JP2014171293A - Device and method of controlling cooling fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device of controlling a cooling fan for vehicles, capable of improving the power consumption when driving the cooling fan of a radiator for vehicles.SOLUTION: In a device 1 of controlling a cooling fan, a target rotation number setting part 24 sets a target rotation number Nref to be allocated depending on a command Duty ratio inputted from an engine ECU 2. A position detector 21 detects a rotation position of a rotor from each induction voltage of a stator coil of a brushless motor 10. A rotation number calculation part 22 calculates a motor rotation number Nfbk from a rotor position signal Pos of the rotor. A duty controller 23 compares the target rotation number Nref and the motor rotation number Nfbk calculated by the rotation number calculation part 22 with each other, and controls a duty ratio of a PWM voltage to be applied to the brushless motor 10 so that the motor rotation number Nfbk is accorded with the target rotation number Nref.

Description

  The present invention relates to a cooling fan control device and a control method for driving a cooling fan of a radiator of a vehicle.

  As a cooling fan control device that drives a cooling fan of a vehicle radiator with an electric motor, for example, there is a control device that drives the cooling fan with a brushless motor. As such a control device for driving the cooling fan, the voltage applied to the coil of the brushless motor is controlled by changing the pulse width modulation signal, that is, the duty ratio (duty ratio) of the PWM (Pulse Width Modulation) voltage. Things are known.

  FIG. 10 is a diagram for explaining a conventional cooling fan control device 1A. For example, in the cooling fan control device 1A, the engine ECU (Electronic Control Unit) 2 outputs a command duty ratio (command duty ratio) signal for controlling the driving of the brushless motor 10 to the control device 1A. . As shown in FIG. 2, the command duty ratio is output as a PWM signal that regulates the driving of the brushless motor 10 by the ratio of the on time Ton (Ton / T) with respect to a predetermined pulse period T, that is, the duty ratio.

  The cooling fan control device 1 </ b> A includes a position detection unit 21, which detects the position of the rotor (rotor) of the brushless motor 10 from the voltage induced in the stator winding of the brushless motor 10. To do. By detecting the position of the rotor 11, the timing for switching the energization pattern applied to the stator winding of the brushless motor 10 is determined.

  Then, the duty control unit 23A determines the stator of each phase based on the switching timing of the energization pattern applied to the stator winding, the duty ratio indicated by the command duty ratio input from the engine ECU 2, and the motor rotation speed. A PWM voltage to be applied to the winding is generated, and this PWM voltage is applied to the brushless motor 10.

  In addition, as a control device for the cooling fan of the related radiator, the temperature of the cooling water of the radiator is measured, and the number of rotations of the cooling fan is controlled according to the temperature of the cooling water so that the cooling water temperature approaches a predetermined value. There is a thing (refer patent document 1).

JP-A-11-257076

  By the way, since the cooling fan of the radiator of the vehicle is disposed in the engine room of the vehicle, the environment (temperature, humidity, atmospheric pressure) of this space is caused by heat generation of the engine or the humidity change due to rain and snow. Etc.) change significantly. In the duty control method of the conventional cooling fan control device 1A shown in FIG. 10, the control device 1A does not depend on the external environment (temperature, humidity, atmospheric pressure, etc.), and the PWM voltage having a constant duty value indicated by the command duty ratio. Therefore, when the load is light (for example, when the engine room is hot and the air resistance is low), the rotational speed of the brushless motor 10 increases more than necessary, causing unnecessary power consumption. was there. Further, when the brushless motor 10 rotates at a high speed, the load increases and the heat generated by the electronic components inside the control device 1A increases. This causes a wasteful power loss and contributes to a reduction in power consumption.

  In the cooling fan control device described in Patent Document 1 described above, the rotation of the cooling fan depends on the coolant temperature T1 on the engine discharge side and the coolant temperature T2 just before the coolant is supplied to the engine. A method for controlling the number is disclosed. However, the cooling fan control device described in Patent Document 1 is not intended to improve the power consumption when driving the cooling fan, and the rotation number detection method of the motor driving the cooling fan and its rotation A specific method of number control is not disclosed.

  The present invention has been made in view of such circumstances, and an object of the present invention is to improve the power consumption of a cooling fan for a vehicle radiator that is driven by an electric motor. A control device and a control method are provided.

  A cooling fan control device according to the present invention controls an electric motor that drives a cooling fan of a radiator of a vehicle, and also controls a rotation speed of the electric motor based on a command signal from the engine control device of the vehicle. A fan duty control unit that receives a command duty ratio signal that is input from the engine control device of the vehicle, and a command duty ratio value that is input from the engine control device; A target rotational speed setting unit for setting the target rotational speed of the electric motor assigned in advance, a position detecting unit for detecting a rotational position of the rotor of the electric motor and outputting a position signal of the rotor, and the position A rotation speed calculation unit that calculates the rotation speed of the electric motor based on a position signal output from the detection unit and the target rotation speed setting unit are set. A voltage applied to the electric motor so that the number of revolutions of the electric motor is compared with the number of revolutions of the electric motor calculated by the number-of-rotations calculation unit and the number of revolutions of the electric motor becomes a value corresponding to the target number of revolutions And a duty control unit for controlling the duty ratio of the first to second.

