JP6354562B2 - Motor control device - Google Patents

Description

  The present invention relates to a motor control device for driving a water pump of a vehicle.

  In a water-cooled engine, the engine is cooled by circulating cooling water with antifreeze added to a water jacket that is a flow path of cooling water provided in an engine block or the like. A water pump for circulating cooling water is attached to the engine block of the water-cooled engine, and the water pump is driven by a pump driving motor whose supply power is controlled by an ECU (Electronic Control Unit) provided in the vehicle. Is done.

  Since the cooling water is for cooling the engine, the flow rate of the cooling water to be circulated is not as high as that of the engine that has been warmed up in an engine that has not been warmed up immediately after starting. Patent Document 1 discloses an invention of an operation method of a centrifugal pump in which the amount of cooling water discharged from the pump is reduced as compared with the normal time by rotating the impeller of the pump in a direction opposite to the normal time.

JP 2004-197621 A

  However, in the invention described in Patent Document 1, the amount of cooling water discharged is less than when the impeller is reversed, and an intermediate discharge amount between the case where the impeller is reversely rotated and the case where the impeller is rotated forward is considered. There was no problem.

  As described above, in the engine immediately after starting, it is not necessary to cool the engine by actively circulating the cooling water, as in the invention described in Patent Document 1, when the impeller of the water pump is reversed. The amount of cooling water discharged may also be excessive.

  If it is not necessary to cool the engine, it may be possible to stop the operation of the water pump. However, if the circulation of the cooling water in the engine is stopped, the temperature of the cooling water will be reduced in the flow path near the engine combustion chamber. There is a phenomenon that it is high and low in the flow path of other parts of the engine. The temperature of the cooling water is detected by a water temperature sensor provided at one corner of the flow path of the cooling water. However, as described above, if the temperature of the cooling water varies depending on the location of the flow path, the ECU controls the engine. Information on the temperature of the cooling water cannot be obtained accurately, and the engine control may be hindered.

  Therefore, in the engine immediately after starting, it is necessary to control the motor for driving the pump so as to ensure the circulation of the cooling water that can accurately detect the temperature of the cooling water by the water temperature sensor.

  Also, if the impeller is rotated in the reverse direction, the cooling water discharge amount from the water pump can be reduced, but there is a difference from the cooling water discharge amount from the water pump when the impeller is rotated in the forward direction. There was a problem that it could not be controlled.

  The present invention has been made in view of the above, and an object of the present invention is to provide a motor control device capable of continuously controlling the discharge amount of cooling water by a water pump.

  In order to solve the above-described problem, the motor control device according to claim 1 is configured to rotate the rotor of the three-phase motor based on an induced voltage generated in a non-conducting phase coil of the three-phase motor that drives the water pump. When the detection unit for detecting the position and the three-phase motor rotates in the order of intermittent reverse rotation, continuous reverse rotation, low-speed normal rotation, and high-speed normal rotation as the engine coolant temperature rises, Either one phase coil is de-energized according to the rotational position of the rotor, and one coil of the other two phase coils is energized to the other coil, and then the other coil is energized to the one coil. And a control unit for controlling the drive circuit.

  According to this motor control device, the motor driving the water pump is intermittently reverse-rotated, continuously reverse-rotated, low-speed normal rotation, and high-speed normal rotation in this order as the engine coolant temperature rises. Control the drive circuit.

  When the motor is rotated forward at a low speed, one of the three-phase coils is deenergized according to the calculated rotor position, and one of the other two-phase coils is switched from one coil to the other. After energizing one coil, the other coil is energized to one coil. By energizing the energized coil with a current in the opposite direction to the energized current, the current that continues to flow in the energized coil is canceled out so that the motor can rotate forward at low speed. As a result, the motor can be intermittently reversely rotated, continuously reversely rotated, low-speed normal rotation, and high-speed normal rotation, and the amount of cooling water discharged by the water pump can be controlled continuously.

  The motor control device according to claim 2 is the motor control device according to claim 1, wherein energization from the other coil to the one coil after energization from the one coil to the other coil is It is shorter than the energization from one coil to the other coil.

  According to this motor control device, the motor can be rotated forward at a low speed by performing reverse energization in a short time to cancel out the current that continues to flow through the energized coil.

