Electric pump and method for notifying a failure state of an electric pump

Abstract

An electric pump includes a pump, a motor that drives the pump, a motor drive section that has a switching element and drives the motor using electric power output from the switching element, and a control section that outputs a PWM signal that drives the switching element to the motor drive section, the PWM signal output from the control section being used for monitoring a state of the motor, wherein, at the time of abnormal stop of the motor, the control section sets a frequency of the PWM signal used in the monitoring of the state of the motor to a frequency outside a frequency range used at the time of normal operation of the motor.

Description

TECHNICAL FIELD

[0001] The present application relates to an electric pump and a method for notifying a failure state of an electric pump.

[0002] This application claims priority based on U.S. Provisional Application No. 62 / 958,313 filed on January 8, 2020, and the contents of which are incorporated herein. BACKGROUND

[0003] In Patent Literature 1, an electric pump provided with a control section that outputs a pulse signal showing a rotational state of a motor is described.

[0004] In the electric pump described in Patent Literature 1, the motor drives a pump connected to the motor, and a drive section including a plurality of semiconductor switching elements drives the motor by a three-phase alternating voltage. An input signal for driving the motor is input from an ECU (Electronic Control Unit) to the control section of the electric pump. The control section of the electric pump outputs a drive signal for driving the motor to the drive section based on the input signal input from the ECU. Further, the control section of the electric pump outputs a pulse signal showing the rotational state of the motor to the ECU. The control section is configured so that both the frequency and the duty of the pulse signal are changed so as to be able to discriminate that the motor is in a driving state or a stopped state, and a plurality of states of the motor in the stopped state. Specifically, the control section combines information of the frequency and information of the duty of the pulse signal, and outputs one pulse signal to the ECU. The control section is configured so that the frequency and the duty of one pulse signal can be individually changed (controlled).

[0005] Further, in Patent Literature 1, the following content or the like is described: in a case where the motor is in the stopped state, the control section sets the frequency of the pulse signal to 4 Hz, and the control section changes the duty of the pulse signal in correspondence with the plurality of states of the motor in the stopped state.

[0006] Further, in Patent Literature 1, the following content or the like is described: in a case where the motor is normally stopped, the control section sets the frequency of the pulse signal to 4 Hz, and sets the duty of the pulse signal to 50%, and in the case where the motor is normally stopped, the input signal sent from the ECU to the control section is a stop signal for stopping the motor.

[0007] Further, in Patent Literature 1, the following content is described: in a case where the motor is in the driving state (i.e., not in the stopped state), the control section makes the pulse signal variable in a frequency range different from 4 Hz in accordance with the rotational speed of the motor. In the electric pump described in Patent Literature 1, in a case where the rotational speed of the motor is 160 rpm or less, the frequency of the pulse signal is set to 4 Hz (although not in the stopped state), and in a case where the rotational speed of the motor is greater than 160 rpm, the frequency of the pulse signal is once functionally made larger as the rotational speed of the motor becomes larger.

[0008] Further, in Patent Literature 1, it is described that, in a case where the motor is normally driven, the control section sets the duty ratio of the pulse signal to 50%, and in a case where the motor is in an abnormal driving state due to the idling of the pump, the control section sets the duty ratio of the pulse signal to 70%, as long as the duty ratio in the state where the motor is normally driven and the duty ratio in the state where the motor is abnormally driven are different from each other.

[0009] Prior Art Documents

[0010] Patent Literature

[0011] Patent Literature 1: Japanese Patent Application Publication No. 2019-080382. SUMMARY

[0012] PROBLEMS TO BE SOLVED BY THE INVENTION

[0013] In a general electric pump in which a PWM (Pulse Width Modulation) signal is used as an I / F (interface) signal, the frequency of the PWM signal output (emitted) from a control section is used as a parameter showing the rotational speed of a motor.

[0014] In order to communicate the failure state of the motor of the electric pump to an ECU or the like, in a case where both the frequency and the duty ratio of the signal are changed as in the technology described in Patent Literature 1, the ECU or the like needs to recognize both the frequency and the duty ratio of the signal, which can increase the burden on the processing capacity of the ECU or the like.

[0015] In view of the above-described problems, an object of the present application is to provide an electric pump and a failure state notification method of an electric pump, which can suppress an increase in the burden of processing for monitoring the state of a motor and can monitor the state of the motor at the time of abnormal stop in detail.

[0016] MEANS FOR SOLVING THE PROBLEMS

[0017] One embodiment of the present application is an electric pump including: a pump; a motor that drives the pump; a motor drive section having a switching element, the motor being driven by electric power output from the switching element; and a control section that outputs a PWM signal that drives the switching element to the motor drive section, the PWM signal output from the control section being used for monitoring the state of the motor, wherein, at the time of abnormal stop of the motor, the control section sets the frequency of the PWM signal used for monitoring the state of the motor to a frequency outside the frequency range used at the time of normal operation of the motor.

[0018] One embodiment of the present application is an electric pump including: a pump; a motor that drives the pump; a motor drive unit that has a switching element and drives the motor using electric power output from the switching element; and a control unit that outputs a PWM signal that drives the switching element to the motor drive unit, the PWM signal output from the control unit being used for monitoring a state of the motor, wherein the control unit sets a duty ratio of the PWM signal used in the monitoring of the state of the motor at an abnormal stop of the motor to a duty ratio different from a duty ratio used at a normal time of the motor, and the control unit includes an output switching unit that switches whether or not to output the PWM signal to the motor drive unit, the output switching unit not outputting the PWM signal used in the monitoring of the state of the motor at the abnormal stop of the motor to the motor drive unit.

[0019] One embodiment of the present application is an electric pump including: a pump; a motor that drives the pump; a motor drive unit that has a switching element and drives the motor using electric power output from the switching element; and a control unit that outputs a PWM signal that drives the switching element to the motor drive unit, the PWM signal output from the control unit being used for monitoring a state of the motor, wherein the control unit sets a frequency of the PWM signal used in the monitoring of the state of the motor at an abnormal stop of the motor to a frequency outside a frequency range used at a normal time of the motor, and sets a duty ratio of the PWM signal used in the monitoring of the state of the motor to a duty ratio different from a duty ratio used at the normal time of the motor.

[0020] One embodiment of the present application is a method for notifying a failure state of an electric pump including: a pump; a motor that drives the pump; a motor drive unit that has a switching element and drives the motor using electric power output from the switching element; and a control unit that outputs a PWM signal that drives the switching element to the motor drive unit, the PWM signal output from the control unit being used for monitoring a state of the motor, wherein the method includes: a first step in which the control unit sets a frequency of the PWM signal used in the monitoring of the state of the motor at a normal time of the motor to a frequency in a first frequency range; and a second step in which the control unit sets the frequency of the PWM signal used in the monitoring of the state of the motor at an abnormal stop of the motor to a frequency in a second frequency range different from the first frequency range.

[0021] One embodiment of the present application is a failure state notification method for an electric pump including a pump, a motor that drives the pump, a motor drive unit that has a switching element and drives the motor using electric power output from the switching element, and a control unit that outputs a PWM signal that drives the switching element to the motor drive unit, the PWM signal output from the control unit being used for monitoring a state of the motor, in which the method includes a first step in which the control unit sets a duty ratio of the PWM signal used for monitoring the state of the motor to a first duty ratio at a normal time of the motor, and a second step in which the control unit sets the duty ratio of the PWM signal used for monitoring the state of the motor to a second duty ratio different from the first duty ratio at an abnormal stop of the motor, the PWM signal used for monitoring the state of the motor at the abnormal stop of the motor not being output to the motor drive unit.

[0022] Effects of Invention

[0023] According to the present application, an electric pump and a failure state notification method for an electric pump that can suppress an increase in the burden of processing for monitoring a state of a motor and can monitor the state of the motor at an abnormal stop in detail can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a view that shows an example of the structure of an electric pump and the like of the first embodiment;

[0025] Figure 2 is a view that shows an example of the relationship between the rotational speed [rpm] of a motor at a normal time and at over-rotation and the frequency [Hz] of a PWM signal output from a control unit to a motor drive unit and the like;

[0026] Figure 3 is a view that shows an example of the waveform of the PWM signal output from the control unit in the case shown by point A of Figure 2 ;

[0027] Figure 4 is a view that shows the waveform of the PWM signal used for monitoring the state of the motor at an abnormal stop of the motor in the first example of the electric pump of the first embodiment;

[0028] Figure 5 is a view that shows the waveform of the PWM signal used for monitoring the state of the motor at an abnormal stop of the motor in the third example of the electric pump of the first embodiment;

[0029] Figure 6 is a view that shows the waveform of the PWM signal used for monitoring the state of the motor at an abnormal stop of the motor in the fourth example of the electric pump of the first embodiment;

[0030] Figure 7 is a flowchart for explaining an example of the processing performed in the electric pump of the first embodiment;

[0031] Figure 8 is a graph showing a waveform of a PWM signal used in monitoring of the state of the motor at the time of abnormal stop of the motor in the first example of the electric pump of the second embodiment;

[0032] Figure 9 is a graph showing a waveform of a PWM signal used in monitoring of the state of the motor at the time of abnormal stop of the motor in the third example of the electric pump of the second embodiment;

[0033] Figure 10 is a graph showing a waveform of a PWM signal used in monitoring of the state of the motor at the time of abnormal stop of the motor in the fourth example of the electric pump of the second embodiment;

[0034] Figure 11 is a flowchart for explaining an example of the processing performed in the electric pump of the second embodiment. DETAILED DESCRIPTION

[0035] Hereinafter, an embodiment of the electric pump and the failure state notification method of the electric pump of the present application will be described.

[0036] <First Embodiment>

[0037] Figure 1 is a graph showing an example of the structure of the electric pump 1 and the like of the first embodiment.

[0038] In the example shown in FIG. 1, the electric pump 1 is provided with a pump 11, a motor 12, a motor drive section 13, and a control section 14. Figure 1

[0039] The pump 11 performs pressure feeding and the like of a fluid (medium) such as water, oil, fuel, and the like. The motor 12 drives the pump 11.

