JP6835602B2 - Fuel cell system cooling system - Google Patents

Description

The present invention relates to a motor drive device.

In a motor drive device that controls a position such as a rotation angle by using a stepping motor, origin correction control for correcting the operating origin position of the stepping motor is generally performed. As such origin correction control, for example, in Patent Document 1, in a flow rate control device for adjusting a fluid flow rate by adjusting a valve opening degree of a rotary valve (valve device) with a stepping motor, a protrusion interlocking with the stepping motor is provided. , A method of rotating a stepping motor to bring it into contact with a stopper portion and performing origin correction based on the stop position of the protrusion portion is disclosed.

Japanese Unexamined Patent Publication No. 2014-207725

In the conventional origin correction control described in Patent Document 1, when the protrusion (rotating member) is brought into contact with the stopper (butting portion), the protrusion rebounds, that is, the stepping motor rotates in the reverse direction. , There is a risk that the correction accuracy of the origin correction will decrease due to the misalignment of the protrusions.

Therefore, an object of the present invention is to provide a motor drive device capable of suppressing a decrease in correction accuracy due to bounce of a rotating member at the time of contact in origin correction control.

The motor drive device according to one aspect of the present invention includes a stepping motor, a rotating member rotationally driven by the stepping motor, an abutting portion arranged so that the rotating member is abutted by the rotational drive, and the stepping motor. A control unit for controlling the operation is provided, and the control unit can execute origin correction control for correcting the origin position of the stepping motor by abutting the rotating member against the abutting portion by the stepping motor. The control unit is configured to drive the stepping motor with two-phase excitation during normal driving, and 1-2-phase excitation that alternately performs one-phase excitation and two-phase excitation during the origin correction control. Or, the stepping motor is driven by one-phase excitation.

According to this aspect, in both the 1-2 phase excitation and the 1 phase excitation, since there is a period in which only a single phase is excited, the drive torque output by the stepping motor can be reduced as compared with the 2 phase excitation. Thereby, when the rotating member is abutted against the abutting portion in the origin correction control, the amount of rebound when the rotating member abuts against the abutting portion can be reduced. As a result, in the origin correction control, it is possible to suppress a decrease in correction accuracy due to rebounding to the abutting portion of the rotating member.

According to the present invention, it is possible to provide a motor drive device capable of suppressing a decrease in correction accuracy due to bounce of a rotating member at the time of contact in origin correction control.

FIG. 1 is a diagram showing a schematic configuration of a motor drive device according to an embodiment. FIG. 2 is a diagram showing the excitation timing of each phase of the stator of the stepping motor in the two-phase excitation performed during normal driving. FIG. 3 is a diagram showing a schematic configuration of a mechanism related to origin correction control of the motor drive device of the embodiment. FIG. 4 is a diagram showing the excitation timing of each phase of the stator of the stepping motor in the 1-2 phase excitation which is an example of the excitation method implemented at the origin correction control. FIG. 5 is a diagram showing the excitation timing of each phase of the stator of the stepping motor in the one-phase excitation which is another example of the excitation method implemented at the time of origin correction control. FIG. 6 is a block diagram showing a configuration of a cooling system of a fuel cell system to which the motor drive device according to the embodiment is applied as a rotary valve (temperature control valve). FIG. 7 is a diagram showing an example of the abutting structure of the rotary valve. FIG. 8 is a flowchart showing an example of origin correction control performed in the cooling system of the fuel cell system. FIG. 9 is a block diagram showing a configuration of an oxide gas piping system of a fuel cell system to which the motor drive device according to the embodiment is applied as an air valve (bypass valve, sealing valve).

Preferred embodiments of the present invention will be described with reference to the accompanying drawings. In each figure, those having the same reference numerals have the same or similar configurations.

An embodiment will be described with reference to FIGS. 1 to 5. First, the basic configuration of the motor drive device 1 according to the present embodiment will be described with reference to FIG. FIG. 1 is a diagram showing a schematic configuration of a motor drive device 1 according to an embodiment. As shown in FIG. 1, the motor drive device 1 includes a stepping motor 2, a drive circuit 3, and a control unit 4.

