JP2012057556A - Abnormality detection device for circulation flow path including electric pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To early and accurately detect an abnormality, regardless of the state of a flow path.SOLUTION: This abnormality detection device includes: number of revolution detection means 15 for detecting the number of revolution of a motor for driving provided in an electric pump 1 installed together with a filter 5 for capturing foreign matter in a circulation flow path 2; storage means 24 for storing the number N0 of revolution of the motor at an equipment installation initial time detected by the number of revolution detection means 15; and number of revolution comparison means 25 for comparing the present number N of revolution of the motor with the stored number N0 of revolution of the motor at the equipment installation initial time to detect an abnormality such as filter clogging from the difference value. The number of revolution of the motor in the electric pump 1 at the equipment installation initial time is stored and the initial time number N0 of revolution is compared with the present number N of revolution, thereby detecting the abnormality.

Description

  The present invention relates to an abnormality detection device for a circulation type flow path provided with an electric pump for detecting an abnormality when an abnormality such as filter clogging occurs in a flow path provided with an electric pump, particularly a closed circulation type flow path. .

  The motor speed in the electric pump installed in the circulation flow path is detected by a rotation detector such as a Hall element, and the minimum speed, overload speed, filter filter preset based on the pump characteristic curve For detecting abnormalities (including the state of the electric pump) in the flow path equipped with the electric pump by comparing each abnormal reference rotational speed such as the clogging rotational speed and motor step-out rotational speed with the detected current rotational speed. In addition, Patent Document 1 discloses that what kind of abnormality is present.

  However, the above has the following problems in order to discriminate from the current rotational speed and the abnormal reference rotational speed determined in advance based on the pump characteristic curve.

  That is, because the rotational speed of the electric pump varies depending on the piping length of the flow path equipped with the electric pump and the load equipment such as the filter and radiator installed in the flow path, the abnormal reference rotational speed is also uniquely determined. It is not fixed, and an abnormal reference rotation speed must be set for each flow path.

  Further, when the electric pump can change the discharge capacity by PWM control, as shown in FIG. 7, even if the magnitude of the PWM capacity variable signal Vsp for changing the PWM duty is the same, the drive power supply voltage fluctuates. For example, since the rotation speed also fluctuates accordingly, the change (difference value) in the rotation speed due to the load change due to filter clogging or the like may be very small as N (min) −N0 (max). There is a risk of erroneous detection that is determined to be abnormal although it is not abnormal, or that it is determined to be normal even though it is abnormal.

  Also, when there are a plurality of load devices and these are switched and used, the load curve changes due to the switching, and in this case as well, the abnormal rotation speed cannot be uniquely determined.

Japanese Patent Laid-Open No. 3-156191

  The present invention has been made in view of the above points, and provides an abnormality detection device for a circulation type flow path including an electric pump capable of accurately performing early detection of abnormality regardless of the state of the flow path. Let it be an issue.

  The present invention provides an electric pump installed in a circulation type channel together with a filter for capturing foreign matter, provided with a rotational speed detection means for detecting the rotational speed of a driving motor, and the initial installation of the equipment detected by the rotational speed detection means The storage means for storing the motor rotational speed N0 and the current motor rotational speed N and the stored motor rotational speed N0 at the initial stage of equipment installation are compared, and abnormality such as filter clogging is detected from the difference value. It is characterized in that it is provided with a rotation speed comparison means for performing the above. The motor rotation speed of the electric pump at the initial stage of equipment installation is stored, and the abnormality is detected by comparing the initial rotation speed with the current rotation speed. When the pump capacity is variable, abnormality detection can be performed without any problem by detecting the rotation speed in a state where the capacity setting is fixed to a specific state.

  At this time, the motor in the electric pump is a variable capacity type whose capacity is controlled by controlling the peak value of the total current supplied to the electric pump according to the magnitude of the variable capacity signal. The motor speed N0 when the capacity variable signal is output is stored in the storage means, and the speed comparison means stores the motor speed N and the memory when the same capacity variable signal as the specific capacity variable signal is output. It is preferable that abnormality detection is performed by comparing the motor rotational speed N0 stored by the means.