  Also, in the cooling fan control device of the present invention, the electric motor is a brushless motor, and the position detecting unit is configured to determine a position of a rotor of the brushless motor based on an induced voltage of a stator winding of the brushless motor. Is detected.

  In the cooling fan control device of the present invention, the command duty ratio is input as a binary signal of a high signal (H signal) or a low signal (L signal), and the target rotational speed setting unit is configured to output the command duty ratio. Depending on whether the ratio is a high signal or a low signal, either the first target rotational speed or the second target rotational speed having a value larger than the first target rotational speed is selected and output. It is characterized by that.

  The cooling fan control method of the present invention controls an electric motor that drives a cooling fan of a radiator of a vehicle, and controls the rotation speed of the electric motor based on a command signal from the engine control device of the vehicle. And a command duty input procedure for inputting a command duty ratio signal indicated by the command signal from the engine control device of the vehicle, and a value of the command duty ratio input from the engine control device. A target rotational speed setting procedure for setting a target rotational speed of the electric motor allocated in advance according to the position, a position detection procedure for detecting a rotational position of the rotor of the electric motor and outputting a position signal of the rotor, A rotation speed calculation procedure for calculating the rotation speed of the electric motor based on the position signal output by the position detection procedure, and the target rotation speed setting The target rotational speed set in order and the rotational speed of the electric motor calculated by the rotational speed calculation procedure are compared, and the electric motor speed is set to a value corresponding to the target rotational speed. And a duty control procedure for controlling a duty ratio of a voltage applied to the motor.

  Further, in the cooling fan control method of the present invention, the electric motor is a brushless motor, and the position detection procedure is based on an induced voltage of a stator winding of the brushless motor. Is detected.

  In the cooling fan control method of the present invention, the command duty ratio is input as a binary signal of a high signal (H signal) or a low signal (L signal), and the target rotational speed setting procedure is performed by the command duty ratio. Depending on whether the ratio is a high signal or a low signal, either the first target rotational speed or the second target rotational speed having a value larger than the first target rotational speed is selected and output. It is characterized by that.

According to the cooling fan control device of the present invention, the target rotational speed setting unit sets the target rotational speed assigned in accordance with the command duty ratio input from the engine control device. The position detection unit detects the rotation position of the rotor, and the rotation number calculation unit calculates the rotation number of the electric motor from the position signal of the rotor. The duty control unit compares the target rotation speed with the rotation speed of the electric motor, and controls the duty ratio of the voltage applied to the electric motor so that the rotation speed of the electric motor becomes a value corresponding to the target rotation speed. To do.
Thereby, when the cooling fan of the radiator for vehicles is driven with an electric motor, the electric cost can be improved.

It is a block diagram which shows the structure of the control apparatus of the cooling fan concerning 1st Embodiment of this invention. It is a figure which shows the example of the signal of the command duty ratio output from engine ECU2. 2 is a diagram illustrating a configuration example of a brushless motor 10 and an inverter 12. FIG. It is a figure which shows the example of the Duty versus rotation speed table. 5 is a flowchart showing a flow of setting processing of a target rotational speed Nref in the target rotational speed setting unit 24. It is a figure for demonstrating the method to detect the rotation position of a rotor, and a motor rotation speed. It is a figure which shows the example of PWM command signal H1-H6 output from the duty control part 23. FIG. 5 is a flowchart showing a flow of duty control processing in a duty control unit 23. It is a figure for demonstrating the control apparatus of the cooling fan concerning 2nd Embodiment of this invention. It is a figure for demonstrating the control apparatus 1A of the conventional cooling fan.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

[First Embodiment]
(Configuration of Cooling Fan Control Device 1)
FIG. 1 is a block diagram showing the configuration of the cooling fan control device according to the first embodiment of the present invention. In this figure, a control device 1 for a cooling fan receives a command duty ratio (command duty ratio) signal from an engine ECU (engine control device) 2 and sets a target rotational speed corresponding to the command duty ratio. The rotational speed of the brushless motor 10 is controlled so as to reach the target rotational speed. As the brushless motor 10 rotates, the cooling fan 3 rotates, and the radiator 4 is cooled by the cooling air generated by the rotation of the cooling fan 3.

The engine ECU 2 generates a command duty ratio signal, which is a control signal for the brushless motor 10, according to the operating state of the engine of the vehicle, and outputs the command duty ratio signal to the control unit 20.
FIG. 2 is a diagram illustrating an example of a command duty ratio signal output from the engine ECU 2. As shown in FIG. 2, the command duty ratio is a PWM signal that regulates the driving of the brushless motor 10 by the ratio of the on time Ton to a predetermined pulse period T (Ton / T), that is, the duty ratio. 2A shows a case where the duty ratio indicating the command duty ratio is small, and FIG. 2B shows a case where the command duty ratio is large.
The engine ECU 2 calculates a required duty ratio based on the vehicle speed, the temperature of the cooling water, and the like so that the cooling water is appropriately cooled by the radiator 4, and the control unit 20 uses the result as a command duty ratio signal. Output to.
As shown in a Duty vs. rotation speed table 25 (FIG. 4) described later. The command duty ratio is output as a signal indicating a multi-stage duty ratio (for example, 10%, 20%,..., 100%, etc.).