As shown in FIG. 1, the stepping motor 2 of the present embodiment is a so-called two-phase unipolar stepping motor. The stepping motor 2 includes a rotatable rotor M made of a cylindrical permanent magnet magnetized in the circumferential direction, and four windings arranged so as to face each other at an interval of 90 degrees with respect to the center of the rotor M. Have the stators S1, S2, S3, and S4, respectively. As the permanent magnet of the rotor M, a ferrite magnet such as Ba ferrite or Sr ferrite, an alnico magnet or the like is used.

The control unit 4 controls the operation of the stepping motor 2. The control unit 4 is connected to the drive circuit 3 and outputs, for example, a signal instructing the drive speed, direction, distance, angle, etc. of the stepping motor 2. Further, the control unit 4 performs origin correction control of the stepping motor 2, which will be described later.

The drive circuit 3 is for reading, distributing, and amplifying the signal from the control unit 4 to excite the windings of the stators S1, S2, S3, and S4 of the stepping motor 2 in a predetermined order. The drive circuit 3 has transistors T1, T2, T3, T4 and the like as switches for energizing and shutting off the windings of the stators S1, S2, S3 and S4 of the stepping motor 2. Further, although not shown in FIG. 1, the drive circuit 3 includes a logic circuit that determines the excitation order of the stators S1, S2, S3, and S4, a power supply control unit that supplies a current to the windings of each stator, and the like. Have.

The control unit 4 of the motor drive device 1 drives such a 4-phase winding stepping motor 2 by two-phase excitation during normal driving. Two-phase excitation will be described with reference to FIG. FIG. 2 is a diagram showing the excitation timing of each phase of the stators S1 to S4 of the stepping motor 2 in the two-phase excitation performed during normal driving. The vertical direction of FIG. 2 represents the stators S1, S2, S3, and S4 of the stepping motor, and the horizontal direction of FIG. 2 represents an excitation pattern for each time unit (pulse). This excitation pattern periodically transitions in the order from the left end to the right end. In FIG. 2, the stator excited in each pulse is shown in black, and the non-excited stator is shown in white.

As shown in FIG. 2, in the two-phase excitation, the timing of exciting the windings of the stators S1, S2, S3, and S4 is shifted by one pulse from the next phase, and the two phases are simultaneously excited while being excited in order. Will be. In two-phase excitation, the pulse width of each phase is two pulses. The control unit 4 controls the two-phase excitation of the stators S1, S2, S3, and S4 via the drive circuit 3 to control the drive of the stepping motor 2. Then, the motor driving device 1 can rotate the rotating member 5 (see FIG. 3) attached to the motor 2 to an arbitrary rotation angle by driving the stepping motor 2 by such a control unit 4.

Further, the motor drive device 1 and the control unit 4 of the present embodiment are configured to be able to perform origin correction control for correcting the origin position of the stepping motor 2. The origin correction control will be described with reference to FIGS. 3 to 5. FIG. 3 is a diagram showing a schematic configuration of a mechanism related to origin correction control of the motor drive device 1 of the embodiment.

As shown in FIG. 3, the motor drive device 1 includes a rotating member 5 that is attached to the stepping motor 2 and is rotationally driven in response to the drive of the stepping motor 2. As shown in FIG. 3, for example, the rotating member 5 is a member extending in the centrifugal direction from the rotating shaft of the stepping motor 2, and is rotatably installed around the rotating shaft.

Further, the motor drive device 1 includes an abutting portion 6 in which the rotating member 5 is arranged so as to be abutted by the rotational drive of the stepping motor 2 at a predetermined position in the rotational direction of the rotating member 5. The rotating member 5 that abuts on the abutting portion 6 is stopped from rotating. As shown in FIG. 3, for example, the abutting portion 6 is a convex portion formed so as to project inward from the inner wall surface of the housing 7 in which the rotating member 5 is housed.