[0040] The motor drive section 13 is, for example, an inverter circuit or the like, and is provided with a switching element 13A and a rotational speed information processing section 13B. The switching element 13A is, for example, a semiconductor switching element such as an IGBT (Insulated Gate Bipolar Transistor), a MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor), or the like. The motor drive section 13 drives the motor 12 by electric power output from the switching element 13A. The rotational speed information processing section 13B acquires information showing the rotational speed of the motor 12 from the motor 12, and sends it to the control section 14. ​

[0041] The control section 14, which is, for example, a gate drive circuit or the like, outputs a PWM (Pulse Width Modulation) signal for driving the switching element 13A to the motor drive section 13.

[0042] In Figure 1 In the example shown, the monitoring device MD monitors the state of the motor 12. The PWM signal output from the control section 14 is used for the monitoring of the state of the motor 12 by the monitoring device MD.

[0043] That is, in Figure 1 In the example shown, the control section 14 is configured to be able to output the PWM signal to both the motor drive section 13 and the monitoring device MD. In detail, the control section 14 has an output switching section 14A and a rotational speed feedback section 14B. The output switching section 14A switches whether or not to output the PWM signal to the motor drive section 13. The rotational speed feedback section 14B acquires information showing the rotational speed of the motor 12 transmitted by the rotational speed information processing section 13B. Further, the rotational speed feedback section 14B generates a PWM signal showing the rotational speed of the motor 12 on the basis of the information showing the rotational speed of the motor 12. The control section 14 transmits the PWM signal showing the rotational speed of the motor 12 generated by the rotational speed feedback section 14B to the monitoring device MD.

[0044] That is, in Figure 1 In the example shown, the control section 14 is able to output the PWM signal for driving the switching element 13A to the motor drive section 13, and is able to output the PWM signal showing the rotational speed of the motor 12 to the monitoring device MD.

[0045] Figure 2 is a graph showing an example of the relationship between the rotational speed (rotational velocity) [rpm] of the motor 12 at the time of normal rotation and the time of over-rotation and the frequency [Hz] of the PWM signal output from the control section 14 to the motor drive section 13 or the like. In the normal time of the motor 12, the time of normal rotation of the motor 12 and the time of normal stop of the motor 12 are included.

[0046] In Figure 2 In the example shown, as shown by point A, when the motor 12 is stably rotating at 5000 [rpm], a PWM signal of 125 [Hz] is output from the control section 14 to the motor drive section 13, and is output from the control section 14 to the monitoring device MD.

[0047] As shown by point B, when the motor 12 is stably rotating at 800 [rpm], a PWM signal of 20 [Hz] is output from the control section 14 to the motor drive section 13, and is output from the control section 14 to the monitoring device MD.

[0048] As shown at point C, at the time of normal stop of the motor 12 (i.e., at the time of normality of the motor 12 and the rotational speed of the motor 12 is 0 [rpm]), the PWM signal of 4 [Hz] is not output from the control section 14 to the motor drive section 13, but is output from the control section 14 to the monitoring device MD.

[0049] As shown at point D, at the time of rotation of the motor 12 at 8000 [rpm] (in detail, over-rotation), the PWM signal of 200 [Hz] is output from the control section 14 to the motor drive section 13, and is output from the control section 14 to the monitoring device MD.

[0050] Figure 3 is a graph showing an example of a waveform of the PWM signal output from the control section 14 in the case shown at point A of Figure 2 In detail, Figure 3 (A) shows an example of a waveform of the PWM signal output from the control section 14 in the case shown at point A of Figure 2 (B) shows an example of a waveform of the PWM signal output from the control section 14 in the case shown at point B of Figure 3 (C) shows an example of a waveform of the PWM signal output from the control section 14 in the case shown at point C of Figure 2 (D) shows an example of a waveform of the PWM signal output from the control section 14 in the case shown at point D of Figure 3 Figure 2 In the example shown in Figure 3 and Figure 2 (A), when the motor 12 is stably rotating at 5000 [rpm], the control section 14 outputs the PWM signal of which the frequency is 125 [Hz] and the duty ratio is 50 [%] to the monitoring device MD. Therefore, the monitoring device MD which receives the PWM signal of which the frequency is 125 [Hz] and the duty ratio is 50 [%] can recognize that the motor 12 is stably rotating at 5000 [rpm]. At this time, the control section 14 outputs the PWM signal for rotating the motor 12 at 5000 [rpm] to the motor drive section 13.

[0051] In the example shown in Figure 2 and Figure 3 (A), when the motor 12 is stably rotating at 5000 [rpm], the control section 14 outputs the PWM signal of which the frequency is 125 [Hz] and the duty ratio is 50 [%] to the monitoring device MD. Therefore, the monitoring device MD which receives the PWM signal of which the frequency is 125 [Hz] and the duty ratio is 50 [%] can recognize that the motor 12 is stably rotating at 5000 [rpm]. At this time, the control section 14 outputs the PWM signal for rotating the motor 12 at 5000 [rpm] to the motor drive section 13.

[0052] In the example shown in Figure 2 and Figure 3 ​In the example shown in (B), when the motor 12 is rotating stably at 800 rpm, the control unit 14 outputs a PWM signal with a frequency of 20 Hz and a duty cycle of 50% to the monitoring device MD. Therefore, the monitoring device MD, which receives the PWM signal with a frequency of 20 Hz and a duty cycle of 50%, can recognize that the motor 12 is rotating stably at 800 rpm. At this time, the control unit 14 outputs the PWM signal used to make the motor 12 rotate at 800 rpm to the motor control unit 13.

[0053] exist Figure 2 and Figure 3 In the example shown in (C), when the motor 12 stops normally, the control unit 14 outputs a PWM signal with a frequency of 4 Hz and a duty cycle of 50% to the monitoring device MD. Therefore, the monitoring device MD, which receives the PWM signal with a frequency of 4 Hz and a duty cycle of 50%, can recognize that the motor 12 has stopped normally. At this time, the control unit 14 does not output the PWM signal to the motor control unit 13.

[0054] exist Figure 2 and Figure 3 In the example shown in (D), when motor 12 rotates at 8000 rpm, control unit 14 outputs a PWM signal with a frequency of 200 Hz and a duty cycle of 50% to motor drive unit 13 and monitoring device MD. Therefore, monitoring device MD, which receives the PWM signal with a frequency of 200 Hz and a duty cycle of 50%, can detect that motor 12 is rotating at 8000 rpm. In detail, monitoring device MD estimates that electric pump 1 has entered an abnormal load reduction state, for example, due to leakage of the pressurized medium.

[0055] exist Figure 2 and Figure 3 In the example shown, Figure 2 The intervals indicated by the double-headed arrows (the interval where the frequency of the PWM signal is higher than 4 [Hz] and less than 20 [Hz] (the interval where the speed of motor 12 is higher than 0 [rpm] and less than 800 [rpm]) and the interval where the frequency of the PWM signal is higher than 125 [Hz] (the interval where the speed of motor 12 is higher than 5000 [Hz])) correspond to areas that are not normally used.

[0056] Figure 4 This is a diagram showing the waveform of the PWM signal used in monitoring the state of the motor 12 in a first example of the electric pump 1 according to the first embodiment, when the motor 12 stops abnormally. More specifically, Figure 4(A) shows an example of the waveform of the PWM signal output from the control unit 14 when the motor 12 stops abnormally due to an excessive voltage of the power supply (not shown) supplying power to the motor 12 (i.e., when the power supply voltage is abnormally high and the speed of the motor 12 is 0 [rpm]). Figure 4 (B) shows an example of the waveform of the PWM signal output from the control unit 14 when the motor 12 stops abnormally due to the voltage of the power supply supplying power to the motor 12 being too low (i.e., when the power supply voltage is abnormally low and the speed of the motor 12 is 0 [rpm]). Figure 4 (C) shows an example of the waveform of the PWM signal output from the control unit 14 when the motor 12 stops abnormally due to excessive temperature (i.e., when the temperature is abnormally high and the speed of the motor 12 is 0 [rpm]).

[0057] exist Figure 4 In the example shown in (A), when the motor 12 stops abnormally due to excessive power supply voltage, the control unit 14 outputs a PWM signal with a frequency of 1 Hz and a duty cycle of 50% to the monitoring device MD. Therefore, the monitoring device MD, which receives the PWM signal with a frequency of 1 Hz and a duty cycle of 50%, can identify that the motor 12 has stopped abnormally due to excessive power supply voltage.

[0058] exist Figure 4 In the example shown in (B), when the motor 12 stops abnormally due to insufficient power supply voltage, the control unit 14 outputs a PWM signal with a frequency of 2.5 Hz and a duty cycle of 50% to the monitoring device MD. Therefore, the monitoring device MD, which receives the PWM signal with a frequency of 2.5 Hz and a duty cycle of 50%, can identify that the motor 12 has stopped abnormally due to insufficient power supply voltage.

[0059] exist Figure 4 In the example shown in (C), when the motor 12 stops abnormally due to excessive temperature, the control unit 14 outputs a PWM signal with a frequency of 8 Hz and a duty cycle of 50% to the monitoring device MD. Therefore, the monitoring device MD, which receives the PWM signal with a frequency of 8 Hz and a duty cycle of 50%, can recognize that the motor 12 has stopped abnormally due to excessive temperature.

[0060] That is, in Figure 4 In the first example of the electric pump 1 of the first embodiment shown, when the motor 12 stops abnormally, the monitoring device MD can monitor the state of the motor 12 in detail when the abnormal stop is caused by simply changing the frequency of the PWM signal output from the control unit 14.

[0061] That is, in the first example of the electric pump 1 of the first embodiment, the duty ratio of the PWM signal output from the control portion 14 does not need to be varied, that is, the processing load of monitoring the state of the motor 12 does not need to be increased, and the monitoring device MD can identify the cause of the abnormal stop of the motor 12 (excessive large power supply voltage, excessive small power supply voltage, or excessive large motor temperature).

[0062] In other words, in the first example of the electric pump 1 of the first embodiment, at the time of the abnormal stop of the motor 12, the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to a frequency (1 [Hz], 2.5 [Hz], 8 [Hz]) outside the frequency range (4 [Hz], 20 [Hz] or more and 125 [Hz] or less) used at the time of the normal of the motor 12.