Returning to FIG. 1, the brushless motor 10 has a rotor (rotor) having a permanent magnet and a stator (stator), and a stator winding of three phases (U, V, W) surrounds the stator. It is a brushless motor wound in order in the direction.
Here, FIG. 3 is a diagram illustrating a configuration example of the brushless motor 10 and the inverter 12. For example, as shown in FIG. 3, the brushless motor 10 is an outer rotor type, and is configured by attaching eight permanent magnets (magnets) including an N pole and an S pole to the inner peripheral surface of a cylindrical rotor. The rotor 11 (magnet rotor) is included. The brushless motor 10 is fixed inside the rotor 11 and includes U-phase, V-phase, and W-phase stator windings 10u, 10v, and 10w that are star-connected. A total of 12 stator windings composed of The brushless motor 10 is a sensorless type brushless motor that does not have a sensor (for example, a Hall IC or the like) that detects the rotational position of the rotor 11. Note that the brushless motor 10 may be configured to include a rotor to which permanent magnets (magnets) other than eight are attached and a corresponding stator winding. The cooling fan 3 is attached so as to be rotatable integrally with the rotor 11.

  The inverter 12 is a three-phase bridge circuit in which two switching elements are bridge-connected between positive and negative terminals of a power source (for example, a battery) 14. This three-phase bridge circuit is based on the PWM command signals H1 to H6 input from the control unit 20 (more precisely, based on the drive signals G1 to G6 output from the driver circuit 13), and the direct current supplied from the power supply 14 The voltage is converted into a three-phase AC voltage, and this three-phase AC voltage is applied to each phase of the brushless motor 10.

  As shown in FIG. 3, the inverter 12 includes six transistors Q1 to Q6 connected in a three-phase bridge form, and a flywheel diode Dx connected in antiparallel between the drains and sources of the transistors Q1 to Q6. It is comprised including. In the example shown in FIG. 3, the transistors Q1 to Q6 are constituted by power MOSFETs (Metal Oxide Semiconductor Field Effect Transistors). The gates of the six transistors Q1 to Q6 that are bridge-connected are connected to the driver circuit 13.

The connection point a between the transistors Q1 and Q4 is connected to the star-connected stator winding 10u of the brushless motor 10, and the connection point b between the transistors Q2 and Q4 is connected to the stator winding 10v. A connection point c between the transistors Q3 and Q6 is connected to the stator winding 10w. As a result, the six transistors Q1 to Q6 perform the switching operation by the drive signals (gate signals) G1 to G6 input from the driver circuit 13, and the DC power supply voltage of the power supply 14 applied to the inverter 12 is changed to the three-phase. It is converted into (U phase, V phase, W phase) AC voltages Vu, Vv, Vw and supplied to the stator windings 10u, 10v, and 10w.
The transistors Q1 to Q6 are not limited to power MOSFETs but may be bipolar transistors or IGBTs (insulated gate bipolar transistors).

  The driver circuit 13 receives the PWM command signals H1 to H6 output from the control unit 20, and generates drive signals (gate signals) G1 to G6 for turning on / off switching elements in the inverter 12.

  The induced voltage I / F (interface) circuit 15 is a circuit that detects the induced voltage induced in the three-phase stator windings 10 u, 10 v, and 10 w of the brushless motor 10. For example, when 120 ° energization is performed on the stator windings 10u, 10v, and 10w (when energization is performed only during the period of 120 ° during the phase of 180 °), the U, V, and W phases are not energized. A phase is generated, and the induced voltage induced in the stator windings 10u, 10v, and 10w can be detected by detecting the voltage of the non-conduction phase.

  Returning to FIG. 1, the induced voltage I / F circuit 15 receives the induced voltages (analog signals) of the stator windings 10u, 10v, and 10w from the respective three-phase motor terminals. The induced voltage I / F (interface) circuit 15 divides the voltage into a voltage that can be input to the comparators 17A to 17C (resistor R1 and resistor R2) and a primary CR that removes noise from the pulse width modulation signal. Pulsed from low-pass filter circuits 15A, 15B, and 15C composed of filters (resistor R1 and capacitor C1), a circuit 16 that detects an equivalent neutral point potential, and an analog signal of an induced voltage that appears in the equivalent neutral point potential and the non-conduction phase. Comparators 17A, 17B, and 17C that generate signals, and low-pass filters (primary CR filters) 18A, 18B, and 18C that cut high-frequency components from the outputs of the comparators 17A to 17C.

  Here, the circuit 16 that detects the equivalent neutral point potential employs a two-phase comparison method that detects the equivalent neutral point potential from the motor terminal voltages of the V phase and the W phase for the U phase, for example. ing. In this way, a substantially flat voltage is obtained as the equivalent neutral point potential. It should be noted that a three-phase comparison method for obtaining an equivalent neutral point potential using all three-phase signals of U, V, and W may be employed. In this case, the potential at the equivalent neutral point is a substantially triangular wave centered at 1/2 of the power supply voltage.

  The comparators 17A to 17C output a low level signal when the induced voltage analog signal is higher than the equivalent neutral point potential, and output a high level signal when the induced voltage analog signal is lower than the equivalent neutral point potential. A pulse signal is generated. In each of the comparators 17A to 17C, a pulse signal having a resolution of 120 electrical degrees is created. These signals are input to the position detector 21 via low-pass filter circuits 18A to 18C, respectively.

