JP4696899B2 - DC motor drive control device and pump unit - Google Patents

Description

  The present invention relates to a DC motor drive control device and a pump unit.

Conventionally, a rotor rotational position is detected by an encoder provided in the vicinity of a direct current brushless motor, and pulse width modulation control (hereinafter referred to as PWM (Pulse Width Modulation) control) is performed based on the detected rotor rotational position information. There is known a motor drive device that drives the motor (for example, see Patent Document 1).
Japanese Patent Laid-Open No. 10-80178

  However, in the conventional motor drive device, the switching means (transistor, etc.) which is one of the component parts generate high heat due to the characteristics of PWM control, and the heat dissipation parts are increased in size and cost, and further the switching means. There was a possibility of shortening the service life.

  The present invention has been proposed in view of the above-described circumstances, and by suppressing the high heat generation of the switching means that is one of the component parts, the heat radiation component is increased in size and cost, and the switching means is shortened. It is an object of the present invention to provide a DC motor drive control device and a pump unit that can suppress the lifetime.

  A DC motor drive control device according to the present invention detects a rotor rotational position of a DC motor, determines an energization state to a plurality of phases of motor windings based on the detected rotation position, and determines a DC motor based on the determined energization state. The drive control is performed.

This DC motor drive control device includes first control means for performing peak width control after performing pulse width modulation control and then performing PWM peak current control when the DC motor is operated from a stopped state. In the first control means, as PWM peak current control, current is supplied to the motor windings of a plurality of phases at a duty ratio exceeding 0% and less than 100%, and the value of the current supplied to the motor windings is a first predetermined value. When the current value is reached, control is performed to stop the current supply to the motor winding until the phase of energization to the motor winding is switched, and peak current control is performed to the motor winding of a plurality of phases with a duty ratio of 100%. Control to stop the current supply to the motor winding until the phase of the current supply to the motor winding is switched when the value of the current supplied to the motor winding reaches the second predetermined current value. The motor winding is energized by comparing the first voltage value when the current supplied to the motor winding is converted into a voltage with the second voltage value having a magnitude corresponding to the target rotational speed of the DC motor. The value of the current to be generated is the first predetermined current value or It is determined that the second predetermined current value has been reached, the current supply to the motor winding is stopped, the second voltage value is increased as the target rotational speed of the DC motor is increased, and the target rotational speed is a predetermined value. The increase rate of the second voltage value in the case of less than the predetermined value is set higher than the increase rate of the second predetermined voltage value in the case where the target rotational speed is equal to or greater than the predetermined value.

According to another aspect of the present invention, there is provided a second control means for performing pulse width modulation control after performing peak current control when the DC motor is stopped from the operating state, and then performing PWM peak current control. It has. As the PWM peak current control, the second control means supplies current to the motor windings of a plurality of phases at a duty ratio exceeding 0% and less than 100%, and the value of the current supplied to the motor windings is a first predetermined value. When the current value is reached, control is performed to stop the current supply to the motor winding until the phase of energization to the motor winding is switched, and peak current control is performed to the motor winding of a plurality of phases with a duty ratio of 100%. Control to stop the current supply to the motor winding until the phase of the current supply to the motor winding is switched when the value of the current supplied to the motor winding reaches the second predetermined current value. The motor winding is energized by comparing the first voltage value when the current supplied to the motor winding is converted into a voltage with the second voltage value having a magnitude corresponding to the target rotational speed of the DC motor. The value of the current to be generated is the first predetermined current value or It is determined that the second predetermined current value has been reached, the current supply to the motor winding is stopped, the second voltage value is decreased as the target rotational speed of the DC motor is lowered, and the target rotational speed is a predetermined value. The decrease rate of the second voltage value in the case of less than the predetermined value is set higher than the decrease rate of the second predetermined voltage value in the case where the target rotational speed is equal to or greater than the predetermined value.

  In a normal DC motor drive control device, when a DC motor is driven, PWM control is performed at an initial stage of drive, and then peak current control is performed to achieve a target motor rotation speed.

  On the other hand, in the present invention, when the DC motor is operated from a stopped state, PWM control is performed, and then peak current control is performed after performing PWM peak current control. In other words, in the present invention, PWM control and PWM peak current control are performed during the period in which PWM control has been performed in the past, and the number of switching operations is reduced by the amount of PWM peak current control. The heat generation of the means can be suppressed. Therefore, by suppressing the high heat generation of the switching means, which is one of the component parts, it is possible to suppress an increase in size and cost of the heat dissipating parts and a shortening of the life of the switching means.

  According to another invention, when the DC motor is stopped from the operating state, the peak current control is performed, and then the PWM peak current control is performed, and then the PWM control is performed. Also in this case, similarly to the above, the number of times of switching is reduced compared to the conventional case, and heat generation of the switching means can be suppressed. Therefore, by suppressing the high heat generation of the switching means, which is one of the component parts, it is possible to suppress an increase in size and cost of the heat dissipating parts and a shortening of the life of the switching means.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or similar elements are denoted by the same reference numerals, and description thereof is omitted.