  According to a third aspect of the present invention, in the motor control device according to the first or second aspect, after the energization from the one coil to the other coil, the energization from the other coil to the one coil is performed. The generation of the induced voltage generated in the non-conducting phase coil is reduced.

  According to this motor control device, by canceling the current that continues to flow through the coil after being energized, the generation of the induced voltage in the non-energized phase can be reduced, and the rotor position can be easily detected based on the induced voltage during low-speed rotation. Become.

  A motor control device according to a fourth aspect of the present invention is the motor control device according to any one of the first to third aspects, wherein the control unit causes the three-phase motor to be driven by an induced voltage immediately after the engine is started. The drive circuit is controlled so as to continuously reversely rotate to a rotational speed at which the position of the rotor can be detected, and after the rotation of the three-phase motor reaches the rotational speed, the coil of the three-phase motor is The three-phase motor is intermittently reversely rotated by controlling the drive circuit so as to be energized intermittently.

  According to this motor control device, immediately after the engine is started, the motor is continuously reversely rotated until the rotor position can be detected by the induced voltage. After the rotor position can be detected, the motor coil is intermittently energized. By doing so, the motor can be intermittently reversely rotated.

It is a disassembled perspective view of the pump drive motor which concerns on embodiment of this invention. It is the schematic which shows an example of the motor control apparatus which concerns on embodiment of this invention. It is the schematic which showed an example of the operation | movement of the impeller of the water pump using the motor which concerns on embodiment of this invention, (A) rotated the impeller forward, (B) rotated the impeller reversely Each case is shown. (A) shows the flow rate of the water pump when the impeller is continuously reversely rotated, and (B) shows the flow rate of the water pump when the impeller is intermittently reversely rotated. It is the schematic which contrasted the motor application voltage applied to a motor, the flow volume of the cooling water which a water pump discharges, and an average flow volume in the case of rotating an impeller reversely intermittently. It is the graph which represented the piping resistance at the time of discharging cooling water by ratio of flow volume and pressure. It is the schematic which showed the voltage between each phase and GND by having operated the inverter circuit in energization from the U phase coil of a motor to the V phase coil, and (A) is (B ) Indicates the case where the impeller is rotated at a low speed in the forward direction. It is the schematic which showed an example of the signal applied to the gate of inverter FET in the motor control apparatus which concerns on embodiment of this invention, (A) is the case of one-side PWM drive, (B) is the case of balanced drive. Each is shown. It is the flowchart which showed an example of control of the motor control apparatus which concerns on embodiment of this invention.

  FIG. 1 is an exploded perspective view of a pump drive motor 10 (hereinafter abbreviated as “motor 10”) according to the present embodiment. As shown in FIG. 1, the motor 10 includes a housing 12, a base member 14, a rotor 16, a stator 18, a control board 20, a shield cover 22, and a stator holder 24.

  The housing 12 is made of resin. The housing 12 integrally includes a plate-shaped housing main body 26 and a peripheral wall portion 30 of the rotor housing chamber 28 having an opening 28 </ b> A for housing the rotor 16. A connector 32 is provided at one end portion of the housing body 26, and the peripheral wall portion 30 of the rotor housing chamber 28 is formed in a cylindrical shape at a position closer to the other end portion than the central portion of the housing body 26.

  The motor 10 is preferably used as, for example, a water pump that circulates engine coolant, and the rotor housing chamber 28 is a pump formed in the engine block when the housing 12 is attached to an engine block or the like of an automobile. It communicates with the room.

  The base member 14 is made of, for example, an aluminum alloy as an example of a metal having high heat conductivity and conductivity. The base member 14 is formed with a bottom wall portion 31 of the rotor accommodating chamber 28, and a joining portion 38 and a shaft support portion 40 are formed on the bottom wall portion 31. The joint portion 38 and the shaft support portion 40 are each formed in a cylindrical shape.

  The joint portion 38 is formed on the outer side in the radial direction of the shaft support portion 40, and is formed coaxially with the distal end portion of the peripheral wall portion 30. The joint portion 38 protrudes toward the rotor accommodating chamber 28 and is joined to the outer peripheral portion at the distal end portion of the peripheral wall portion 30. A sealing material such as an O-ring is provided between the inner peripheral portion of the joint portion 38 and the outer peripheral portion at the distal end portion of the peripheral wall portion 30.

