JP2009019560A - Control system for turbocharger with electric motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the regenerative phenomenon of an electric motor of a turbocharger with an electric motor from occurring and to improve the efficiency and reduce the size of the electric motor. <P>SOLUTION: In this control system for the turbocharger with an electric motor, the assist electric motor to which a drive signal is supplied by an inverter is connected to a turbocharger installed on an engine. The turbocharger control system comprises: a rotating state detecting means for detecting a rotating state value indicating the rotating state of the electric motor; and a control means for generating an inverter control signal for performing a weak field control to weak the induced electromotive force of the electric motor and outputting it to the inverter when the rotating state value detected by the rotating state detecting means is equal to or higher than a preset rotating state setting value. The rotating state setting value is set to the rotating state value of the electric motor obtained when the induced electromotive force of the electric motor matches the DC voltage of the inverter. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a turbocharger control system with an electric motor.

In recent years, as an engine supercharger, an electric motor is connected to a rotating shaft of a turbocharger that recovers exhaust energy and increases the supercharging pressure to the engine, and an electric motor (for example, a permanent magnet synchronous motor) is used according to the operating state of the engine. Attention has been focused on a turbocharger with an electric motor that assists the rotation of the turbine by driving. For the technology relating to such a turbocharger with an electric motor, refer to the following Patent Documents 1 to 5.
JP-A-6-257450 JP-A-6-257451 Japanese Patent Application Laid-Open No. 6-257452 JP-A-6-280593 Japanese Patent Laid-Open No. 5-98987

  By the way, after the assist by the permanent magnet synchronous motor is stopped, the induced electromotive force (EMF) of the permanent magnet synchronous motor is supplied to the inverter in the motor free run state until the maximum rotation speed is reached by driving with only the turbine alone. Regenerative phenomenon in which the current flows backward from the permanent magnet synchronous motor to the inverter when the DC voltage is higher than the generated DC voltage (the permanent magnet synchronous motor acts as a generator, converts the rotational energy of the turbine into electric energy, and the inverter on the power source side Phenomenon), the turbine is braked. Such a regenerative phenomenon becomes more prominent as the difference between the motor-assisted rotation speed and the maximum rotation speed after stopping the assist is larger.

  In order to prevent such a regeneration phenomenon, it is necessary to design the permanent magnet synchronous motor so that the induced electromotive force of the permanent magnet synchronous motor does not exceed the DC voltage of the inverter at the maximum rotational speed. Specifically, since the induced electromotive force is approximately proportional to the iron loss of the motor, the iron loss is reduced so that the induced electromotive force at the maximum rotational speed is less than the DC voltage of the inverter, while the copper loss is increased. Therefore, the motor current is designed to be large. However, the permanent magnet synchronous motor designed with such a large current specification has a problem that the balance between the iron loss and the copper loss is lost and the motor loss is biased toward the copper loss side, and the motor efficiency is remarkably lowered. . Further, since it is necessary to increase the number of windings in order to increase the copper loss, the motor itself is increased in size, and the cost and weight are increased, and the installation space for the motor is a serious problem.

  The present invention has been made in view of such circumstances, and an object of the present invention is to prevent the regenerative phenomenon of the electric motor in the turbocharger with electric motor and to increase the efficiency and size of the electric motor.

In order to solve the above-described problems, in the present invention, as a first solving means related to a turbocharger control system with an electric motor, an assist electric motor to which a drive signal is supplied by an inverter is connected to a turbocharger attached to the engine. A control system for a turbocharger with an electric motor, wherein a rotational state grasping means for grasping a rotational state value indicating a rotational state of the electric motor, and the rotational state value grasped by the rotational state grasping means are preset. Control means for generating an inverter control signal for performing field-weakening control to weaken the induced electromotive force of the electric motor when the value is equal to or higher than a rotational state set value, and outputting the inverter control signal to the inverter;
The rotation state set value is set to a rotation state value of the motor when an induced electromotive force of the motor matches a DC voltage of the inverter.

