JP2007028757A - Motor controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor controller whose configuration can be simplified with the production of high-frequency noise suppressed. <P>SOLUTION: In a fuel supply device 1, ECU 50 is provided with: a PWM signal generation unit 51 that generates a high-frequency PWM signal for driving the motor M of a fuel pump; and a CR circuit 52 for averaging a high-frequency PWM signal of a frequency out of the audible range, generated at the PWM signal generation unit 51. A fuel pump controller 60 is provided with: a waveform shaping circuit 61 for making a high-frequency PWM signal, made gentle, steep again; and a power MOSFETQ1 for controlling driving of the motor M based on the high-frequency PWM signal made steep. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a motor control device that controls driving of a motor by a rectangular wave driving signal. More specifically, the present invention relates to a motor control device capable of simplifying the configuration.

  Conventionally, for example, as a motor control device, there is a fuel pump control device that controls a fuel pump (motor) that supplies fuel to an internal combustion engine. In such a fuel pump control device, the drive of the fuel pump (motor) is controlled by converting the frequency of the drive signal transmitted to the fuel pump control device (from low frequency to high frequency) (Patent Document 1). That is, in such a control system, as shown in FIG. 8, the fuel control ECU 101 generates a low frequency signal (for example, about 100 Hz) and transmits the low frequency signal to the fuel pump control device 102. The low frequency signal transmitted to the fuel control apparatus 102 is received by the low frequency duty signal receiving means 121, and the signal is converted into a high frequency duty signal by the frequency conversion means 122. The drive control of the fuel pump (motor) 103 is performed by the converted high frequency duty signal.

JP-A-5-296113

However, in the control system described above, the fuel pump control device 102 requires the frequency conversion means 122 for converting the low frequency signal into the high frequency signal. The frequency conversion means 122 is composed of several tens of electronic elements, and there is a problem that the configuration of the fuel pump control device 102 is complicated.
It is possible to eliminate the frequency conversion means 122 by generating a high frequency signal in the fuel control ECU 101 and inputting it to the fuel pump control device 102. There is a problem that high-frequency noise is generated.

  Accordingly, the present invention has been made to solve the above-described problems, and an object thereof is to provide a motor control device capable of simplifying the configuration while suppressing the generation of high-frequency noise. .

  The motor control device according to the present invention made to solve the above problems includes a motor, a first controller including a drive signal generation unit that generates a rectangular wave drive signal for driving the motor, and the drive In a motor control device having a second controller including a moving unit that drives the motor based on the drive signal generated by the signal generation unit, the first controller generates a high-frequency drive signal by the drive signal generation unit. And an annealing control means for performing an annealing process for increasing the time constant of the high-frequency drive signal, and the second controller sharpens the waveform of the signal subjected to the annealing process by the annealing control means. It has the waveform shaping means to do.

  In this motor control device, a first controller generates a high-frequency rectangular drive signal, which is a motor drive signal, and increases the time constant of the drive signal by the smoothing control means provided in the first controller for the drive signal. An annealing process is performed. Then, the signal subjected to the annealing process is output from the first controller and input to the second controller. Then, in the second controller, the waveform of the processed signal is sharpened by the waveform shaping circuit and shaped into a rectangular wave signal, and the motor is driven by driving the drive unit with the shaped signal. Control is implemented.

  It should be noted that the waveform of the signal subjected to the annealing process is shaped into a rectangular wave when the driving unit (for example, a transistor) is driven with the signal subjected to the annealing process increasing switching loss and generating heat. This is because it becomes larger.

  Thus, in the motor control device of the present invention, since a high frequency signal is input to the second controller, a frequency conversion circuit is unnecessary. Instead, the second controller includes a waveform shaping circuit. This waveform shaping circuit can be composed of several electronic elements, and has a very simple structure as compared with a frequency conversion circuit (comprised of several tens of electronic elements). Thereby, since the configuration of the second controller becomes very simple, it is possible to simplify the motor control device. Therefore, according to the present invention, an inexpensive and small motor control device can be realized.

  In addition, since the signal transmitted from the first controller to the second controller is subjected to smoothing processing, the high-frequency noise level is reduced. That is, generation of high frequency noise is suppressed. Therefore, according to the motor control device of the present invention, the configuration can be simplified while suppressing the generation of high-frequency noise.

  In the motor control apparatus according to the present invention, it is desirable that a freewheeling diode is connected in parallel to the motor.

