JP2012067807A - Controller of electric pump for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a controller capable of inhibiting passage of an overcurrent and inhibiting the overshooting of flow rate even when an electric pump, provided to assist a mechanical pump driven by an engine, is operated before stopping the engine.SOLUTION: The electric pump is operated before stopping the engine by the control of a motor current by adjusting an applied voltage of a motor. When shift stages to the electric pump following the rotation stop of the engine are judged by engine rotation speed, motor rotation speed, a downstream side pressure of a one-way valve provided at the discharge side of the electric pump, etc. the control of the motor current by the adjustment of the applied voltage of the motor is shifted to the control of motor rotation speed by the adjustment of the applied voltage of the motor.

Description

  The present invention relates to a control device for an electric pump for a vehicle, and more particularly, to a control device for an electric pump provided to assist a mechanical pump driven by an engine.

  In Patent Document 1, in a vehicle with an idle stop mechanism that supplies hydraulic pressure of a speed change mechanism connected to an engine by a mechanical oil pump driven by the engine, a shift is performed during engine idle stop control (when the engine is stopped). A technique for supplying hydraulic pressure to the mechanism from an electric oil pump is disclosed.

JP 2009-293649 A

As described above, when the electric oil pump is used while the engine is stopped, the discharge side of the electric oil pump is connected to the discharge side of the mechanical oil pump via the one-way valve so that the engine is rotating. Thus, during the operation of the mechanical oil pump, the oil is prevented from flowing back to the electric oil pump side.
In the control of the electric oil pump, in order to secure the required flow rate, the applied voltage of the pump is changed so that the pump rotation speed approaches the target value, and the electric oil pump is provided for stopping the engine. In some cases, the hydraulic oil pressure is reduced when the mechanical oil pump is stopped.

However, while the engine (mechanical oil pump) immediately after the start of the electric oil pump continues to rotate, the one-way valve does not open because the downstream pressure of the one-way valve is maintained high, The increase in the rotational speed of the electric oil pump has reached its peak.
Therefore, if the control is performed such that the applied voltage is changed so that the pump rotation speed as the control amount approaches the target value, the applied voltage becomes high and excessive current flows, and the one-way valve opens. As a result of increasing and changing the applied voltage until the one-way valve is opened and the pump load is suddenly reduced, there is a problem in that an overshoot of the flow rate occurs.

  The present invention has been made in view of the above problems, and provides a control device for an electric pump for a vehicle that can suppress an excessive current from flowing through the electric pump and can suppress an overshoot of a flow rate. Objective.

  Therefore, according to the present invention, while the rotation of the engine is stopped, the electric pump is operated by controlling the rotation speed of the motor by operating the applied voltage of the motor, and the excessive current is limited before the engine is stopped (for example, , Control the motor current by operating the applied voltage of the motor), operate the electric pump, and release and release the control to limit the excessive current at the transition to the electric pump when the engine stops rotating A higher current than before was allowed.

  According to the above invention, when the electric pump is operated while the engine is rotating, it is possible to suppress an excessive current from flowing through the electric pump and to suppress an overshoot of the flow rate.

1 is a block diagram showing a hydraulic pump system for an automobile AT (automatic transmission) to which a control device for a vehicle electric pump according to the present invention is applied in an embodiment. It is a circuit diagram which shows the structure of the motor control apparatus and brushless motor in embodiment. It is a time chart which shows the electricity supply pattern of the brushless motor in embodiment. It is a flowchart which shows the main routine of the drive control of the electric oil pump in embodiment. It is a flowchart which shows the switching process of the electricity supply mode in embodiment. It is a figure which shows the positioning process of the brushless motor in embodiment. It is a time chart which shows the characteristic of the low speed sensorless control in embodiment. It is a figure which shows the switching process of the electricity supply mode at the time of starting of the brushless motor in embodiment. It is a flowchart which shows the setting process of the applied voltage of the brushless motor in embodiment. It is a time chart which shows the correlation of the engine rotational speed, pump rotational speed, pump applied voltage, and pump current in embodiment. It is a flowchart which shows another example of the setting process of the applied voltage in embodiment.

Embodiments of the present invention will be described below.
FIG. 1 is a block diagram showing a configuration of a hydraulic pump system for an automobile AT (automatic transmission) to which a control device for an electric pump for a vehicle according to the present invention is applied.
In the automobile AT hydraulic pump system shown in FIG. 1, a mechanical oil pump (mechanical pump) driven by the output of an engine (internal combustion engine) 12 is used as an oil pump for supplying oil (hydraulic oil) to the hydraulic circuit of the transmission 7. Pump) 6 and an electric oil pump (electric pump) 1 driven by a motor are provided in parallel.

Further, an engine control module (ECM) 13 that controls the engine 12 receives signals from various sensors (including a sensor that detects the engine rotation speed) that detect operating conditions of the engine 12, and these signals. Based on the above, fuel injection and ignition to the engine 12 are controlled.
Further, the engine control module (ECM) 13 stops the engine 12 when the idle stop execution condition (automatic stop condition) is satisfied, and restarts the engine 12 when the idle stop stop condition (automatic start condition) is satisfied. It has an idle stop control function.

