotation speed in determining step-out. Therefore, it is possible to provide an electric pump device capable of detecting step-out in a plurality of rotation speed regions while suppressing the complexity of the structure. Further, since whether or not step-out is determined by comparing the rotation speed detected by the rotation speed detecting unit with a predetermined threshold value (whether or not the rotation speed is smaller than the predetermined threshold value), it is not necessary to perform calculation by a relatively complicated equation. Therefore, the electric pump device can be provided in which the increase in the load on the drive device can be suppressed.

That is, in the electric motor driving device having another configuration of the present application, the command value input from the outside is a duty ratio corresponding to the target rotation speed of the electric motor. In this configuration, since step-out occurs due to the rotation speed of the electric motor, a predetermined threshold value for determining step-out can be appropriately selected in accordance with a command value input from the outside.

Drawings

Fig. 1 is a block diagram of a drive device (electric pump device) of an electric motor according to an embodiment.

Fig. 2 is a diagram showing a relationship between an input instruction and a predetermined threshold value for determining whether or not step-out is occurring in one embodiment.

Fig. 3 is a flowchart for explaining an operation of the electric motor driving device according to the embodiment.

Description of reference numerals:

13 … a rotation speed detection unit; 15 … step-out judging section; 20 … a drive part; 100 … driving device; 110 … electric motor; 200 … electric pump device; 210 … electric pump.

Detailed Description

Next, embodiments of the present invention will be explained with reference to the drawings.

The configuration of the drive device 100 (electric pump device 200) of the electric motor 110 according to the present embodiment will be described with reference to fig. 1 and 2. The electric motor 110 is a dc brushless motor having no position detection sensor.

As shown in fig. 1, the electric pump device 200 is configured to be driven by the electric motor 110. The electric pump device 200 is, for example, an electric pump device for cooling an inverter.

The driving device 100 includes an Integrated Circuit (IC) 10. The IC10 is configured to input a command value. Specifically, the command value is a duty ratio (%) corresponding to the target rotation speed of the electric motor 110.

Further, the IC10 includes a power supply voltage correction unit 11. The voltage of the power supply supplied to the IC10 is input to the power supply voltage correction unit 11. In addition, the voltage of the power supply supplied to the IC10 may fluctuate. Therefore, the power supply voltage correction unit 11 is configured to output a signal related to correction to the output PWM duty calculation unit 12 so that the fluctuation of the voltage of the power supply supplied to the IC10 does not affect the rotation speed of the electric motor 110.

Further, IC10 includes output PWM duty calculation unit 12. The output PWM duty calculation unit 12 is configured to generate a PWM signal based on the input command value and the correction-related signal output from the power supply voltage correction unit 11.

The driving device 100 includes a driving unit 20. The driving unit 20 is configured to drive the electric motor 110 in accordance with a command value input from the outside. Specifically, the driving unit 20 drives switching elements (not shown) inside the driving unit 20 based on the PWM signal output from the output PWM duty calculation unit 12. Accordingly, the electric motor 110 is driven at a desired rotational speed.

The driving device 100 further includes a position detection unit 30. The position detecting unit 30 is configured to detect (estimate) a position of a rotor (not shown) based on an induced voltage generated in the electric motor 110.

Further, IC10 includes a rotation speed detection unit 13. The rotation speed detecting unit 13 is configured to detect (estimate) the rotation speed of the rotor based on the position of the rotor (not shown) detected (estimated) by the position detecting unit 30. The rotation speed of the rotor detected by the rotation speed detector 13 is output to the outside of the IC 10.

Further, the IC10 includes a threshold value determination unit 14. The threshold value determining unit 14 is configured to determine a threshold value (rotation speed) for determining whether or not the electric motor 110 is out of step. Here, in the present embodiment, the predetermined threshold value is configured to be changed in accordance with a command value (duty ratio (%)) input from the outside. Specifically, as shown in fig. 2, the predetermined threshold includes a 1 st threshold when the command value input from the outside is equal to or greater than the predetermined value, and a 2 nd threshold smaller than the 1 st threshold when the command value input from the outside is smaller than the predetermined value. For example, the predetermined value of the command value (duty ratio) is 30%. For example, the 1 st threshold is 800 rpm. For example, the 2 nd threshold is 160 rpm. One of the 1 st threshold and the 2 nd threshold is selected as a predetermined threshold in accordance with a command value input from the outside. For example, the 1 st threshold and the 2 nd threshold are stored in a storage unit (not shown) in advance, and one of the 1 st threshold and the 2 nd threshold is selected based on the command value. Since step-out occurs due to the rotation speed of the electric motor, a predetermined threshold value for determining step-out can be appropriately selected in accordance with a command value (duty ratio) input from the outside.