  The shaft support portion 40 is formed on the radially inner side of the peripheral wall portion 30 and protrudes into the rotor accommodating chamber 28. One end of a shaft 44 extending in the axial direction of the rotor accommodating chamber 28 is press-fitted inside the shaft support portion 40, whereby the shaft 44 is supported by the shaft support portion 40.

  The rotor 16 is rotatably accommodated in the rotor accommodating chamber 28. The rotor 16 is rotatably supported on the shaft 44 via a bearing 46. The rotor 16 is composed of a permanent magnet, and an impeller member 48 is provided in the axial direction of the shaft 44.

  An impeller 56 is formed on the impeller member 48. The impeller 56 is accommodated in the pump chamber of the engine block. When the impeller 56 rotates in the pump chamber, the liquid flows into the pump chamber and the liquid is discharged from the pump chamber. In addition, since the rotor storage chamber 28 communicates with the pump chamber, when the liquid flows into the pump chamber 36, the rotor storage chamber 28 is filled with the liquid.

  The stator 18 is provided around the peripheral wall portion 30, and faces the rotor 16 in the radial direction via the peripheral wall portion 30. The stator 18 has a winding wound around an annular stator core. By controlling the polarity of the voltage applied to the windings of the stator 18, a so-called rotating magnetic field is generated in the stator 18. The permanent magnet constituting the rotor 16 attracts or repels the rotating magnetic field generated in the stator 18 so that the rotor 16 rotates following the rotating magnetic field.

  The control board 20 has a plurality of elements mounted on a board body 64 such as a printed board. The substrate body 64 is superimposed on the bottom wall portion 31 from the side opposite to the rotor accommodating chamber 28. The substrate main body 64 may be overlapped with the bottom wall portion 31 via an inclusion such as a heat transfer sheet or a heat transfer gel between the substrate main body 64 and the bottom wall portion 31.

  The shield cover 22 is formed of a ferromagnetic material such as iron. The shield cover 22 surrounds the control board 20 from the side opposite to the bottom wall 31 with respect to the control board 20 and the surrounding part 72 surrounding the control board 20 and the base member 14 and a holding part 76 of the stator holder 24 described later. And a covering portion 74 for covering. The shield cover 22 forms the outer portion of the motor 10.

  The stator holder 24 is made of a ferromagnetic material such as iron. The stator holder 24 has a cylindrical holding portion 76. The holding portion 76 is provided between the stator 18 and the surrounding portion 72. The stator 18 is held by the holding portion 76 by press-fitting the stator core around which the winding is wound into the inner peripheral portion of the holding portion 76.

  An extension flange 78 extending toward the enclosure portion 72 along the plate-shaped housing body 26 is formed at the end of the holding portion 76 on the housing body 26 side. Further, a first flange 80 is formed on the peripheral edge of the shield cover 22 described above, and a second flange 82 is formed on the peripheral edge of the stator holder 24. The first flange 80 and the second flange 82 are coupled to each other by a fastener or the like. The first flange 80 and the second flange 82 are an example of a connection portion between the shield cover 22 and the stator holder 24.

  The control board 20 is accommodated in a space formed when the shield cover 22 and the stator holder 24 are fixed to each other.

  The board body 64 of the control board 20 is formed with an extension 86 extending on the same side as the extension flange 78 described above. In a space formed between the extension flange 78 and the extension portion 86 on the side of the holding portion 76, an electric component 90 larger than the element mounted on the substrate body 64 is disposed. The electrical component 90 is, for example, a noise prevention element, and is mounted on the surface of the substrate body 64 on the bottom wall portion side. The base member 14 is formed with a support portion 92 extending from the bottom wall portion 31 to the same side as the extension portion 86, and the extension portion 86 is overlapped with the support portion 92.

  FIG. 2 is a schematic diagram showing an example of the motor control device 100 according to the present embodiment. In the inverter circuit 114, the ignition switch 124 is turned on, the electric power supplied from the vehicle-mounted battery 120 is switched, and a voltage to be applied to the coil of the stator 18 of the motor main body 118 is generated. For example, the inverters FET 114A and 44D perform switching to generate a voltage to be applied to a U-phase coil, the inverters FET 114B and 44E to a V-phase coil, and the inverters FET 114C and 44F to a W-phase coil.