 Further, as a second solving means related to the turbocharger control system with an electric motor, in the first solving means, the rotation state value of the electric motor reaches an assist rotation state value that regulates the stop of the assist by the electric motor. In addition, the motor is designed so that the induced electromotive force of the motor matches the DC voltage of the inverter, and the rotation state set value is set to the assist rotation state value.

 Further, as a third solving means relating to the turbocharger control system with an electric motor, in the first or second solving means, the electric motor is a sensorless permanent magnet synchronous motor driven by receiving a supply of a three-phase driving signal. The rotational state grasping means detects a rotational position of a rotor of the sensorless permanent magnet synchronous motor and outputs a rotational position detection signal indicating the rotational position, and differentiates the rotational position detection signal. Speed calculating means for calculating an angular speed as a rotation state value of the sensorless permanent magnet synchronous motor by processing, and the control means is configured to set the angular speed set in advance to the angular speed calculated by the speed calculating means. When the value exceeds the value, the q-axis current of the armature in the motor becomes zero, and the d-axis current weakens the induced electromotive force of the motor. That generates the inverter control signal so as to flow in a direction to output to the inverter, it is characterized.

Further, as a fourth solving means related to the turbocharger control system with electric motor,
The solution means includes a current detection means for detecting a current flowing in each of at least two-phase drive signal lines, and the control means is inputted from an angular velocity command value inputted from a host controller and the velocity calculation means. Speed control means for generating a q-axis current command value based on a difference value from the angular velocity calculation value, and reference q-axis current command value generation means for generating a reference q-axis current command value such that the q-axis current becomes zero A switch that selectively outputs one of a q-axis current command value generated by the speed control unit and a reference q-axis current command value generated by the reference q-axis current command value generation unit, and the current Based on the current detected by the detection means, the armature shaft current detection means for detecting the q-axis current and the d-axis current, and the angular velocity calculation value input from the speed calculation means is equal to or greater than the angular velocity setting value. If A d-axis current command for controlling the switch so that the reference q-axis current command value is output and generating a d-axis current command value such that the d-axis current flows in a direction that weakens the induced electromotive force of the motor. A d-axis of the armature based on a value generation means, a d-axis current command value generated by the d-axis current command value generation means, and a d-axis current detection value output from the armature shaft current detection means; A d-axis current control means for generating a voltage command value; a q-axis current command value output from the switch or a reference q-axis current command value; and a q-axis current detection value output from the armature shaft current detection means. Q-axis current control means for generating a q-axis voltage command value of the armature based on the voltage operation amount for generating a three-phase voltage operation amount of the motor based on the d-axis voltage command value and the q-axis voltage command value Based on the generating means and the three-phase voltage manipulated variable, And generates a PWM signal for controlling the switching of the inverter as a converter control signal, characterized in that it comprises a PWM signal generating means for outputting to said inverter.

Further, as a fifth solving means related to the turbocharger control system with electric motor,
Alternatively, in the second solution means, the electric motor is a sensorless permanent magnet synchronous motor driven by receiving a supply of a three-phase drive signal, and the rotation state grasping means detects a voltage of at least one phase of the drive signal line. Voltage detecting means for detecting, current detecting means for detecting a current flowing through each of the at least two-phase drive signal lines, and rotation of the sensorless permanent magnet synchronous motor when the assist is stopped based on the voltage detected by the voltage detecting means. Rotation state detection means for detecting a state value, rotation state estimation means for estimating a rotation state value during assist by the sensorless permanent magnet synchronous motor based on the current detected by the current detection means, and when the assist is stopped While the rotation state value detected by the rotation state detection means is selected, the rotation state estimation is performed during the assist. Output selection means for selecting and outputting the rotation state value estimated by the stage, and the control means is a value in which the rotation state value output from the output selection means is greater than or equal to a preset rotation state setting value. In this case, the inverter control signal is generated and output to the inverter so that the q-axis current of the armature in the motor becomes zero and the d-axis current flows in a direction that weakens the induced electromotive force of the motor. It is characterized by that.