  When the drive signal is turned off and the motor is stopped, a voltage is generated by regenerative braking, and the generated voltage is applied to the coil resistance of the motor. For this reason, a large current flows through the motor, which places an excessive burden on the motor.

  Therefore, in the motor control device of the present invention, a freewheeling diode is connected in parallel to the motor. Therefore, the voltage generated when the motor is stopped can be divided and handled by the coil resistance of the motor and the freewheeling diode. Therefore, an excessive load is not applied to the motor when the motor is stopped.

  In the motor control device according to the present invention, it is preferable that a synchronous rectification transistor that is turned on in the opposite phase to the drive signal is connected in parallel to the motor.

  As described above, by connecting the freewheeling diode in parallel to the motor, it is possible to prevent an excessive load from being applied to the motor when the motor is stopped. However, in this case, there is a problem that the total heat generation amount in the motor control device becomes large due to the loss due to the forward voltage drop generated in the freewheeling diode.

  Therefore, in the motor control device of the present invention, synchronous rectification transistors that are turned on in the opposite phase to the drive signal are connected in parallel to the motor. That is, a synchronous rectification transistor is provided instead of the freewheeling diode. Thereby, the loss due to the forward voltage drop generated in the freewheeling diode can be reduced. As a result, since the total heat generation amount in the motor control device can be reduced, the motor control device can be further reduced in size.

  The motor control device according to the present invention is suitable for application to a fuel supply device (fuel pump). That is, the present invention may be applied as a fuel pump motor provided in a fuel pump in which the motor is mounted in a fuel tank by a mounting plate, and the second controller is a fuel pump controller disposed in the mounting plate.

  As described above, the motor control device of the present invention can be reduced in size by simplifying the configuration. Therefore, by applying the present invention to the fuel supply device (fuel pump), the fuel pump controller can be arranged on the mounting plate, and the fuel pump controller can be integrated with the fuel supply device.

  Thereby, the motor wire length from the fuel pump controller to the fuel pump motor can be shortened. Therefore, since noise radiation from the motor wire can be reduced, noise countermeasures can be simplified. Further, since the fuel controller can be cooled with the nearby fuel, the heat dissipation structure can be simplified.

  According to the motor control device of the present invention, as described above, the configuration can be simplified while suppressing the generation of high-frequency noise.

  Hereinafter, a most preferred embodiment in which the motor control device of the present invention is embodied will be described in detail based on the drawings. In the present embodiment, the motor control device of the present invention is applied to a controller of a fuel supply device (fuel pump) that supplies fuel to an internal combustion engine.

  The fuel supply apparatus will be described with reference to FIGS. FIG. 1 is a front view showing a schematic configuration of the fuel supply apparatus. FIG. 2 is a side view showing a schematic configuration of the fuel supply apparatus. 3 is a cross-sectional view taken along line III-III shown in FIG.

  As shown in FIGS. 1 and 2, the fuel supply device 1 includes a mounting plate 10 for attaching the fuel supply device 1 to the fuel tank 34, a filter case 22 for housing a fuel filter (not shown), and a fuel case (not shown). A fuel pump case 30 that houses the fuel pump is provided. The mounting plate 10 is formed of a resin material. The attachment plate 10 is attached to an attachment hole 34 a formed in the fuel tank 34. As a result, the fuel supply device 1 is mounted in the fuel tank 34 via the mounting plate 10. When the attachment plate 10 is attached to the attachment hole 34a, the attachment hole 34a is blocked by the attachment plate 10. A circuit case 14 and a discharge pipe mounting portion 12 are formed on the upper surface of the mounting plate 10 (the outer surface of the fuel tank 34).

  A circuit case 14 formed on the upper surface of the mounting plate 10 accommodates a fuel pump controller 60 (see FIG. 4) that controls driving of the fuel pump (motor). The fuel pump controller 60 corresponds to the “second controller” of the present invention. A connector 13 is formed integrally with the circuit case 14. A fuel pump controller 60 accommodated in the circuit case 14 is connected to the connector 13. An electric motor M (see FIG. 4) built in the fuel pump is connected to the fuel controller 60 via a motor wire. On the other hand, a power source such as a battery and a controller unit (ECU) 50 for engine control are connected to the terminals of the connector 13. The controller unit (ECU) 50 corresponds to the “first controller” of the present invention.

  A discharge pipe 11 is attached to a discharge pipe attachment portion 12 formed on the upper surface of the attachment plate 10. The other end of the discharge pipe 11 is connected to an injector (not shown) attached to the engine via a fuel pipe. The fuel discharged from the fuel supply device 1 to the discharge pipe 11 is supplied from the fuel pipe to the engine via the injector.