[0063] Therefore, in the first example of the electric pump 1 of the first embodiment, the monitoring device MD can identify the state of the normal stop of the motor 12 and the state of the abnormal stop of the motor 12 by identifying only the frequency of the PWM signal. In detail, the monitoring device MD can identify the cause of the abnormal stop of the motor 12 by identifying only the frequency of the PWM signal.

[0064] [Table 1]

[0065] .

[0066] Table 1 shows the PWM signal used in the monitoring of the state of the motor 12 at the time of the abnormal stop of the motor 12 in the second example of the electric pump 1 of the first embodiment.

[0067] As shown in Table 1, in the second example of the electric pump 1 of the first embodiment, at the time of the normal stop of the motor 12, the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 4 [Hz] in the frequency range (4 [Hz], 20 [Hz] or more and 125 [Hz] or less) used at the time of the normal of the motor 12, and sets the duty ratio of the PWM signal to 50 [%].

[0068] In the second example of the electric pump 1 of the first embodiment, at the time of the abnormal stop of the motor 12, and in the case where the failure state of the motor 12 is failure A (excessive small voltage of the power supply), the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 1 [Hz] outside the frequency range (4 [Hz], 20 [Hz] or more and 125 [Hz] or less) used at the time of the normal of the motor 12, and sets the duty ratio of the PWM signal to 50 [%].

[0069] In the second example of the electric pump 1 of the first embodiment, in a case where the abnormal stop of the motor 12 occurs and the failure state of the motor 12 is failure B ("excessive voltage" of the power supply), the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 2 [Hz] outside the frequency range (4 [Hz], 20 [Hz] or more and 125 [Hz] or less) used at the normal time of the motor 12, and sets the duty ratio of the PWM signal to 50 [%].

[0070] In the second example of the electric pump 1 of the first embodiment, in a case where the abnormal stop of the motor 12 occurs and the failure state of the motor 12 is failure C ("excessive current" of the motor 12), the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 6 [Hz] outside the frequency range (4 [Hz], 20 [Hz] or more and 125 [Hz] or less) used at the normal time of the motor 12, and sets the duty ratio of the PWM signal to 50 [%].

[0071] In the second example of the electric pump 1 of the first embodiment, in a case where the abnormal stop of the motor 12 occurs and the failure state of the motor 12 is failure D ("excessive heat" of the motor 12), the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 7 [Hz] outside the frequency range (4 [Hz], 20 [Hz] or more and 125 [Hz] or less) used at the normal time of the motor 12, and sets the duty ratio of the PWM signal to 50 [%].

[0072] In the second example of the electric pump 1 of the first embodiment, in a case where the abnormal stop of the motor 12 occurs and the failure state of the motor 12 is failure E ("motor lock"), the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 8 [Hz] outside the frequency range (4 [Hz], 20 [Hz] or more and 125 [Hz] or less) used at the normal time of the motor 12, and sets the duty ratio of the PWM signal to 50 [%].

[0073] In the second example of the electric pump 1 of the first embodiment, in a case where the abnormal stop of the motor 12 occurs and the failure state of the motor 12 is failure F ("instruction abnormality (ground short circuit) to the motor driving portion 13), the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 10 [Hz] outside the frequency range (4 [Hz], 20 [Hz] or more and 125 [Hz] or less) used at the normal time of the motor 12, and sets the duty ratio of the PWM signal to 50 [%].

[0074] In the second example of the electric pump 1 of the first embodiment, in a case where the abnormal stop of the motor 12 and the failure state of the motor 12 are the failure G ("instruction abnormality (frequency abnormality at the time of stop instruction)" to the motor driving portion 13), the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 12 [Hz] outside the frequency range (4 [Hz], 20 [Hz] or more and 125 [Hz] or less) used at the normal time of the motor 12, and sets the duty ratio of the PWM signal to 50 [%].

[0075] That is, in the second example of the electric pump 1 of the first embodiment, the duty ratio of the PWM signal used in the monitoring of the motor 12 in the states of the failure A ("excessively small voltage" of the power supply), the failure B ("excessively large voltage" of the power supply), the failure C ("excessively large current" of the motor 12), the failure D ("excessively large heat" of the motor 12), the failure E ("motor lock"), the failure F ("instruction abnormality (ground short circuit)" to the motor driving portion 13), and the failure G ("instruction abnormality (frequency abnormality at the time of stop instruction)" to the motor driving portion 13) is set to 50 [%] which is equal to the duty ratio used at the normal stop of the motor 12.

[0076] In the second example of the electric pump 1 of the first embodiment, at the normal rotation of the motor 12, the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 20 [Hz] to 125 [Hz] in the frequency range (4 [Hz], 20 [Hz] or more and 125 [Hz] or less) used at the normal time of the motor 12, and sets the duty ratio of the PWM signal to 50 [%].

[0077] That is, in the second example of the electric pump 1 of the first embodiment, at the abnormal stop of the motor 12, the monitoring device MD can monitor the state of the motor 12 at the abnormal stop in detail by changing only the frequency of the PWM signal output from the control portion 14.

[0078] That is, in the second example of the electric pump 1 of the first embodiment, it is not necessary to change the duty ratio of the PWM signal output from the control portion 14, that is, it is not necessary to increase the processing load of the monitoring of the state of the motor 12, and the monitoring device MD can identify the cause of the abnormal stop of the motor 12 (excessively large voltage of the power supply, excessively small voltage of the power supply, excessively large current of the motor, excessively large heat of the motor, motor lock, instruction abnormality (ground short circuit), or instruction abnormality (frequency abnormality at the time of stop instruction)).

[0079] Furthermore, in the second example of the electric pump 1 in the first embodiment, the output switching unit 14A of the control unit 14 does not output the PWM signal used for monitoring the motor 12 in the following states: fault A (power supply "too low voltage"), fault B (power supply "too high voltage"), fault C (motor 12 "overcurrent"), fault D (motor 12 "overheating"), fault E ("motor lockup"), fault F ("command abnormality to motor drive unit 13 (ground short circuit)"), and fault G ("command abnormality to motor drive unit 13 (frequency abnormality when stop command)").

[0080] As described above, in the second example of the electric pump 1 in the first embodiment, the monitoring device MD identifies seven fault states as the cause of abnormal stop of the motor 12 by recognizing the frequency of the PWM signal. However, in other examples of the electric pump 1 in the first embodiment, the monitoring device MD can also identify two fault states as the cause of abnormal stop of the motor 12 by recognizing the frequency of the PWM signal.

[0081] In this example, when the fault state of the motor 12 is the first fault state (e.g., "too low voltage" of the power supply), the control unit 14 sets the frequency of the PWM signal used in monitoring the state of the motor 12 to a first frequency (e.g., 1 Hz) outside the frequency domain used when the motor 12 is in normal operation (4 Hz, 20 Hz or more and 125 Hz or less).

[0082] When the fault state of motor 12 is a second fault state (e.g., "excessive voltage") that is different from the first fault state (e.g., "low voltage" of the power supply), the control unit 14 sets the frequency of the PWM signal used in monitoring the state of motor 12 to a second frequency (e.g., 2Hz) that is outside the frequency domain used when motor 12 is in normal operation (4Hz, 20Hz or more and 125Hz or less) and different from the first frequency (e.g., 1Hz).

[0083] Furthermore, the control unit 14 sets the duty cycle of the PWM signal used in monitoring the motor 12 in the first fault state (e.g., "too low voltage" of the power supply) and the duty cycle of the PWM signal used in monitoring the motor 12 in the second fault state (e.g., "too high voltage" of the power supply) to values ​​equal to the duty cycle (50%) used when the motor 12 is normally stopped.

[0084] In this example, the output switching unit 14A also does not output the PWM signal used in monitoring the motor 12 in the first fault state (e.g., "too low voltage" of the power supply) and the second fault state (e.g., "too high voltage" of the power supply) to the motor drive unit 13.

[0085] Figure 5 is a view showing a waveform of a PWM signal used in monitoring of the state of the motor 12 at the time of abnormal stop of the motor 12 in the third example of the electric pump 1 of the first embodiment.

[0086] As described above, in the second example of the electric pump 1 of the first embodiment, in the case where the abnormal stop of the motor 12 occurs and the failure state of the motor 12 is the failure G ("instruction abnormality (frequency abnormality at the time of stop instruction)" to the motor driving portion 13), the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 12 [Hz] which is outside the frequency range (4 [Hz], 20 [Hz] or more and 125 [Hz] or less) used at the normal time of the motor 12, and sets the duty ratio of the PWM signal to 50 [%].

[0087] On the other hand, in the third example of the electric pump 1 of the first embodiment, in the case where the abnormal stop of the motor 12 occurs and the failure state of the motor 12 is the failure G ("instruction abnormality (frequency abnormality at the time of stop instruction)" to the motor driving portion 13), the control portion 14 sets the PWM signal used in the monitoring of the state of the motor 12 to a signal composed of a pulse train in which a first pulse having a frequency of 8 [Hz] and a second pulse having a frequency of 15 [Hz] are combined as shown in Figure 5

[0088] That is, in the third example of the electric pump 1 of the first embodiment, the control portion 14 sets the PWM signal used in the monitoring of the state of the motor 12 at the time of abnormal stop of the motor 12 to a signal composed of a pulse train in which a first pulse having a first frequency (8 [Hz]) outside the frequency range (4 [Hz], 20 [Hz] or more and 125 [Hz] or less) used at the normal time of the motor 12 and a second pulse having a second frequency (15 [Hz]) different from the first frequency (8 [Hz]) and outside the frequency range (4 [Hz], 20 [Hz] or more and 125 [Hz] or less) used at the normal time of the motor 12 are combined.

[0089] Therefore, in the third example of the electric pump 1 of the first embodiment, the control portion 14 can output a plurality of PWM signals used in the monitoring of the state of the motor 12 at the time of abnormal stop of the motor 12 to the monitoring device MD, and can recognize a failure state more than seven kinds.

[0090] Further, in the third example of the electric pump 1 of the first embodiment, the output switching portion 14A also does not output the PWM signal used in the monitoring of the state of the motor 12 to the motor driving portion 13 at the time of abnormal stop of the motor 12.