When executing the origin correction control, the control unit 4 of the motor drive device 1 corrects the origin position of the stepping motor 2 by abutting the rotating member 5 against the abutting portion 6 by the stepping motor 2. For example, the control unit 4 can correct the position where the rotating member 5 abuts on the abutting portion 6 so as to be the origin position. In particular, in the present embodiment, the control unit 4 is configured to drive the stepping motor 2 by 1-2 phase excitation or 1 phase excitation during the abutting operation of the origin correction control.

FIG. 4 is a diagram showing the excitation timing of each phase of the stators S1 to S4 of the stepping motor 2 in the 1-2 phase excitation which is an example of the excitation method implemented at the origin correction control. FIG. 5 is a diagram showing the excitation timing of each phase of the stators S1 to S4 of the stepping motor 2 in the one-phase excitation which is another example of the excitation method implemented at the time of origin correction control. The basic configurations of FIGS. 4 and 5 are the same as those of FIG.

As shown in FIG. 5, in one-phase excitation, only one phase of the stators S1, S2, S3 and S4 is excited. As shown in FIG. 5, when excited in the order of S1 → S2 → S3 → S4, the stepping motor 2 is rotationally driven by a predetermined step angle. Further, if the order of excitation is reversed from that in FIG. 5, the rotation is reversed. In one-phase excitation, the pulse width of each phase is one pulse, which is half that of two-phase excitation.

As shown in FIG. 4, in 1-2 phase excitation, 1-phase excitation and 2-phase excitation are alternately repeated. As shown in FIG. 4, in the 1-2 phase excitation, the pulse width of each phase is 3 pulses, and the excitation is performed by shifting the pulse width from the next phase by 2 pulses. As a result, the state in which only one phase is excited and the state in which the two phases are simultaneously excited are repeated, and the two phases are excited in order.

The control unit 4 is physically an electronic circuit mainly composed of a well-known microcomputer including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and an interface. Each function of the control unit 4 described above loads the application program stored in the ROM into the RAM and executes it in the CPU to operate various devices under the control of the CPU and to operate the data in the RAM or the ROM. It is realized by reading and writing.

The effect of the motor drive device 1 according to the present embodiment will be described. As described above, in the motor drive device 1 according to the present embodiment, the stepping motor 2, the rotating member 5 rotationally driven by the stepping motor 2, and the abutting portion 6 arranged so that the rotating member 5 abuts by the rotational drive. And a control unit 4 that controls the operation of the stepping motor 2. The control unit 4 is configured to be able to execute origin correction control for correcting the origin position of the stepping motor 2 by abutting the rotating member 5 against the abutting portion 6 by the stepping motor 2. Further, the control unit 4 drives the stepping motor 2 by two-phase excitation during normal driving, and 1-2-phase excitation or two-phase excitation that alternately performs one-phase excitation and two-phase excitation during origin correction control. The stepping motor 2 is driven by one-phase excitation.

In both the 1-2 phase excitation and the 1 phase excitation, since there is a period for exciting only a single phase, the drive torque output by the stepping motor 2 is reduced as compared with the 2 phase excitation. As a result, when the rotating member 5 is abutted against the abutting portion 6 in the origin correction control, the amount of rebound when the rotating member 5 abuts against the abutting portion 6 can be reduced. Therefore, the motor drive device 1 of the present embodiment can suppress a decrease in correction accuracy due to bounce of the rotating member 5 with respect to the abutting portion 6 in the origin correction control.

Next, an application example of the motor drive device 1 according to the above embodiment will be described with reference to FIGS. 6 to 8. FIG. 6 is a block diagram showing a configuration of a cooling system 10 of a fuel cell system to which the motor drive device 1 according to the embodiment is applied as a rotary valve 14 (temperature control valve). FIG. 7 is a diagram showing an example of the abutting structure of the rotary valve 14.

The cooling system 10 of the fuel cell system shown in FIG. 6 appropriately maintains the operating temperature of the fuel cell by appropriately supplying cooling water to the fuel cell (FC) stack 11 in the system. The cooling system 10 includes an FC stack 11, a radiator 12, a water pump 13, and a rotary valve 14.