  In order to set the drive control of the electric pump to peak current control, if the pump is a DC pump, even if the pump drive power supply voltage fluctuates, an abnormality is detected based on the rotation speed under a specific peak current control By doing so, it is possible to accurately detect abnormality without being affected by fluctuations in the drive voltage.

  In the case where the circulation type flow path has a plurality of parallel flow path portions, it is assumed that a valve for selectively connecting the plurality of parallel flow path portions to the circulation type flow path is provided. The motor rotation speed detection and the current motor rotation speed detection may be performed in a state where only a specific one of the plurality of parallel flow path portions is connected to the circulation flow path. Even when each parallel flow path portion has a load device and is switched and used, abnormality detection can be performed.

  In the present invention, the abnormality can be detected accurately even when the initial rotational speed is different because the piping length of the circulation flow path and the installed equipment are different, and the abnormal reference rotational speed is set according to the flow path. It is not necessary to set.

It is a block circuit diagram in an example of an embodiment of the invention. It is a piping diagram same as the above. It is a block circuit diagram in an example of other embodiments. It is a characteristic view which shows the motor characteristic under peak current control same as the above, and the rotation speed fluctuation amount by load reduction by filter clogging etc. It is a pump characteristic (Q-Ht-N) figure under the peak current control same as the above. Furthermore, it is a piping diagram in another example. It is a characteristic view which shows the motor characteristic under PWM control in a prior art example, and the rotation speed fluctuation amount by load reduction by filter clogging etc.

  The present invention will be described in detail based on an example of an embodiment. FIG. 2 shows a heat source 3, an electric pump 1 for circulating a fluid as a heat medium heated by the heat source 3, and a radiator 4 for heat dissipation. Is provided in the circulation type flow path 2, and the electric pump 1 changes its capability by PWM control based on the control of the control unit 10. When used for heating, in the flow path 2, the temperature of the fluid is increased by the heat source 3 such as gas or electricity, and then the heat is exchanged by the radiator 4 to increase the indoor temperature.

  And in such a closed circulation type flow path 2, in order to collect the foreign material in the flow path 2 (cutting waste of piping, iron powder in the radiator 4, etc.), generally suction | inhalation of the electric pump 1 is carried out. A filter 5 is arranged in the vicinity of the mouth, but if this filter 5 is clogged, the pressure loss in the circulation-type flow path 2 increases, so that the amount of pumped water decreases, and finally the suction blockage state occurs. It becomes an idling state where the circulating pumping amount is 0 L / min. And when the bearing of the electric pump 1 is a canned pump using a submerged sliding bearing, the bearing is abnormally heated and a malfunction of the pump lock occurs.

  In order to prevent such a situation, it is necessary to detect an abnormality in the flow path 2 when the amount of pumped water before the idling operation is reduced. However, the rotational speed of the electric pump 1 is determined as described above. Depending on the pipe length and the load of the heat source 3, the radiator 4, the filter 5, etc., the initial rotational speed varies, and at the same time, the rotational speed value to be detected as abnormal varies.

  For this purpose, in the present invention, the control unit 10 stores the initial rotational speed N0 in the initial stage of installation, and performs abnormality detection according to the difference between the stored initial rotational speed N0 and the current rotational speed N. It is said.

  FIG. 1 shows an example in which the driving motor 12 in the electric pump 1 is a direct current motor including a plurality of coils 13 (three phases in the illustrated example) and a magnet rotor 14. It is. A position sensor 15 that detects the magnetic pole position of the magnet rotor 14 in the motor 12 inputs the output signal to the distribution circuit 16 in the control unit 10, thereby energizing which phase of the coil 16 to generate rotational torque. Whether to be performed is determined based on a prescribed truth value, and gate signals (three high-side gate signals and three low-side gate signals) that match the truth table are output from the gate signal generation circuit 17.