  The drains of the inverters FETs 114A, 114B, and 114C are connected to the positive electrode of the on-vehicle battery 120. The sources of the inverters FET 114D, 114E, and 114F are connected to the negative electrode of the battery 120.

  In the present embodiment, the rotational speed and position (rotational position) of the rotor 16 are detected by an induced voltage generated by the rotation of the rotor 16 of the motor body 118. In general, the brushless DC motor detects a magnetic field of a rotor magnet or a sensor magnet provided coaxially with the shaft 44 by a hall element, and detects the rotational speed and position (rotational position) of the rotor 16 based on the detected magnetic field. . However, since the motor main body 118 according to the present embodiment is used for the engine water pump 128, the rotor accommodating chamber 28 in which the rotor 16 is accommodated also has a structure in which the engine coolant is circulated. In the motor 10 according to the present embodiment, the Hall element is not used, and the rotational speed and position of the rotor 16 are detected by the induced voltage generated in the coil of the non-energized phase.

  The induced voltage is a sinusoidal analog signal that changes in accordance with the rotation of the rotor 16. In this embodiment, the induced voltage is converted into a rectangular wave pulse signal by the position detection circuit 116 including a comparator and input to the microcomputer 110. To do.

  The microcomputer 110 calculates the position of the rotor 16 from the signal input from the position detection circuit 116, and based on the calculated position of the rotor 16 and the signal input from the ECU 122, which is a higher-level control device, of the inverter circuit 114. The duty ratio of PWM (Pulse Width Modulation) control related to switching control is calculated. The ECU 122 is connected to a water temperature sensor 126 that detects the temperature of the cooling water of the engine. The motor body 118 rotates so that the amount of cooling water discharged from the water pump 128 increases as the temperature of the cooling water increases. Control the speed. The water temperature sensor 126 is provided at one corner of a cooling water flow path such as a water jacket or a radiator of the engine.

  The signal of the duty ratio calculated by the microcomputer 110 is output to the inverter circuit 114 via the pre-driver 112, and the inverter circuit 114 generates a voltage based on the duty ratio and applies it to the coil of the motor main body 118.

  FIG. 3 is a schematic view showing an example of the operation of the impeller 56 of the water pump using the motor 10 according to the present embodiment. FIG. 3A shows a case where the impeller 56 is rotated forward, and FIG. The case where 56 is reversely rotated is shown, respectively.

  As shown in FIG. 3A, when the impeller 56 is rotated forward, the water molecules 60 of the cooling water in the pump chamber 58 hit the blades of the impeller 56 and are pushed out toward the discharge port 58A. Further, as shown in FIG. 3B, when the impeller 56 is rotated in the reverse direction, the efficiency as a pump is lost as compared with the case where the impeller 56 is rotated in the forward direction. A small amount of cooling water is pushed out toward the discharge port 58A.

  Therefore, the flow rate of the cooling water discharged by the water pump can be changed by changing the rotation of the impeller 56 from the normal rotation to the reverse rotation. Further, by intermittently rotating the impeller 56 reversely, the flow rate can be further reduced as compared with the case where the impeller 56 is continuously reversely rotated.

  4A shows the flow rate of the water pump when the impeller 56 is continuously rotated in the reverse direction, and FIG. 4B shows the flow rate of the water pump when the impeller 56 is rotated in the reverse direction intermittently. Yes. Although FIG. 4A shows reverse rotation, the impeller 56 is continuously rotated, so that the flow rate 130 of the cooling water discharged from the water pump is substantially constant, although there is some change, and the average flow rate 132 Will not deviate greatly.

  In FIG. 4B, the flow rate 134 of the cooling water discharged from the water pump varies greatly between “ON” when the impeller 56 rotates in the reverse direction and “OFF” when the impeller 56 stops rotating. The average flow rate 136 is lower than when the impeller 56 is continuously reversely rotated.

  FIG. 5 is a schematic diagram comparing the motor applied voltage 138 applied to the motor 10 with the flow rate 134 of cooling water discharged from the water pump and the average flow rate 136 when the impeller 56 is intermittently reversely rotated. By intermittently energizing the motor applied voltage 138, the impeller 56 is intermittently reversely rotated to suppress the average flow rate 136.