The electric oil pump 1 is driven by a brushless motor 2 that is directly connected. The motor control unit (MCU) 3 controls the brushless motor 2 based on a command from the AT control unit (ATCU) 4.
However, the motor used for the electric oil pump 1 is not limited to the brushless motor, and may be an electric motor including a brush (commutator).
The ECM 13 transmits information indicating whether the idle stop is permitted / not permitted to the ATCU 4. Since the mechanical oil pump 6 also stops its operation while the engine 12 is stopped due to the idle stop, the ATCU 4 operates the electric oil pump 1 during the idle stop so that the oil for the transmission 7 is stopped. Command is output to the MCU 3 so as to perform the supply (securing the hydraulic pressure).

The suction port of the electric oil pump 1 is connected to a suction side pipe 5 a whose one end is opened in the oil pan 10, and the discharge side pipe 5 b is connected to the discharge port of the electric oil pump 1. .
A one-way valve 11 that allows oil to flow from the electric oil pump 1 toward the transmission 7 is interposed in the discharge side pipe 5b. This one-way valve 11 is a mechanical check valve that opens when the pressure on the upstream side becomes higher than the set pressure on the downstream side.

On the other hand, the suction port of the mechanical oil pump 6 is connected to a suction side pipe 9 a whose one end is opened in the oil pan 10, and the discharge side pipe 9 b is connected to the discharge port of the mechanical oil pump 6. Is done.
Then, the discharge side pipe 5 b of the electric oil pump 1 and the discharge side pipe 9 b of the mechanical oil pump 6 are joined together and connected to the hydraulic pressure supply pipe 8, and the hydraulic pressure is supplied to the transmission 7 by the hydraulic pressure supply pipe 8. The

While the engine 12 is rotating (during operation), the mechanical oil pump 6 driven by the engine 12 sucks the oil in the oil pan 10 and pumps the oil toward the transmission 7.
At this time, the brushless motor 2 is off, the pressure on the downstream side of the one-way valve 11 is higher than the pressure on the upstream side, and the one-way valve 11 maintains the closed state. The oil flow is blocked by the one-way valve 11.

On the other hand, when the engine 12 stops rotating due to idling stop, the mechanical oil pump 6 also stops rotating and cannot pump oil. As a result, when the operating hydraulic pressure in the transmission 7 decreases, a start shock or the like is generated due to a delay in the hydraulic response when the engine 12 is restarted to start.
Therefore, when the idle stop condition of the engine 12 is established and the idle stop permission state is established, the AT control device 4 transmits a motor start command to the motor control device 3 to prepare the electric oil in advance in preparation for the rotation stop of the engine 12. By starting the pump 1, the hydraulic pressure in the transmission 7 is prevented from dropping as the engine 12 is idling.

  When the brushless motor 2 is started and the electric oil pump 1 starts to rotate, the hydraulic pressure in the discharge side pipe 5b on the upstream side of the one-way valve 11 is increased, while the engine 12 is idled to stop the mechanical oil pump 6 Therefore, the one-way valve 11 is opened, and the discharge pressure of the electric oil pump 1 is supplied to the transmission 7. When the engine 12 is stopped, the electric oil pump 1 Continue driving to maintain the operating pressure.

FIG. 2 shows details of the motor control device 3 and the brushless motor 2.
The motor control device 3 includes a motor drive circuit 212 and a controller 213 including a microcomputer, and the controller 213 communicates with the AT control device 4.
The brushless motor 2 is a three-phase DC brushless motor (three-phase synchronous motor), and includes U-phase, V-phase, and W-phase three-phase windings 215U, 215V, and 215W in a cylindrical stator (not shown), A permanent magnet rotor 216 is disposed in a space formed at the center of the stator.

The motor drive circuit 212 is configured by connecting, for example, six switching elements 217a to 217f made of IGBT, for example, to a three-phase bridge and connecting diodes 218a to 218f in antiparallel to the switching elements 217a to 217f. And a power supply circuit 219.
Control terminals (gate terminals) of the switching elements 217a to 217f are connected to the controller 213, and on / off of the switching elements 217a to 217f is controlled by a pulse width modulation operation by the controller 213.

The controller 213 is a circuit that generates a pulse width modulation signal (PWM signal) to the motor drive circuit 212 and controls the applied voltage V of the brushless motor 2, and detects the rotational position of the rotor 216 based on the phase voltage. The energization to each phase is controlled by a so-called sensorless system that determines the energization mode based on this position information.
The AT control device 4 calculates a target rotational speed TGNP or a target current TGAP as a target value of the control amount of the brushless motor 2 and transmits it to the motor control device 3, while the brushless motor from the motor control device 3. Information on the rotational speed NP of 2 is received.

