JP2016032414A - Pump controller, on-vehicle pump unit, and pump controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pump controller capable of driving an oil pump efficiently.SOLUTION: A pump controller 1 includes an inverter 10 to be connected between an on-vehicle DC power supply B and a motor M for driving an oil pump P, an operating conditions storage section 20 for prestoring the minimum operating conditions of the motor M including the working voltage and on-duty satisfying a request oil-pressure requested for the oil pump P, an applied voltage detector 30 for detecting the current applied voltage from the DC power supply B, a duty ratio setting section 40 for setting a duty ratio based on the current applied voltage and minimum operating conditions, and a PWM control section 50 for controlling a switching element of the inverter 10 at a set duty ratio.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pump control device that controls the output of an oil pump mounted on a vehicle, a vehicle-mounted pump unit including the pump control device, and a pump control method.

  Conventionally, a motor has been used as one of the power sources of an oil pump. As a technique for controlling this type of motor, there are those described in Patent Documents 1 and 2, which are cited below.

  The electric pump unit described in Patent Document 1 includes a pump that sucks and discharges oil, an electric motor that drives the pump, and a motor control device that includes a drive circuit that PWM-drives the electric motor based on hydraulic pressure. Configured. The motor control device is operated by current feedback control by obtaining the oil pressure from the load torque of the motor and the oil temperature without using the oil pressure sensor.

  The sensorless / brushless motor control device described in Patent Document 2 includes an inverter that drives a motor, an inverter drive circuit that controls the inverter, and torque control means that issues a control command to the inverter drive circuit. The torque control means controls in the sensorless start mode when starting the motor, and switches to the current control mode after starting the motor.

JP 2012-31832 A JP 2010-233301 A

  Since the techniques described in Patent Documents 1 and 2 perform current feedback control, the pump can be driven efficiently when the load is heavy. However, when the load is light, the duty is 100%, resulting in excessive output and a large power loss.

  The oil pump is selected so as to have a hydraulic pressure required for the oil pump (hereinafter referred to as “required hydraulic pressure”) even under worst conditions (for example, when the applied voltage to the motor is the lowest). The applied voltage is not always low but can be high. When the voltage applied to the motor is high, the oil pump has a large margin for the required work amount having the required hydraulic pressure, and the power loss increases.

  In view of the above problems, an object of the present invention is to provide a pump control device that can efficiently drive an oil pump, a vehicle-mounted pump unit that includes the pump control device, and a pump control method.

  In order to achieve the above object, the pump control device according to the present invention is characterized by an inverter connected between a DC power source mounted on a vehicle and a motor that drives the oil pump, and the oil pump. An operation condition storage unit that preliminarily stores the minimum operation condition of the motor including an operation voltage and on-duty that satisfy a required hydraulic pressure, an application voltage detection unit that detects a current application voltage from the DC power source, and the current A duty ratio setting unit that sets a duty ratio based on an applied voltage and the minimum operating condition, and a PWM control unit that PWM-controls a switching element included in the inverter with the set duty ratio. .

  With such a characteristic configuration, the oil pump is selected so as to have the required hydraulic pressure even when the applied voltage becomes the lowest voltage in the operating voltage range. The required hydraulic pressure can be provided as described above. On the other hand, when the applied voltage from the DC power supply is higher than the lowest voltage in the operating voltage range having the required hydraulic pressure, the applied voltage from the DC power supply is converted to a voltage corresponding to the lowest voltage to drive the motor. Therefore, the required hydraulic pressure can be provided while reducing wasteful power consumption. Therefore, according to this pump control apparatus, it is possible to drive the oil pump efficiently while providing the required oil pressure regardless of the voltage applied from the DC power supply.

  In addition, a characteristic configuration of the on-vehicle pump unit according to the present invention for achieving the above object is that the oil pump, the motor, and the pump control device are provided.

  With such a characteristic configuration, a pump unit having an oil pump that can be driven efficiently can be formed.

  In order to achieve the above object, the pump control method according to the present invention is characterized in that a DC power source mounted on a vehicle and an inverter connected between a motor driving an oil pump are driven to drive the DC power source. The output conversion step of converting the output of the motor into an alternating current and supplying it to the motor, and the minimum operating condition of the motor including the operating voltage and on-duty that satisfy the required hydraulic pressure required by the oil pump are stored in the operating condition storage unit in advance. An operating condition storing step, an applied voltage detecting step for detecting a current applied voltage from the DC power supply, a duty ratio setting step for setting a duty ratio based on the current applied voltage and the minimum operating condition, And a PWM control step for PWM-controlling the switching element of the inverter with the set duty ratio.