The FC stack 11 receives the supply of reaction gas (oxidation gas, fuel gas) and generates electric power by an electrochemical reaction. The radiator 12 cools the cooling water flowing through the cooling system 10. The water pump 13 circulates cooling water between the FC stack 11 and the radiator 12. In the example of FIG. 6, the water pump 13 discharges the cooling water cooled by the radiator 12 and supplies it to the FC stack 11.

The rotary valve 14 is provided between the FC stack 11 and the radiator 12 to switch the flow of cooling water. In the example of FIG. 6, the rotary valve 14 switches to a flow path for supplying the cooling water output from the FC stack 11 to the radiator 12 or a flow path for bypassing the radiator 12 and supplying the water pump 13. For example, the cooling system 10 sets the rotary valve 14 so that when the FC stack 11 is operating at a high temperature, the cooling water is supplied to the radiator 12, cooled by the radiator 12, and then supplied to the FC stack 11. Switching, thereby cooling the FC stack 11. Further, when the operating temperature of the FC stack 11 is low, for example, at the time of starting, the cooling system 10 switches the rotary valve 14 so that the cooling water bypasses the radiator 12, thereby suppressing excessive cooling of the FC stack 11. To do.

The rotary valve 14 can switch the flow path by adjusting the rotation angle of the valve body (not shown). The motor drive device 1 of the present embodiment is applied to the rotary valve 14 as a drive source of the valve body. For example, as shown in FIG. 7, the rotary valve 14 has a first gear 16, a second gear 17, and a third gear 18 housed in a housing 15 and connected to each other. The first gear 16 is connected to a stepping motor (not shown) and interlocks with the rotation of the stepping motor. The third gear 18 is connected to the valve body of the rotary valve 14 and interlocks with the rotation of the valve body.

In the example of FIG. 7, the rotating member 5A is provided at the outer edge end of the third gear 18, and the abutting portion 6A protruding from the inner wall surface of the housing 15 is provided. These rotating members 5A and abutting portions 6A have the same functions as the rotating members 5 and abutting portions 6 described with reference to FIG. That is, when executing the origin correction control, the stepping motor rotationally drives the third gear and the rotating member 5A via the first gear 16 and the second gear 17, and abuts the rotating member 5A against the abutting portion 6A. By doing so, the origin position of the stepping motor is corrected.

FIG. 8 is a flowchart showing an example of origin correction control performed in the cooling system 10 of the fuel cell system described with reference to FIGS. 6 and 7. In step S1, it is determined whether or not the cooling water flow rate (rotational speed of the water pump 13) of the cooling system 10 is equal to or less than a predetermined amount. When the flow rate of the cooling water is larger than the predetermined amount (No in step S1), the determination in step S1 is performed again after waiting for a predetermined time in step S2.

On the other hand, as a result of the determination in step S1, when the cooling water flow rate of the cooling system 10 is equal to or less than a predetermined amount (Yes in step S1), the upper limit of the cooling water flow rate (the number of rotations of the water pump 13) is set in step S3. Be changed. In this step, the setting is changed so that the upper limit value is reduced as compared with the normal driving. The upper limit of the changed cooling water flow rate is, for example, as described above, when the motor driving device 1 of the present embodiment drives the stepping motor by 1-2 phase excitation or 1 phase excitation when the origin correction control is performed. Even when the torque is reduced, it is preferable that the reduced drive torque is set to a small amount so that the valve body of the rotary valve 14 can be operated.

After the cooling water flow rate of the cooling system 10 is suppressed in step S3 in this way, the origin correction control of the stepping motor is performed in step S4. In the origin correction control, for example, the stepping motor is controlled to rotate in a predetermined step toward the side approaching the abutting portion 6A so that the rotating member 5A abuts on the abutting portion 6A.

When the origin correction control is completed, in step S5, the upper limit value of the cooling water flow rate changed in step S3 is released, and the value is returned to the normal one to end the main control flow.

When the fuel cell system is mounted on the vehicle, the determination in step S1 may not be performed if the flowchart of FIG. 8 is executed when the vehicle is started or stopped.