FIG. 3 shows the applied voltage V to each phase for each energization mode.
The energization mode includes six energization modes (1) to (6) that are sequentially switched every electrical angle of 60 deg. In each energization mode (1) to (6), the switching elements 217a to 217f are pulsed in accordance with the command voltage. Driven by a width modulated signal.

  In the present embodiment, the angular position of the U-phase coil is set to the reference position (deg), the angular position for switching from the energization mode (3) to the energization mode (4) is set to 30 deg, and the energization mode (4) to the energization mode. The angle position for switching to (5) is 90 deg, the angle position for switching from the energization mode (5) to the energization mode (6) is 150 deg, and the energization mode (6) is switched to the energization mode (1). Is set to 210 deg, the angular position for switching from the energization mode (1) to the energization mode (2) is set to 270 deg, and the angular position for switching from the energization mode (2) to the energization mode (3) is set to 330 deg. Is set.

In the energization mode (1), the switching element 217a and the switching element 217d are turned on, and all others are turned off, so that the voltage V is applied to the U phase, the voltage -V is applied to the V phase, A current is passed toward the V phase.
In the energization mode (2), the switching element 217a and the switching element 217f are turned on, and all others are turned off, so that the voltage V is applied to the U phase, the voltage -V is applied to the W phase, A current is passed toward the W phase.

In the energization mode (3), the switching element 217c and the switching element 217f are turned on, and all others are turned off, so that the voltage V is applied to the V phase, the voltage -V is applied to the W phase, and from the V phase. A current is passed toward the W phase.
In the energization mode (4), the switching element 217b and the switching element 217c are turned on and all others are turned off, so that the voltage V is applied to the V phase, the voltage −V is applied to the U phase, A current is passed toward the U phase.

In the energization mode (5), the switching element 217b and the switching element 217e are turned on and all others are turned off, so that the voltage V is applied to the W phase, the voltage −V is applied to the U phase, A current is passed toward the U phase.
In the energization mode (6), the switching element 217e and the switching element 217d are turned on, and all others are turned off, so that the voltage V is applied to the W phase, the voltage -V is applied to the V phase, A current is passed toward the V phase.

As described above, each of the switching elements 217a to 217f is energized for 120 deg every 240 deg by switching the six energization modes (1) to (6) for every 60 deg electrical angle. Such an energization method is called a 120-degree energization method.
FIG. 4 shows a main routine of control of the electric oil pump 1 (brushless motor 2), which is performed by the AT control device 4.

First, in step S101, information on the operating conditions of the engine 12 (including information on permission / non-permission of idling stop, information on the engine rotational speed, etc.), and the rotational speed NP of the electric oil pump 1 (brushless motor 2). Get information about
In step S102, it is determined whether or not idle stop is permitted. If idle stop is not permitted, the process returns to step S101 to reacquire various information.

On the other hand, if it is determined in step S102 that the idle stop is permitted, the process proceeds to step S103, and the hydraulic oil is supplied to the transmission 7 by the electric oil pump 1 instead of the mechanical oil pump 6. Therefore, drive control of the electric oil pump 1 is performed.
The drive control of the electric oil pump 1 performed in step S103 includes switching control of the energization mode (energization phase) of the brushless motor 2 and setting control of the applied voltage V of the brushless motor 2. This will be described in detail later.

  When the drive control of the electric oil pump 1 is being performed, the process further proceeds to step S104, where it is determined whether or not there is an idle stop stop request. If there is no idle stop stop request, the process returns to step S103. When the drive control of the electric oil pump 1 is continued and the engine 12 is restarted, the driving of the electric oil pump 1 is stopped by ending this routine as it is.

Here, the energization mode switching control in step S103 will be described with reference to the flowchart of FIG.
The routine shown in the flowchart of FIG. 5 is started with a drive start command for the electric oil pump 1 as a trigger.

First, in step S201, when starting the brushless motor 2, a positioning operation for determining the initial position of the brushless motor 2 is performed.
Specifically, for example, as shown in FIG. 6, the phase energization corresponding to the energization mode (3), that is, Vu = 0, Vv = Vin, Vw = −Vin is set and the phase energization state is maintained. Thus, the initial value of the motor angle is 90 deg.

However, positioning for determining the initial position is not limited to the position of 90 deg by phase energization corresponding to the energization mode (3), and other energization modes (1), (2), (4) to (4) to ( Phase energization corresponding to any one of 6) can be performed, and furthermore, phase energization of a pattern not corresponding to any of the energization modes (1) to (6) may be performed.
When the phase energization for positioning the brushless motor 2 at the initial position is performed in step S201, the time required for the brushless motor 2 to rotate to the initial position is changed to the phase energization state in step S201 in the next step S202. It is determined whether or not the set time corresponding to is continued. When the set time elapses, it is estimated that the brushless motor 2 has actually reached the initial position, and the process proceeds to step S203.