[0091] Figure 6 ​is a view showing a waveform of a PWM signal used in monitoring of the state of the motor 12 at the time of abnormal stop of the motor 12 in the fourth example of the electric pump 1 of the first embodiment.

[0092] In the fourth example of the electric pump 1 of the first embodiment, in the case where the abnormal stop of the motor 12 occurs and the failure state of the motor 12 is the failure G ("instruction abnormality (frequency abnormality at the time of stop instruction)" to the motor driving portion 13), the control portion 14 sets the PWM signal used in monitoring of the state of the motor 12 to a signal composed of a pulse string in which a first pulse of a first frequency (8 [Hz]) obtained by repeating a first pulse of 8 [Hz] three times and a second pulse of a second frequency (15 [Hz]) obtained by repeating a second pulse of 15 [Hz] three times are combined, as shown in Figure 6

[0093] That is, in the fourth example of the electric pump 1 of the first embodiment, the control portion 14 sets the PWM signal used in monitoring of the state of the motor 12 to a signal composed of a pulse string in which a first pulse of a first frequency (8 [Hz]) obtained by repeating a first pulse of 8 [Hz] three times and a second pulse of a second frequency (15 [Hz]) obtained by repeating a second pulse of 15 [Hz] three times are combined, at the time of abnormal stop of the motor 12.

[0094] Therefore, in the fourth example of the electric pump 1 of the first embodiment, as in the third example of the electric pump 1 of the first embodiment, the control portion 14 can output a plurality of PWM signals used in monitoring of the state of the motor 12 to the monitoring device MD at the time of abnormal stop of the motor 12, and can recognize a failure state more than seven kinds.

[0095] Further, in the fourth example of the electric pump 1 of the first embodiment, the output switching portion 14A also outputs the PWM signal used in monitoring of the state of the motor 12 to the motor driving portion 13 at the time of abnormal stop of the motor 12.

[0096] Figure 7 is a flowchart for explaining one example of a process executed in the electric pump 1 of the first embodiment.

[0097] In the fourth example of the electric pump 1 of the first embodiment, in the case where the abnormal stop of the motor 12 occurs and the failure state of the motor 12 is the failure G ("instruction abnormality (frequency abnormality at the time of stop instruction)" to the motor driving portion 13), the control portion 14 sets the PWM signal used in monitoring of the state of the motor 12 to a signal composed of a pulse string in which a first pulse of a first frequency (8 [Hz]) obtained by repeating a first pulse of 8 [Hz] three times and a second pulse of a second frequency (15 [Hz]) obtained by repeating a second pulse of 15 [Hz] three times are combined, as shown in Figure 7 ​In the example shown, in step Sll, the control section 14 determines whether it is normal time of the motor. For example, in a case where the voltage of the power source that supplies power to the motor 12 is excessively large, in a case where the voltage of the power source is excessively small, in a case where the temperature of the motor 12 is excessively large (i.e., in a case of overheating of the motor 12), in a case where the current flowing through the motor 12 is excessively large (i.e., in a case of overcurrent of the motor 12), in a case where the motor is locked, in a case where an abnormality in the command to the motor drive section 13 (ground short) has occurred, in a case where an abnormality in the command to the motor drive section 13 (abnormal frequency at the time of stop command) has occurred, in a case where the motor 12 is in an over-rotation state, and the like, the control section 14 determines that it is an abnormality of the motor 12, and proceeds to step S17. On the other hand, in a case where the control section 14 determines that it is normal time of the motor, it proceeds to step S12.

[0098] In step S12, the control section 14 determines whether it is stop time of the motor. In a case where the control section 14 determines that it is stop time of the motor (i.e., in a case of normal stop of the motor 12), it proceeds to step S13. On the other hand, in a case where the control section 14 determines that it is not stop time of the motor (i.e., in a case of stable rotation of the motor 12), it proceeds to step S15.

[0099] In step S13, the control section 14 sets the frequency of the PWM signal to 4 [Hz] that is a frequency in a first frequency range (4 [Hz], 20 [Hz] or more and 125 [Hz] or less) used at normal time of the motor 12, and sets the duty ratio of the PWM signal to 50 [%].

[0100] Next, in step S14, the control section 14 does not output the PWM signal whose frequency (4 [Hz]) and duty ratio (50 [%]) are set in step S13 to the motor drive section 13, but outputs it to the monitoring device MD. The PWM signal output to the monitoring device MD is used for monitoring of the state of the motor 12.

[0101] In step S15, the control section 14 sets the frequency of the PWM signal to a frequency of 20 [Hz] or more and 125 [Hz] or less that is a frequency in the first frequency range (4 [Hz], 20 [Hz] or more and 125 [Hz] or less) used at normal time of the motor 12, and sets the duty ratio of the PWM signal to 50 [%].

[0102] Next, in step S16, the control section 14 outputs the PWM signal in which the frequency (a frequency of 20 [Hz] or more and 125 [Hz] or less) and the duty ratio (50 [%]) are set in step S15 to the monitoring device MD. The PWM signal output to the monitoring device MD is used for monitoring of the state of the motor 12. At this time, the control section 14 outputs the PWM signal for rotating the motor 12 at a rotational speed of 800 [rpm] or more and 5000 [rpm] or less to the motor control section 13.

[0103] In step S17, the control section 14 determines whether it is the stop of the motor. In the case where the control section 14 determines that it is the stop of the motor (i.e., the abnormal stop of the motor 12), the processing proceeds to step S18. On the other hand, in the case where the control section 14 determines that it is not the stop of the motor (i.e., the abnormal rotation of the motor 12), the processing proceeds to step S20.

[0104] In step S18, the control section 14 sets the frequency of the PWM signal to a frequency (e.g., 1 [Hz], 2.5 [Hz], 8 [Hz], or the like) in a second frequency range (a frequency range of less than 4 [Hz], higher than 4 [Hz], and lower than 20 [Hz]) different from the first frequency range (4 [Hz], 20 [Hz] or more and 125 [Hz] or less) used at the normal time of the motor 12, and sets the duty ratio of the PWM signal to 50 [%].

[0105] Next, in step S19, the control section 14 does not output the PWM signal in which the frequency (e.g., a frequency of 1 [Hz], 2.5 [Hz], 8 [Hz], or the like) and the duty ratio (50 [%]) are set in step S18 to the motor drive section 13, but outputs it to the monitoring device MD. The PWM signal output to the monitoring device MD is used for monitoring of the state of the motor 12.

[0106] In step S20, the control section 14 sets the frequency of the PWM signal to a frequency (e.g., 200 [Hz] or the like) higher than the first frequency range (4 [Hz], 20 [Hz] or more and 125 [Hz] or less) used at the normal time of the motor 12, and sets the duty ratio of the PWM signal to 50 [%].

[0107] Next, in step S21, the control section 14 outputs the PWM signal in which the frequency (e.g., 200 [Hz] or the like) and the duty ratio (50 [%]) are set in step S20 to the monitoring device MD. The PWM signal output to the monitoring device MD is used for monitoring of the state of the motor 12. At this time, the control section 14 outputs the PWM signal for rotating the motor 12 to the motor control section 13.

[0108] <Second Embodiment>

[0109] The second embodiment of the electric pump and the method for notifying the fault status of the electric pump of the present invention will be described below.

[0110] The electric pump 1 of the second embodiment is configured in the same way as the electric pump 1 of the first embodiment, except for the aspects described later. Therefore, the electric pump 1 of the second embodiment can achieve the same effects as the electric pump 1 of the first embodiment, except for the aspects described later.

[0111] Figure 8 This is a diagram showing the waveform of the PWM signal used in monitoring the state of motor 12 in the first example of the electric pump 1 according to the second embodiment when motor 12 stops abnormally. In detail, Figure 8 (A) shows an example of the waveform of the PWM signal output from the control unit 14 when the motor 12 stops abnormally due to the excessive voltage of the power supply supplying power to the motor 12 (i.e., when the power supply voltage is abnormally high and the speed of the motor 12 is 0 [rpm]). Figure 8 (B) shows an example of the waveform of the PWM signal output from the control unit 14 when the motor 12 stops abnormally due to the voltage of the power supply supplying power to the motor 12 being too low (i.e., when the power supply voltage is abnormally low and the speed of the motor 12 is 0 [rpm]). Figure 8 (C) shows an example of the waveform of the PWM signal output from the control unit 14 when the motor 12 stops abnormally due to excessive temperature (i.e., when the temperature is abnormally high and the speed of the motor 12 is 0 [rpm]).

[0112] exist Figure 8 In the example shown in (A), when the motor 12 stops abnormally due to excessive power supply voltage, the control unit 14 outputs a PWM signal with a frequency of 4 Hz and a duty cycle of 10 % to the monitoring device MD. Therefore, the monitoring device MD, which receives the PWM signal with a frequency of 4 Hz and a duty cycle of 10 % %, can identify that the motor 12 has stopped abnormally due to excessive power supply voltage.

[0113] exist Figure 8 In the example shown in (B), when the motor 12 stops abnormally due to insufficient power supply voltage, the control unit 14 outputs a PWM signal with a frequency of 4 Hz and a duty cycle of 20% to the monitoring device MD. Therefore, the monitoring device MD, which receives the PWM signal with a frequency of 4 Hz and a duty cycle of 20%, can identify that the motor 12 has stopped abnormally due to insufficient power supply voltage.

[0114] exist Figure 8In the example shown in (C), when the motor 12 abnormally stops due to the temperature of the motor 12 being excessively high, the control section 14 outputs a PWM signal having a frequency of 4 [Hz] and a duty ratio of 80 [%] to the monitoring device MD. Therefore, the monitoring device MD that receives the PWM signal having a frequency of 4 [Hz] and a duty ratio of 80 [%] can recognize that the motor 12 abnormally stops due to the temperature of the motor 12 being excessively high.