  FIG. 6 is a graph showing pipe resistance when cooling water is discharged as a ratio of flow rate to pressure. As shown in FIG. 6, as the flow rate of the cooling water discharged from the water pump increases, a higher pressure is required, and the pipe resistance increases. In the present embodiment, when the flow rate is small, the impeller 56 of the water pump is intermittently reversely rotated, and the rotation of the impeller 56 is changed from continuous reverse rotation to low-speed normal rotation and high-speed normal rotation as the flow rate increases. Switch to rotation. In the case of low-speed positive rotation, the duty ratio of the voltage applied to the motor 10 is reduced, and in the case of high-speed positive rotation, the duty ratio of the voltage applied to the motor 10 is increased.

  FIG. 7 is a schematic diagram showing the voltage between each phase and GND due to the operation of the inverter circuit 114 in energization from the U-phase coil 18U to the V-phase coil 18V of the motor 10, and FIG. (B) shows a case where the impeller 56 is rotated forward at a low speed.

  When the impeller 56 shown in FIG. 7A is rotated at high speed and forward, the duty ratio of the voltage applied to the motor 10 is increased. In FIG. 7A, the power supplied from the battery 120 is applied to the U-phase coil 18U with the inverter FET 114A turned on, and grounded via the V-phase coil 18V and the inverter FET 114E.

  The lower table in FIG. 7A is, in order from the top, the switching concept of the inverter FET 114A and the inverter FET 114D for switching to energize the U-phase coil 18U, the inverter FET 114B for switching to energize the V-phase coil 18V, and The switching concept of inverter FET114E and the change of the voltage of W phase coil 18W are shown.

  The switching concept of the inverter FET 114A and the inverter FET 114D that perform switching for energizing the U-phase coil 18U in the table of FIG. 7A indicates that the inverter FET 114A is continuously turned on. Further, the switching concept of the inverter FET 114B and the inverter FET 114E that performs switching for energizing the V-phase coil 18V indicates that the inverter FET 114B and the inverter FET 114E are alternately turned on and off.

  In FIG. 7A, the inverter FET 114A is continuously on, and the inverter FET 114B and the inverter FET 114E are intermittently turned on and off by PWM control. While the inverter FET that performs switching for energizing the U-phase coil 18U is continuously turned on, the inverter FET that performs switching for energizing the V-phase coil 18V is PWM controlled. Then, the case as shown in FIG. 7A is referred to as one-side PWM drive.

  In FIG. 7A, a current 140 is a current when the inverter FET 114E is turned on. The current 140 flows to the U-phase coil 18U via the inverter FET 114A that is continuously turned on, and further flows to the ground region via the V-phase coil 18V and the inverter FET 114E.

  In FIG. 7A, a current 142 is a current when the inverter FET 114E is turned off and the inverter FET 114B is turned on. The current 142 is due to the effect of the current 140 flowing. Even if the inverter FET 114E is turned off, the current 140 flows in the same direction as the current 140, that is, from the U-phase coil 18U to the V-phase coil 18V. This is due to an electromotive force that tries to pass a current through.

  Since the inverter FET 114E is off, the current 142 does not flow to the ground region, but only circulates through the circuit including the U-phase coil 18U, the V-phase coil 18V, the inverter FET 114B, and the inverter FET 114A. However, as will be described later, the induced voltage generated in the W-phase coil 18W may be affected by the currents 140 and 142.

  In the case of FIG. 7A, since the power of the battery 120 is not energized in the W-phase coil 18W, the bottom waveform in the table of FIG. 7A is due to the induced voltage generated in the W-phase coil 18W. is there.

  The motor 10 according to the present embodiment detects the position of the rotor 16 by detecting the induced voltage generated in the coil of the phase where the electric power of the battery 120 is not energized without using the Hall element as described above. However, the voltage of the W-phase coil 18W in the lowermost stage in the table of FIG. 7A changes in amplitude in small increments due to the influence of the currents 140 and 142, and the optimum signal for detecting the position of the rotor 16 can be extracted. Timing may be limited.