  FIG. 1 is a configuration diagram of a liquid supply apparatus including a pump unit according to the first embodiment of the present invention. As shown in the figure, the liquid supply apparatus 100 includes a pump unit 1, a bathtub 101, a first pipe 102, a second pipe 103, a heating unit 104, and a third pipe 105.

  The pump unit 1 includes a DC motor drive control device and a DC motor, which will be described later, and is driven by the DC motor drive control device and integrated with a rotor that is a component part of the DC motor. Is configured to absorb and discharge fluid. In the liquid supply apparatus 100, the liquid is circulated by driving the pump unit 1.

  The bathtub 101 is used in, for example, a bathroom or a hot water pool, and is made of artificial marble, stainless steel, FRP (Fiberglass Reinforced Plastics), or the like, and stores liquid to be circulated in the liquid supply apparatus 100. An outflow port 101a is provided on the lower side surface of the bathtub 101, and an inflow port 101b is provided on the upper side surface. The liquid stored in the bathtub 101 flows out of the outlet 101a and then returns to the bathtub 101 from the inlet 101b.

  The first pipe 102 is a pipe made of heat-resistant PVC, stainless steel, or the like, and has one end connected to the outlet 101 a of the bathtub 101 and the other end connected to the pump unit 1. For this reason, the liquid in the bathtub 101 reaches the pump unit 1 through the first pipe 102 from the outlet 101a. The second pipe 103 is a pipe made of heat-resistant PVC, stainless steel, or the like, like the first pipe 102, and has one end connected to the pump unit 1 and the other end connected to the heating unit 104. For this reason, the liquid that has flowed into and discharged from the pump unit 1 reaches the heating unit 104 through the second pipe 103.

  The heating unit 104 heats the liquid to a predetermined temperature using gas, electricity, kerosene, or the like. For example, when a temperature to be heated is set by an operation panel (not shown), the liquid is set to the set temperature. It becomes the structure heated so that it may become. The third pipe 105 is a pipe made of heat-resistant PVC, stainless steel, or the like, like the other pipes 102 and 103, and one end is connected to the heating unit 104 and the other end is connected to the inlet 101 b of the bathtub 101. Yes. For this reason, the liquid heated in the heating unit 104 is returned to the bathtub 101 through the third pipe 105.

  Next, the details of the pump unit 1 will be described with reference to FIG. FIG. 2 is a configuration diagram of a DC motor or the like mounted on the pump unit 1 shown in FIG. In FIG. 2, the configuration of the impeller and the like is omitted. As shown in the figure, the pump unit 1 includes a DC motor 10 and a DC motor drive control device 20. The DC motor 10 includes a stator 11 on which thin iron plates (thickness of about 0.5 mm) are stacked, a multi-phase motor winding wound around the stator 11, a magnet rotor 12 as a rotor, and a rotor 12 The rotary shaft 13 is arranged so as to rotate with the rotation and pass through the rotation center of the rotor 12, and the rotational position detection sensor 14 that detects the rotational position of the rotor 12. Here, the rotational position detection sensor 14 includes a Hall sensor, a Hall IC (Integrated Circuit), or the like. Further, the rotational position detection sensor 14 may be configured to detect the rotational position of the rotor 12 using the induced voltage of the motor winding.

  In such a DC motor 10, information on the rotor rotational position detected by the rotational position detection sensor 14 is transmitted to the DC motor drive control device 20, and in the DC motor drive control device 20, the energization state of the motor windings of the plurality of phases is determined. A current is supplied to the motor windings of the plurality of phases according to the determined energization state. As a result, the DC motor 10 is driven by the stator 11 acting as an electromagnet, and the magnetic field of the electromagnet and the magnetic poles of the magnet rotor 12 are attracted and repelled to generate rotational torque in the rotor 12.

  The DC motor drive control device 20 is mounted on the electrical base 6 shown in FIG. The DC motor drive control device 20 adjusts so as to obtain a predetermined motor output (rotation speed) by limiting the peak of the current, that is, the maximum value of the current when supplying the current to the motor winding. Yes. This control is called peak current control. More specifically, in the peak current control, the current supply to the motor windings of the plurality of phases is performed with a duty ratio of 100%, and the value of the current supplied to the motor windings reaches a predetermined current value (second predetermined current value). Sometimes control that stops the current supply to the motor winding until the next phase switching time of energization to the motor winding. Further, the DC motor drive control device 20 performs PWM control at the initial drive stage of the DC motor 10 so that the DC motor 10 can be started smoothly.

  Further, the pump unit 1 is provided with a signal input / output unit 30, and various signals are input / output to / from the DC motor drive control device 20 through the signal input / output unit 30. Specifically, the drive voltage of the DC motor 10 is input from the signal line 31 of the signal input / output unit 30, and the reference voltage (GND) of the internal circuit is input from the signal line 32. Further, a control voltage of the DC motor drive control device 20 is input from the signal line 33, and a rotation target signal (hereinafter referred to as an SP signal) is input from the signal line 34. Here, the SP signal is a signal that is a rotation target of the DC motor 10, and the DC motor drive control device 20 controls the rotation speed of the DC motor 10, that is, the motor output, according to the magnitude of the SP signal (voltage signal). It becomes.