In step S203, low speed sensorless control is started as rotational drive control of the brushless motor 2 by switching the energization mode.
In the low speed sensorless control, when the motor rotation speed NP is divided into a low speed range and a high speed range, the non-conduction phase is set in the low speed range by the two-phase applied pulse voltage in the three-phase stator winding. The induced voltage (pulse induced voltage) is detected, and as shown in FIG. 7, the terminal voltage of the non-conduction phase is compared with the terminal voltage of the non-conduction phase and the threshold value (plus threshold value or negative threshold value) for each conduction mode. Is a control for switching between the two phases (energization mode) to which the voltage is applied when the value reaches the threshold value.

In the low-speed sensorless control, since the saturation state of the magnetic circuit changes depending on the position of the rotor, an induced voltage corresponding to the position of the rotor is generated in the non-conducting phase by the two-phase applied pulse voltage. The rotor position is estimated from the induced voltage of the non-energized phase, and the switching timing of the energized mode is detected.
By performing the low-speed sensorless control described above, the energization control is performed without causing the brushless motor 2 to step out even when the electric oil pump 1 is operated from a state where the motor rotation speed does not increase while the engine is rotating. Is possible.

When starting to rotate the brushless motor 2 from the initial position by low-speed sensorless control in step S203, the energization mode is switched twice during a time within the range where the rotor 216 does not respond, and the energization mode after the switching is performed. Torque is generated by the rotor 216 being attracted to the resultant magnetic flux generated in step S1, so that rotation starts from the initial position.
For example, when the initial position is set as an angular position of 90 deg by phase energization in the energization mode (3), the phase energization corresponding to the energization mode (3) is maintained as shown in FIG. Thus, the current changes in response, but the rotor 216 does not rotate and is switched to the energization mode (5) through the energization mode (4) at the time T (eg 500 μsec), and is drawn by the combined magnetic flux in the energization mode (5). Thus, the rotor 216 starts to rotate from the initial position of 90 deg to 210 deg.

And if it starts to rotate from 90deg of an initial position, based on the terminal voltage of the V phase which is a non-energized phase of energization mode (5), the switch timing to energization mode (6) will be judged, and it will change to energization mode (6). Thereafter, the energization mode is sequentially switched by detecting the energization mode switching timing based on the terminal voltage of the non-energization phase, and the brushless motor 2 is rotated.
When the low speed sensorless control is started, in step S204, it is determined whether or not the motor rotational speed NP is equal to or higher than a threshold value for dividing the low speed range and the high speed range. If the motor rotational speed NP at that time is less than the threshold value, If the low-speed sensorless control is continued as it is, and the motor rotation speed NP at that time is equal to or greater than the threshold value, the process proceeds to step S205, and an induced voltage (speed electromotive force) generated by the rotation of the rotor is detected. Shift to high-speed sensorless control that switches the energization mode at the zero cross point of (speed electromotive force).

After shifting to high-speed sensorless control, in step S206, it is determined whether or not the motor rotational speed NP is lower than [threshold-hysteresis], and the motor rotational speed NP can be lower than [threshold-hysteresis]. In this case, the control returns to the low speed sensorless control again.
The hysteresis (> 0) shifts to high-speed sensorless control so that frequent switching between low-speed sensorless control and high-speed sensorless control is not performed when the motor rotation speed NP fluctuates in the vicinity of the threshold value. After that, even if the motor rotation speed NP falls below the threshold value, switching to the low speed sensorless control is not performed, and switching to the low speed sensorless control is performed only when the motor rotation speed NP decreases to [threshold-hysteresis].

If the motor rotation speed NP is equal to or greater than [threshold-hysteresis], the process proceeds to step S207, where it is determined whether a stop command for the electric oil pump 1 has been output. If not output, the process returns to step S104 to continue the motor drive by high-speed sensorless control. When a stop command is output, the routine is terminated to cut off the energization of each phase of the brushless motor 2.
The flowchart of FIG. 9 shows details of setting control of the applied voltage V in step S103.

In step S301, it is determined whether or not the engine 12 is rotating. As described above, the brushless motor 2 is started based on the idle stop permission determination, while the fuel injection / ignition in the engine 12 is stopped after the brushless motor 2 is started, and the engine 12 (mechanical oil) is started after the brushless motor 2 is started. The rotation of the pump 6) is stopped.
That is, at the time of transition from the mechanical oil pump 6 to the electric oil pump 1, the electric oil pump 1 is operated before the rotation of the engine 12 stops, and both the mechanical oil pump 6 and the electric oil pump 1 are oiled. By providing a transient period for discharging the operating pressure, it is possible to prevent the operating pressure from dropping due to a delay in the rise of the electric oil pump 1.

Accordingly, when the brushless motor 2 is activated and immediately after the activation, it is determined that the engine 12 is rotating and the engine 12 is rotating in step S301, and the process proceeds to step S302.
The rotation / stoppage of the engine 12 can be determined based on whether or not the output of the pulse signal from the crank angle sensor that generates the pulse signal in synchronization with the rotation of the engine 12 is interrupted.