Further, as a sixth solving means relating to the turbocharger control system with electric motor,
Alternatively, in the second solution means, the electric motor is a sensorless permanent magnet synchronous motor driven by receiving a supply of a three-phase drive signal, and the rotation state grasping means detects a voltage of at least one phase of the drive signal line. A voltage detection means for detecting power supply current detection means for detecting a power supply current supplied to the inverter, and a rotation state value when the assist of the sensorless permanent magnet synchronous motor is stopped based on the voltage detected by the voltage detection means. Rotation state detection means for detecting, rotation state estimation means for estimating a rotation state value during assist by the sensorless permanent magnet synchronous motor based on the power supply current detected by the power supply current detection means, and the rotation when the assist is stopped While the rotational state value detected by the state detection means is selected, the rotational state estimation is performed during the assist. Output selection means for selecting and outputting the rotation state value estimated by the means, and the control means is a value in which the rotation state value output from the output selection means is greater than or equal to a preset rotation state setting value. In this case, the inverter control signal is generated and output to the inverter so that the q-axis current of the armature in the motor becomes zero and the d-axis current flows in a direction that weakens the induced electromotive force of the motor. It is characterized by that.

Further, as a seventh solving means relating to the turbocharger control system with electric motor,
Alternatively, in the second solution means, the electric motor is a sensorless permanent magnet synchronous motor driven by receiving a supply of a three-phase drive signal, and the rotation state grasping means detects a voltage of at least one phase of the drive signal line. A voltage detection means for detecting, an arm current detection means for detecting an arm current flowing in the switch arm of the inverter, and a rotation state value when the assist of the sensorless permanent magnet synchronous motor is stopped based on the voltage detected by the voltage detection means Rotation state detection means for detecting the rotation state estimation means for estimating a rotation state value at the time of assist by the sensorless permanent magnet synchronous motor based on the arm current detected by the arm current detection means, and when the assist is stopped While selecting the rotation state value detected by the rotation state detection means, the assist Output selection means for selecting and outputting the rotation state value estimated by the rotation state estimation means, and the control means rotates the rotation state value output from the output selection means in advance. The inverter control signal is generated so that the q-axis current of the armature in the motor becomes zero and the d-axis current flows in a direction that weakens the induced electromotive force of the motor when the value is equal to or greater than the state set value. Output to the inverter.

Further, as the eighth solution means for the turbocharger control system with electric motor,
In the solving means, the rotation state estimating means includes an armature shaft current detecting means for detecting the q-axis current and the d-axis current based on the current detected by the current detecting means, and the armature shaft current detecting means. Estimating means for estimating the rotational state value based on a q-axis current detection value and a d-axis current detection value output from the control unit, the control means comprising: a rotational state command value input from a host controller; Speed control means for generating a q-axis current command value based on a difference value from the rotation state value output from the estimation means, and a reference q for generating a reference q-axis current command value such that the q-axis current becomes zero Any one of the shaft current command value generating means, the q axis current command value generated by the speed control means, and the reference q axis current command value generated by the reference q axis current command value generating means is selectively output. And the output The switch is controlled so that the reference q-axis current command value is output when the rotation state value output from the selection means is equal to or greater than the rotation state set value, and the d-axis current is D-axis current command value generating means for generating a d-axis current command value that flows in a direction to weaken the induced electromotive force, and d generated by the d-axis current command value generating means.
A d-axis current control means for generating a d-axis voltage command value for the armature based on a shaft current command value and a d-axis current detection value output from the armature shaft current detection means; q-axis current control means for generating a q-axis voltage command value of the armature based on a q-axis current command value or a reference q-axis current command value and a q-axis current detection value output from the armature axis current detection means A voltage manipulated variable generating means for generating a three-phase voltage manipulated variable of the electric motor based on the d-axis voltage command value and a q-axis voltage command value, and an inverter control signal based on the three-phase voltage manipulated variable PWM that generates a PWM signal for controlling switching of the inverter and outputs the PWM signal to the inverter
And a signal generation means.