  FIG. 3 is a detailed configuration diagram of the DC motor drive control device 20 shown in FIG. As shown in FIG. 3, the DC motor drive control device 20 includes an amplifier 21 and a control IC 22. An SP signal is input to the non-inverting input terminal of the amplifier 21, and the amplifier 21 amplifies the input SP signal at a ratio of resistors R1 and R2. The amplified voltage signal Vo (sp) is input to the control IC 22. Here, when the voltage value of the SP signal is Vi, the voltage signal Vo (sp) can be expressed as Vo (sp) = (1 + R2 / R1) × Vi.

  The control IC 22 operates by inputting a control voltage from the signal line 33, and controls the output of the DC motor 10 in accordance with the magnitude of the input voltage signal Vo (sp). The control IC 22 includes a power supply circuit therein, and generates a reference voltage by charging a connected capacitor C. Further, a signal from the rotational position detection sensor 14 is input to the control IC 22. The control IC 22 is configured to change the energization state of the motor winding based on the rotor position detected by the rotational position detection sensor 14. When this energization state is changed, the control IC 22 outputs an on / off control signal to each FET (Field Effect Transistor) constituting the switching means 23 so that the FET is switched between the on state and the off state.

  A bootstrap circuit 24 is provided for each phase between the control IC 22 and the upper arm FET group 23 a of the switching means 23. The bootstrap circuit 24 is a circuit that shifts the level of the ON signal of each FET output from the control IC 22 to the voltage level of the drive voltage from the signal line 33. For this reason, the ON signal of each FET output from the control IC 22 is raised to the control voltage by the bootstrap circuit 24 and then the FET is turned on. Note that the bootstrap circuit 24 is not provided between the lower arm FET group 23b.

  Further, the DC motor drive control device 20 includes an amplifier 25. A shunt resistor R3 is connected to the non-inverting input terminal of the amplifier 25, and a current Im flowing through the motor winding flows through the shunt resistor R3. For this reason, a voltage having a value of (Im × R3) is input to the non-inverting input terminal of the amplifier 25. Resistors R4 and R5 are connected to the inverting input terminal of the amplifier 25, and the amplifier 25 is configured to amplify the voltage (Im × R3) at a ratio of the resistors R4 and R5. Therefore, the amplified voltage signal Vo (im) can be expressed as Vo (im) = (1 + R5 / R4) × Im × R3. The amplified voltage signal Vo (im) corresponds to the first voltage value when the current supplied to the motor winding is converted into a voltage.

  The amplified voltage signal Vo (im) is input to the non-inverting input terminal of the comparator 26. The comparator 26 uses the above-described reference voltage as a power supply voltage, and a voltage signal Vi (sp) obtained by dividing the SP signal by resistors R6 and R7 is input to the inverting input terminal. The voltage signal Vi (sp) corresponds to a second voltage value having a magnitude corresponding to the rotational speed of the DC motor 10.

  The comparator 26 compares the voltage signals Vi (sp) and Vo (im). The comparator 26 outputs an L level voltage signal Vo (si) when Vi (sp)> Vo (im), and an H level voltage signal Vo when Vi (sp) ≦ Vo (im). (Si) is output. Note that one end of the resistor R8 is connected to the connection point A of the resistors R6 and R7, and a reference voltage is supplied from the other end of the resistor R8. The resistance value of the resistor R8 is about 10 times that of the resistor R7.

  The voltage signal Vo (si) is input to the latch circuit 27. The latch circuit 27 enters a latched state when an H level voltage signal Vo (si) is input. When the latch circuit 27 enters the latch state, the on / off control signal supplied from the control IC 22 to the upper arm FET group 23a reaches the ground G via a diode connected between the control IC 22 and the bootstrap circuit 24. It becomes. Therefore, when the H level voltage signal Vo (si) is input to the latch circuit 27 and the latch state is entered, all the FETs of the upper arm FET group 23a are turned off, and no current flows through the motor winding. It becomes.

  Here, the control IC 22 outputs a rotation signal S to the latch circuit 27 at each phase switching timing. When this rotation signal S is input, the latch circuit 27 releases the latch state. As a result, the on / off control signal from the control IC 22 reaches the upper arm FET group 23a.

  Next, how the DC motor 10 is driven by the DC motor drive control device 20 will be described. FIG. 4 is a time chart showing how the DC motor 10 is driven by the DC motor drive control device 20 according to the present embodiment. FIG. 4A shows a PWM carrier signal and a voltage signal Vo (sp). ) Indicates an on / off control signal input to the upper arm FET group 23a. 4A and 4B, the vertical axis represents voltage, and the horizontal axis represents time.

  First, as shown in FIG. 4A, the PWM carrier signal has a triangular waveform with an amplitude range of 2 to 5 [V]. Then, the SP signal that is the rotation target of the DC motor 10 is input to the DC motor drive control device 20, the SP signal is amplified by the amplifier 21, and the amplified voltage signal Vo (sp) is input to the control IC 22 at time t1. To do. The voltage signal Vo (sp) increases in proportion to the voltage until time t2, and maintains a constant voltage value (that is, a voltage value corresponding to the rotation target) after time t2.

  As shown in FIG. 4A, the voltage signal Vo (sp) is less than the voltage value of the PWM carrier signal until time t3. As shown in FIG. 4B, the on / off control signal of the upper arm FET group 23a is L level. As a result, the DC motor 10 is not driven.