  Further, in the mode for detecting the abnormality of the flow path 2, the control unit 10 outputs a specified variable capability signal Vsp0 and compares it with the output signal of the triangular wave generation circuit 18 having an internal specified frequency (about several kHz to 20 kHz). The comparison circuit 20 inputs a PWM signal having a specified duty to the gate signal generation circuit 17.

  The gate signal generation circuit 17 takes the logical product of the output signal of the distribution circuit 16 and the output signal of the comparison circuit 20, and among the six gate signals, the three signals on the high side of the inverter are high. After the level shift by the side driver 21, it is sent to the switching elements 22-1 to 22-3 in the inverter circuit 22. On the other hand, the output signal of the gate signal generation circuit 17 is directly input to the switching elements 22-4 to 22-6 constituting the low side of the inverter circuit 22. When the switching elements 22-1 and 22-5 are turned on, a current flows from the U phase to the V phase.

  Further, in the control unit 10, information on the position sensor 15 is input from the distribution circuit 16 to the rotational speed signal generating circuit 23, and the rotational speed signal for switching the H level / L level state at each phase switching is the rotational speed signal. Output from the generation circuit 23. Of these rotation speed signals, the rotation speed N0 (at the time of the ability variable signal Vsp0) at the initial stage of device installation is stored in the rotation speed storage circuit 24.

  Then, the difference between the stored initial rotational speed N0 and the current rotational speed N (at the time of the variable capacity signal Vsp0) is sequentially and periodically compared by the rotational speed comparison circuit 25, and the value of N0−N is equal to or greater than the specified rotational speed N1. If so, the control unit 10 determines that the flow path 2 is abnormal, and notifies the determination result.

  Even when the configuration of the flow path 2 is different, the abnormality detection can be performed accurately because the abnormality detection is performed by comparing the initial rotation speed N0 at the initial stage of installation with the current rotation speed N for each flow path 2. .

  FIG. 3 shows another example. This shows a case where the control unit 10 performs peak current control instead of PWM control. In the peak current control, the torque of the DC motor 12 is controlled by limiting the peak value of the total current supplied to the DC motor 12 serving as a drive source according to the magnitude of the capacity variable signal Vsp generated by the control unit 10. Control.

  The total current is converted into a voltage value by the shunt resistor 26, and the converted voltage signal is amplified several times to several tens of times by the amplifier circuit 17, and then compared with the voltage of the capability variable signal Vsp generated in the control unit 10. Input to the circuit 18. When the comparison circuit 18 compares the magnitudes of the voltages and the output signal of the amplification circuit 17 becomes larger than the voltage Vsp, the latch circuit 26 latches the gate signal and turns it off. This latch state is released by a latch release signal generated by the latch release circuit 27 for each lower limit value of the output signal of the triangular wave signal generation circuit 18. That is, when the signal of the latch release circuit 27 is input to the latch circuit 26, if the gate signal is latched in the OFF state, it is released.

  The motor 12 whose peak current value is controlled in accordance with the magnitude of the variable capability signal Vsp in this way has characteristics as shown in FIG. That is, the motor torque is substantially constant below the rotational speed at which the peak current is limited. For this reason, even if the voltage of the drive power supply fluctuates, the operating point of the motor is almost the same under peak current control.

  In the circulation flow path abnormality detection mode, a predetermined capacity variable signal Vsp0 is generated using the above points. In this case, in the initial state where the device is installed in the flow path 2, even if the drive power supply voltage fluctuates, the number of revolutions N0 is unique. Further, when the load resistance is reduced due to clogging in the filter 5 or the like and an abnormal state occurs, a unique abnormal rotational speed N is obtained even if the drive power supply voltage fluctuates.

  For this reason, when N−N0 becomes larger than the prescribed N1, it can be determined that an abnormality has occurred in the circulation flow path 2. Further, even when the driving power supply voltage fluctuates, the prescribed N1 that is determined to be abnormal can be sufficiently large, so that the abnormality can be accurately detected.