  With such a configuration, as in the above-described characteristic configuration of the pump control device, when the applied voltage from the DC power supply is higher than the lowest voltage in the operating voltage range having the required hydraulic pressure, the DC power supply The applied voltage can be converted to a voltage corresponding to the lowest voltage to drive the motor, so that the required hydraulic pressure can be provided while reducing wasteful power consumption. Therefore, it is possible to drive the oil pump efficiently while having the required oil pressure regardless of the voltage applied from the DC power supply.

It is a block diagram which shows typically the structure of a pump control apparatus and a vehicle-mounted pump unit. It is a figure which shows the pump characteristic of an oil pump. It is a figure which shows the example of a setting of a duty ratio. It is a flowchart which shows the process of a pump control apparatus.

  The pump control device according to the present invention is configured to have a function of efficiently controlling the operation of the oil pump regardless of the level of the voltage applied to the motor that drives the oil pump. Hereinafter, the pump control device 1 of the present embodiment will be described in detail. The pump control device 1 is used to control the operation of the oil pump P mounted on the vehicle. For this reason, the pump control apparatus 1 is also mounted on the vehicle.

  FIG. 1 is a block diagram schematically showing the configuration of the pump control device 1. As shown in FIG. 1, the pump control device 1 includes an inverter 10, an operation condition storage unit 20, an applied voltage detection unit 30, a duty ratio setting unit 40, and a PWM control unit 50. In particular, the operation condition storage unit 20, the applied voltage detection unit 30, the duty ratio setting unit 40, and the PWM control unit 50 are described above for performing various processes for controlling the operation of the oil pump P using the CPU as a core member. Are constructed by hardware and / or software. Further, as shown in FIG. 1, an on-vehicle pump unit 100 according to the present invention is constituted by the oil pump P, the motor M, and the pump control device 1.

  The inverter 10 is connected between a DC power source B mounted on the vehicle and a motor M that drives the oil pump P. The DC power supply B mounted on the vehicle corresponds to a so-called battery. The oil pump P is driven by a motor M, and distributes oil as a base of hydraulic pressure supplied to equipment provided in the vehicle. In the present embodiment, the motor M is a three-phase motor, and includes a rotor including a permanent magnet and a stator that generates a magnetic field for applying a rotational force to the rotor. The stator includes a three-phase stator coil of U phase, V phase, and W phase. Each stator coil may be Y-connected or Δ-connected.

  The inverter 10 controls the motor M, and converts the DC voltage output from the DC power source B into an AC voltage. As shown in FIG. 1, the inverter 10 includes high-side transistors Q1, Q3, and Q5 connected to the positive voltage side of the DC power supply B, and a low-side transistor Q2 connected to the negative voltage side of the DC power supply B. A total of six transistors Q1 to Q6 including Q4 and Q6 are formed. For example, when only the transistor Q1 and the transistor Q4 are simultaneously turned on, current flows from the DC power source B to the transistor Q1, the stator coil of the motor M, and the transistor Q4. On the other hand, when only the transistor Q3 and the transistor Q2 are simultaneously turned on, a current flows from the DC power source B to the transistor Q3, the stator coil of the motor M, and the transistor Q2. Thereby, the output of the DC power supply B is converted into an AC voltage.

  The direction of the current flowing through the stator coil of the motor M differs between when only the transistor Q1 and the transistor Q4 are turned on and when only the transistor Q3 and the transistor Q2 are turned on. Therefore, an electromagnetic force corresponding to the direction in which the current flows acts on each stator coil, and an attractive force and a repulsive force are generated between the electromagnetic force and a permanent magnet provided in the rotor. Therefore, the rotor can obtain a rotational force by sequentially turning on the upper and lower pair transistors formed by the high-side transistor and the low-side transistor selected from the transistors Q1 to Q6.

  The transistors Q1 to Q6 are provided with diodes D1 to D6 so that the cathode terminal is connected to the collector terminal and the anode terminal is connected to the emitter terminal. Here, energy is stored in each stator coil during energization, but these diodes D1 to D6 are applied to peripheral components by back electromotive force generated due to the energy when the energization of each stator coil is stopped. It is arranged to prevent adverse effects. The process of driving the inverter 10 to convert the output of the DC power source B into AC and supplying it to the motor M is called an output conversion process.

  The operating condition storage unit 20 stores in advance the minimum operating conditions of the motor M including the operating voltage that satisfies the required oil pressure required for the oil pump P and the on-duty. The required oil pressure required for the oil pump P is the oil pressure required for the oil pump P as the oil pressure required to drive the equipment provided in the vehicle. Such a required oil pressure is defined by the discharge flow rate of the oil pump P and the pressure corresponding to the flow rate. An example of such required oil pressure is shown in FIG.