  Thereafter, at time t3, the voltage signal Vo (sp) reaches the voltage value of the PWM carrier signal. As a result, the on / off control signal for the FET of any phase among the FETs of the upper arm FET group 23a becomes the H level, and the driving of the DC motor 10 is started. Thereafter, this state is maintained until time t4.

  However, the voltage signal Vo (sp) again becomes less than the voltage value of the PWM carrier signal at time t4. Therefore, the on / off control signal of the upper arm FET group 23a becomes L level again. The on / off control signal alternately changes between the H level and the L level until time t5. That is, in the period from time t3 to t5, the DC motor drive control device 20 performs PWM control.

  Here, the voltage value of the voltage signal Vo (sp) gradually increases during the period of time t3 to t5. For this reason, the ON / OFF control signal is gradually increased in the H level period (the ON / OFF control signal is gradually decreased in the L level period). That is, as shown in FIG. 4B, the period P2 in which the ON / OFF control signal becomes H level after that becomes longer than the period P1 in which the ON / OFF control signal becomes H level. Similarly, the period P3 is longer than the period P2, and the period P4 is longer than the period P3. Thus, the duty ratio gradually increases during the period from time t3 to t5 when the PWM control is performed.

  Then, after time t5, the voltage signal Vo (sp) does not become less than the voltage value of the PWM carrier signal, and the on / off control signal for the FET of any phase among the FETs of the upper arm FET group 23a is Becomes H level. Note that the DC motor drive control device 20 realizes the target motor rotation speed by performing peak current control that limits the value of the current flowing through the motor winding after time t5.

  The above is the control of the DC motor drive control device 20, but in the DC motor drive control device 20 according to the present embodiment, not only the PWM control but also the PWM control and the peak in the period of time t3 to t5 shown in FIG. PWM peak current control corresponding to simultaneous control with current control is performed. Hereinafter, the PWM peak current control will be described with reference to FIG. In FIG. 5, in addition to PWM peak current control, peak current control and PWM control will also be described.

  FIG. 5 is a time chart showing the detailed operation when starting the DC motor 10 by the DC motor drive control device 20 according to the present embodiment, (a) shows the state of the voltage in the stopped state of the DC motor 10, (B) shows the state of voltage in PWM control, (c) shows the state of voltage in PWM peak current control, and (d) shows the state of voltage in peak current control. 5A to 5D, the vertical axis represents voltage, and the horizontal axis represents time.

  First, it is assumed that the DC motor 10 is stopped. At this time, as shown in FIG. 5A, a voltage signal Vi (sp) obtained by dividing the reference voltage by resistors R7 and R8 (that is, the voltage shown in FIG. 5A) is applied to the inverting input terminal of the comparator 26. V1) is input. On the other hand, since the DC motor 10 is stopped, the current Im flowing through the motor winding is “0”, and the voltage signal Vo (im) input to the non-inverting input terminal of the comparator 26 is “0”. Therefore, the comparator 26 outputs the L level voltage signal Vo (si), and the latch circuit 27 does not enter the latch state.

  Next, it is assumed that an SP signal is input to the DC motor drive control device 20 in order to drive the DC motor 10. Here, as shown in FIG. 4, the SP signal reaches a certain voltage value (voltage value corresponding to the target rotational speed) over a certain period of time. Therefore, at the initial stage of SP signal input, the SP signal is not so large, and the voltage signal Vi (sp) input to the inverting input terminal of the comparator 26 as shown in FIG. The voltage V2 is slightly larger than the voltage V1. In this state, the voltage signal Vo (sp) amplified by the amplifier 21 is between the upper limit value and the lower limit value of the PWM carrier signal referred to in FIG. 4 (that is, between 5V and 2V in FIG. 4). Therefore, PWM control is performed. During PWM control, the voltage signal Vo (im) input to the non-inverting input terminal of the comparator 26 does not become equal to or higher than the voltage signal Vi (sp). Therefore, the comparator 26 outputs the L level voltage signal Vo (si), and the latch circuit 27 does not enter the latch state.

  Next, it is assumed that the SP signal input to the DC motor drive control device 20 is slightly increased. At this time, PWM peak current control is performed as shown in FIG. In other words, current is supplied to the motor windings of a plurality of phases with a duty ratio exceeding 0% and less than 100%, and when the value of the current supplied to the motor windings reaches the first predetermined current value, the motor windings are supplied. Control is performed to stop the current supply to the motor winding until the next phase switching time of energization. Here, whether or not the value of the current flowing through the motor winding has reached the first predetermined current value is determined based on the voltage signal Vo (im) (with the first voltage value) and the voltage signal Vi (sp). This is done by comparing (with the second voltage value).