As shown in fig. 1, in the present embodiment, IC10 includes step-out determining unit 15. The step-out determining unit 15 is configured to determine that the electric motor 110 is stepping out when the rotation speed detected by the rotation speed detecting unit 13 is less than a predetermined threshold value. The step-out determining unit 15 selects the 1 st threshold (e.g., 800rpm) when the command value (duty ratio) is, for example, 30% or more. When the rotation speed detected by the rotation speed detector 13 is less than the 1 st threshold value, the step-out determiner 15 determines that the electric motor 110 is being stepped out. Specifically, the step-out determining unit 15 determines that the electric motor 110 is out of step when the rotation speed detected by the rotation speed detecting unit 13 is less than the 1 st threshold value for a predetermined period of time (for example, 3 seconds). Therefore, step-out can be detected in a region where the rotation speed of the electric motor 110 is relatively high. For example, when the command value (duty ratio) is less than 30%, the step-out determining unit 15 selects the 2 nd threshold (e.g., 160 rpm). When the rotation speed detected by the rotation speed detector 13 is less than the 2 nd threshold value, the step-out determiner 15 determines that the electric motor 110 is being stepped out. Specifically, the step-out determining unit 15 determines that the electric motor 110 is out of step when the rotation speed detected by the rotation speed detecting unit 13 is less than the 2 nd threshold value for a predetermined period of time (for example, 3 seconds). Therefore, step-out can be detected in a region where the rotation speed of the electric motor 110 is relatively low.

In the present embodiment, when the step-out determining unit 15 determines that the electric motor 110 is out of step, the voltage command to the electric motor 110 is stopped and the electric motor 110 is stopped. Specifically, when it is determined by the step-out determining unit 15 that the electric motor 110 is being stepped out, the output of the PWM signal from the output PWM duty calculating unit 12 to the driving unit 20 is stopped. Thus, the electric motor 110 is stopped. The electric motor 110 is stopped for 1 second, for example. At this time, the rotor of the electric motor 110 stops at a predetermined position.

When the step-out determining unit 15 determines that the electric motor 110 is out of step, the stopped electric motor 110 is restarted. That is, the electric motor 110 is restarted in a state where the rotor of the electric motor 110 is stopped at a predetermined position. That is, the output of the PWM signal from the output PWM duty calculation unit 12 to the drive unit 20 is restarted. Therefore, the electric motor 110 is started while suppressing step-out.

Next, the operation of the drive device 100 for the electric motor 110 will be described with reference to fig. 3.

First, in step S1, an instruction value is input to the IC 10.

Next, in step S2, the threshold determination unit 14 determines a predetermined threshold. Specifically, when the command value is equal to or greater than a predetermined value, the 1 st threshold is selected. When the command value is smaller than a predetermined value, the 2 nd threshold is selected.

Next, in step S3, the power supply voltage correction unit 11 recognizes the voltage of the power supply to the IC10 by inputting the voltage of the power supply to the IC10 to the power supply voltage correction unit 11. Then, the power supply voltage correction unit 11 outputs a signal related to the correction to the output PWM duty calculation unit 12.

Next, in step S4, output PWM duty calculation unit 12 generates a PWM signal based on the input command value and the correction-related signal output from power supply voltage correction unit 11. Then, the electric motor 110 is driven by the driving unit 20 based on the generated PWM signal.

Next, at step S5, the rotation speed detecting unit 13 detects (estimates) the rotation speed of the rotor (not shown) from the position of the rotor detected (estimated) by the position detecting unit 30. Then, the step-out determining unit 15 recognizes the rotation speed of the rotor by inputting the detected rotation speed of the rotor to the step-out determining unit 15.