In step S302, control is performed to determine the applied voltage V so that the current (current flowing in the energized phase) AP of the brushless motor 2 approaches the target current TGAP (current control for controlling the current AP by operating the applied voltage V). Information on the applied voltage V is output to the motor control device 3.
Specifically, when the motor current AP is lower than the target current TGAP, the applied voltage V is increased, and when the motor current AP is higher than the target current TGAP, the applied voltage V is decreased. For the determination of the applied voltage V, for example, proportional / integral / derivative control based on the deviation between the motor current AP and the target current TGAP can be used.

The motor control device 3 that has received the command value of the applied voltage V drives the switching elements 217a to 217f with a signal that has been subjected to pulse width modulation in accordance with the command voltage value.
The target current TGAP is a current value with which the hydraulic pressure can be secured in the steady state of the electric oil pump 1, and control for determining the applied voltage V so that a motor rotational speed NP, which will be described later, approaches the target rotational speed TGNP ( It is set and stored in advance as a current lower than the allowable maximum current in the rotational speed control for controlling the motor rotational speed NP by operating the applied voltage V. That is, the target current TGAP is preferably determined according to a target hydraulic pressure equivalent value, and is determined in advance so that the motor current does not become an overcurrent when the electric oil pump 1 or the like is normal.

Accordingly, in the control (current control) for determining the applied voltage V so that the current AP approaches the target current TGAP (current control), the control for determining the applied voltage V so that the motor rotational speed NP approaches the target rotational speed TGNP (rotational speed control). ) Will limit the motor current lower.
When the engine 12 is rotating and the discharge pressure of the mechanical oil pump 6, that is, the pressure downstream of the one-way valve 11 is high, the one-way valve 11 is closed even when the electric oil pump 1 is started. Therefore, the increase in the rotational speed NP of the electric oil pump 1 (brushless motor 2) reaches a peak.

For this reason, if control is performed to determine the applied voltage V so that the rotational speed NP of the electric oil pump 1 (brushless motor 2) approaches the target, the rotational speed NP does not reach the target, so the applied voltage V is gradually increased. As a result, the current becomes excessive as the applied voltage V increases, and the switching elements 217a to 217f of the motor drive circuit 212 may be damaged.
Furthermore, when the one-way valve 11 is closed, the upstream pressure increases, so that when the one-way valve 11 is opened, the oil discharged from the electric oil pump 1 flows out at once, and the oil flow rate is exceeded. Shooting may occur.

  On the other hand, if the control for determining the applied voltage V is performed so that the current AP of the brushless motor 2 approaches the target TGAP as described above, the applied voltage V is applied so that the motor rotational speed MP approaches the target rotational speed TGNP. The current (in other words, the pressure on the upstream side of the one-way valve 11) can be suppressed from being excessive, as compared with the case where control (rotational speed control) is performed to determine the current. It is possible to suppress the damage of the drive circuit and the overshoot of the flow rate due to the excessive current.

  That is, the motor rotational speed NP is set to the target rotational speed from the control (current control) that determines the applied voltage V so that the current AP approaches the target TGAP at the transition to the electric oil pump 1 when the engine 12 stops rotating. If the control shifts to control (rotational speed control) that determines the applied voltage V so as to approach TGNP, a higher current is allowed as the motor current, and the current control is a control that limits an excessive current, The transition from current control to rotational speed control corresponds to the cancellation of the control that limits the excessive current.

In step S302, when the control for determining the applied voltage V is performed so that the current of the brushless motor 2 approaches the target, the process further proceeds to step S303, and the deviation ΔNP between the target value TGNP and the actual motor rotational speed NP. It is determined whether or not the absolute value of is less than or equal to the threshold value, in other words, whether or not the motor rotational speed NP is increased and is sufficiently close to the target.
The target value TGNP is a target value of the motor rotation speed NP when the engine 12 is stopped. As will be described later, when the process proceeds from step S303 to step S304, the motor rotation speed NP approaches the target value TGNP. The applied voltage V is determined.

However, as the target value TGNP used in step S302, a motor rotational speed set in advance for control switching determination, that is, a rotational speed different from the target rotational speed in the applied voltage operation can be used.
When the process of stopping the engine 12 (fuel injection / ignition stop) is performed and the rotation of the engine 12 decreases from the idle rotation speed and the discharge pressure of the mechanical oil pump 6 decreases, the one-way valve 11 opens, When the direction valve 11 is opened, the load on the electric oil pump 1 is reduced and the rotational speed NP of the electric oil pump 1 is increased.

Therefore, the one-way valve 11 is opened to detect that the load on the electric oil pump 1 is reduced based on an increase in the rotational speed NP of the electric oil pump 1. In this embodiment, an increase change in the speed NP is determined based on a comparison between the rotational speed deviation ΔNP and a threshold value.
When the one-way valve 11 is opened and the load on the electric oil pump 1 is reduced, the applied voltage V is determined so that the rotational speed NP of the electric oil pump 1 (brushless motor 2) approaches the target TGNP. However, the applied voltage V is not increased until the current becomes excessive, and the rotational speed NP of the electric oil pump 1 (brushless motor 2) is maintained in the vicinity of the target TGNP. The required flow rate can be secured stably.