  The PWM peak current control will be specifically described. In the state of FIG. 5C, the voltage signal Vi (sp) input to the inverting input terminal of the comparator 26 is a voltage V3 that is slightly higher than the voltage V2. A current value corresponding to the voltage V3 corresponds to the first predetermined current value. On the other hand, the voltage signal Vo (im) input to the non-inverting input terminal of the comparator 26 reaches the voltage V3 at time t11. As a result, the comparator 26 outputs the H level voltage signal Vo (si), the latch circuit 27 enters the latch state, and the ON / OFF control signal from the control IC 22 reaches the ground G through the diode and the latch circuit 27. . Therefore, as shown in FIG. 5C, the voltage signal Vo (im) becomes “0” after time t11. Thereafter, at time t12, the rotation signal S indicating the phase switching of energization to the motor winding is input from the control IC 22 to the latch circuit 27. As a result, the latch state of the latch circuit 27 is released, and current is supplied to the motor winding again. As described above, in the state of FIG. 5C, peak current control for limiting the peak current is performed.

  Further, in the state of FIG. 5C, the voltage signal Vo (sp) amplified by the amplifier 21 is between the upper limit value and the lower limit value of the PWM carrier signal referred to in FIG. 4 (that is, 5V in FIG. 4). PWM control is performed. Thus, in the state of FIG. 5C, PWM peak current control, which is simultaneous control of PWM control and peak current control, is performed. In addition, after time t12, the above is repeated.

  Next, it is assumed that the SP signal input to the DC motor drive control device 20 reaches a voltage value corresponding to the target motor rotation speed. At this time, peak current control is performed as shown in FIG. That is, a current is supplied to the motor windings of a plurality of phases with a duty ratio of 100%, and the current switching to the motor windings is switched when the value of the current supplied to the motor windings reaches the second predetermined current value. Control is performed to stop the current supply to the motor winding until the time. Here, as in the PWM peak current control, whether or not the value of the current flowing through the motor winding has reached the second predetermined current value is determined by the voltage signal Vo (im) and (first voltage value and ), By comparing the voltage signal Vi (sp) with (the second voltage value).

  The peak current control will be specifically described. In the state of FIG. 5D, the voltage signal Vi (sp) input to the inverting input terminal of the comparator 26 is a voltage V4 that is slightly higher than the voltage V3. A current value corresponding to the voltage V4 corresponds to the second predetermined current value. On the other hand, the voltage signal Vo (im) input to the non-inverting input terminal of the comparator 26 reaches the voltage V4 at time t21. As a result, the comparator 26 outputs an H level voltage signal Vo (si), and the latch circuit 27 enters a latched state. Therefore, as shown in FIG. 5C, the voltage signal Vo (im) becomes “0” after the time t21. Thereafter, at time t22, the rotation signal S indicating the phase switching of energization to the motor winding is input from the control IC 22 to the latch circuit 27. As a result, the latch state of the latch circuit 27 is released, and current is supplied to the motor winding again. As described above, in the state of FIG. 5C, peak current control for limiting the peak current is performed.

  In the state of FIG. 5 (c), the voltage signal Vo (sp) amplified by the amplifier 21 exceeds the upper limit value of the PWM carrier signal referred to in FIG. 4 (that is, exceeds 5V in FIG. 4). And PWM control is not performed. Further, after time t22, the above is repeated.

  Here, conventionally, as shown in FIG. 5C, PWM peak current control, which is simultaneous control of PWM control and peak current control, is not executed. For this reason, conventionally, PWM control is executed during a period in which PWM peak current control is executed, and the number of switching times of the FET increases. Therefore, conventionally, the switching means 23 generates a large amount of heat, which may lead to an increase in the size and cost of the heat dissipating component and a shortened life of the switching means 23.

  On the other hand, in the DC motor drive control device 20 according to the present embodiment, the PWM peak current control is executed, so that the number of times of switching decreases (that is, between time t11 and time t12 in FIG. 5C). Heat generation is suppressed). Thereby, in this embodiment, the enlargement of a heat radiating component, cost increase, and the lifetime reduction of the switching means 23 can be suppressed.

  Furthermore, the DC motor drive control device 20 according to this embodiment has the following effects in addition to the above-described suppression of heat generation. FIG. 6 is a graph showing a state of starting the DC motor 10 by the DC motor drive control device 20 according to the present embodiment and a state of starting the DC motor by the conventional DC motor drive control device. In FIG. 6, the vertical axis represents the current flowing through the motor winding, and the horizontal axis represents the voltage signal Vo (sp). In FIG. 6, a solid line indicates a state of starting the DC motor 10 by the DC motor drive control device 20 according to the present embodiment, and a broken line indicates a state of starting the DC motor by the DC motor drive control device according to the related art. ing. Further, in FIG. 6, the DC motor drive control device of the prior art is in a motor stop state when the voltage signal Vo (sp) is less than about 0.6 V, and performs PWM control at about 0.6 or more and less than 3.1 V. .Peak current control is performed at 1V or more. Further, the DC motor drive control device 20 according to the present embodiment is in a motor stop state when the voltage signal Vo (sp) is less than about 0.6 V, and performs PWM control when the voltage signal Vo (sp) is less than about 0.6 to less than 1.7 V. PWM peak current control is performed at 0.7V or more and less than 3.1V, and peak current control is performed at 3.1V or more.

  In the DC motor drive control by the conventional DC motor drive control device, as shown in FIG. 6, when the voltage signal Vo (sp) rises, the motor torque decreases due to a temporary and rapid current drop, and the motor torque There was a possibility of causing the ileum of the rotor 12 due to the decrease of the above. And when motor torque fell, it was not able to expect smooth and reliable starting of a DC motor.