  If the timing at which an optimal signal for detecting the position of the rotor 16 can be extracted is limited, the position of the rotor 16 is more difficult to detect as the rotational speed of the motor 10 is lower. This is because as the rotational speed of the motor 10 decreases, the timing at which a non-energized coil such as the W-phase coil 18W shown in FIG. Therefore, when the rotational speed of the motor 10 is low, in the present embodiment, when the impeller 56 is rotated forward at a low speed, PWM control different from the one-side PWM drive shown in FIG. .

  When the impeller 56 shown in FIG. 7B is rotated at a low speed in the forward direction, the duty ratio of the voltage applied to the motor 10 is reduced. In the lower table of FIG. 7B, from the top, the switching concept of the inverter FET 114A and the inverter FET 114D that switches to energize the U-phase coil 18U, the inverter FET 114B that performs switching to energize the V-phase coil 18V, and The switching concept of inverter FET114E and the change of the voltage of W phase coil 18W are shown.

  The switching concept of the inverter FET 114A and the inverter FET 114D that performs switching for energizing the U-phase coil 18U in the table of FIG. 7B indicates that the inverter FET 114A and the inverter FET 114D are alternately turned on and off. Further, in the switching concept of the inverter FET 114B and the inverter FET 114E that perform switching for energizing the V-phase coil 18V, the inverter FET 114E is turned on when the inverter FET 114A is turned on, and the inverter FET 114B is turned on when the inverter FET 114D is turned on. It is shown that.

  In FIG. 7B, a current 144 is a current when the inverter FET 114A and the inverter FET 114E are turned on. The current 144 flows to the U-phase coil 18U via the inverter FET 114A, and further flows to the ground region via the V-phase coil 18V and the inverter FET 114E.

  In FIG. 7B, a current 146 is a current when the inverter FET 114B and the inverter FET 114D are turned on. The current 146 flows to the V-phase coil 18V via the inverter FET 114B, and further flows to the ground region via the U-phase coil 18U and the inverter FET 114D. Current 146 is a current in the opposite direction to current 144 in U-phase coil 18U and V-phase coil 18V.

  The current 144 is a current that flows in the same direction as the current 140 of FIG. 7A in the U-phase coil 18U and the V-phase coil 18V. As a result of the current 144 flowing, the U-phase coil 18U and the V-phase coil 18V A current similar to the current 142 in FIG. However, in FIG. 7B, a current 146 in the opposite direction to the current 144 flows through the U-phase coil 18U and the V-phase coil 18V, and thus the same as the current 142 in FIG. The current is offset. As a result, the induced voltage generated in the W-phase coil 18W generates a spike wave to some extent, but the power supply voltage applied in the W-phase, which is a non-conducting phase when the FET is turned off, which becomes significant noise, is suppressed. This makes it easy to extract a signal that is optimal for detecting the position.

  FIG. 7B shows that the current generated due to the current 144 is canceled by passing a current 146 in the direction opposite to that of the current 144 immediately after the current 144 is passed. To be balanced. In this embodiment, the case shown in FIG. 7B is referred to as balanced drive.

  FIG. 8 is a schematic diagram illustrating an example of a signal applied to the gates of the inverters FETs 114A to 114F in the motor control apparatus 100 according to the present embodiment. FIG. 8A is a one-side PWM drive, and FIG. Each case of balanced drive is shown. The PWM period 150 is a period necessary for PWM control for energizing the ground region from one coil to another, and in FIG. 8, grounding is performed from the U-phase coil 18U to the V-phase coil 18V. This is the period required for PWM control for energizing one pulse in the region. In the present embodiment, the PWM cycle 150 is approximately 50 μsec.

  As shown in FIG. 8A, a high level signal is continuously applied to the gate of the inverter FET 114A related to the energization of the U-phase coil 18U. As a result, the inverter FET 114A is continuously applied in the PWM cycle 150. Is turned on. Further, a high level signal is applied to the gate of the inverter FET 114E related to the energization of the V-phase coil 18V immediately after the dead time 152, and the inverter FET 114E is turned on. As a result, the U-phase coil 18U and the V-phase coil 18V A current 140 shown in FIG. 7A flows. The dead time 152 is a time provided to prevent the inverter FETs connected in series from being simultaneously turned on.