  The minimum operating condition of the motor M including the operating voltage that satisfies the required hydraulic pressure and the on-duty is an operating condition of the motor M for realizing the above-described required hydraulic pressure by the oil pump P. Such operating conditions are determined by the input voltage applied to the motor M and the on-duty of this input voltage. Therefore, the operating voltage that satisfies the required hydraulic pressure corresponds to an input voltage that is applied to the motor M in order to realize the required hydraulic pressure by the oil pump P. The on-duty corresponds to the on-duty of the input voltage. In the present embodiment, in order to facilitate understanding, the input voltage is defined by a DC voltage and the on-duty is 100%. Therefore, in the following description, the minimum operating condition of the motor M is defined only by the input voltage. To do. Such a minimum operation condition of the motor M is stored in advance in the operation condition storage unit 20, and such a step of storing in advance is referred to as an operation condition storage step.

  The applied voltage detection unit 30 detects the current applied voltage from the DC power supply B. In the present embodiment, the DC power source B is a battery mounted on the vehicle. For this reason, the applied voltage corresponds to the output voltage of the battery, but the output voltage of the battery may vary depending on the period of use, the power generation state, and the like. The applied voltage detection unit 30 detects the current applied voltage in order to obtain the latest value of the applied voltage that can vary in this way. The detection result is transmitted to a duty ratio setting unit 40 described later. The process of detecting the current applied voltage from the DC power source B by the applied voltage detection unit 30 is referred to as an applied voltage detection process.

  The duty ratio setting unit 40 sets the duty ratio based on the current applied voltage and the minimum operating condition. The current applied voltage is a detection result transmitted from the applied voltage detection unit 30 described above. The minimum operation condition is a minimum operation condition of the motor M stored in advance in the operation condition storage unit 20. Here, as shown in FIG. 3, the current applied voltage is V1, and the input voltage as the minimum operating condition is V2. In this case, the duty ratio setting unit 40 calculates the ratio between the applied voltage V1 and the input voltage V2, and sets this ratio as the duty ratio. Specifically, as shown in FIG. 3, when the duty ratio is D, D = V2 / V1 × 100 (%) is set. The duty ratio set in this way is transmitted to the PWM control unit 50 described later. The step of setting the duty ratio based on the current applied voltage and the minimum operating condition is referred to as a duty ratio setting step.

  The PWM control unit 50 performs PWM control of the switching element included in the inverter 10 with the set duty ratio. The set duty ratio is a duty ratio set by the duty ratio setting unit 40 described above. The switching elements included in the inverter 10 are the transistors Q1 to Q6 described above. Since the PWM control is a known pulse width modulation control, the description thereof is omitted. For this reason, the PWM control unit 50 performs PWM control of the transistors Q1 to Q6 using the duty ratio set by the duty ratio setting unit 40, so that, for example, from the DC power source B as shown by the one-dot chain line in FIG. Even when the applied voltage is higher than the input voltage under the minimum operating condition, the oil pump P can be operated along the characteristic indicated by the solid line. Therefore, the required hydraulic pressure can be realized while suppressing unnecessary power consumption until the required hydraulic pressure is provided (between the discharge pressure is 0 and P1). A process in which the PWM control unit 50 performs PWM control of the switching element included in the inverter 10 with the set duty ratio is referred to as a PWM control process.

  Here, the PWM control unit 50 monitors a current (hereinafter referred to as “motor current”) flowing through the motor M via the inverter 10. When the motor current reaches a predetermined value, the PWM control unit 50 performs PWM control so that the motor M is controlled with a constant current. Specifically, control is performed to reduce the voltage applied to the motor M while keeping the motor current constant. As a result, the rotational speed of the motor M is reduced while the motor current is constant. Therefore, as shown in FIG. 2, it is possible to reduce the discharge flow rate of the oil pump P while maintaining the discharge hydraulic pressure constant when the discharge pressure exceeds the required hydraulic pressure. In the present embodiment, the fact that the discharge pressure exceeds the required oil pressure is set in advance so as to be identified by the corresponding motor current.

  Here, in the present embodiment, the rotation speed of the motor M is calculated from the ripple of the motor current. When the rotational speed of the motor M calculated based on the ripple of the motor current decreases to a predetermined value during the control of the motor M with the constant current described above, the PWM control unit 50 changes the rotational speed at that time from the control with the constant current. Switch to constant voltage control again to maintain. Thereby, after the discharge flow rate is reduced while maintaining P1 as the discharge pressure, the discharge flow rate can be reduced according to the discharge pressure.

  Note that the viscosity of oil used for vehicle hydraulic control changes according to temperature. For this reason, if the oil pump P is driven under the same conditions regardless of the temperature, there is a possibility that the required oil pressure cannot be provided. Therefore, it is preferable to change the switching time point from the constant current control to the constant voltage control according to the oil temperature. Specifically, when the oil temperature is low, the viscosity increases and the flow resistance increases. Therefore, the motor when the motor M is switched from constant current control to constant voltage control as the oil temperature decreases. It is good to set the rotation speed of M large. This makes it possible to reduce the wasteful power consumption while providing the required oil pressure regardless of the temperature of the oil.