  On the other hand, in this embodiment, the PWM peak current control is interposed during the transition period from the PWM control to the peak current control, so that the current flows through the motor winding without causing a temporary and rapid current drop. The value of the current increases as the voltage signal Vo (sp) increases. Thereby, in the DC motor drive control device 20 according to the present embodiment, the DC motor 10 can be smoothly and reliably started. As described above, in the present embodiment, the DC motor 10 can be started smoothly and reliably in addition to suppressing the heat generation of the switching means 23.

  As described above, according to the DC motor drive control device 20 according to the present embodiment, when the DC motor 10 is operated from the stopped state, the PWM control is performed, and then the peak current control is performed after the PWM peak current control is performed. To do. That is, in the present embodiment, the PWM control and the PWM peak current control are performed in the period in which the conventional PWM control is performed, and the number of times of switching is reduced as compared with the conventional case by the amount of the PWM peak current control being performed. Heat generation of the switching means 23 can be suppressed. Therefore, by suppressing the high heat generation of the switching means 23 which is one of the component parts, it is possible to suppress an increase in the size and cost of the heat dissipation parts and a shortening of the life of the switching means 23.

  In addition, when the DC motor 10 is stopped from the operating state, peak current control is performed, and then PWM peak current control is performed, and then PWM control is performed. Also in this case, similarly to the above, the number of times of switching is reduced compared to the conventional case, and the heat generation of the switching means 23 can be suppressed. Therefore, by suppressing the high heat generation of the switching means 23 which is one of the component parts, it is possible to suppress an increase in the size and cost of the heat dissipation parts and a shortening of the life of the switching means 23.

  Furthermore, according to the pump unit 1 according to the present embodiment, stable fluid absorption and discharge can be performed by the smooth and reliable start-up of the DC motor 10.

  Next, a second embodiment of the present invention will be described. The pump unit 1 according to the second embodiment is the same as that of the first embodiment, but the configuration of the DC motor drive control device 20 is different from that of the first embodiment.

  FIG. 7 is a configuration diagram of the DC motor drive control device 20 according to the second embodiment. As shown in the figure, in the DC motor drive control device 20 according to the second embodiment, the voltage signal Vo (sp) amplified by the amplifier 21 is applied to the non-inverting input terminal of the comparator 26 via the diode and the resistor R9. Entered. Thereby, in the second embodiment, the voltage signal Vi (sp) input to the non-inverting input terminal of the comparator 26 is changed.

  FIG. 8 is a graph showing the relationship between various voltages, where (a) shows the voltage signal Vo (sp) and each divided value, and (b) shows the voltage signal input to the non-inverting input terminal of the comparator 26. Vi (sp) is shown. In FIG. 8, it is assumed that the resistance values of the resistors R1 and R2 are equal. The reference voltage is 7.5 V, the resistances R6, R7, and R9 have the same resistance value, and the resistance R8 has a resistance value about nine times that of the resistance R7.

  First, as shown in FIG. 8A, the amplifier 21 amplifies the input SP signal to a voltage value about twice as large. That is, when a 2V SP signal is input, the voltage signal Vo (sp) is 4V, and when a 3V SP signal is input, the voltage signal Vo (sp) is 6V. When the SP signal reaches 3V, the voltage signal Vo (sp) becomes 6V and the amplifier 21 is saturated. Thereby, even if the SP signal is set to 3V or higher, the voltage signal Vo (sp) is maintained at 6V.

  Further, the reference voltage is 7.5V, and the resistor R8 has a resistance value about nine times that of the resistor R7. Therefore, as shown in FIG. 8A, the divided voltage value of the resistors R7 and R8 is 0.75V. Become. Further, since the resistance values of the resistors R6 and R7 are equal, the divided voltage value of the resistors R6 and R7 is ½ of the voltage value of the SP signal. That is, the divided voltage values of the resistors R6 and R7 increase proportionally with the increase of the SP signal, and when the SP signal becomes 6V, the divided voltage values of the resistors R6 and R7 become 3V. Further, the divided voltage values of the resistors R7 and R9 are ½ of the voltage signal Vo (sp) because the resistance values of the resistors R7 and R9 are equal. That is, the divided voltage value of the resistors R7 and R9 is 3V when the voltage signal Vo (sp) is 6V, and does not increase above 3V.

  Here, the voltage signal Vi (sp) input to the inverting input terminal of the comparator 26 is as shown by the broken line in FIG. 8B in the case of the first embodiment. That is, in the first embodiment, the voltage signal Vi (sp) is determined from the relationship between the divided voltage values of the resistors R7 and R8 and the divided voltage values of the resistors R6 and R7, and when the voltage value of the SP signal is less than about 1V. 0.75V. Further, when the voltage value of the SP signal is about 1V or more, the voltage signal Vi (sp) increases by 0.45V every time the SP signal increases by 1V. Thus, in the first embodiment, the voltage signal Vi (sp) has a constant increase rate when the voltage value of the SP signal is about 1V or more.