  Thereafter, after the inverter FET 114E is turned off and the dead time 152 has elapsed, a high level signal is applied to the gate of the inverter FET 114B, and the inverter FET 114B is turned on. As a result, the current 142 shown in FIG. 7A flows through the U-phase coil 18U and the V-phase coil 18V.

  The inverter FET 114C and the inverter FET 114F related to energization of the W-phase coil 18W are both turned off in the PWM cycle 150. As a result, the W-phase coil 18W is not energized.

  As shown in FIG. 8B, in the balanced drive, a high level signal is applied to the gates of the inverter FET 114A and the inverter FET 114E after the dead time 152 has elapsed, and the inverter FET 114A and the inverter FET 114E are turned on. As a result, the current 144 shown in FIG. 7B flows through the U-phase coil 18U and the V-phase coil 18V.

  Thereafter, after the inverter FET 114A and the inverter FET 114E are turned off and the dead time 152 has elapsed, a high level signal is applied to the gates of the inverter FET 114D and the inverter FET 114B, and the inverter FET 114D and the inverter FET 114B are turned on. As a result, current 146 shown in FIG. 7B flows through U-phase coil 18U and V-phase coil 18V.

  The inverter FET 114C and the inverter FET 114F related to energization of the W-phase coil 18W are both turned off in the PWM cycle 150. As a result, the W-phase coil 18W is not energized.

  As described above, since the current 146 is in the opposite direction to the current 144, the current flowing through the U-phase coil 18U and the V-phase coil 18V can be canceled by the influence of the current 144. As a result, noise generated in the induced voltage of the non-conducting phase due to the energization of the current 144 can be suppressed, and the position detection of the rotor 16 by the induced voltage generated in the non-conducting phase becomes easy.

  The energization time of the current 146 for canceling the current due to the influence of the current 144 may be shorter than the energization time of the current 144 as shown in FIG. Since the energization time of the current 146 relative to the energization time of the current 144 varies depending on the specifications of the motor 10 and the like, it is specifically determined through an experiment using an actual machine.

  Note that the balanced drive shown in FIG. 8B facilitates position detection of the rotor 16, but the inverter FET is switched more frequently than in the case of the one-side PWM drive shown in FIG. 8A. If the rotational speed of 10 is the same, the balanced drive becomes more prominent than when the field emission noise is the one-side PWM drive. However, in the present embodiment, the balanced drive is used when the duty ratio is low, that is, when the rotation speed of the motor 10 is low. Therefore, since the switching frequency of the inverter FET per unit time is small, the field emission noise radiated by the switching is not a problem in practice.

  7 and 8, the energization of the U-phase coil 18U and the V-phase coil 18V has been described. However, the energization of the V-phase coil 18V and the W-phase coil 18W and the energization of the W-phase coil 18W and the U-phase coil 18U. Since this is the same, detailed description is omitted. As shown in FIG. 7 and FIG. 8, one of the three-phase coils is deenergized, and one of the other two-phase coils is energized from one phase coil to the other phase coil. Control is performed according to the position of the rotor 16 calculated from the induced voltage generated in the coil of the non-energized phase.

  As described above, in the present embodiment, as the discharge amount of the water pump increases, the impeller 56 is intermittently reversely rotated, continuously reversely rotated, and normally rotated. Also, when the impeller 56 is rotated forward, balanced drive is performed when the discharge amount of the water pump is relatively small, and single-side PWM drive is performed when the discharge amount of the water pump is large.

  FIG. 9 is a flowchart showing an example of control of the motor control device 100 according to the present embodiment. In step 900, it is determined whether the engine of the vehicle has been started. If the determination is affirmative, in step 902, information on the temperature of the engine coolant detected by the water temperature sensor 126 is acquired.

  In step 904, the motor 10 is reversely rotated intermittently. However, in step 904, since the motor 10 has just started to rotate, first, the current is forcibly supplied to the designated coil to move the rotor 16 to a specific position, and the coils of each phase are sequentially applied to the coils at a constant low speed. Apply current. When the rotational speed increases and the position of the rotor 16 can be detected by the induced voltage, the coils of each phase are intermittently energized to rotate the motor 10. Is intermittently reversed.

  In step 906, it is determined whether or not the temperature of the cooling water is equal to or higher than the first threshold value. If the determination is affirmative, the motor 10 is continuously reversely rotated in step 908. If the determination in step 906 is negative, the procedure returns to step 904 and the motor 10 is intermittently reversely rotated.

