JP2004232607A - Pump driving device and control method for pump driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pump driving device, having high versatility and realizing energy-saving and reduction of size by restraining extra pressure loss of a pump due to a flow change caused by configuration of a piping system and opening and closing of a valve. <P>SOLUTION: This pump driving motor 6 includes a motor control circuit 7 adapted to control the pump pressure according to a flow rate on the basis of correlation (ω=ωO + coefficient A × motor current I) (wherein ωO is a motor basic rotational frequency) that when a flow rate of a fluid flowing through a pump chamber 2 changes, the rotational frequency of a rotary blade 3 body linearly changes depending on increase/decrease of a motor current. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
FIELD OF THE INVENTION
The present invention relates to, for example, a pump driving device used for floor heating, a water heater, and the like, and more specifically, a pump including a rotating body that is arranged in a pump chamber and sends out a fluid, and a rotating shaft of the rotating body and a rotating shaft of the rotor. The present invention relates to a pump driving device in which a pump driving motor that drives a pump in combination with a pump driving device is mounted, and a control method of the pump driving device.
[0002]
[Prior art]
2. Description of the Related Art A centrifugal pump that sends out a fluid at a predetermined pressure is used for electric appliances such as a floor heater and a water heater. As this centrifugal pump, a pump drive device has been developed in which a pump having rotating blades for sending a fluid to a pump chamber and a pump driving motor for rotating the rotating blades are assembled.
[0003]
FIG. 3 shows an example of the pump driving device. In the pump 51, a rotary blade 54 is rotatably provided in a pump chamber 53 provided in a part of a pipe 52 through which a fluid passes. The rotating shaft of the rotating blades 54 and the rotating shaft of the rotor are connected to each other, and a pump driving motor (brushless motor) 55 is integrated with the pump 51. As the pump drive motor 55, an AC (alternating current) motor is used because it is inexpensive. However, since the operation is performed for a long time, energy saving and improvement in efficiency can be achieved. ) Motors have been used.
[0004]
In order to drive and control the DC motor, expensive components such as a pressure sensor 56 for measuring the pressure of the fluid and a flow sensor 57 for measuring the flow rate had to be used. The command voltage calculation circuit 58 calculates so that the difference between a preset pressure command value (voltage conversion value) P0 and a detection value (voltage conversion value) P1 of the pressure sensor 56 becomes zero (P0−P1 = 0). ), And outputs the command voltage obtained by the calculation to the motor control circuit 59. The motor control circuit 59 controls the motor control voltage based on a comparison between the command voltage value and the reference voltage value to variably control the rotation speed of the pump drive motor 55. The valve section 60 provided in the pipe 52 is opened and closed to increase and decrease the flow rate of the fluid and to switch the pipe system.
[0005]
In the above-described pump driving device, since relatively expensive components such as the pressure sensor 56 and the flow rate sensor 57 are used, the manufacturing cost increases, and the pressure loss of the piping system increases in proportion to the square of the flow rate. There has been proposed a drive control method for a DC pump that performs drive control in order to ensure a rated flow rate flowing through the pump (see Patent Document 1). This drive control method includes a storage means for storing pump characteristic data indicating a relationship between a head H ₀ when a rated voltage V _{0 is} applied, a rated flow Q ₀ , and a current I _0, and a current detection for detecting a winding current of a motor. means and includes a flow rate operation circuit for calculating the flow rate from the value of the current detection value and the applied voltage, the flow rate calculated in the flow rate calculation circuit and adjusts the applied voltage such that the rated flow Q _0.
[0006]
[Patent Document 1]
JP-A-2001-342989
[Problems to be solved by the invention]
The drive control method of the DC pump disclosed in Patent Document 1 is a drive control method for ensuring the rated flow rate of the fluid flowing through the pump, and does not consider the operation of a valve provided in a piping system. . Therefore, this control method is valid if the valve openings of the piping system are all constant. However, if the valve openings are different even at one point, the rated flow rate flowing through the pump is different, and the rated voltage V the relationship between the lift H ₀ and the flow rate Q ₀ of ₀ it is necessary to store in the storage means. Therefore, it takes time to adjust the control means and restricts the valve opening / closing operation, so that it is difficult to use the piping system only for a limited use.