  On the other hand, in the second embodiment, the increase rate of the voltage signal Vi (sp) is not constant as shown by the solid line in FIG. Specifically, in the second embodiment, the voltage signal Vi (sp) is determined from the relationship between the divided values of the resistors R7 and R8, the divided values of the resistors R6 and R7, and the divided values of the resistors R7 and R9. When the voltage value of the SP signal is less than about 0.75V, it becomes 0.75V. When the voltage value of the SP signal is about 0.75 V or more, the voltage signal Vi (sp) is increased by about 0.6 V every time the SP signal is increased by 1 V. Further, when the voltage value of the SP signal is about 3V or more, the voltage signal Vi (sp) increases by about 0.25V every time the SP signal increases by 1V. Thus, in the second embodiment, the increase rate of the voltage signal Vi (sp) varies depending on the voltage value of the SP signal.

  Here, the magnitude of the SP signal indicates the target rotational speed of the DC motor 10. For this reason, in the second embodiment, not only the value of the voltage signal Vi (sp) is increased as the target rotational speed of the DC motor 10 increases, but also the voltage signal Vi () when the target rotational speed is less than a predetermined value. The rate of increase in the value of sp) is set higher than the rate of increase in the value of the voltage signal Vi (sp) when the target rotational speed is equal to or greater than the predetermined value. As a result, the second embodiment has the following effects.

  FIG. 9 shows a current value when the DC motor 10 is started by the DC motor drive control apparatus 20 according to the second embodiment, and a current value when the DC motor 10 is started by the DC motor drive control apparatus 20 according to the first embodiment. It is a graph which shows the comparison with. In FIG. 9, the vertical axis represents the current value, and the horizontal axis represents the voltage signal Vo (sp).

  As shown by the broken line in FIG. 9, in the first embodiment, the value of the current supplied to the motor winding increases in proportion to the increase in the voltage signal Vo (sp). On the other hand, as shown by the solid line in FIG. 9, in the second embodiment, the value of the current gradually increases in the section where the SP signal is 3V or more. This increase in current is similar to Vi (sp) shown in FIG. That is, in the first embodiment, the slope of Vi (sp) is constant, and accordingly, the slope of the current value is constant. On the other hand, in the second embodiment, the slope of Vi (sp) is steep when the SP signal is less than 3V, and the slope of Vi (sp) is gentle when the SP signal is 3V or more. The SP signal is steep when it is less than 3V, and it is moderate when it is 3V or more.

  Here, the output control of the DC motor 10 is characterized in that it becomes difficult on the side where the SP signal is high. For this reason, when the SP signal is 3 V or higher, it is difficult to control the motor rotation speed. However, in the second embodiment, the increase in the current value is moderate in the section where the SP signal is 3V or more. For this reason, in the second embodiment, it is easy to adjust the value of the current that flows through the motor winding in the section where the SP signal is 3 V or more, and the current that flows through the motor winding in the section where the control of the motor speed is likely to be difficult. It is easy to control the motor rotation speed by appropriately adjusting. Thereby, the DC motor drive control device 20 according to the second embodiment can improve the control accuracy of the motor output.

In this way, according to the DC motor drive control device 20 according to the second embodiment, similarly to the first embodiment, by suppressing the high heat generation of the switching means 23 that is one of the component parts, Increase in size, cost, and shortening of the life of the switching means 23 can be suppressed. Further, according to the pump unit 1 according to the second embodiment, as in the first embodiment, the fluid can be stably absorbed and discharged by the smooth and reliable start-up of the DC motor 10. According to the DC motor drive control device 20 according to the embodiment, the rate of increase in the value of the voltage signal Vi (sp) when the target rotational speed is less than the predetermined value is expressed as the voltage when the target rotational speed is greater than or equal to the predetermined value. The rate of increase of the value of the signal Vi (sp) is set higher. This allows a large amount of current to flow through the motor winding when the target rotational speed is less than the predetermined value, and increases the current passed through the motor winding when the target rotational speed is equal to or greater than the predetermined value. The rate can be moderated. Here, the output control of the DC motor 10 is characterized in that it is difficult on the side where the SP signal is high. For this reason, as described above, when the target rotational speed is equal to or higher than the predetermined value, the increase rate of the current flowing through the motor winding is moderated, so that the motor winding can be applied to the motor winding in a section where the control of the motor rotational speed is difficult. It is easy to control the motor rotation speed by appropriately adjusting the current to flow. Therefore, it is possible to improve the control accuracy of the motor output.

  In the second embodiment, the starting stage of the DC motor 10 has been described as shown in FIG. 9, but the control accuracy of the motor output can be similarly improved when the DC motor 10 is stopped. That is, the rate of decrease of the voltage signal Vi (sp) when the target rotational speed is less than a predetermined value is smaller than the rate of decrease of the value of the voltage signal Vi (sp) when the target rotational speed is greater than or equal to the predetermined value. By increasing the value, the control accuracy of the motor output can be improved in the same manner as described above.

  As described above, the present invention has been described based on the embodiment, but the present invention is not limited to the above embodiment, and may be modified without departing from the gist of the present invention. It goes without saying that various modifications can be made in accordance with the design and the like as long as the technical idea according to the present invention is not deviated from other embodiments.