Next, in step S6, the step-out determining unit 15 determines whether or not the rotation speed detected by the rotation speed detecting unit 13 is less than a predetermined threshold value for a time period of, for example, 3 seconds. When the step-out determining unit 15 determines that the rotation speed is not less than the predetermined threshold value, the process returns to step S1. When the step-out determining unit 15 determines that the rotation speed is less than the predetermined threshold value, it determines that the electric motor 110 is step-out. Then, the process proceeds to step S7.

Next, in step S7, the voltage command to the electric motor 110 is stopped, and the electric motor 110 is stopped for, for example, 1 second.

Next, in step S8, the electric motor 110 is restarted.

(Effect of the present embodiment)

The present embodiment can obtain the following effects.

In the present embodiment, as described above, the predetermined threshold value for the step-out determining unit 15 to determine step-out is changed in accordance with the command value input from the outside. Therefore, since the predetermined threshold value is changed based on the command value inputted from the outside, it is possible to detect step-out from the predetermined threshold value corresponding to the command value in the region of a plurality of command values (i.e., the number of revolutions). Since step-out is determined only based on the rotation speed (whether or not the rotation speed is less than a predetermined threshold), it is not necessary to provide an amplifier or the like for detecting the current value, unlike the case where a current value or the like is used in addition to the rotation speed in determining step-out. Therefore, it is possible to detect step-out in a region of a plurality of rotation speeds while suppressing the structure from becoming complicated. Since whether or not step-out is determined by comparing the rotation speed detected by the rotation speed detecting unit 13 with a predetermined threshold value (whether or not the rotation speed is smaller than the predetermined threshold value), it is not necessary to perform calculation by a relatively complicated equation. Therefore, an increase in the load on the drive device 100 can be suppressed.

In the present embodiment, as described above, when the command value input from the outside is equal to or greater than the predetermined value (the region in which the rotation speed is relatively high), it is possible to easily determine whether or not the electric motor 110 is out of step based on the comparison between the rotation speed detected by the rotation speed detecting unit 13 and the 1 st threshold value. In addition, when the command value input from the outside is smaller than a predetermined value (a region in which the rotation speed is relatively low), whether or not the electric motor 110 is out of step can be easily determined based on the comparison between the rotation speed detected by the rotation speed detecting unit 13 and the 2 nd threshold value.

In the present embodiment, as described above, since the electric motor 110 is stopped when it is determined that the electric motor 110 is out of step, continuation of the driving of the electric motor 110 can be suppressed in a state where the electric motor 110 is out of step.

In the present embodiment, as described above, by restarting the electric motor 110 in a state in which the rotor is stopped at the predetermined position, the electric motor 110 can be started while suppressing step-out.

[ modified examples ]

The presently disclosed embodiments are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than the description of the above embodiments, and also includes all modifications (variations) within the meaning and scope equivalent to the claims.

For example, in the above-described embodiment, the example in which 2 thresholds (1 st threshold and 2 nd threshold) are used to determine that the electric motor is out of step has been described, but the present invention is not limited to this. For example, 3 or more thresholds may be used to determine that the electric motor is out of step. In addition, the threshold value for determining that the electric motor is out of step may be continuously changed in accordance with the command value.

In the above embodiment, the example in which the predetermined value (duty ratio) for selecting the 1 st threshold value and the 2 nd threshold value is 30% has been shown, but the present invention is not limited to this. For example, the predetermined value may be a value other than 30%.

In the above embodiment, the 1 st threshold is 800rpm, and the 2 nd threshold is 160rpm, but the present invention is not limited thereto. For example, the 1 st threshold and the 2 nd threshold may be values other than the above values.

In the above-described embodiment, the example in which the electric motor is stopped for 1 second when the step-out determining unit determines that the electric motor is being stepped out has been described, but the present invention is not limited to this. For example, the period of time during which the electric motor is stopped may be a value other than 1 second.

In the above-described embodiment, the electric pump device is exemplified as the electric water pump device, but the present invention is not limited thereto. For example, the present invention can be applied to an electric pump device such as an electric oil pump device.