  From the lower surface of the mounting plate 10 (the inner surface of the fuel tank 34), the bracket portion 16 and the heat radiating plate 32 hang down into the fuel tank 34. The bracket portion 16 is formed integrally with the mounting plate 10. A mounting piece 18 is formed at the lower end of the bracket portion 16. The attachment piece 18 is adapted to engage with an engagement hole 20 formed in the filter case 22. When the attachment piece 18 is engaged with the engagement hole 20, the filter case 22 is coupled to the attachment plate 10. A fuel pump case 30 is coupled to the filter case 22.

  A fuel pump (not shown) is accommodated in the fuel pump case 30. A suction filter 26 is attached by a mounting piece 28 to a fuel suction port (not shown) provided at the lower end of the fuel pump. The suction filter 26 removes foreign matter from the fuel sucked into the fuel pump.

  As shown in FIG. 3, one end of a connection pipe 38 is attached to a fuel discharge port provided at the upper end of the fuel pump via a pressure regulator 36. The pressure regulator 36 adjusts the pressure of the fuel discharged from the fuel pump and returns excess fuel out of the fuel discharged from the fuel pump into the fuel tank 34.

  The filter case 22 has an arc shape when viewed from the mounting plate 10 side, and a fuel pump case 30 is fitted inside the filter case 22. A fuel filter (not shown) is accommodated in the filter case 22. The fuel filter removes foreign matter from the fuel discharged from the fuel pump. A fuel inlet 40 and a fuel outlet 42 are formed on the upper surface of the filter case 22. The fuel inflow port 40 is connected to the discharge port of the fuel pump through the connection pipe 38. The fuel discharge port 42 is connected to the discharge pipe mounting portion 12 of the mounting plate 10 by a fuel pipe (not shown).

  The fuel supply device 10 further includes a liquid level gauge 35 as shown in FIGS. 1 and 2. The liquid level gauge includes a float 37, an arm 24, and a sensor unit (not shown). The sensor unit is detachably attached to the attachment plate 10. The float 37 moves up and down as the liquid level of the fuel in the fuel tank 34 changes. When the float 37 moves up and down, the arm 24 swings and the angle of the arm 24 changes. The amount of fuel in the fuel tank 34 is measured by detecting a change in the rotation angle of the arm 24 by the sensor unit.

  Next, the control system of the fuel supply apparatus 1 will be described with reference to FIGS. 4 and 5. FIG. 4 is a block diagram showing the configuration of the control system of the fuel supply apparatus. FIG. 5 is a circuit diagram showing a configuration of a waveform shaping circuit provided in the fuel pump controller.

  The control system of the fuel supply apparatus 1 includes an ECU 50 and a fuel pump controller 60. The ECU 50 and the fuel pump controller 60 are connected by a signal line 55. The fuel pump controller 60 is connected to a motor M of the fuel pump via a motor wire 65.

  The ECU 50 is provided with a PWM signal generator 51 and a CR circuit 52 including a resistor R1 and a capacitor C1. The PWM signal generation unit 51 generates a signal (PWM signal) for driving the fuel pump (motor M). The PWM signal generation unit 51 generates a high-frequency PWM signal having a frequency outside the audible range, and transmits the high-frequency PWM signal to the fuel pump controller 60 via the signal line 55. In the present embodiment, the PWM signal generation unit generates a 20 kHz PWM signal.

Here, if the high-frequency PWM signal having a frequency outside the audible range generated by the PWM signal generation unit 51 is transmitted to the fuel pump controller 60 as it is, radiation noise (high-frequency noise) from the signal line 55 is generated.
In contrast, in the present embodiment, the ECU 50 is provided with a CR circuit 52 including a resistor R1 and a capacitor C1. By such a CR circuit 52, the high-frequency PWM signal having a frequency outside the audible range generated by the PWM signal generation unit 51 is subjected to an annealing process (a process for increasing the time constant) and then transmitted to the fuel pump controller 60. It has become so. Therefore, the signal on the signal line 55 has a large time constant as shown in FIG. For this reason, generation | occurrence | production of a high frequency noise is suppressed.

  The fuel pump controller 60 includes a waveform shaping circuit 61, a power MOSFET Q1 for driving the motor M, a freewheeling diode D1 connected in parallel to the motor M, and an inductor L1 and a capacitor C2 for noise countermeasures. Is provided. The switching operation of the power MOSFET Q1 is controlled by the PWM signal output from the waveform shaping circuit 61 so that the driving of the motor M is controlled.