  Next, a method for controlling the oil pump P by the pump control device 1 will be described with reference to the flowchart of FIG. When the pump control device 1 receives a drive command for the oil pump P, the duty ratio setting unit 40 satisfies the minimum operating condition of the motor M that satisfies the required hydraulic pressure required for the oil pump P stored in the operating condition storage unit 20 in advance. (Step # 01). On the other hand, the applied voltage detection unit 30 starts detection of the current applied voltage from the DC power supply B (step # 02), and the detection result is transmitted to the duty ratio setting unit 40.

  The duty ratio setting unit 40 calculates and sets the duty ratio from the applied voltage from the DC power source B and the minimum operating condition (step # 03). The set duty ratio is transmitted to the PWM control unit 50, and the PWM control unit 50 performs PWM control of the switching element of the inverter 10 with the duty ratio (step # 04). This PWM control is continued until the motor current reaches a predetermined value (step # 05: No).

  When the motor current reaches a predetermined value (step # 05: Yes), the PWM control unit 50 changes the motor M to control with a constant current (step # 06). The control of the motor M with this constant current is continued until the rotational speed of the motor M reaches a predetermined rotational speed (step # 07: No). When the rotation speed of the motor M reaches a predetermined rotation speed (step # 07: Yes), the PWM control unit 50 switches the motor M to control with a constant voltage again (step # 08). This control is continued until the oil pump P is stopped (step # 09: No).

[Other Embodiments]
In the above embodiment, the example has been described in which the minimum operating condition of the motor M is defined including the operating voltage and the on-duty, and the on-duty is 100%. However, the minimum operating condition is defined by both the operating voltage and the on-duty. The present invention can be applied even in the case where it is used. Specifically, it is assumed that the operating voltage is V3, the on-duty is 50%, and the applied voltage from the DC power source B is V1. In this case, the duty ratio setting unit 40 obtains the converted operation voltage V4 when the on-duty is 100% from the minimum operation condition. That is, V4 = V3 × (50/100) = V3 / 2. Next, the duty ratio D is obtained from the converted operation voltage V3 / 2 and the applied voltage V1. That is, D = (V3 / 2) / V1 × 100 (%). By performing PWM control with such a duty ratio, the oil pump P can be operated with energy saving as in the above-described embodiment.

  In the above embodiment, the constant current control is performed after the pump control device 1 has the required hydraulic pressure, and then the constant voltage control is performed. However, the constant current control and the constant voltage control are not performed. It is also possible to do.

  In the above-described embodiment, the inverter 10 is described as including the transistors Q1 to Q6. However, instead of the transistors Q1 to Q6, the inverter 10 may be configured using an FET (Field Effect Transistor) or an IGBT (Insulated). Gate Bipolar Transistor) may be used.

  INDUSTRIAL APPLICABILITY The present invention can be used for a pump output control device that controls the output of a pump mounted on a vehicle, a vehicle-mounted pump unit that includes the pump output control device, and a pump output control method.

DESCRIPTION OF SYMBOLS 1: Pump control apparatus 10: Inverter 20: Operation condition memory | storage part 30: Applied voltage detection part 40: Duty ratio setting part 50: PWM control part 100: In-vehicle pump unit B: DC power supply M: Motor P: Oil pump

Claims (3)

An inverter connected between a DC power source mounted on the vehicle and a motor that drives the oil pump;
An operation condition storage unit that stores in advance the minimum operation condition of the motor including an operation voltage and an on-duty that satisfy a required oil pressure required for the oil pump;
An applied voltage detector for detecting a current applied voltage from the DC power supply;
A duty ratio setting unit for setting a duty ratio based on the current applied voltage and the minimum operating condition;
A PWM control unit that PWM-controls a switching element included in the inverter with the set duty ratio;
A pump control device comprising: The oil pump;
The motor;
A pump control device according to claim 1;
An on-vehicle pump unit comprising: An output conversion step of driving an inverter connected between a DC power source mounted on a vehicle and a motor driving an oil pump to convert the output of the DC power source into AC and supplying the AC to the motor;
An operation condition storage step of previously storing in the operation condition storage unit the minimum operation condition of the motor including an operation voltage and an on-duty that satisfy a required oil pressure required for the oil pump;
An applied voltage detection step of detecting a current applied voltage from the DC power supply;
A duty ratio setting step for setting a duty ratio based on the current applied voltage and the minimum operating condition;
A PWM control step for PWM-controlling the switching element of the inverter with the set duty ratio;
A pump control method comprising:

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