Further, as a ninth solving means relating to the turbocharger control system with electric motor,
In the solving means, the rotation state estimating means converts a power supply current detected by the power supply current detecting means into a current flowing in each of at least two-phase drive signal lines, and
Armature shaft current detection means for detecting the q-axis current and d-axis current based on the current converted by the current conversion means; q-axis current detection value and d-axis output from the armature shaft current detection means Estimation means for estimating the rotational state value based on a current detection value, and the control means is a difference between the rotational state command value input from the host controller and the rotational state value output from the estimation means. Speed control means for generating a q-axis current command value based on the value, reference q-axis current command value generation means for generating a reference q-axis current command value such that the q-axis current becomes zero, and the speed control means A switch that selectively outputs either the q-axis current command value generated by the reference q-axis current command value generated by the reference q-axis current command value generation unit, and the output selection unit. The rotation state value is The d-axis current is such that when the value exceeds the value, the switch is controlled so that the reference q-axis current command value is output, and the d-axis current flows in a direction that weakens the induced electromotive force of the motor. D-axis current command value generation means for generating a command value, d-axis current command value generated by the d-axis current command value generation means, and d-axis current detection value output from the armature shaft current detection means, D-axis current control means for generating a d-axis voltage command value for the armature based on the q-axis current command value or reference q-axis current command value output from the switch and the armature shaft current detection means for output. Q-axis current control means for generating a q-axis voltage command value for the armature based on the detected q-axis current value, and three phases of the motor based on the d-axis voltage command value and the q-axis voltage command value A voltage operation amount generating means for generating a voltage operation amount; Based on the voltage manipulated variable, characterized in that it comprises a PWM signal generating means for outputting to the inverter to generate a PWM signal for controlling the switching of the inverter as the inverter control signal.

Further, as a tenth solving means according to the turbocharger control system with electric motor, in the seventh solving means, the rotational state estimating means uses the arm current detected by the arm current detecting means as an at least two-phase drive signal. Current converting means for converting the current flowing in each of the wires, armature shaft current detecting means for detecting the q-axis current and the d-axis current based on the current converted by the current converting means, and the armature shaft current Estimation means for estimating the rotational state value based on a q-axis current detection value and a d-axis current detection value output from the detection means, and the control means is a rotational state command value input from a host controller. Speed control means for generating a q-axis current command value based on a difference value between the rotation state value output from the estimation means and a reference q-axis current such that the q-axis current becomes zero Any of a reference q-axis current command value generating means for generating a command value, a q-axis current command value generated by the speed control means, and a reference q-axis current command value generated by the reference q-axis current command value generating means A switch that selectively outputs one of the above, and the reference q-axis current command value is output when the rotation state value output from the output selection means is greater than or equal to a rotation state set value. A d-axis current command value generating means for controlling the switch and generating a d-axis current command value so that the d-axis current flows in a direction to weaken the induced electromotive force of the motor; and the d-axis current command value generating means D-axis current control means for generating a d-axis voltage command value for the armature based on the generated d-axis current command value and the d-axis current detection value output from the armature axis current detection means; and the switch Q-axis current command value output from Q-axis current control means for generating a q-axis voltage command value of the armature based on a reference q-axis current command value and a q-axis current detection value output from the armature axis current detection means; and the d-axis Based on the voltage command value and the q-axis voltage command value, a voltage operation amount generating means for generating a three-phase voltage operation amount of the electric motor, and switching the inverter as the inverter control signal based on the three-phase voltage operation amount. PWM signal generating means for generating a PWM signal for control and outputting the PWM signal to the inverter.

Further, as eleventh solving means relating to the turbocharger control system with electric motor, in the fifth to tenth solving means, the voltage detecting means detects a voltage of a one-phase drive signal line, and detects the rotational state. The means detects a rotational state value of the sensorless permanent magnet synchronous motor based on a zero cross point of the voltage of the one-phase drive signal line.