For this reason, the absolute value of the deviation ΔNP between the target rotational speed TGNP of the electric oil pump 1 and the actual rotational speed NP is equal to or less than the threshold value, and the rotational speed of the electric oil pump 1 by opening the one-way valve 11 When the increase change of NP can be estimated, the process proceeds to step S304, and the control shifts to control for determining the applied voltage V so that the rotational speed NP of the electric oil pump 1 (brushless motor 2) approaches the target TGNP.
Specifically, in step S304, the applied voltage V is increased when the actual rotational speed NP is lower than the target TGNP, and the applied voltage V is increased when the actual rotational speed NP is higher than the target TGNP. For example, proportional / integral / differential control based on the deviation between the actual rotational speed NP and the target TGNP can be used to determine the applied voltage V.

  It should be noted that the control for determining the applied voltage V so that the rotational speed NP of the electric oil pump 1 (brushless motor 2) approaches the target TGNP is performed by the above-described proportional / integral / differential control before the rotation of the engine 12 decreases. When used, the integral portion is accumulated because the actual rotational speed NP does not reach the target TGNP, and even after the rotation of the engine 12 is reduced, the applied voltage V is maintained at a high value by the integral portion, and an excessive current is generated. The flowing state continues.

On the other hand, if the control of determining the applied voltage V is started so that the rotation speed NP approaches the target TGNP after waiting for the rotation reduction of the engine 12 (opening of the one-way valve 11), the rotation speed NP is set to the target. Since it can be increased to TGNP, the integral component does not accumulate excessively, and it is possible to suppress the application voltage V from becoming excessive and causing an overcurrent to flow.
Even if the increase in the rotational speed NP of the electric oil pump 1 cannot be detected, when the engine 12 stops rotating and the mechanical oil pump 6 stops, the discharge pressure of the electric oil pump 1 When the one-way valve 11 is opened, the load on the electric oil pump 1 is reduced, and the rotational speed NP of the electric oil pump 1 is increased, and the rotational speed NP of the electric oil pump 1 (brushless motor 2) is increased. Even if control for determining the applied voltage V so as to approach the target TGNP is performed, it can be determined that the applied voltage V does not increase until the current becomes excessive.

Therefore, even when it is determined that the rotation of the engine 12 has stopped, the process proceeds to step S304, and the control shifts to control for determining the applied voltage V so that the rotational speed NP of the electric oil pump 1 (brushless motor 2) approaches the target. .
That is, if the absolute value of the deviation ΔNP between the target value TGNP and the actual motor rotational speed NP is equal to or smaller than the threshold value, or if it is detected that the engine 12 has stopped rotating, the process proceeds to step S304.

  When the control shifts to control for determining the applied voltage V so that the rotational speed NP of the electric oil pump 1 (brushless motor 2) approaches the target, in step S305, it is determined whether or not a stop command for the electric oil pump 1 has been issued. judge. If the stop command is not generated, in other words, if the idle stop is continuing, the process returns to step S301 and the control of the applied voltage of the electric oil pump 1 is continued.

  In step S303, the switching timing from the current control to the rotational speed control at the transition stage from the mechanical oil pump 6 to the electric oil pump 1 when the rotation of the engine 12 is stopped is determined based on the target value TGNP and the actual motor rotation. The determination is made based on the deviation ΔNP from the speed NP or the rotation stop of the engine 12, but also when the rotation stop instruction of the engine 12 is generated, when the set time has elapsed from the rotation stop instruction of the engine 12, The switching from the current control to the rotational speed control can be performed at any time when the rotational speed NE decreases to the set rotational speed (> 0 rpm) or when a set time elapses after the engine 12 stops rotating.

Further, when the operating hydraulic pressure (line pressure) supplied to the transmission 7, that is, the pressure on the downstream side of the one-way valve 11 decreases and reaches a set pressure, switching from current control to rotational speed control is performed. Can be made.
That is, the determination in step S303 is between the timing at which the one-way valve 11 can be estimated to be opened soon and the timing at which the one-way valve 11 can be reliably estimated to be opened. What is necessary is just to be able to judge the transition stage to the oil pump 1.

  However, if the switching timing from the current control to the rotational speed control is too early, the period during which the excessive current flows becomes long. Conversely, if the switching timing from the current control to the rotational speed control is too late, the motor current is unnecessarily lowered. Limiting and delaying to reach the target rotational speed TGNP will delay the switching timing in advance so that switching from current control to rotational speed control is performed within an appropriate period that satisfies these requirements. Fits.

FIG. 10 shows changes in the rotational speed NP, applied voltage V, and current AP of the brushless motor 2 when the control method of the brushless motor 2 is switched when the rotation of the engine 12 (mechanical oil pump 6) stops. It is a time chart.
When it is determined that idle stop is permitted at time t1, the brushless motor 2 is started, and the brushless motor 2 is driven by controlling the applied voltage V so that the motor current AP approaches the target value TGAP.