[0115] That is, in the first example of the electric pump 1 of the second embodiment, by changing only the duty ratio of the PWM signal output from the control section 14, the monitoring device MD can monitor the state of the motor 12 at the time of abnormal stop in detail. Figure 8

[0116] That is, in the first example of the electric pump 1 of the second embodiment, it is not necessary to change the frequency of the PWM signal output from the control section 14, that is, it is not necessary to increase the burden of the process of monitoring the state of the motor 12, and the monitoring device MD can recognize the cause of the abnormal stop of the motor 12 (excessively high power supply voltage, excessively low power supply voltage, or excessively high motor temperature).

[0117] In other words, in the first example of the electric pump 1 of the second embodiment, at the time of abnormal stop of the motor 12, the control section 14 sets the duty ratio of the PWM signal used in the monitoring of the state of the motor 12 to a duty ratio (for example, 10 [%], 20 [%], or 80 [%]) different from the duty ratio (50 [%]) used at the time of normal operation of the motor 12.

[0118] Therefore, in the first example of the electric pump 1 of the second embodiment, the monitoring device MD can recognize the state of normal stop of the motor 12 and the state of abnormal stop of the motor 12 by recognizing only the duty ratio of the PWM signal. In detail, the monitoring device MD can recognize the cause of the abnormal stop of the motor 12 by recognizing only the duty ratio of the PWM signal.

[0119] Further, in the first example of the electric pump 1 of the second embodiment, the output switching section 14A of the control section 14 does not output the PWM signal used in the monitoring of the state of the motor 12 at the time of abnormal stop of the motor 12 to the motor drive section 13.

[0120] [Table 2]

[0121] .

[0122] Table 2 shows the PWM signal used in the monitoring of the state of the motor 12 at the time of abnormal stop of the motor 12 in the second example of the electric pump 1 of the second embodiment.

[0123] ​As shown in Table 2, in the second example of the electric pump 1 of the second embodiment, at the time of the normal stop of the motor 12, the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 4 [Hz], and sets the duty ratio of the PWM signal to 50 [%].

[0124] In the second example of the electric pump 1 of the second embodiment, at the time of the abnormal stop of the motor 12, and in the case where the failure state of the motor 12 is failure A ("over-small voltage" of the power supply), the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 4 [Hz], and sets the duty ratio of the PWM signal to 5 [%] which is different from the duty ratio 50 [%] used at the time of the normal of the motor 12.

[0125] In the second example of the electric pump 1 of the second embodiment, at the time of the abnormal stop of the motor 12, and in the case where the failure state of the motor 12 is failure B ("over-large voltage" of the power supply), the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 4 [Hz], and sets the duty ratio of the PWM signal to 10 [%] which is different from 50 [%] and 5 [%].

[0126] In the second example of the electric pump 1 of the second embodiment, at the time of the abnormal stop of the motor 12, and in the case where the failure state of the motor 12 is failure C ("over-current" of the motor 12), the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 4 [Hz], and sets the duty ratio of the PWM signal to 20 [%] which is different from 50 [%], 5 [%], and 10 [%].

[0127] In the second example of the electric pump 1 of the second embodiment, at the time of the abnormal stop of the motor 12, and in the case where the failure state of the motor 12 is failure D ("over-heat" of the motor 12), the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 4 [Hz], and sets the duty ratio of the PWM signal to 30 [%] which is different from 50 [%], 5 [%], 10 [%], and 20 [%].

[0128] In the second example of the electric pump 1 of the second embodiment, at the time of the abnormal stop of the motor 12, and in the case where the failure state of the motor 12 is failure E ("motor lock"), the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 4 [Hz], and sets the duty ratio of the PWM signal to 70 [%] which is different from 50 [%], 5 [%], 10 [%], 20 [%], and 30 [%].

[0129] In the second example of the electric pump 1 of the second embodiment, in a case where the motor 12 is abnormally stopped and the failure state of the motor 12 is the failure F ("instruction abnormality (ground short circuit) to the motor driving portion 13"), the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 4 [Hz], and sets the duty ratio of the PWM signal to 80 [%] which is different from 50 [%], 5 [%], 10 [%], 20 [%], 30 [%], and 70 [%].

[0130] In the second example of the electric pump 1 of the second embodiment, in a case where the motor 12 is abnormally stopped and the failure state of the motor 12 is the failure G ("instruction abnormality (frequency abnormality at the time of stop instruction) to the motor driving portion 13"), the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 4 [Hz], and sets the duty ratio of the PWM signal to 90 [%] which is different from 50 [%], 5 [%], 10 [%], 20 [%], 30 [%], 70 [%], and 80 [%].

[0131] That is, in the second example of the electric pump 1 of the second embodiment, the frequency of the PWM signal used in the monitoring of the motor 12 in the states of the failure A ("excessively small voltage of the power supply"), the failure B ("excessively large voltage of the power supply"), the failure C ("excessively large current of the motor 12"), the failure D ("excessively large heat of the motor 12"), the failure E ("motor lock"), the failure F ("instruction abnormality (ground short circuit) to the motor driving portion 13"), and the failure G ("instruction abnormality (frequency abnormality at the time of stop instruction) to the motor driving portion 13") is set to 4 [Hz] which is equal to the frequency used at the time of normal stop of the motor 12.

[0132] In the second example of the electric pump 1 of the second embodiment, at the time of normal rotation of the motor 12, the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 20 [Hz] to 125 [Hz] in the frequency range (4 [Hz], 20 [Hz] or more and 125 [Hz] or less) used at the time of normal rotation of the motor 12, and sets the duty ratio of the PWM signal to 50 [%].

[0133] That is, in the second example of the electric pump 1 of the second embodiment, at the time of abnormal stop of the motor 12, the monitoring device MD can monitor the state of the motor 12 at the time of abnormal stop in detail by changing only the duty ratio of the PWM signal output from the control portion 14.

[0134] That is, in the second example of the electric pump 1 of the second embodiment, it is not necessary to vary the frequency of the PWM signal output from the control portion 14, that is, it is not necessary to increase the processing load of monitoring the state of the motor 12, and the monitoring device MD can identify the cause of the abnormal stop of the motor 12 (excessive voltage of the power supply, insufficient voltage of the power supply, excessive current of the motor, excessive heat of the motor, motor lock, command abnormality (ground short circuit), or command abnormality (frequency abnormality at the time of a stop command)).

[0135] Further, in the second example of the electric pump 1 of the second embodiment, the output switching portion 14A of the control portion 14 does not output the PWM signal used in the monitoring of the motor 12 in the states of the fault A (excessive voltage of the power supply), the fault B (excessive voltage of the power supply), the fault C (excessive current of the motor 12), the fault D (excessive heat of the motor 12), the fault E (motor lock), the fault F (command abnormality (ground short circuit) to the motor drive portion 13), and the fault G (command abnormality (frequency abnormality at the time of a stop command) to the motor drive portion 13) to the motor drive portion 13.

[0136] As described above, in the second example of the electric pump 1 of the second embodiment, the monitoring device MD identifies 7 kinds of fault states as the cause of the abnormal stop of the motor 12 by identifying the duty ratio of the PWM signal, but in other examples of the electric pump 1 of the second embodiment, the monitoring device MD can identify 2 kinds of fault states as the cause of the abnormal stop of the motor 12 by identifying the duty ratio of the PWM signal.

[0137] In this example, in the case where the fault state of the motor 12 is a first fault state (for example, excessive voltage of the power supply), the control portion 14 sets the duty ratio of the PWM signal used in the monitoring of the state of the motor 12 to a first duty ratio (for example, 5[%]) different from the duty ratio (50[%]) used at the normal time of the motor 12.

[0138] In the case where the fault state of the motor 12 is a second fault state (for example, excessive voltage of the power supply) different from the first fault state (for example, excessive voltage of the power supply), the control portion 14 sets the duty ratio of the PWM signal used in the monitoring of the state of the motor 12 to a second duty ratio (for example, 10[%]) different from the duty ratio (50[%]) used at the normal time of the motor 12 and the first duty ratio (for example, 5[%]).

[0139] Further, the control portion 14 sets the frequency of the PWM signal used in the monitoring of the motor 12 in the first fault state (for example, excessive voltage of the power supply) and the frequency of the PWM signal used in the monitoring of the motor 12 in the second fault state (for example, excessive voltage of the power supply) to a value equal to the frequency (4[Hz]) used at the normal stop of the motor 12.

[0140] In this example, the output switching section 14A also does not output the PWM signal used in the monitoring of the state of the motor 12 in the first failure state (for example, "excessively small voltage" of the power supply) and the second failure state (for example, "excessively large voltage" of the power supply) to the motor driving section 13.

[0141] Figure 9 is a view showing a waveform of the PWM signal used in the monitoring of the state of the motor 12 at the time of the abnormal stop of the motor 12 in the third example of the electric pump 1 of the second embodiment.

[0142] As described above, in the second example of the electric pump 1 of the second embodiment, in the case where the abnormal stop of the motor 12 occurs and the failure state of the motor 12 is the failure G ("instruction abnormality (frequency abnormality at the time of the stop instruction)" to the motor driving section 13) at the time of the abnormal stop of the motor 12, the control section 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 4 [Hz] and sets the duty ratio of the PWM signal to 90 [%] which is different from the duty ratio (50 [%]) used at the normal time of the motor 12.

[0143] On the other hand, in the third example of the electric pump 1 of the second embodiment, in the case where the abnormal stop of the motor 12 occurs and the failure state of the motor 12 is the failure G ("instruction abnormality (frequency abnormality at the time of the stop instruction)" to the motor driving section 13) at the time of the abnormal stop of the motor 12, the control section 14 sets the PWM signal used in the monitoring of the state of the motor 12 to a signal composed of a pulse train in which a first pulse having a duty ratio of 10 [%] and a second pulse having a duty ratio of 30 [%] are combined as shown in Figure 9

[0144] That is, in the third example of the electric pump 1 of the second embodiment, the control section 14 sets the PWM signal used in the monitoring of the state of the motor 12 at the time of the abnormal stop of the motor 12 to a signal composed of a pulse train in which a first pulse having a first duty ratio (10 [%]) which is different from the duty ratio (50 [%]) used at the normal time of the motor 12 and a second pulse having a second duty ratio (30 [%]) which is different from the first duty ratio (10 [%]) and the duty ratio (50 [%]) used at the normal time of the motor 12 are combined.