Further, as a twelfth solving means relating to the turbocharger control system with an electric motor, in the fifth to tenth solving means, the voltage detecting means detects a voltage of each of two-phase drive signal lines, and the rotation The state detection means detects a rotation state value of the sensorless permanent magnet synchronous motor based on a difference between voltages of the two-phase drive signal lines.

  In the present invention, when the rotational state value of the electric motor is equal to or greater than a preset rotational state setting value, an inverter control signal for performing field-weakening control that weakens the induced electromotive force of the electric motor is generated to generate the inverter Output to. Thereby, the backflow of the electric current from an electric motor to an inverter does not generate | occur | produce, a regeneration phenomenon can be prevented, and the freedom degree of design of an electric motor increases. That is, it is possible to design an electric motor with a small current specification with high motor efficiency by increasing the iron loss while reducing the copper loss. Therefore, according to the present invention, it is possible to prevent the regenerative phenomenon of the motor in the turbocharger with the motor and to increase the efficiency and size of the motor.

  Furthermore, when the rotation state value of the motor reaches the assist rotation state value that stipulates that the motor stops assisting, the motor is designed so that the induced electromotive force of the motor matches the DC voltage of the inverter, and the rotation state setting The value is preferably set to the assist rotation state value. By designing the electric motor in this way and setting the rotational state set value to the assist rotational state value, it is possible to obtain the maximum efficiency and miniaturization effect of the electric motor.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is a block diagram showing the configuration of the turbocharger control system with an electric motor according to the first embodiment. As shown in FIG. 1, a turbocharger control system with an electric motor according to the first embodiment includes an electric turbocharger 1, a motor drive unit 2, a U-phase current sensor 3, a V-phase current sensor 4, and a W-phase current sensor 5. And an inverter control unit 6 and a speed calculator 7.

    The turbocharger 1 with an electric motor is composed of a permanent magnet synchronous motor 1a, a rotational position sensor 1b, a turbine 1c, and a compressor 1d, and the motor drive unit 2 includes a DC power source 2a, a booster circuit 2b, a smoothing capacitor 2c, and an inverter 2d. It is configured. The permanent magnet synchronous motor (electric motor) 1a is a sensorless type permanent magnet synchronous motor that does not include a sensor that detects the rotation state (rotation position, rotation speed, rotation speed, etc.) of the armature, and is coaxial with the rotation shaft of the turbine 1c. The three-phase (U-phase, V-phase, and W-phase) motor drive signals connected to the inverter 2d are rotationally driven to assist (assist) the rotation of the turbine 1c.

  The rotational position sensor (rotational position detecting means) 1b detects the rotational position of the armature of the permanent magnet synchronous motor 1a, and outputs a rotational position detection signal θ indicating the rotational position to the speed calculator 7. More specifically, the rotational position sensor 1b detects the magnetic force of the armature with a Hall element, and outputs a pulse signal that becomes one pulse (pulse indicating the position of the N pole) for each rotation of the armature. The turbine 1c and the compressor 1d are coaxially connected to constitute a turbocharger. By rotating the turbine 1c using exhaust energy of an engine (not shown), the compressor 1d is rotated and the intake air is passed to the engine. To pay.

 The DC power supply 2a is one in which one or a plurality of batteries are connected in series, and outputs a predetermined DC power supply voltage to the booster circuit 2b. The booster circuit 2b is, for example, a DC / DC converter, boosts the DC power supply voltage supplied from the DC power supply 2a, and supplies it to the inverter 2d. The smoothing capacitor 2c is provided to smooth the DC voltage supplied to the inverter 2d. The inverter 2d generates a three-phase motor drive signal composed of a U phase, a V phase, and a W phase by switching the DC voltage supplied from the booster circuit 2b based on the PWM signal supplied from the inverter control unit 6. And supplied to the permanent magnet synchronous motor 1a.