(Configuration of control unit 20)
The control unit 20 is a control unit configured using, for example, a microcomputer or a microcontroller. The control unit 20 receives a command duty ratio signal from the engine ECU 2 and controls the rotational speed of the brushless motor 10 to be a target rotational speed corresponding to the command duty ratio.
As shown in FIG. 1, the control unit 20 includes a position detection unit 21, a rotation speed calculation unit 22, a duty control unit 23, a target rotation speed setting unit 24, a duty versus rotation speed table 25, and a command duty. And an input unit 26.

  The command duty input unit 26 receives a command duty ratio signal from the engine ECU 2 of the vehicle, and outputs the command duty ratio value to the target rotational speed setting unit 24.

(Operation of target rotational speed setting unit 24)
The target rotational speed setting unit 24 extracts the target rotational speed Nref of the brushless motor 10 with reference to the duty vs. rotational speed table 25 based on the value of the command duty ratio input from the command duty input unit 26. The target rotational speed setting unit 24 outputs a signal of the target rotational speed Nref to the duty control unit 23.

Here, FIG. 4 is a diagram illustrating an example of the Duty vs. rotation speed table 25.
As shown in FIG. 4, the duty vs. rotation speed table 25 associates a command duty ratio (Duty% value) with a value (rpm) of the target rotation speed Nref of the brushless motor 10 corresponding to this command duty ratio. Has been recorded. For example, the command duty ratio is input as a signal indicating a multi-stage duty% value such as 10%, 20%,..., 100%, and the target rotational speed setting unit 24 sets the duty% value indicated by the command duty ratio. Based on the above, the duty vs. rotation speed table 25 is referred to, and the target rotation speed Nref corresponding to the duty% value indicated by the command duty ratio is extracted.

  For example, when 50% is input as the value of the command duty ratio to the target rotational speed setting unit 24, the target rotational speed setting unit 24 refers to the duty vs. rotational speed table 25, and the target rotational speed corresponding to 50%. “1200 rpm” is extracted as Nref. The target rotational speed setting unit 24 generates a signal of the target rotational speed Nref corresponding to “1200 rpm” and outputs it to the duty control unit 23.

  FIG. 5 is a flowchart showing a flow of processing for setting the target rotational speed Nref in the target rotational speed setting unit 24.

Referring to the flowchart of FIG. 5, command duty input unit 26 inputs a command duty ratio signal from engine ECU 2 every predetermined control cycle (for example, a cycle of several hundreds msec) (step ST1). The command duty input unit 26 outputs the value indicated by the command duty ratio to the target rotational speed setting unit 24 (step ST2).
Subsequently, the target rotation speed setting unit 24 refers to the duty vs. rotation speed table 25 based on the value of the command duty ratio input from the command duty input unit 26 (step ST3), and the target rotation corresponding to the command duty ratio. The number Nref is set (step ST4).
The target rotational speed setting unit 24 outputs the signal of the target rotational speed Nref set in step ST4 to the duty control unit 23 (step ST5).
As described above, the target rotational speed setting unit 24 can set the target rotational speed Nref corresponding to the duty ratio indicated by the command duty ratio, and output a signal of the target rotational speed Nref to the duty control unit 23. it can.

(Operations of the position detector 21 and the rotational speed calculator 22)
The position detection unit 21 in the control unit 20 inputs the U-phase, V-phase, and W-phase position detection signals Su, Sv, and Sw output from the induced voltage I / F circuit 15, and each position detection signal Su. , Sv, and Sw are detected as rising edges or falling edges, and the rotational position and rotational direction of the rotor (rotor) 11 are determined.

  FIG. 6 is a diagram for explaining a method of detecting the rotational position of the rotor and the motor rotational speed. In FIG. 6, the rotor position pattern Sn (n is a positive number from 1 to 6) indicating the order of the rotation positions of the rotor 11 in the horizontal direction and the induced voltage I / Three position detection signals (position detection signals for U phase, V phase, and W phase) Su, Sv, and Sw output from the F circuit 15 and a rotor position signal Pos of the rotor 11 output from the position detection unit 21 Are shown side by side.

  For example, in the rotor position pattern S1 shown in FIG. 6, the U-phase position detection signal Su is “H (high signal)”, the V-phase position detection signal Sv is “L (low signal)”, and the W-phase position detection signal Sw is Next, in the rotor position pattern S2, the U-phase position detection signal Su is “H”, the V-phase position detection signal Sv is “L”, and the W-phase position detection signal Sw is “L” in the rotor position pattern S2. When the patterns are detected in the order of the rotor position patterns S1 to S6 shown in FIG. 6, it can be determined that the brushless motor 10 is rotating forward. Similarly, in the case of reverse rotation, when the rotor position pattern Sn is detected in a predetermined order, it can be determined that the brushless motor 10 is rotating in reverse.