  Here, when the power MOSFET Q1 is driven by a PWM signal that has been subjected to a smoothing process (a process for increasing the time constant), the switching loss in the power MOSFET Q1 increases and heat generation increases. For this reason, the waveform shaping circuit 61 is provided in the present embodiment. Then, the waveform shaping circuit 61 makes the waveform of the PWM signal subjected to the annealing process (a process for increasing the time constant) sharpened again. Thus, since the power MOSFET Q1 is driven by the PWM signal that has been sharpened again, the switching loss in the power MOSFET Q1 is suppressed, so that heat generation can be suppressed.

  As such a waveform shaping circuit 61, a push-pull driver constituted by a Schmitt circuit 70 and two power MOSFETs 71 and 72 as shown in FIG. 5 is used in the present embodiment. The power MOSFETs 71 and 72 are turned on in opposite phases. For this reason, in this push-pull driver, the power MOSFETs 71 and 72 operate alternately to sharpen the waveform of the high-frequency PWM signal after the smoothing process input to the waveform shaping circuit 61 again.

  Here, the fuel pump controller 60 does not require the frequency conversion means 122 provided in the conventional fuel pump control apparatus 102. This is because the fuel pump controller 60 receives the high-frequency PWM signal generated by the ECU 50. In the fuel pump controller 60, a waveform shaping circuit 61 is provided instead of the frequency conversion means 122. The waveform shaping circuit 61 is a very simple circuit composed of three electronic elements as shown in FIG. On the other hand, the frequency conversion means 122 that has been conventionally required is composed of several tens of electronic elements. For this reason, the fuel pump controller 60 has a very small number of electronic elements to be used as compared with the conventional one, and the configuration is simplified. As a result, the fuel pump controller 60 can be reduced in size, and as described above, the fuel pump controller 60 can be housed in the circuit case 14 formed on the upper surface of the mounting plate 10.

  By housing the fuel pump controller 60 in the circuit case 14 in this way, the length of the motor wire 65 that connects the fuel pump controller 60 and the motor M of the fuel pump can be shortened. Thereby, since noise radiation from the motor wire 65 can be reduced, a noise countermeasure product (capacitor C2, inductor L1) can be simplified. Further, since the fuel controller 60 can be cooled with the nearby fuel, the heat dissipation structure can be simplified.

  The fuel pump controller 60 is provided with a freewheeling diode D1 connected in parallel to the motor M. For this reason, when the motor M is stopped, the current accumulated in the coil of the motor M is circulated to the motor M via the freewheeling diode D1. As a result, the voltage generated when the motor M is stopped can be divided and handled by the coil resistance of the motor M and the freewheeling diode D1, so that an excessive load is not applied to the motor M.

  In the fuel supply device 1 having the above-described configuration, the PWM signal generation unit 51 of the ECU 50 generates a high-frequency PWM signal for driving the motor M of the fuel pump. The high-frequency PWM signal having an audible frequency outside the audible range generated by the PWM signal generation unit 51 is transmitted to the fuel pump controller 60 via the signal line 55 after being subjected to a smoothing process by the CR circuit 52. Thereby, even if the ECU 50 generates a high-frequency PWM signal and transmits it to the fuel pump controller 60, the generation of high-frequency noise can be suppressed.

  In the fuel pump controller 60, the waveform shaping circuit 61 sharpens the high-frequency PWM signal subjected to the annealing process again. Thereafter, the power MOSFET Q1 is driven based on the sharpened high-frequency PWM signal. Thus, since the power MOSFET Q1 is driven based on the sharpened high-frequency PWM signal, the switching loss in the power MOSFET Q1 is reduced, so that heat generation in the power MOSFET Q1 can be suppressed.

  Thereafter, the drive of the fuel pump motor M is controlled by the operation (switching operation) of the power MOSFET Q1. Thereby, the fuel discharged from the discharge pipe 11 is supplied to the engine via the injector while the amount of fuel discharged from the discharge pipe 11 of the fuel supply device 1 is controlled.

  Next, a modification of the fuel pump controller will be described with reference to FIG. FIG. 6 is a block diagram showing a deformable configuration of the control system of the fuel supply apparatus. In this modification, as shown in FIG. 6, a rectifying transistor Q2 is provided instead of the freewheeling diode D1. The rectifier transistor (MOSFET) Q2 is turned on in a phase opposite to that of the power MOSFET Q1, and is driven by an output signal from the waveform shaping circuit 61. By providing such a rectifying transistor Q2, it is possible to reduce the loss due to the forward drop voltage generated in the freewheeling diode D1 and to reduce the total heat generation amount. As a result, the fuel pump controller 60 can be further reduced in size.