It is a block diagram of the liquid supply apparatus containing the pump unit which concerns on 1st Embodiment of this invention. It is a block diagram of DC motors etc. which are mounted on the pump unit shown in FIG. It is a detailed block diagram of the DC motor drive control apparatus shown in FIG. It is a time chart which shows the mode of the drive of the DC motor by the DC motor drive control apparatus which concerns on this embodiment, (a) shows a PWM carrier signal and the voltage signal Vo (sp), (b) is upper arm FET group The on / off control signal input to the is shown. It is a time chart which shows detailed operation | movement when starting a DC motor with the DC motor drive control apparatus which concerns on this embodiment, (a) shows the mode of the voltage in the stop state of a DC motor, (b) is PWM control. (C) shows the state of the voltage in PWM peak current control, and (d) shows the state of the voltage in peak current control. It is a graph which shows the mode of starting of the DC motor by the DC motor drive control apparatus which concerns on this embodiment, and the mode of starting of the DC motor by the DC motor drive control apparatus of a prior art. It is a block diagram of the DC motor drive control apparatus which concerns on 2nd Embodiment. It is a graph which shows the relationship of various voltages, (a) shows voltage signal Vo (sp) and each divided voltage value, (b) shows voltage signal Vi (sp) input to the non-inverting input terminal of the comparator. Show. It is a graph which shows the comparison with the electric current value at the time of starting of the DC motor by the DC motor drive control device which concerns on 2nd Embodiment, and the electric current value at the time of starting of the DC motor by DC motor driving control device which concerns on 1st Embodiment. .

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Pump unit 10 ... DC motor 11 ... Stator 12 ... Rotor 13 ... Rotating shaft 14 ... Rotation position detection sensor 20 ... DC motor drive control device 21 ... Amplifier 22 ... Control IC
DESCRIPTION OF SYMBOLS 23 ... Switching means 23a ... Upper arm FET group 23b ... Lower arm FET group 24 ... Bootstrap circuit 25 ... Amplifier 26 ... Comparator 27 ... Latch circuit 30 ... Signal input / output part 100 ... Liquid supply apparatus 101 ... Bathtub 101a ... Flow Outlet 101b ... Inlet 102 ... First piping 103 ... Second piping 104 ... Heating section 105 ... Third piping

Claims (3)

A DC motor drive control device that detects a rotor rotational position of a DC motor, determines an energization state to a plurality of phases of motor windings based on the detected rotation position, and performs drive control of the DC motor based on the determined energization state Because
When the DC motor is operated from a stopped state, it comprises a first control means for performing pulse width modulation control and then performing PWM peak current control and then performing peak current control,
The first control means includes
When the PWM peak current control supplies current to the motor windings of a plurality of phases with a duty ratio exceeding 0% and less than 100%, and the value of the current supplied to the motor windings reaches the first predetermined current value Control to stop the current supply to the motor winding until the phase switching point of energization to the motor winding.
As the peak current control, current is supplied to the motor windings of a plurality of phases with a duty ratio of 100%, and when the value of the current supplied to the motor windings reaches the second predetermined current value, There line control to stop the current supply to the motor windings to the phase switching time of the energization,
By comparing the first voltage value when the current supplied to the motor winding is converted into a voltage with the second voltage value having a magnitude corresponding to the target rotational speed of the DC motor, the current passed through the motor winding Determining that the value of the first predetermined current value or the second predetermined current value has been reached, and stopping the current supply to the motor winding,
The second voltage value is increased as the target rotational speed of the DC motor is increased, and the rate of increase of the second voltage value when the target rotational speed is less than a predetermined value is determined. A DC motor drive control device characterized in that it is higher than the increase rate of the second predetermined voltage value in the case . A DC motor drive control device that detects a rotor rotational position of a DC motor, determines an energization state to a plurality of phases of motor windings based on the detected rotation position, and performs drive control of the DC motor based on the determined energization state Because
When stopping the DC motor from the operating state, the second motor is provided with a second control unit that performs peak current control and then performs PWM peak current control and then performs pulse width modulation control.
The second control means includes
When the PWM peak current control supplies current to the motor windings of a plurality of phases with a duty ratio exceeding 0% and less than 100%, and the value of the current supplied to the motor windings reaches the first predetermined current value Control to stop the current supply to the motor winding until the phase switching point of energization to the motor winding.
As the peak current control, current is supplied to the motor windings of a plurality of phases with a duty ratio of 100%, and when the value of the current supplied to the motor windings reaches the second predetermined current value, There line control to stop the current supply to the motor windings to the phase switching time of the energization,
By comparing the first voltage value when the current supplied to the motor winding is converted into a voltage with the second voltage value having a magnitude corresponding to the target rotational speed of the DC motor, the current passed through the motor winding Determining that the value of the first predetermined current value or the second predetermined current value has been reached, and stopping the current supply to the motor winding,
The second voltage value is decreased as the target rotational speed of the DC motor becomes lower, and the rate of decrease of the second voltage value when the target rotational speed is less than a predetermined value is set so that the target rotational speed is greater than or equal to the predetermined value. A DC motor drive control device characterized in that it is higher than the decreasing rate of the second predetermined voltage value in the case . DC motor drive control device according to claim 1 or 2 ,
A DC motor driven by the DC motor drive control device to absorb and discharge liquid by rotating an impeller integrated with the rotor;
A pump unit comprising:

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