  Then, the position detector 21 generates a rotor position signal Pos corresponding to each of the rotor position patterns S1 to S6. For example, when the rotor 11 of the brushless motor 10 is at the rotational position of the rotor position pattern S1, the position detection signals Su, Sv, and Sw are an H signal, an L signal, and an H signal, respectively. That is, the position detection signals Su, Sv, and Sw become HLH (indicated by signals in which the position detection signals Su, Sv, and Sw are arranged in parallel), and the rotor position corresponding to the rotor position pattern S1. A signal Pos is generated. The rotor position signal Pos corresponding to the rotor position pattern S1 is referred to as a rotor position signal “A” for convenience. Further, in the case of the rotor position pattern S2, the rotor position signal Pos becomes H-L-L, and the rotor position signal Pos becomes "B".

That is, the rotor position signal Pos output from the position detector 21 corresponds to the rotor position patterns “S1” to “S6” every 60 ° when the rotor position rotates 360 °. " Thus, when the rotor 11 of the brushless motor 10 is driven in the forward rotation direction, the position detection unit 21 corresponds to the patterns “A to” of the rotor position signal Pos corresponding to the patterns S1 to S6 of the rotor position pattern Sn. F ”is output to the rotation speed calculation unit 22 and the duty control unit 23. The rotor position signal Pos “A to F” is used to determine the energization pattern for generating torque in the rotor 11 and the switching timing of the energization pattern every 60 °.
Similarly, when the brushless motor 10 rotates in the reverse direction, the position detector 21 generates and outputs a rotor position signal Pos corresponding to the rotor position pattern Sn.

The rotation speed calculation unit 22 can calculate the motor rotation speed Nfbk by inputting the rotor position signal Pos from the position detection unit 21 and measuring the switching timing T1 of the rotor position signal Pos. Further, the motor rotation speed Nfbk can be calculated by measuring a period T2 in which the U-phase position detection signal Su is “H”.
Then, the rotation number calculation unit 22 outputs the calculated motor rotation number Nfbk to the duty control unit 23 as a feedback signal of the rotation number of the brushless motor 10.

(Operation of duty control unit 23)
The duty control unit 23 inputs a signal of the target rotation number Nref from the target rotation number setting unit 24 and inputs a signal of the motor rotation number Nfbk from the rotation number calculation unit 22 as a feedback signal. Further, the duty control unit 23 receives the rotor position signal Pos from the position detection unit 21.

  Then, the duty control unit 23 generates PWM command signals H1 to H6 for rotationally driving the brushless motor 10 based on the target rotational speed Nref, the motor rotational speed Nfbk, and the rotor position signal Pos. The duty control unit 23 outputs the PWM command signals H <b> 1 to H <b> 6 to the driver circuit 13.

FIG. 7 is a diagram illustrating an example of PWM command signals H1 to H6 output from the duty control unit 23. FIG. 7 shows an example in the case of the 120 ° energization method, for example, a waveform when the brushless motor 10 is rotated forward.
As shown in FIG. 7A, the PWM command signals H1 to H6 output from the duty control unit 23 have a pattern every 60 ° according to the rotor position pattern of the rotor 11 that switches every 60 °. This is a signal that changes, and is a signal for giving six energization patterns P1 to P6 to the stator windings 10u, 10v, and 10w.

In FIG. 7A, the PWM command signal H1 is a signal for turning on / off the transistor Q1 on the U-phase upper arm side of the three-phase bridge circuit, and the PWM command signal H4 is a three-phase bridge. This is a signal for turning on / off the transistor Q4 on the lower arm side of the U phase of the circuit.
The PWM command signal H2 is a signal for turning on / off the V-phase upper arm side transistor Q2 of the three-phase bridge circuit, and the PWM command signal H5 is the V-phase lower arm side of the three-phase bridge circuit. This is a signal for turning on / off the transistor Q5.
The PWM command signal H3 is a signal for turning on / off the transistor Q3 on the W-phase upper arm side of the three-phase bridge circuit, and the PWM command signal H6 is the lower-arm side of the W-phase of the three-phase bridge circuit. This is a signal for turning on / off the transistor Q6.
Each of the PWM command signals H1 to H6 is converted by the driver circuit 13 into drive signals G1 to G6 for driving the transistors Q1 to Q6, and the on / off of the transistors Q1 to Q6 is controlled by the drive signals G1 to G6. Is done.

  For example, when the PWM command signal H1 is a high signal (H signal), the drive signal G1 of the driver circuit 13 is activated, and the transistor Q1 corresponding to the PWM command signal H1 is turned on. When the PWM command signal H1 is a low signal (L signal), the drive signal G1 of the driver circuit 13 is deactivated and the transistor Q1 is turned off. It corresponds to the transistor Q4 corresponding to the other PWM command signal H4, the transistor Q2 corresponding to the PWM command signal H2, the transistor Q5 corresponding to the PWM command signal H5, the transistor Q3 corresponding to the PWM command signal H3, and the PWM command signal H6. The same applies to the transistor Q6.