Here, the operation stop process of the engine 12 is executed, whereby the rotation of the mechanical oil pump 6 is reduced, and the motor current AP is controlled near the target value TGAP until the one-way valve 11 is opened. Therefore, the motor current is prevented from becoming excessive, and the upstream pressure (pump load) of the one-way valve 11 does not increase excessively.
Then, based on permission of idling stop, fuel injection / ignition of the engine 12 is stopped based on the rotation stop instruction of the engine 12 at time t2, and when the rotation of the engine 12 stops at time t3, the motor current AP is set to the target value. Limiting excessive current by shifting from control (current control) that determines the applied voltage V so as to approach TGAP to control (rotational speed control) that determines the applied voltage V so that the motor rotational speed approaches the target value The control to release is released so that a higher current is allowed.

  When the rotation of the engine 12 stops, the rotation of the mechanical oil pump 6 also stops. When the rotation of the mechanical oil pump 6 stops, the pressure on the downstream side of the one-way valve 11 decreases, so that the one-way valve 11 If the valve is open and the one-way valve 11 is open, the pressure rise on the upstream side of the one-way valve 11 can be suppressed, so that the rotation can be increased and the applied voltage V is set so that the motor rotation speed NP approaches the target value TGNP. Even if the control shifts to the control for determining the required flow rate, the generation of excessive current due to the increase of the applied voltage V can be suppressed, and the motor rotational speed NP is controlled near the target TGNP, thereby ensuring a stable required flow rate. Can do.

Further, the applied voltage V is set so that the motor rotational speed NP approaches the target value TGNP from the state where the one-way valve 11 is opened and the load of the electric oil pump 1 is decreased and the rotation of the electric oil pump 1 is increasing. Therefore, the motor rotation speed NP can be smoothly increased toward the target rotation speed TGNP.
By the way, in the above embodiment, the current control of the electric oil pump 1 is performed during the rotation of the engine 12 to limit the excessive current. However, the activation of the electric oil pump 1 during the rotation of the engine 12 is performed. The engine speed is controlled from time to time, while the engine is rotating (before the shift to the electric oil pump 1 when the engine 12 stops rotating) by switching the limit value of the maximum current. It is possible to suppress an excessive current during the 12 rotation.

An embodiment for switching the limit value of the maximum current will be described with reference to the flowchart of FIG.
Each step of the flowchart of FIG. 11 is different from each step of the flowchart of FIG. 9 described above only in steps S402 and S404, which are steps for controlling energization of the brushless motor 2, and other steps S401, S403, In step S405, processing similar to that in steps S301, S303, and S305 described above is performed.

When it is determined in step S401 that the engine 12 is rotating and the process proceeds to step S402, control (current control) is performed to determine the applied voltage V so that the current AP of the brushless motor 2 approaches the target current TGAP. Then, the electric oil pump 1 is operated.
That is, in the embodiment shown in the flowchart of FIG. 9, the motor current AP is set to the target value TGAP from the start of the electric oil pump 1 to the transition to the electric oil pump 1 when the rotation of the engine 12 stops. Control (current control) for determining the applied voltage V so as to approach was performed, and thereafter, control (rotational speed control) for determining the applied voltage V so as to bring the motor rotational speed NP closer to the target value TGNP was performed.

On the other hand, in the embodiment shown in FIG. 11, the electric oil pump 1 is operated by rotational speed control during the engine rotation at the start of the electric oil pump 1.
Here, when the rotational speed control is performed, the applied voltage V is excessively increased without the motor rotational speed NP reaching the target TGNP because the one-way valve 11 is closed as described above. Excessive current will flow.

Therefore, in step S402, the rotational speed control is performed, but the applied voltage V is allowed within a range where the actual current AP does not exceed the maximum current limit value APMAX, so that the actual motor rotational speed NP is the target. Even if the motor current AP has reached the limit value APMAX even when the value is below the value TGNP, the maximum current limit control is performed so that the applied voltage V is not further increased.
In the rotational speed control during engine rotation in step S402, the limit value APMAX is a value adapted to a state where the engine speed is rotating (the one-way valve 11 is closed) and the rotational speed NP does not reach the target value TGNP. Set APMAX1.

  This limit value APMAX1 is a current value lower than the limit value APMAX2 used after determining the shift to the electric oil pump 1 due to the engine stoppage, and even if the actual motor rotation speed NP is lower than the target value TGNP. Even in a state where the motor rotation speed NP is not increased by limiting the motor current AP to the limit value APMAX1 or less, the applied voltage V is increased and an excessive current flows. Moreover, the upstream pressure of the one-way valve 11 is suppressed from becoming excessive.