[0008]
An object of the present invention is to solve the above-mentioned problems of the prior art, suppress an excessive pressure loss of a pump due to a flow rate change caused by a piping system configuration and valve opening / closing, realize energy saving, miniaturization, and achieve versatility. An object of the present invention is to provide a high pump driving device and a method of controlling the pump driving device.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, the present invention has the following configuration.
In a pump driving apparatus, a pump provided with a rotating body that is disposed in a pump chamber and sends out a fluid, and a DC motor that drives the pump by connecting the rotating shaft of the rotating body and the rotating shaft of the rotor to each other, is provided. Is to control the pump pressure according to the flow rate based on the correlation (Equation 1) that when the flow rate of the fluid flowing through the pump chamber changes, the rotation speed of the rotating body changes linearly according to the increase and decrease of the motor current. It is characterized by having a possible control circuit.
Further, the motor control circuit calculates the calculated voltage value calculated from the motor current value by the voltage conversion value according to (Equation 1), and the voltage conversion value corresponding to the actual rotation speed of the rotor detected by the rotation speed detection unit. And a command voltage calculation circuit for outputting a motor command voltage obtained by calculation so as to make the difference between the two zero. Specifically, the calculated voltage value is a calculated voltage obtained by multiplying the motor current detected by the current detection unit by a coefficient A and converting the reference voltage value corresponding to the motor basic rotation speed ω ₀ to a converted voltage value. Value is used.
[0010]
Also, a control method of a pump driving device is provided, in which a pump provided with a rotating body arranged in a pump chamber for sending out a fluid and a DC motor for driving the pump by connecting the rotating shaft of the rotating body and the rotating shaft of the rotor are connected. In the above, when the flow rate of the fluid flowing through the pump chamber changes, the rotation speed of the rotating body linearly changes in accordance with the increase or decrease of the motor current. It is characterized by controlling.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
The pump driving device according to the present embodiment will be described as a pump driving device using a centrifugal pump in which rotary vanes are provided in a pump chamber as an example.
FIG. 1 is a circuit diagram showing a configuration of a pump driving device, and FIG. 2 is a graph showing a relationship between a pressure and a flow rate of a fluid and a power consumption and a flow rate.
[0012]
First, a schematic configuration of the pump driving device will be described with reference to FIG.
The pump 1 includes a rotating blade 3 as an example of a rotating body that sends a fluid to the pump chamber 2. The pump 1 is connected to a part of a pipe 4 for feeding a fluid under pressure. The pipe 4 may be connected to the pump 1 in series or may be connected in parallel. A valve part 5 is provided in a part of the pipe 4. By opening and closing the valve part 5, the flow rate of the fluid flowing through the pipe 4 can be adjusted and a pipe system can be selected. .
[0013]
A pump driving motor (DC brushless motor) 6 is integrally assembled with the pump 1. The pump drive motor 6 drives the pump 1 by connecting the rotation axis of the rotor to the rotation axis of the rotary blade 3. In this embodiment, a three-phase brushless motor (for example, an outer rotor type motor) is used as the pump drive motor 6. The pump drive motor 6 has a correlation (Equation 1) that when the flow rate of the fluid flowing through the pump chamber 2 increases, the rotation speed of the rotary blade 3 linearly increases and decreases according to the increase and decrease of the motor current flowing through the coil 6a of the stator core. , A motor control circuit (inverter) 7 for controlling the pump pressure with respect to the flow rate.
(Equation 1)
ω = ω ₀ + coefficient A × motor current I (ω ₀ ; motor basic rotation speed)
Here, the motor basic rotation speed ω ₀ refers to the rotation speed of the motor in a state where all the valve units 5 provided in the piping system through which the fluid including the piping 4 circulates are closed. The correlation between the motor rotation speed and the flow rate is such that the motor shaft torque of the DC motor is proportional to the motor current (motor current), and the shaft torque increases and decreases as the pumping flow rate increases and decreases. The increase / decrease of the flow rate is established on the premise that a relationship can be estimated from the motor current.
[0014]
The motor control circuit 7 includes a command voltage calculation circuit 8, and controls the drive operation of the pump drive motor 6 based on the command voltage output from the command voltage calculation circuit 8. The command voltage calculation circuit 8 calculates a calculated voltage value (a reference voltage value corresponding to the motor basic rotation speed ω ₀ ) calculated by the motor current value detection according to (Equation 1) by the motor current value by a coefficient A. and then a value obtained by adding the voltage converted value) is calculated as the difference between the actual rotation voltage (voltage converted value) based on the detection of the actual rotational speed omega ₁ of the rotor is zero. The command voltage obtained by this calculation is output to the motor control circuit 7.