Further, the duty control unit 23 compares the target rotational speed Nref input from the target rotational speed setting unit 24 with the motor rotational speed Nfbk input from the rotational speed calculation unit 22, and according to the comparison result, the PWM command signal H1. Change the duty ratio at ~ H6.
That is, the duty control unit 23 performs, for example, a PI (proportional integration) operation with the target rotation speed Nref as a command input and the motor rotation speed Nfbk as a hoodback signal, and a PWM command signal according to the result of this PI operation. The duty ratio of H1 to H6 is changed. That is, when the motor speed Nfbk is smaller than the target speed Nref (Nref> Nfbk), the duty control unit 23 increases the duty ratio of the PWM command signals H1 to H6, and conversely, the motor is higher than the target speed Nref. When the rotation speed Nfbk is large (Nref <Nfbk), the duty ratio of the PWM command signals H1 to H6 is decreased. Thereby, the duty control unit 23 can control the target rotation speed Nref and the motor rotation speed Nfbk to coincide with each other.

  For example, as shown in FIG. 7B, when the load of the brushless motor 10 is light, the duty control unit 23 outputs a PWM command signal having a low duty ratio (for example, a PWM signal having a duty ratio of 20%), and brushless. When the load of the motor 10 is heavy, a PWM command signal having a high duty ratio (for example, a PWM signal having a duty ratio of 80%) is output. Thereby, the duty control unit 23 can control the motor rotation speed Nfbk of the brushless motor 10 so as to coincide with the target rotation speed Nref regardless of the load of the brushless motor 10.

The duty ratio control time (duty ratio change response time) in the duty control unit 23 can be set according to the duty control cycle in the duty control unit 23 and the duty change amount to be changed in each control cycle. it can. For example, by reducing the amount of change in duty that is changed for each control cycle, the duty ratio can be gradually changed, and the motor rotational speed Nfbk of the brushless motor 10 can be gradually brought closer to the target rotational speed Nref.
Further, the comparison between the target rotational speed Nref and the motor rotational speed Nfbk in the duty control unit 23 is not limited to the PI operation, but is a P (proportional) operation, an I (integral) operation, or a PID (proportional / integral). -It may be performed by a differentiation operation.

FIG. 8 is a flowchart showing the flow of duty control processing in the duty control unit 23. Hereinafter, the flow of the duty control process will be described with reference to the flowchart shown in FIG.
The duty control unit 23 inputs the target rotation number Nref from the target rotation number setting unit 24 at every predetermined control cycle (for example, a cycle of several hundred μsec or msec) (step ST11), and from the rotation number calculation unit 22 The current motor rotation speed Nfbk of the brushless motor 10 is input (step ST12). Moreover, the duty control part 23 inputs the rotor position signal Pos of the rotor 11 from the position detection part 21 (step ST13).

  Subsequently, the duty control unit 23 compares the target rotational speed Nref with the current motor rotational speed Nfbk (feedback signal) of the brushless motor 10, and the target rotational speed Nref and the motor rotational speed Nfbk match (or substantially match). It is determined whether or not (step ST14).

  If it is determined in step ST14 that the target rotation speed Nref and the motor rotation speed Nfbk match (or substantially match) (step ST14: YES), the duty control unit 23 sets the current value. The duty ratio is maintained as it is (step ST15). Then, the duty control unit 23 generates PWM command signals H1 to H6 based on the maintained duty ratio and the rotor position signal Pos (step ST19). The duty control unit 23 outputs the generated PWM command signals H <b> 1 to H <b> 6 to the driver circuit 13.

  On the other hand, when it is determined in step ST14 that the target rotational speed Nref and the motor rotational speed Nfbk do not match (or substantially match) (step ST14: NO), the duty control unit 23 determines that the target rotational speed Nref is It is determined whether or not it is larger than the motor rotation speed Nfbk (step ST16).

  When it is determined in step ST16 that the target rotational speed Nref is larger than the motor rotational speed Nfbk (step ST16: YES), the duty control unit 23 increases the currently set duty ratio by a predetermined amount. (Step ST17). Then, the duty control unit 23 generates PWM command signals H1 to H6 based on the duty ratio increased by the predetermined amount and the rotor position signal Pos (step ST19). The duty control unit 23 outputs the generated PWM command signals H <b> 1 to H <b> 6 to the driver circuit 13.

On the other hand, in the determination process of step ST16, when it is determined that the target rotation speed Nref is smaller than the motor rotation speed Nfbk (step ST16: NO), the duty control unit 23 decreases the currently set duty ratio by a predetermined amount. (Step ST18). Then, the duty control unit 23 generates PWM command signals H1 to H6 based on the duty ratio decreased by the predetermined amount and the rotor position signal Pos (step ST19). The duty control unit 23 outputs the generated PWM command signals H <b> 1 to H <b> 6 to the driver circuit 13.
Thereby, the duty control unit 23 can control the duty of the PWM command signals H1 to H6 so that the target rotational speed Nref and the motor rotational speed Nfbk are matched (or substantially matched).

[Second Embodiment]
In the cooling fan control device 1 according to the first embodiment described above, the example in which the command duty ratio input from the engine ECU 2 is input using a multi-stage duty ratio as illustrated in FIG. 4 has been described, but the present invention is not limited thereto. Alternatively, the command duty ratio signal may be a binary signal of a high signal (H signal) and a low signal (L signal).