If it is determined in step S403 that the operation is shifted to the hydraulic pressure supply by the electric oil pump 1 by the opening operation of the one-way valve 11 accompanying the rotation stop of the engine 12, the process proceeds to step S404 and the motor rotation speed NP is set. The control (rotational speed control) for determining the applied voltage V so as to approach the target value TGNP is continued as it is, but the limit value APMAX is set to APMAX2, which is a current value higher than the APMAX1.
That is, by proceeding to step S404, the current limitation by the limit value APMAX1, in other words, the control for limiting the excessive current generated by performing the rotational speed control in the closed state of the one-way valve 11 is canceled, and more It switches to the state which accept | permits a high electric current (APMAX2), and makes it possible to increase the motor rotational speed NP toward the target rotational speed TGNP.
Note that when the process proceeds to step S404, the current limit based on the limit value APMAX may be stopped.

In the above embodiment, by switching the limit value APMAX of the current AP, an excessive current flows even if the rotational speed control is performed from the closed state of the one-way valve 11 (before the engine 12 stops rotating). It can suppress simply that the upstream pressure of the direction valve 11 becomes excessive.
The present invention is not limited to an oil pump that supplies oil to a transmission. For example, as a water pump that supplies cooling water to an engine, a mechanical water pump that is driven by an engine and an electric motor that is driven by a motor. It can also be applied to a vehicle equipped with a water pump.

Here, technical ideas other than the claims that can be grasped from the above embodiment will be described together with effects.
(A) In the control device for an electric pump for a vehicle according to any one of claims 1 to 3,
The electric pump and the mechanical pump are oil pumps for supplying hydraulic oil to a transmission connected to an engine;
A control apparatus for an electric pump for a vehicle that operates the electric pump while the engine is stopped by an idle stop function.

  According to the above configuration, even if the engine is idle stopped and the mechanical oil pump is stopped, the hydraulic pressure can be supplied to the transmission by the electric oil pump instead, and the starting performance after restart can be maintained. Even if the oil pump is operated before the engine is stopped, it is possible to protect the drive circuit by suppressing excessive current flow, and to prevent the upstream pressure of the one-way valve from becoming excessive. The occurrence of overshoot can be suppressed.

(B) In the control device for an electric pump for a vehicle according to any one of claims 1 to 3,
The motor that drives the electric pump is a brushless motor, and the energization mode to each phase of the brushless motor is detected at least on the low speed side, and the voltage induced in the non-energized phase by the pulse voltage applied to the energized phase, A control device for an electric pump for a vehicle that compares a detected non-energized phase voltage with a threshold value for each energization mode and switches a phase to which a voltage is applied when the non-energized phase voltage reaches the threshold value.

  According to the above invention, even if the motor that drives the electric pump is a brushless motor, the energization mode can be switched from the low speed range, the electric pump is operated before the engine stops, and the rotation speed does not increase. Also, the occurrence of step-out can be suppressed.

(C) In the vehicle electric pump control device according to claim 1,
Before the engine is stopped, the electric pump is operated by controlling the rotational speed of the motor by operating the applied voltage of the motor,
As a control for limiting the excessive current, a control for limiting the actual current to a maximum current or less is performed, and as a control for limiting the excessive current, the electric pump for a vehicle that switches the maximum current to a higher current value is used. Control device.

  In the above configuration, since the motor rotation speed is controlled by operating the applied voltage of the motor from the start of the electric pump before the engine is stopped, the applied voltage is not increased before the engine is stopped. When the current exceeds the maximum current due to the increase in the applied voltage, the increase in the applied voltage is limited and the current is kept below the maximum current. In the transition stage, the maximum current is switched to a higher current value so that the rotational speed can be increased to the target rotational speed.

  DESCRIPTION OF SYMBOLS 1 ... Electric oil pump (electric pump), 2 ... Brushless motor, 3 ... Motor controller, 6 ... Mechanical oil pump (mechanical pump), 11 ... One-way valve, 12 ... Engine, 212 ... Motor drive circuit 213: Controller, 215U, 215V, 215W ... Winding, 216 ... Permanent magnet rotor, 217a to 217f ... Switching element

Claims (3)

An electric pump driven by a motor and having a one-way valve interposed in a discharge-side pipe; and a mechanical pump driven by an engine and having a discharge-side pipe connected to a pipe downstream of the one-way valve; A control device for controlling the electric pump in a vehicle comprising:
While the rotation of the engine is stopped, the electric pump is operated by controlling the rotation speed of the motor by operating the applied voltage of the motor,
The control to limit the excessive current is performed before the engine is stopped to operate the electric pump, and the control to limit the excessive current is released at the transition to the electric pump when the engine stops rotating. A control device for an electric pump for a vehicle that allows a higher current than before release. The control for limiting the excessive current is the control of the current of the motor by operating the applied voltage of the motor,
2. The release of the control for limiting the excessive current is a transition from the control of the motor current by operating the applied voltage of the motor to the control of the rotational speed of the motor by operating the applied voltage of the motor. The control apparatus of the electric pump for vehicles as described.   The stage of transition to the electric pump accompanying the rotation stop of the engine is determined based on at least one of the rotation speed of the engine, the rotation speed of the motor, and the downstream pressure of the one-way valve. The control apparatus of the electric pump for vehicles of 1 or 2.