[0015]
The command voltage calculation circuit 8 receives the motor basic rotation speed ω ₀ (command voltage value) and the motor current value flowing through the motor control circuit 7 detected by the current detection circuit 9 serving as a current detection unit. The value is calculated. Moreover, the actual rotation voltage corresponding to the actual revolution speed omega ₁ detected by the rotation speed detection circuit 10 is a rotation speed detector (voltage conversion value) is input, such that the difference between the operation voltage value is zero The operation is performed, and the command voltage obtained by the operation is output.
The rotation speed of the pump drive motor 6 is detected by a rotation speed detector 11 such as a magnetic pole detecting element (Hall element) corresponding to the magnetic pole position of the rotor magnet. The detection signal of the three phases detected by the rotation speed detector 11 synthesized in synthesizer (FG) 12, the corresponding combined signal at a rotational speed detection circuit 10 converts F-V to the actual revolution speed omega ₁ It is converted to the actual rotation voltage value.
[0016]
The motor control circuit 7 compares the command voltage input from the command voltage calculation circuit 8 with the voltage generated by the triangular wave transmission circuit 13 by using the comparator 14 to generate a PWM control signal (pulse width modulation signal). Control the voltage. The three-phase distribution circuit 15 turns on / off the transistors Q1 to Q6 according to the rotor rotational position of the pump drive motor 6 detected by the rotational speed detector 11, and supplies current so as to generate an alternating magnetic field in the stator coil 6a. Is switched. When the overcurrent detector 16 detects an overcurrent flowing through the pump drive motor 6, the overcurrent detector 16 turns off the transistors Q1 to Q6 to protect the transistors.
[0017]
Here, the relationship between the pressure and the flow rate of the fluid flowing through the pump 1 and the power consumption and the flow rate will be described with reference to FIG. In FIG. 2, a curve A indicates a pressure P-flow rate Q characteristic when no rotation operation of the pump 1 is controlled. As the flow rate Q increases, the pump pressure decreases due to various factors such as an increase in pressure loss in the pump and an increase in the motor load and a decrease in the motor rotation speed.
[0018]
On the other hand, a straight line B indicates the pressure P-flow rate Q characteristic when the motor speed ω is variably controlled while detecting the flow rate Q according to the present invention. According to the motor rotation speed control by (Equation 1) described above, for example, as the valve unit 5 is opened and the flow rate Q increases, the motor current of the pump drive motor 6 increases, so that the motor rotation speed ω increases and the pump output (pressure P) increases. Further, when the valve section 5 is closed, the flow rate Q decreases, and the motor current of the pump drive motor 6 decreases, so that the motor speed ω decreases, so that the pump output (pressure P) decreases. Therefore, by appropriately selecting the motor basic rotational speed ω ₀ (including zero) and the value of the coefficient A (the control loop does not diverge) so as to maintain the rated output of the pump drive motor 6, the flow rate Q can be increased or decreased. , The pump output (pressure P) can be controlled to increase or decrease. Thereby, for example, the motor rotation speed can be changed by following a change in the flow rate of the fluid flowing through the pump 1 by fine adjustment of the valve section 5, so that the pressure generated by the pump can be changed according to the flow rate of the fluid. As a result, the flow rate changes without reducing the valve section 5 more than necessary. For this reason, the pressure loss generated in the valve section 5 is small and the current consumption of the motor is suppressed, so that energy saving can be realized.
[0019]
In FIG. 2, a broken line C indicates the input power W-flow rate Q characteristic when the rotation operation of the pump 1 is not controlled. If the rotation of the pump is not controlled at all, the smaller the flow rate Q, the more wasteful power consumption occurs. On the other hand, the broken line D indicates the input power W-flow rate Q characteristic when the motor speed ω is variably controlled while detecting the flow rate Q according to the present invention. If the drive control according to the present invention is performed, for example, the motor speed can be controlled to decrease following the decrease in the flow rate Q of the fluid flowing through the pump 1 only by finely adjusting the valve unit 5 to slightly close it. The pressure loss generated in the section 5 can be reduced, and unnecessary power consumption can be suppressed. In particular, as the value of the basic rotation speed ω ₀ is set lower, the slope of the broken line D increases, and the energy saving effect increases.