  FIG. 9 is a view for explaining a cooling fan control device according to the second embodiment of the present invention. As shown in FIG. 9, the command duty ratio output from the engine ECU 2 to the target rotational speed setting unit 24A in the control unit 20 is a binary signal of a high signal (H signal) or a low signal (L signal). Is output as

Then, when a low signal (L signal) is input as the command duty ratio, the target rotational speed setting unit 24A sets the target rotational speed Nref to a low rotational speed (for example, 1200 rpm), and controls the target rotational speed Nref. The data is output to the unit 23.
On the other hand, when a high signal (H signal) is input as the command duty ratio, the target rotational speed setting unit 24A sets the target rotational speed Nref to a high rotational speed (for example, 2400 rpm), and controls the target rotational speed Nref. The data is output to the unit 23.

  Thereby, in the cooling fan control device of the second embodiment, the rotation speed of the brushless motor 10 can be set by a binary signal of a high signal or a low signal of the command duty ratio, and the power consumption when driving the brushless motor 10 Can be improved.

The embodiment of the present invention has been described above. Here, the correspondence relationship between the present invention and the above-described embodiment will be supplementarily described. That is, the cooling fan control device according to the present invention corresponds to the cooling fan control device 1, the electric motor according to the present invention corresponds to the brushless motor 10, and the cooling fan according to the present invention corresponds to the cooling fan 3.
The command duty input unit 26 corresponds to the command duty input unit 26 in the present invention, the position detection unit in the present invention corresponds to the position detection unit 21, and the rotation speed calculation unit in the present invention corresponds to the rotation speed calculation unit 22. Corresponds. Further, the duty control unit in the present invention corresponds to the duty control unit 23, and the target rotation number setting unit in the present invention is the target rotation number setting unit 24 (FIG. 1) or the target rotation number setting unit 24A (FIG. 9). Correspond.

  (1) In the above embodiment, the cooling fan control device 1 controls the electric motor (brushless motor 10) that drives the cooling fan 3 of the radiator of the vehicle, and from the engine control device (engine ECU 2) of the vehicle. Is a cooling fan control device 1 that controls the rotation speed of the electric motor (brushless motor 10) based on the command signal of the vehicle, and a command duty ratio signal indicated by the command signal from the engine control device (engine ECU 2) of the vehicle. A command duty input unit 26 for inputting the target duty, and a target rotational speed setting unit 24 for setting the target rotational speed Nref of the electric motor (brushless motor 10) assigned in advance according to the value of the command duty ratio input from the engine control device; The rotational position of the rotor 11 of the electric motor (brushless motor 10) is detected and the rotor 11 A position detector 21 that outputs a position signal (rotor position signal Pos), and a motor rotation speed Nfbk of the electric motor (brushless motor 10) is calculated based on the position signal (rotor position signal Pos) output from the position detector 21. The rotational speed calculation unit 22 to be compared, the target rotational speed Nref set by the target rotational speed setting unit 24, and the motor rotational speed Nfbk of the electric motor (brushless motor 10) calculated by the rotational speed calculation unit 22, A duty control unit for controlling a duty ratio of a voltage applied to the electric motor (brushless motor 10) so that the motor rotation speed Nfbk of the electric motor (brushless motor 10) becomes a value corresponding to the target rotation speed Nref. .

In the cooling fan control device 1 having such a configuration, the target rotational speed Nref corresponding to the command duty ratio input from the engine ECU 2 is set, and the motor rotational speed Nfbk of the electric motor (brushless motor 10) is set to the target rotational speed Nref. Thus, the duty ratio of the voltage (PWM voltage) applied to the brushless motor 10 is controlled.
That is, in the cooling fan control device 1, the target rotational speed setting unit 24 sets the target rotational speed Nref assigned in accordance with the command duty ratio input from the engine ECU 2. The position detector 21 detects the rotational position of the rotor 11 from the induced voltages of the stator windings 10u, 10v, and 10w, and outputs a rotor position signal Pos. The rotation speed calculation unit 22 calculates the motor rotation speed Nfbk based on the rotor position signal Pos of the electric motor (brushless motor 10). Then, the duty control unit 23 compares the target rotational speed Nref and the motor rotational speed Nfbk, and the stator windings 10u, 10v, and 10w of the brushless motor 10 are set so that the motor rotational speed Nfbk becomes the target rotational speed Nref. The duty ratio of the PWM voltage applied to is controlled.
Thus, in the cooling fan control device 1 of the present invention, the rotational speed of the brushless motor 10 is controlled by the target rotational speed Nref corresponding to the value of the command duty ratio. It is possible to avoid an increase in the rotational speed of the brushless motor 10.
Thereby, in the cooling fan control apparatus 1, when the cooling fan 3 of the radiator for vehicles is driven, the power consumption can be improved.

(2) In the above embodiment, the electric motor is the brushless motor 10, and the position detection unit 21 applies the induced voltages Vu, Vv, and Vw of the stator windings 10 u, 10 v, and 10 w of the brushless motor 10. Based on this, the position of the rotor 11 of the brushless motor 10 is detected.
Thereby, in the cooling fan control device 1, when the cooling fan 3 of the vehicle radiator is driven by the sensorless brushless motor 10, the power consumption of the sensorless brushless motor 10 can be improved.