FIG. 5 shows the pump characteristics (Q-Ht-N) when the pump suction side is gradually closed in the state where this peak current control method is adopted, and the drive power supply voltage is rated as described in FIG. Even if the voltage fluctuates by ± 10%, the result almost coincides with the relationship of Q-Ht and QN. Here, when the rotational speed N of the pump is about 5 L / min (before entering the idling state) with respect to the rotational speed N0 in the initial state before the suction side blockage, N−N0 is the specified N1. When it becomes above, it can be considered as abnormality of a circulation path, and N0 = 3800min < ^-1 >, N = 4700min < ^-1 >, N1 = 900min < ^-1 > and N1 can be prescribed | regulated with a big value in FIG.

  FIG. 6 includes a plurality of load devices (radiators 4-1 to 4-N) arranged in parallel in the flow channel 2 and each load device arranged in parallel by closing the valves 6-1 to 6N from the flow channel 2 individually. The case where it can be separated is shown. In this case, radiators 4-1 to 4-N are provided in each room to heat a plurality of rooms, and heating of each room can be turned on and off by opening and closing valves 6-1 to 6-N. Is assumed.

  In this case, in the abnormality detection mode for determining whether an abnormality has occurred in the circulation flow path 2, only a specific radiator 4-i is connected to the flow path 2 and the other radiators are disconnected from the flow path 2 by closing valves. In this state, the above-described detection operation and abnormality detection operation for the initial rotational speed N0 may be performed. Even in a system having a plurality of circulation channels 2, an abnormality caused by clogging of the filter 5 or the like can be detected.

  In addition, although the heating system was taken as an example here as the circulation type flow path 2 having the electric pump 1, in the case of having various circulation type flow paths such as a fuel cell, an in-vehicle motor / pump, and a heat pump device, Abnormalities due to clogging of the filter 5 and the like in the flow path 2 can be detected accurately and early, and the occurrence of problems in the idle operation state of the electric pump 1 can be prevented.

DESCRIPTION OF SYMBOLS 1 Electric pump 2 Flow path 3 Heat source 4 Radiator (heat exchanger)
5 Filter 10 Control Unit 11 DC Power Supply 12 DC Motor 13 Coil 14 Magnet Rotor 15 Position Sensor 23 Rotation Speed Signal Generation Circuit 24 Rotation Speed Storage Circuit 25 Rotation Speed Comparison Circuit

Claims (3)

  An electric pump installed together with a foreign matter capturing filter in the circulation type flow path is provided with a rotation speed detection means for detecting the rotation speed of the driving motor, and the motor rotation speed at the initial stage of equipment installation detected by the rotation speed detection means The rotational speed at which the storage means for storing N0 is compared with the current motor rotational speed N and the stored motor rotational speed N0 at the initial stage of equipment installation, and abnormality such as the filter clogging is detected from the difference value. An abnormality detection device for a circulation type flow path provided with an electric pump, comprising a comparison means.   The motor in the above electric pump is a variable capacity type whose capacity is controlled by controlling the peak value of the total current supplied to the electric pump in accordance with the magnitude of the variable capacity signal. The motor rotation speed N0 when the signal is output is stored in the storage means, and the rotation speed comparison means is stored in the storage means and the motor rotation speed N when the same capacity variable signal as the specific capacity variable signal is output. The abnormality detection device for a circulation type flow path provided with the electric pump according to claim 1, wherein abnormality detection is performed by comparing with the motor rotational speed N 0.   The circulation type flow path includes a plurality of parallel flow path portions and a valve for selectively connecting the plurality of parallel flow path portions to the circulation type flow path. 3. The electric pump according to claim 1, wherein the current motor speed detection is performed in a state where only a specific one of the plurality of parallel flow path portions is connected to the circulation flow path. An abnormality detection device for a circulating flow path provided.

Images