[0145] Therefore, in the third example of the electric pump 1 of the second embodiment, the control section 14 can output a plurality of PWM signals used in the monitoring of the state of the motor 12 at the time of the abnormal stop of the motor 12 to the monitoring device MD and can recognize a failure state more than seven kinds.

[0146] ​Further, in the third example of the electric pump 1 of the second embodiment, the output switching section 14A does not output the PWM signal used in the monitoring of the state of the motor 12 at the time of the abnormal stop of the motor 12 to the motor drive section 13 either.

[0147] Figure 10 is a view showing a waveform of the PWM signal used in the monitoring of the state of the motor 12 at the time of the abnormal stop of the motor 12 in the fourth example of the electric pump 1 of the second embodiment.

[0148] In the fourth example of the electric pump 1 of the second embodiment, in the case where the abnormal stop of the motor 12 occurs and the failure state of the motor 12 is the failure G ("instruction abnormality (frequency abnormality at the time of stop instruction)" to the motor drive section 13), the control section 14 sets the PWM signal used in the monitoring of the state of the motor 12 to a signal composed of a pulse string in which a first pulse in which the duty ratio is 10 [%] is repeated, for example, three times and a second pulse in which the duty ratio is 30 [%] is repeated, for example, three times are combined as shown in Figure 10

[0149] That is, in the fourth example of the electric pump 1 of the second embodiment, the control section 14 sets the PWM signal used in the monitoring of the state of the motor 12 at the time of the abnormal stop of the motor 12 to a signal composed of a pulse string in which a first pulse in which the duty ratio different from that used at the normal time of the motor 12 (50 [%]) (10 [%]) is repeated and a second pulse in which the duty ratio different from that used at the normal time of the motor 12 (50 [%]) and the first duty ratio (10 [%]) (30 [%]) is repeated are combined.

[0150] Therefore, in the fourth example of the electric pump 1 of the second embodiment, as in the third example of the electric pump 1 of the second embodiment, the control section 14 can output a plurality of PWM signals used in the monitoring of the state of the motor 12 at the time of the abnormal stop of the motor 12 to the monitoring device MD, and can recognize a failure state more than seven kinds.

[0151] Further, in the fourth example of the electric pump 1 of the second embodiment, the output switching section 14A does not output the PWM signal used in the monitoring of the state of the motor 12 at the time of the abnormal stop of the motor 12 to the motor drive section 13 either.

[0152] Figure 11 is a flowchart for explaining one example of the processing performed in the electric pump 1 of the second embodiment.

[0153] In Figure 11 ​In the example shown, in step S31, the control section 14 determines whether it is normal time of the motor. For example, in a case where the voltage of the power source that supplies power to the motor 12 is excessively large, in a case where the voltage of the power source is excessively small, in a case where the temperature of the motor 12 is excessively large (i.e., in a case of overheating of the motor 12), in a case where the current flowing through the motor 12 is excessively large (i.e., in a case of overcurrent of the motor 12), in a case where the motor is locked, in a case where an abnormality in the command to the motor drive section 13 (ground short) has occurred, in a case where an abnormality in the command to the motor drive section 13 (abnormal frequency at the time of stop command) has occurred, in a case where the motor 12 is in an over-rotation state, and the like, the control section 14 determines that it is an abnormality of the motor 12, and proceeds to step S37. On the other hand, in a case where the control section 14 determines that it is normal time of the motor, it proceeds to step S32.

[0154] In step S32, the control section 14 determines whether it is stop time of the motor. In a case where the control section 14 determines that it is stop time of the motor (i.e., in a case of normal stop of the motor 12), it proceeds to step S33. On the other hand, in a case where the control section 14 determines that it is not stop time of the motor (i.e., in a case of stable rotation of the motor 12), it proceeds to step S35.

[0155] In step S33, the control section 14 sets the frequency of the PWM signal to a frequency (4 [Hz]) used at the time of stop of the motor 12, and sets the duty ratio of the PWM signal to a first duty ratio (50 [%]) used at the time of normal time of the motor 12.

[0156] Next, in step S34, the control section 14 outputs the PWM signal whose frequency (4 [Hz]) and duty ratio (50 [%]) were set in step S33 to the monitoring device MD, and does not output it to the motor drive section 13. The PWM signal output to the monitoring device MD is used for monitoring of the state of the motor 12.

[0157] In step S35, the control section 14 sets the frequency of the PWM signal to a frequency in a frequency range (20 [Hz] or more and 125 [Hz] or less) used at the time of normal rotation of the motor 12, and sets the duty ratio of the PWM signal to the first duty ratio (50 [%]) used at the time of normal time of the motor 12.

[0158] Next, in step S36, the control section 14 outputs the PWM signal whose frequency (a frequency of 20 [Hz] or more and 125 [Hz] or less) and duty ratio (50 [%]) were set in step S35 to the monitoring device MD. The PWM signal output to the monitoring device MD is used for monitoring of the state of the motor 12. At this time, the control section 14 outputs the PWM signal for causing the motor 12 to rotate at a rotational speed of 800 [rpm] or more and 5000 [rpm] or less to the motor drive section 13.

[0159] In step S37, the control portion 14 determines whether it is the time of stop of the motor. In the case where the control portion 14 determines that it is the time of stop of the motor (i.e., at the time of abnormal stop of the motor 12), the processing proceeds to step S38. On the other hand, in the case where the control portion 14 determines that it is not the time of stop of the motor (i.e., at the time of abnormal rotation of the motor 12), the processing proceeds to step S40.

[0160] In step S38, the control portion 14 sets the frequency of the PWM signal to a frequency (4 [Hz]) used at the time of stop of the motor 12, and sets the duty ratio of the PWM signal to a second duty ratio (e.g., "10%", "20%", "80%", etc.) different from the first duty ratio ("50%").

[0161] Next, in step S39, the control portion 14 outputs the PWM signal in which the frequency (4 [Hz]) and the duty ratio (e.g., "10%", "20%", "80%", etc.) are set in step S38 to the monitoring device MD, and does not output it to the motor driving portion 13. The PWM signal output to the monitoring device MD is used for monitoring of the state of the motor 12.

[0162] In step S40, the control portion 14 sets the frequency of the PWM signal to a frequency (e.g., 200 [Hz], etc.) higher than the frequency range (20 [Hz] or more and 125 [Hz] or less) used at the time of normal rotation of the motor 12, and sets the duty ratio of the PWM signal to 50 [%].

[0163] Next, in step S41, the control portion 14 outputs the PWM signal in which the frequency (e.g., 200 [Hz], etc.) and the duty ratio (50 [%]) are set in step S40 to the monitoring device MD. The PWM signal output to the monitoring device MD is used for monitoring of the state of the motor 12. At this time, the control portion 14 outputs the PWM signal for rotating the motor 12 to the motor driving portion 13.

[0164] <Third Embodiment>

[0165] Hereinafter, a third embodiment of the electric pump and the method of notifying the failure state of the electric pump according to the present application will be described.

[0166] The electric pump 1 of the third embodiment is configured similarly to the electric pump 1 of the above-described first embodiment except for the following aspects. Therefore, according to the electric pump 1 of the third embodiment, the same effects as those of the electric pump 1 of the above-described first embodiment can be achieved except for the following aspects.

[0167] [Table 3]

[0168] .

[0169] Table 3 shows a PWM signal used in the monitoring of the state of the motor 12 at the time of abnormal stop of the motor 12 in one example of the electric pump 1 of the third embodiment.

[0170] As shown in Table 3, in one example of the electric pump 1 of the third embodiment, at the time of normal stop of the motor 12, the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 4 [Hz], and sets the duty ratio of the PWM signal to 50 [%].

[0171] In one example of the electric pump 1 of the third embodiment, at the time of abnormal stop of the motor 12, and in the case where the failure state of the motor 12 is failure A ("excessively small voltage" of the power supply), the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 2 [Hz] different from the frequency (4 [Hz]) used at the time of normal stop of the motor 12, and sets the duty ratio of the PWM signal to 20 [%] different from the duty ratio (50 [%]) used at the time of normal of the motor 12.

[0172] In one example of the electric pump 1 of the third embodiment, at the time of abnormal stop of the motor 12, and in the case where the failure state of the motor 12 is failure B ("excessively large voltage" of the power supply), the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 2 [Hz] different from the frequency (4 [Hz]) used at the time of normal stop of the motor 12, and sets the duty ratio of the PWM signal to 80 [%] different from the duty ratio (50 [%]) used at the time of normal of the motor 12 and 20 [%].

[0173] In one example of the electric pump 1 of the third embodiment, at the time of abnormal stop of the motor 12, and in the case where the failure state of the motor 12 is failure C ("excessively large current" of the motor 12), the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 7 [Hz] different from the frequency (4 [Hz]) used at the time of normal stop of the motor 12 and 2 [Hz], and sets the duty ratio of the PWM signal to 20 [%] different from the duty ratio (50 [%]) used at the time of normal of the motor 12 and 80 [%].

[0174] In the example of the electric pump 1 of the third embodiment, in a case where the abnormal stop of the motor 12 occurs and the failure state of the motor 12 is the failure D ("overheat" of the motor 12), the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 7 [Hz] which is different from the frequency (4 [Hz]) used at the normal stop of the motor 12 and 2 [Hz], and sets the duty ratio of the PWM signal to 80 [%] which is different from the duty ratio (50 [%]) used at the normal time of the motor 12 and 20 [%].

[0175] In the example of the electric pump 1 of the third embodiment, in a case where the abnormal stop of the motor 12 occurs and the failure state of the motor 12 is the failure E ("motor lock"), the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 10 [Hz] which is different from the frequency (4 [Hz]), 2 [Hz], and 7 [Hz] used at the normal stop of the motor 12, and sets the duty ratio of the PWM signal to 20 [%] which is different from the duty ratio (50 [%]) used at the normal time of the motor 12 and 80 [%].