As described above, in the configuration in which the motor drive device 1 of the present embodiment is applied as the drive source of the rotary valve 14 of the cooling system 10 of the fuel cell system, the cooling system 10 is operated before the origin correction control of the stepping motor is performed. It is preferable that the flow rate of the flowing cooling water is equal to or less than a certain threshold value (for example, the upper limit value after the change in step S3). In the cooling system 10, as the flow rate of the cooling water increases, the driving torque required to operate the rotary valve 14 increases. In the present embodiment, since the origin correction control is changed from the two-phase excitation to the 1-2 phase excitation or the one-phase excitation, the drive torque of the stepping motor during the origin correction control is reduced. In the present embodiment, since the cooling water flow rate is reduced in advance before the origin correction control, the rotary valve 14 can be suitably operated even with the drive torque lowered during the origin correction control.

Similar to the cooling system 10 of FIGS. 6 to 8, the motor drive device 1 according to the embodiment can be applied to the oxide gas piping system 20 of the fuel cell system as shown in FIG. FIG. 9 is a block diagram showing a configuration of an oxide gas piping system 20 of a fuel cell system to which the motor drive device 1 according to the embodiment is applied as an air valve (bypass valve 24, sealing valve 22, 23).

The oxidation gas piping system 20 supplies air as an oxidation gas to the FC stack 11 and discharges excess air from the FC stack 11. The oxidation gas piping system 20 has an air pump 21 for discharging air to the FC stack 11 in the intake system, and a sealing valve 22 for adjusting the flow of the oxidation gas in the intake system. The exhaust system also has a sealing valve 23 that regulates the flow of oxidizing gas. The upstream side of the sealing valve 22 of the intake system and the downstream side of the sealing valve 23 of the exhaust system are connected by a bypass flow path, and a bypass valve 24 for adjusting the flow rate of the bypass flow path is provided. ..

The motor drive device 1 of the present embodiment is the drive source of the valve body of the air valve (bypass valve 24, sealing valve 22, 23) of the oxidation gas piping system 20 as in the rotary valve 14 described with reference to FIG. Can be applied as. Further, the origin correction control described with reference to the flowchart of FIG. 8 replaces the cooling water flow rate calculated based on the rotation speed of the water pump 13 with the air flow rate of the air pump 21, and also in the configuration of FIG. It can be carried out in the same way.

The embodiments described above are for facilitating the understanding of the present invention, and are not for limiting and interpreting the present invention. Each element included in the embodiment and its arrangement, material, condition, shape, size, etc. are not limited to those exemplified, and can be changed as appropriate. In addition, the configurations shown in different embodiments can be partially replaced or combined.

In the above embodiment, as shown in FIG. 1, a two-phase unipolar stepping motor is exemplified as a control target of the motor drive device 1, but if two-phase excitation, one-two-phase excitation, and one-phase excitation can be performed, other Type of stepping motor may be used.

1 ... Motor drive device, 2 ... Stepping motor, 4 ... Control unit, 5, 5A ... Rotating member, 6, 6A ... Butting part

Claims (1)

It is the cooling system of the fuel cell system.
With a fuel cell
A water pump that supplies cooling water to the fuel cell,
A radiator that cools the cooling water supplied to the water pump,
A rotary valve that switches the flow of cooling water supplied to the water pump to a flow path that passes through the radiator or a flow path that bypasses the radiator.
A motor drive device for driving the rotary valve is provided.
The motor drive device
With a stepping motor
A rotating member that is rotationally driven by the stepping motor,
An abutting portion where the rotating member is arranged so as to hit by rotational drive,
A control unit that controls the operation of the stepping motor is provided.
The control unit is configured to be capable of executing origin correction control for correcting the origin position of the stepping motor by abutting the rotating member against the abutting portion by the stepping motor.
The control unit drives the stepping motor with two-phase excitation during normal driving, and 1-2-phase excitation or two-phase excitation that alternately performs one-phase excitation and two-phase excitation during origin correction control, or The stepping motor is driven by one-phase excitation,
The origin correction control is executed while the rotation speed of the water pump is controlled to be equal to or lower than a predetermined threshold value .
Wherein the predetermined threshold is lower than that during normal driving of the water pump, and Ru is set to operable values the rotary valve by an output torque of said stepping motor,
Cooling system.