Further, expensive parts such as a pressure sensor and a flow rate sensor are not required for the motor control circuit 7, and pressure control can be performed in accordance with the flow rate of the pump 1 only inside the motor control circuit 7 of the pump drive motor 6, so that the entire pump drive device can be controlled. Can be designed compactly. Further, the connection form of the pipes 4 connected to the pump 1 may be in series or in parallel, regardless of the open / closed state of the valve and the number of valve parts, so that a highly versatile pump drive device can be provided.
[0020]
The preferred embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment. For example, a DC motor used for a centrifugal pump may be either an outer rotor type or an inner rotor type. Of course, many modifications can be made without departing from the spirit of the law.
[0021]
【The invention's effect】
According to the pump driving device and the control method of the pump driving device according to the present invention, when the flow rate of the fluid flowing through the pump chamber changes, the pump driving motor linearly changes the rotation speed of the rotating body according to the increase and decrease of the motor current. Since the pump pressure can be controlled by following the flow rate change based on the correlation (Equation 1) that changes, the extra pressure loss due to the pump flow rate change is small, and the current consumption of the motor can be suppressed, so that energy saving can be achieved. realizable.
Further, the motor control circuit is configured to calculate the voltage value calculated by the motor current value detection in accordance with the equation (1) and the voltage conversion value corresponding to the actual rotation speed of the rotor detected from the rotation speed detection unit. Is calculated by the command voltage calculation circuit so that the difference between the two becomes zero, and the command voltage obtained by the calculation is output to control the motor applied voltage. Control can be performed, and expensive components such as a pressure sensor and a flow sensor are not required. Therefore, the entire pump driving device can be designed compactly and inexpensively. In addition, the connection form of the pipes connected to the pump may be in series or in parallel, and the open / closed state of the valves and the number of valve parts may be independent. Therefore, a highly versatile pump drive device can be provided.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing a configuration of a pump driving device.
FIG. 2 is a graph showing the relationship between fluid pressure and flow rate and power consumption and flow rate.
FIG. 3 is a circuit diagram showing a configuration of a conventional pump driving device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Pump 2 Pump room 3 Rotating blade 4 Piping 5 Valve part 6 Pump drive motor 7 Motor control circuit 8 Command voltage calculation circuit 9 Current detection circuit 10 Revolution detection circuit 11 Revolution detector 12 Combiner 13 Triangular wave transmission circuit 14 Comparator 15 Three-phase distribution circuit 16 Overcurrent detector

Claims (4)

In a pump driving device in which a pump provided with a rotating body that sends out a fluid disposed in a pump chamber and a DC motor that drives the pump by connecting the rotating shaft of the rotating body and the rotating shaft of the rotor are assembled,
The pump drive motor converts the pump pressure to the flow rate based on a correlation (Equation 1) that when the flow rate of the fluid flowing through the pump chamber changes, the rotation speed of the rotating body changes linearly according to the increase and decrease of the motor current. A pump drive device comprising a motor control circuit that can be controlled in response to the request.
(Equation 1)
ω = ω ₀ + coefficient A × motor current I (ω ₀ ; motor basic rotation speed) The motor control circuit calculates a voltage conversion value calculated according to (Equation 1) with a voltage conversion value by detecting a motor current value, and a voltage conversion value corresponding to the actual rotation speed of the rotor detected by the rotation speed detection unit. 2. The pump drive device according to claim 1, further comprising a command voltage calculation circuit that outputs a motor command voltage obtained by calculation to make the difference zero. As the calculated voltage value, a calculated voltage value obtained by multiplying a motor voltage detected by the current detection unit by a coefficient A and adding a converted voltage value to a reference voltage value corresponding to the motor basic rotation speed ω ₀ is used. 3. The pump driving device according to claim 2, wherein: In a control method of a pump driving device in which a pump provided with a rotating body that sends out a fluid arranged in a pump chamber and a DC motor that drives the pump by connecting a rotating shaft of the rotating body and a rotating shaft of a rotor are assembled,
When the flow rate of the fluid flowing through the pump chamber changes, the rotation speed of the rotating body linearly changes in accordance with the increase or decrease of the motor current. A method for controlling a pump driving device, comprising:
(Equation 1)
ω = ω ₀ + coefficient A × motor current I (ω ₀ ; motor basic rotation speed)

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