[0176] In the example of the electric pump 1 of the third embodiment, in a case where the abnormal stop of the motor 12 occurs and the failure state of the motor 12 is the failure F ("command abnormality (ground short circuit) to the motor driving portion 13"), the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 15 [Hz] which is different from the frequency (4 [Hz]), 2 [Hz], 7 [Hz], and 10 [Hz] used at the normal stop of the motor 12, and sets the duty ratio of the PWM signal to 20 [%] which is different from the duty ratio (50 [%]) used at the normal time of the motor 12 and 80 [%].

[0177] In the example of the electric pump 1 of the third embodiment, in a case where the abnormal stop of the motor 12 occurs and the failure state of the motor 12 is the failure G ("command abnormality (frequency abnormality at the time of the stop command) to the motor driving portion 13"), the control portion 14 sets the frequency of the PWM signal used in the monitoring of the state of the motor 12 to 15 [Hz] which is different from the frequency (4 [Hz]), 2 [Hz], 7 [Hz], and 10 [Hz] used at the normal stop of the motor 12, and sets the duty ratio of the PWM signal to 80 [%] which is different from the duty ratio (50 [%]) used at the normal time of the motor 12 and 20 [%].

[0178] That is, in one example of the electric pump 1 in the third embodiment, the frequency of the PWM signal used in monitoring the motor 12 under the states of fault A ("too low voltage" of the power supply), fault B ("too high voltage" of the power supply), fault C ("overcurrent" of the motor 12), fault D ("overheating" of the motor 12), fault E ("motor lock-up"), fault F ("command abnormality (ground short circuit)" to the motor drive unit 13) and fault G ("command abnormality (frequency abnormality when stopping command)" to the motor drive unit 13) is set to a frequency other than the frequency domain used when the motor 12 is in normal operation (frequency domain of 4 [Hz], 20 [Hz] or more and 125 [Hz] or less) (frequency less than 4 [Hz], higher than 4 [Hz] and lower than 20 [Hz]), and the duty cycle of the PWM signal is set to a duty cycle (20 [%], 80 [%]) that is different from the duty cycle used when the motor 12 is in normal operation (50 [%]).

[0179] In one example of the electric pump 1 in the third embodiment, when the motor 12 is rotating normally, the control unit 14 sets the frequency of the PWM signal used for monitoring the state of the motor 12 to 20 Hz to 125 Hz in the frequency range (4 Hz, 20 Hz or more and 125 Hz or less) used when the motor 12 is operating normally, and sets the duty cycle of the PWM signal to 50%.

[0180] That is, in one example of the electric pump 1 in the third embodiment, when the motor 12 stops abnormally, the monitoring device MD can monitor the state of the motor 12 in detail when the abnormal stop is caused by changing the frequency and duty cycle of the PWM signal output from the control unit 14.

[0181] That is, in one example of the electric pump 1 in the third embodiment, it is not necessary to change the duty cycle of the PWM signal output from the control unit 14 when the motor 12 is normal. In other words, it is not necessary to increase the burden of monitoring the state of the motor 12. The monitoring device MD can identify the cause of abnormal stop of the motor 12 (excessive power supply voltage, insufficient power supply voltage, motor overcurrent, motor overheating, motor lock-up, abnormal command (ground short circuit) or abnormal command (abnormal frequency when stop command is given)).

[0182] Further, in the example of the electric pump 1 of the third embodiment, the output switching section 14A of the control section 14 does not output the PWM signal used in the monitoring of the motor 12 in the states of the fault A ("under-voltage" of the power supply), the fault B ("over-voltage" of the power supply), the fault C ("overcurrent" of the motor 12), the fault D ("overheat" of the motor 12), the fault E ("motor lock"), the fault F ("instruction abnormality (ground short circuit) to the motor drive section 13), and the fault G ("instruction abnormality (frequency abnormality at the time of the stop instruction) to the motor drive section 13) to the motor drive section 13.

[0183] The above describes the embodiments for implementing the present application, but the present application is not limited to such embodiments, and various modifications and substitutions can be made without departing from the gist of the present application. The structures described in the above embodiments and examples can also be combined.

[0184] Further, the functions of each section of the electric pump 1 in the above embodiments can be implemented as a whole or a part thereof by recording a program for implementing the functions in a computer-readable recording medium, reading the program recorded in the recording medium into a computer system, and executing the program. Further, the "computer system" described herein includes an OS, a peripheral device, and the like.

[0185] Further, the "computer-readable recording medium" refers to a removable medium such as a floppy disk, a magneto-optical disk, a ROM, a CD-ROM, and the like, a storage section such as a hard disk built in a computer system. Further, the "computer-readable recording medium" refers to a medium that dynamically retains a program for a short period of time, such as a communication line when a program is transmitted via a network such as the Internet or a telephone line, and a medium that retains a program for a certain period of time, such as a volatile memory inside a computer system that is a server or a client in this case. Further, the above program can be a program for implementing a part of the above functions, and further, can be a program that can implement the above functions by being combined with a program already recorded in a computer system.

[0186] Explanation of Reference Numerals

[0187] 1... electric pump, 11... pump, 12... motor, 13... motor drive section, 13A... switching element, 13B... rotational speed information processing section, 14... control section, 14A... output switching section, 14B... rotational speed feedback section, MD... monitoring device.

Claims

1. An electric pump, comprising: Pump; The electric motor drives the pump; A motor drive unit includes a switching element, which drives the motor using power output from the switching element; and The control unit outputs a PWM (Pulse Width Modulation) signal to the motor drive unit to drive the switching element. The PWM signal output from the control unit is used to monitor the state of the motor. in, When the motor stops abnormally, the control unit sets the frequency of the PWM signal used for monitoring the motor's status to a frequency outside the frequency domain used when the motor is operating normally. When the motor is in a first fault state, the control unit sets the frequency of the PWM signal used for monitoring the motor's state to a first frequency outside the frequency domain used when the motor is operating normally. When the motor's fault state is a second fault state different from the first fault state, the control unit sets the frequency of the PWM signal used for monitoring the motor's state to a second frequency that is outside the frequency domain used when the motor is operating normally and is different from the first frequency. The control unit sets the duty cycle of the PWM signal used in monitoring the motor during the first fault state and the duty cycle of the PWM signal used in monitoring the motor during the second fault state to values ​​equal to the duty cycle used when the motor is normally stopped. The control unit includes an output switching unit that switches whether to output the PWM signal to the motor drive unit. The output switching unit does not output the PWM signal used in monitoring the motor during the first fault state and the second fault state to the motor drive unit.

2. An electric pump, comprising: Pump; The electric motor drives the pump; A motor drive unit includes a switching element, which drives the motor using power output from the switching element; and The control unit outputs a PWM (Pulse Width Modulation) signal to the motor drive unit to drive the switching element. The PWM signal output from the control unit is used to monitor the state of the motor. in, When the motor stops abnormally, the control unit sets the frequency of the PWM signal used for monitoring the motor's status to a frequency outside the frequency domain used when the motor is operating normally. When the motor is in a first fault state, the control unit sets the frequency of the PWM signal used for monitoring the motor's state to 1Hz. If the motor's fault state is a second fault state different from the first fault state, the control unit sets the frequency of the PWM signal used for monitoring the motor's state to 2Hz. When the motor's fault state is a third fault state, different from the first and second fault states, the control unit sets the frequency of the PWM signal used in monitoring the motor's state to 6Hz. When the motor's fault state is a fourth fault state, different from the first, second, and third fault states, the control unit sets the frequency of the PWM signal used in monitoring the motor's state to 7Hz. If the motor's fault state is a fifth fault state, different from the first, second, third, and fourth fault states, the control unit sets the frequency of the PWM signal used in monitoring the motor's state to 8Hz. If the motor's fault state is a sixth fault state, different from the first, second, third, fourth, and fifth fault states, the control unit sets the frequency of the PWM signal used in monitoring the motor's state to 10Hz. If the motor's fault state is a seventh fault state, which differs from the first, second, third, fourth, fifth, and sixth fault states, the control unit sets the frequency of the PWM signal used in monitoring the motor's state to 12Hz. The control unit sets the duty cycle of the PWM signal used in monitoring the motor under the first fault state, the second fault state, the third fault state, the fourth fault state, the fifth fault state, the sixth fault state, and the seventh fault state to a value equal to the duty cycle used when the motor is normally stopped. The control unit includes an output switching unit that switches whether to output the PWM signal to the motor drive unit. The output switching unit does not output the PWM signal used in monitoring the motor during the first fault state, the second fault state, the third fault state, the fourth fault state, the fifth fault state, the sixth fault state, and the seventh fault state to the motor drive unit.

3. An electric pump, comprising: Pump; The electric motor drives the pump; A motor drive unit includes a switching element, which drives the motor using power output from the switching element; and The control unit outputs a PWM (Pulse Width Modulation) signal to the motor drive unit to drive the switching element. The PWM signal output from the control unit is used to monitor the state of the motor. in, When the motor stops abnormally, the control unit sets the frequency of the PWM signal used for monitoring the motor's status to a frequency outside the frequency domain used when the motor is operating normally. When the motor stops abnormally, the control unit sets the PWM signal used for monitoring the motor's status to a pulse train consisting of a first pulse at a first frequency outside the frequency domain used during normal operation of the motor and a second pulse at a second frequency outside the frequency domain used during normal operation and different from the first frequency. The control unit includes an output switching unit that switches whether to output the PWM signal to the motor drive unit. The output switching unit will not output the PWM signal used for monitoring the motor's status when the motor stops abnormally to the motor drive unit.

4. An electric pump, comprising: Pump; The electric motor drives the pump; A motor drive unit includes a switching element, which drives the motor using power output from the switching element; and The control unit outputs a PWM (Pulse Width Modulation) signal to the motor drive unit to drive the switching element. The PWM signal output from the control unit is used to monitor the state of the motor. in, When the motor stops abnormally, the control unit sets the frequency of the PWM signal used for monitoring the motor's status to a frequency outside the frequency domain used when the motor is operating normally. When the motor stops abnormally, the control unit combines the PWM signal used for monitoring the motor's status with a pulse train obtained by repeatedly executing a first pulse at a first frequency outside the frequency domain used when the motor is operating normally, and a second pulse at a second frequency outside the frequency domain used when the motor is operating normally and different from the first frequency. The control unit includes an output switching unit that switches whether to output the PWM signal to the motor drive unit. The output switching unit will not output the PWM signal used for monitoring the motor's status when the motor stops abnormally to the motor drive unit.