  As described above in detail, in the fuel supply device 1 according to the present embodiment, the ECU 50 generates a PWM signal generation unit 51 that generates a high-frequency PWM signal for driving the motor M of the fuel pump, and a PWM signal generation unit. And a CR circuit 52 that performs a smoothing process on the high-frequency PWM signal generated at 51 outside the audible frequency. Further, the fuel pump controller 60 is provided with a shaping circuit 61 for sharpening the high-frequency PWM signal subjected to the annealing process again, and a power MOSFET Q1 for controlling the driving of the motor M based on the sharpened high-frequency PWM signal. ing.

  In the fuel supply device according to the present embodiment, since the high frequency PWM signal is input to the fuel pump controller 60, a frequency conversion circuit that has been conventionally required is unnecessary. Instead, the fuel pump controller 60 includes a waveform shaping circuit 61. This waveform shaping circuit 61 is composed of three electronic elements, and has a very simple structure as compared with a frequency conversion circuit (comprised of several tens of electronic elements). For this reason, the structure of the fuel pump controller 60 can be made very simple.

  In addition, since the signal transmitted from the ECU 50 to the fuel pump controller 60 is subjected to a smoothing process, generation of high frequency noise can be suppressed. Thus, according to the fuel supply device according to the present embodiment, it is possible to simplify the configuration while suppressing the generation of high-frequency noise.

  It should be noted that the above-described embodiment is merely an example and does not limit the present invention in any way, and various improvements and modifications can be made without departing from the scope of the invention. For example, in the above-described embodiment, the push-pull driver shown in FIG. 5 is illustrated as the waveform shaping circuit 61. However, the waveform shaping circuit 61 may be any circuit that can sharpen the signal waveform other than the push-pull driver. It may be something like this. For example, as shown in FIG. 7, a waveform shaping circuit 61 a can be configured by a Schmitt circuit 70, a power MOSFET 72, and a resistor 75. The resistor 75 needs to use a resistor of several hundred Ω or less.

  In the above-described embodiment, the present invention is applied to the fuel supply device (fuel pump). However, the present invention is not limited to this, and a device that needs to drive and control a motor such as a cooling fan or a radiator fan. It can also be applied to.

It is a front view which shows schematic structure of the fuel supply apparatus which concerns on embodiment. It is a side view which shows schematic structure of the fuel supply apparatus which concerns on embodiment. It is sectional drawing in the III-III line shown in FIG. It is a block diagram which shows the structure of the control system of a fuel supply apparatus. It is a circuit diagram which shows the structure of the waveform shaping circuit with which a fuel pump controller is equipped. It is a block diagram which shows the deformation | transformation structure of the control system of a fuel supply apparatus. It is a circuit diagram which shows the modification of a waveform shaping circuit. It is a block diagram which shows the structure of the conventional fuel pump control apparatus.

Explanation of symbols

1 Fuel Supply Device 10 Mounting Plate 14 Circuit Case 22 Filter Case 30 Fuel Pump Case 34 Fuel Tank 36 Pressure Regulator 40 Fuel Inlet 42 Fuel Discharge Port 50 ECU
51 PWM signal generator 52 CR circuit 55 signal line 60 fuel pump controller 61 waveform shaping circuit M motor Q1 power MOSFET

Claims (4)

A first controller including a motor, a drive signal generation unit configured to generate a rectangular wave drive signal for driving the motor, and a drive unit configured to drive the motor based on the drive signal generated by the drive signal generation unit; A motor controller having a second controller comprising:
The first controller includes annealing control means for generating a high frequency driving signal in the driving signal generation unit and performing an annealing process for increasing a time constant of the high frequency driving signal,
The motor controller according to claim 2, wherein the second controller includes waveform shaping means for sharpening the waveform of the signal subjected to the smoothing process by the smoothing control means. In the motor control device according to claim 1,
A motor control device comprising a freewheeling diode connected in parallel to the motor. In the motor control device according to claim 1,
A motor control device, wherein a synchronous rectification transistor that is turned on in the opposite phase to the drive signal is connected to the motor in parallel. The motor control device according to any one of claims 1 to 3,
The motor control device according to claim 1, wherein the motor is a fuel pump motor provided in a fuel pump attached in a fuel tank by a mounting plate, and the second controller is a fuel pump controller disposed on the mounting plate.

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