(3) In the above embodiment, the command duty ratio (command duty ratio) is input as a binary signal of a high signal (H signal) or a low signal (L signal), and the target rotational speed setting unit 24A (FIG. 9). ) Selects either the first target rotational speed or the second target rotational speed having a value larger than the first target rotational speed, depending on whether the command duty ratio is a high signal or a low signal And output.
Thus, in the cooling fan control device 1, for example, when the command duty ratio is a high signal, the rotation speed of the brushless motor 10 is set to a high rotation speed, and when the command duty ratio is a low signal, the brushless motor 10 is set. The number of rotations can be set to a low number of rotations, and the power consumption when driving the brushless motor 10 can be improved.

Although the embodiment of the present invention has been described above, each processing unit in the control unit 20 illustrated in FIG. 1 may be realized by dedicated hardware, and implements the function of each processing unit. The program may be recorded on a computer-readable recording medium, the program recorded on the recording medium may be read into a computer system and executed to realize the function.
That is, a computer system such as a microcontroller or a microcomputer having a CPU, a ROM, a RAM, and the like is mounted in the control device 1 for the cooling fan, and the CPU reads and executes the software program, thereby controlling the control unit 20. These processing functions may be realized.

  Although the embodiment of the present invention has been described above, the cooling fan control device of the present invention is not limited to the above illustrated example, and various modifications are made without departing from the scope of the present invention. Of course you get.

For example, in the above-described embodiment, an example of controlling the rotation of a sensorless brushless motor has been described. However, the cooling fan control device of the present invention controls the rotation of a brushless motor including a rotation sensor (for example, a Hall IC). It can also be applied to the case.
Furthermore, the cooling fan control device of the present invention can also be applied to the case of controlling the rotation of a three-phase or single-phase AC motor or a DC motor.

DESCRIPTION OF SYMBOLS 1,1A ... Cooling fan control device, 2 ... Engine ECU (engine control device), 3 ... Cooling fan, 4 ... Radiator, 10 ... Brushless motor (electric motor), 10u, 10v, 10w ... Stator winding, 12 Inverter, 13 Driver circuit, 14 Power supply, 15 Induced voltage I / F circuit, 20 Control unit, 21 Position detection unit, 22 Rotational speed calculation unit, 23, 23A Duty control unit, 24, 24A ... target rotation speed setting section, 25 ... duty vs. rotation speed table, 26 ... command duty input section

Claims (6)

A control device for a cooling fan that controls an electric motor that drives a cooling fan of a radiator of a vehicle, and that controls the number of revolutions of the electric motor based on a command signal from the engine control device of the vehicle,
A command duty input unit for inputting a signal of a command duty ratio indicated by the command signal from the engine control device of the vehicle;
A target rotational speed setting unit that sets a target rotational speed of the electric motor assigned in advance according to the value of the command duty ratio input from the engine control device;
A position detection unit that detects a rotation position of the rotor of the electric motor and outputs a position signal of the rotor;
A rotation speed calculation unit that calculates the rotation speed of the electric motor based on a position signal output from the position detection unit;
The target rotational speed set by the target rotational speed setting unit is compared with the rotational speed of the electric motor calculated by the rotational speed calculation unit, and the rotational speed of the electric motor is set to a value corresponding to the target rotational speed. A duty control unit for controlling the duty ratio of the voltage applied to the electric motor,
A control device for a cooling fan, comprising: The electric motor is a brushless motor,
The position detector is
The cooling fan control device according to claim 1, wherein a position of a rotor of the brushless motor is detected based on an induced voltage of a stator winding of the brushless motor. The command duty ratio is input as a binary signal of a high signal (H signal) or a low signal (L signal),
The target rotation speed setting unit is
Depending on whether the command duty ratio is a high signal or a low signal,
The first target speed,
The cooling fan control device according to claim 1, further comprising: selecting and outputting any one of a second target rotational speed having a value larger than the first target rotational speed. A control method of a cooling fan that controls an electric motor that drives a cooling fan of a radiator of a vehicle, and that controls the number of revolutions of the electric motor based on a command signal from the engine control device of the vehicle,
A command duty input procedure for inputting a command duty ratio signal indicated by the command signal from the engine control device of the vehicle;
A target rotational speed setting procedure for setting a target rotational speed of the electric motor assigned in advance according to the value of the command duty ratio input from the engine control device;
A position detection procedure for detecting a rotational position of the rotor of the electric motor and outputting a position signal of the rotor;
A rotation speed calculation procedure for calculating the rotation speed of the electric motor based on the position signal output by the position detection procedure;
The target rotation speed set by the target rotation speed setting procedure is compared with the rotation speed of the electric motor calculated by the rotation speed calculation procedure, and the rotation speed of the electric motor becomes a value corresponding to the target rotation speed. A duty control procedure for controlling the duty ratio of the voltage applied to the electric motor,
A cooling fan control method comprising: The electric motor is a brushless motor,
The position detection procedure includes:
The method of controlling a cooling fan according to claim 4, wherein the position of the rotor of the brushless motor is detected based on an induced voltage of a stator winding of the brushless motor. The command duty ratio is input as a binary signal of a high signal (H signal) or a low signal (L signal),
The target rotational speed setting procedure is as follows:
Depending on whether the command duty ratio is a high signal or a low signal,
The first target speed,
The method for controlling a cooling fan according to claim 4 or 5, wherein one of the second target rotational speeds having a value larger than the first target rotational speed is selected and output.

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