5. An electric pump, comprising: Pump; The electric motor drives the pump; A motor drive unit includes a switching element, which drives the motor using power output from the switching element; and The control unit outputs a PWM (Pulse Width Modulation) signal to the motor drive unit to drive the switching element. The PWM signal output from the control unit is used to monitor the state of the motor. in, When the motor stops abnormally, the control unit sets the PWM signal used for monitoring the motor's status to a signal consisting of a first pulse with a first duty cycle different from that used when the motor is operating normally and a second pulse with a second duty cycle different from that used when the motor is operating normally and the first duty cycle. The control unit includes an output switching unit that switches whether to output the PWM signal to the motor drive unit. The output switching unit will not output the PWM signal used for monitoring the motor's status when the motor stops abnormally to the motor drive unit.

6. An electric pump, comprising: Pump; The electric motor drives the pump; A motor drive unit includes a switching element, which drives the motor using power output from the switching element; and The control unit outputs a PWM (Pulse Width Modulation) signal to the motor drive unit to drive the switching element. The PWM signal output from the control unit is used to monitor the state of the motor. in, When the motor stops abnormally, the control unit sets the PWM signal used for monitoring the motor's status to a pulse train consisting of a pulse obtained by repeatedly repeating a first pulse with a first duty cycle different from the duty cycle used when the motor is in normal operation, and a pulse obtained by repeatedly repeating a second pulse with a second duty cycle different from the duty cycle used when the motor is in normal operation and the first duty cycle. The control unit includes an output switching unit that switches whether to output the PWM signal to the motor drive unit. The output switching unit will not output the PWM signal used for monitoring the motor's status when the motor stops abnormally to the motor drive unit.

7. A method for notifying the fault status of an electric pump, the electric pump comprising: Pump; The electric motor drives the pump; A motor drive unit includes a switching element, which drives the motor using power output from the switching element; and The control unit outputs a PWM (Pulse Width Modulation) signal to the motor drive unit to drive the switching element. The PWM signal output from the control unit is used to monitor the state of the motor. The method comprises the following steps: When the motor is operating normally, the control unit sets the frequency of the PWM signal used for monitoring the motor's status to a frequency in the first frequency domain. When the motor stops abnormally, the control unit sets the frequency of the PWM signal used for monitoring the motor's status to a frequency in a second frequency domain that is different from the first frequency domain. When the motor is in a first fault state, the control unit sets the frequency of the PWM signal used for monitoring the motor's state to a first frequency outside the frequency domain used when the motor is operating normally. When the motor's fault state is a second fault state that is different from the first fault state, the frequency of the PWM signal used in monitoring the motor's state is set to a second frequency that is outside the frequency domain used when the motor is normal and is different from the first frequency. The control unit sets the duty cycle of the PWM signal used in monitoring the motor during the first fault state and the duty cycle of the PWM signal used in monitoring the motor during the second fault state to values ​​equal to the duty cycle used when the motor is normally stopped; and The control unit includes an output switching unit that allows switching between outputting the PWM signal to the motor drive unit and outputting the PWM signal used in monitoring the motor during the first fault state and the second fault state to the motor drive unit.

8. A method for notifying the fault status of an electric pump, the electric pump comprising: Pump; The electric motor drives the pump; A motor drive unit includes a switching element, which drives the motor using power output from the switching element; and The control unit outputs a PWM (Pulse Width Modulation) signal to the motor drive unit to drive the switching element. The PWM signal output from the control unit is used to monitor the state of the motor. in, The method comprises the following steps: When the motor is operating normally, the control unit sets the frequency of the PWM signal used for monitoring the motor's status to a frequency in the first frequency domain. When the motor stops abnormally, the control unit sets the frequency of the PWM signal used for monitoring the motor's status to a frequency in a second frequency domain that is different from the first frequency domain. When the motor is in a first fault state, the control unit sets the frequency of the PWM signal used for monitoring the motor's state to 1Hz. When the fault state of the motor is a second fault state that is different from the first fault state, the control unit sets the frequency of the PWM signal used in monitoring the state of the motor to 2Hz. When the motor's fault state is a third fault state that is different from the first fault state and the second fault state, the control unit sets the frequency of the PWM signal used in monitoring the motor's state to 6Hz; when the motor's fault state is a fourth fault state that is different from the first fault state, the second fault state and the third fault state, the control unit sets the frequency of the PWM signal used in monitoring the motor's state to 7Hz. If the fault state of the motor is a fifth fault state that is different from the first fault state, the second fault state, the third fault state, and the fourth fault state, the control unit sets the frequency of the PWM signal used in monitoring the motor state to 8Hz. When the fault state of the motor is a sixth fault state that is different from the first fault state, the second fault state, the third fault state, the fourth fault state, and the fifth fault state, the control unit sets the frequency of the PWM signal used in monitoring the state of the motor to 10Hz. When the fault state of the motor is a seventh fault state that is different from the first fault state, the second fault state, the third fault state, the fourth fault state, the fifth fault state, and the sixth fault state, the control unit sets the frequency of the PWM signal used in monitoring the motor state to 12Hz. The control unit sets the duty cycle of the PWM signal used in monitoring the motor under the first fault state, the second fault state, the third fault state, the fourth fault state, the fifth fault state, the sixth fault state, and the seventh fault state to a value equal to the duty cycle used when the motor is normally stopped. as well as The control unit includes an output switching unit that allows switching between outputting the PWM signal to the motor drive unit. This switching unit does not output the PWM signal used in monitoring the motor during the first fault state, second fault state, third fault state, fourth fault state, fifth fault state, sixth fault state, and seventh fault state to the motor drive unit.

9. A method for notifying the fault status of an electric pump, the electric pump comprising: Pump; The electric motor drives the pump; A motor drive unit includes a switching element, which drives the motor using power output from the switching element; and The control unit outputs a PWM (Pulse Width Modulation) signal to the motor drive unit to drive the switching element. The PWM signal output from the control unit is used to monitor the state of the motor. The method comprises the following steps: When the motor is operating normally, the control unit sets the frequency of the PWM signal used for monitoring the motor's status to a frequency in the first frequency domain. When the motor stops abnormally, the control unit sets the frequency of the PWM signal used for monitoring the motor's status to a frequency in a second frequency domain that is different from the first frequency domain. When the motor stops abnormally, the control unit sets the PWM signal used for monitoring the motor's status to a signal consisting of a first pulse at a first frequency outside the frequency domain used during normal operation of the motor and a second pulse at a second frequency outside the frequency domain used during normal operation and different from the first frequency; and The control unit has an output switching unit that allows it to switch whether to output the PWM signal to the motor drive unit. The output switching unit does not output the PWM signal used for monitoring the motor's status when the motor stops abnormally to the motor drive unit.

10. A method for notifying the fault status of an electric pump, the electric pump comprising: Pump; The electric motor drives the pump; A motor drive unit includes a switching element, which drives the motor using power output from the switching element; and The control unit outputs a PWM (Pulse Width Modulation) signal to the motor drive unit to drive the switching element. The PWM signal output from the control unit is used to monitor the state of the motor. The method comprises the following steps: When the motor is operating normally, the control unit sets the frequency of the PWM signal used for monitoring the motor's status to a frequency in the first frequency domain. When the motor stops abnormally, the control unit sets the frequency of the PWM signal used for monitoring the motor's status to a frequency in a second frequency domain that is different from the first frequency domain. When the motor stops abnormally, the control unit sets the PWM signal used for monitoring the motor's status to a pulse train consisting of pulses obtained by repeatedly executing a first pulse at a first frequency outside the frequency domain used during normal operation of the motor, and pulses obtained by repeatedly executing a second pulse at a second frequency outside the frequency domain used during normal operation and different from the first frequency; and The control unit has an output switching unit that allows it to switch whether to output the PWM signal to the motor drive unit. The output switching unit does not output the PWM signal used for monitoring the motor's status when the motor stops abnormally to the motor drive unit.

11. A method for notifying the fault status of an electric pump, the electric pump comprising: Pump; The electric motor drives the pump; A motor drive unit includes a switching element, which drives the motor using power output from the switching element; and The control unit outputs a PWM (Pulse Width Modulation) signal to the motor drive unit to drive the switching element. The PWM signal output from the control unit is used to monitor the state of the motor. The method comprises the following steps: When the motor is operating normally, the control unit sets the duty cycle of the PWM signal used for monitoring the motor's status to a first duty cycle. When the motor stops abnormally, the control unit sets the duty cycle of the PWM signal used for monitoring the motor's status to a second duty cycle, different from the first duty cycle; and When the motor stops abnormally, the control unit sets the PWM signal used for monitoring the motor's status to a signal consisting of a first pulse with a first duty cycle different from that used when the motor is operating normally and a second pulse with a second duty cycle different from that used when the motor is operating normally and the first duty cycle. When the motor stops abnormally, the PWM signal used for monitoring the motor's status is not output to the motor drive unit.

12. A method for notifying the fault status of an electric pump, the electric pump comprising: Pump; The electric motor drives the pump; A motor drive unit includes a switching element, which drives the motor using power output from the switching element; and The control unit outputs a PWM (Pulse Width Modulation) signal to the motor drive unit to drive the switching element. The PWM signal output from the control unit is used to monitor the state of the motor. The method comprises the following steps: When the motor is operating normally, the control unit sets the duty cycle of the PWM signal used for monitoring the motor's status to a first duty cycle. When the motor stops abnormally, the control unit sets the duty cycle of the PWM signal used for monitoring the motor's status to a second duty cycle, different from the first duty cycle; and When the motor stops abnormally, the control unit sets the PWM signal used for monitoring the motor's status to a pulse train consisting of a pulse obtained by repeatedly repeating a first pulse with a first duty cycle different from the duty cycle used when the motor is in normal operation, and a pulse obtained by repeatedly repeating a second pulse with a second duty cycle different from the duty cycle used when the motor is in normal operation and the first duty cycle. When the motor stops abnormally, the PWM signal used for monitoring the motor's status is not output to the motor drive unit.

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