  In step 910, it is determined whether or not the temperature of the cooling water is equal to or higher than a second threshold value that is higher than the first threshold value. If the determination in step 910 is negative, the procedure returns to step 906.

  In step 914, it is determined whether the temperature of the cooling water is equal to or higher than a third threshold value that is higher than the second threshold value. If the determination is affirmative, the motor 10 is rotated forward by one-side PWM drive in step 916. If the determination in step 914 is negative, the procedure returns to step 910.

  In step 918, it is determined whether or not the temperature of the cooling water has decreased beyond a predetermined range. If the determination is negative, the forward rotation by the one-side PWM drive is continued. If the determination in step 918 is affirmative, it is determined in step 920 whether the engine of the vehicle has been stopped. If the determination is affirmative, the process ends. If the determination in step 920 is negative, the procedure returns to step 904 and the motor 10 is intermittently reversely rotated.

  As described above, according to the present embodiment, as the engine coolant temperature increases, the rotation of the pump drive motor is intermittently reversely rotated, continuously reversely rotated, low-speed normal rotation, and high-speed normal rotation. Switching control is performed. By such control, the discharge amount of the cooling water by the water pump can be continuously controlled according to the engine temperature.

DESCRIPTION OF SYMBOLS 10 ... Motor for pump drive, 12 ... Housing, 14 ... Base member, 16 ... Rotor, 18 ... Stator, 18U ... U phase coil, 18V ... V phase coil, 18W ... W phase coil, 20 ... Control board, 22 ... Shield Cover, 24 ... Stator holder, 26 ... Housing body, 28 ... Rotor housing chamber, 28A ... Opening, 30 ... Circumferential wall portion, 31 ... Bottom wall portion, 32 ... Connector, 36 ... Pump chamber, 38 ... Joining portion, 40 ... Shaft Support part 44 ... shaft 46 ... bearing 48 ... impeller member 56 ... impeller 58 ... pump chamber 58A ... discharge port 60 ... water molecule 64 ... substrate body 72 ... enclosure part 74 ... cover part 76 ... Holding part, 78 ... Extension flange, 80 ... Flange, 82 ... Flange, 86 ... Extension part, 90 ... Electrical component, 92 ... Supporting part, 100 ... Motor control device, 110 ... Myco , 112 ... predriver 114 ... inverter circuit, 114A, 114B, 114C, 114D, 114E, 114F ... inverter FET, 116 ... position detecting circuit, 118 ... motor main body, 120 ... battery, 122 ... ECU
124 ... Ignition switch, 126 ... Water temperature sensor, 128 ... Water pump, 130 ... Flow rate, 132 ... Average flow rate, 134 ... Flow rate, 136 ... Average flow rate, 138 ... Motor applied voltage, 140, 142, 144, 146 ... Current, 150 ... PWM period, 152 ... Dead time

Claims (4)

A detection unit that detects a rotational position of a rotor of the three-phase motor based on an induced voltage generated in a coil of a non-energized phase of the three-phase motor that drives the water pump;
As the engine coolant temperature rises, the three-phase motor rotates in the order of intermittent reverse rotation, continuous reverse rotation, low-speed normal rotation, and high-speed normal rotation in order of low-speed normal rotation, depending on the rotational position of the rotor The drive circuit is controlled so that any one phase coil is de-energized, and one coil of the other two-phase coils is energized to the other coil, and then the other coil is energized to the one coil. A control unit,
Including a motor control device.   The energization from the other coil to the one coil after energization from the one coil to the other coil is shorter than the energization from the one coil to the other coil. Motor control device.   3. The generation of an induced voltage generated in the coil in the non-conduction phase is reduced by controlling energization from the other coil to the one coil after energization from the one coil to the other coil. Motor control device.   The control unit controls the drive circuit so as to continuously reversely rotate the three-phase motor to a rotational speed at which the position of the rotor can be detected by an induced voltage immediately after the engine is started, 2. After the rotation of the three-phase motor reaches the rotation speed, the drive circuit is controlled to intermittently reversely rotate the three-phase motor by intermittently energizing the coils of the three-phase motor. The motor control apparatus of any one of -3.

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