 The U-phase current sensor (current detection means) 3 detects the motor drive current Iu flowing through the U-phase drive signal line and outputs it to the inverter control unit 6. The V-phase current sensor (current detection means) 4 detects the motor drive current Iv flowing through the V-phase drive signal line and outputs it to the inverter control unit 6. The W-phase current sensor (current detection means) 5 detects the motor drive current Iw flowing through the W-phase drive signal line and outputs it to the inverter control unit 6.

 As shown, the inverter control unit 6 includes a subtractor 6a, a speed controller 6b, a reference q-axis current command value generation unit 6c, a switch 6d, a d-axis current command value generation unit 6e, a d-axis current controller 6f, q It comprises a shaft current controller 6g, a 3-phase / 2-phase converter 6h, a 2-phase / 3-phase converter 6i, and a PWM (Pulse Width Modulation) signal generator 6j.

Subtracter 6a is calculated speed control the difference between the angular velocity calculation value ωk outputted from the angular velocity command value omega ₀ and the speed calculator 7 is supplied from the engine control unit (ECU) is a higher-level controller as a speed error Δω To the device 6b. The speed controller (speed control means) 6b is a kind of PID.
A controller, which calculates a q-axis current command value Iqs corresponding to the speed error Δω by performing a predetermined proportional integral / differential operation on the speed error Δω, and outputs it to the switch 6d.

The reference q-axis current command value generation unit (reference q-axis current command value generation means) 6c generates a reference q-axis current command value Iqo such that the q-axis current of the armature in the permanent magnet synchronous motor 1a becomes zero. Output to the switch 6d. The switch 6d selectively outputs one of the q-axis current command value Iqs and the reference q-axis current command value Iqo to the q-axis current controller 6g under the control of the d-axis current command value generation unit 6e. .

The d-axis current command value generation unit (d-axis current command value generation means) 6e receives the angular velocity calculation value ωk output from the velocity calculator 7, and the angular velocity calculation value ωk is equal to or higher than a preset angular velocity setting value ωs. In order to perform field weakening control of the permanent magnet synchronous motor 1a, the switch 6d is controlled so that the reference q-axis current command value Iqo is output, and permanent magnet synchronization is performed based on a predetermined arithmetic expression. The d-axis current command value Ids is calculated such that the d-axis current of the armature in the motor 1a flows in a direction that weakens the induced electromotive force (EMF) of the permanent magnet synchronous motor 1a, and is output to the d-axis current controller 6f. The d-axis current command value generation unit 6e outputs the q-axis current command value Iqs without performing field-weakening control when the calculated angular velocity value ωk is less than the preset angular velocity setting value. In addition to controlling the switch 6d, the angular velocity calculation value ωk, that is, the d-axis current command value Ids corresponding to the rotation state of the permanent magnet synchronous motor 1a is output to the d-axis current controller 6f.

  The d-axis current controller (d-axis current control means) 6f includes a d-axis current command value Ids input from the d-axis current command value generation unit 6e and a d-axis current input from the three-phase / two-phase converter 6h. Based on the detected value Id, the d-axis voltage command value Vd corresponding to the d-axis current command value Ids is calculated and output to the two-phase / three-phase converter 6i. The q-axis current controller (q-axis current control means) 6g receives the q-axis current command value Iqs or the reference q-axis current command value Iqo input from the switch 6d and the q input from the three-phase / two-phase converter 6h. Based on the detected shaft current value Iq, a q-axis voltage command value Vq corresponding to the q-axis current command value Iqs or the reference q-axis current command value Iqo is calculated and output to the 2-phase / 3-phase converter 6i. The d-axis current controller 6f and the q-axis current controller 6g are a kind of PID controller, and each of the voltage command values Vq, Vd is generated.

A 3-phase / 2-phase converter (armature shaft current detection means) 6h is a U-phase, V-phase, and W-phase motor detected by the U-phase current sensor 3, the V-phase current sensor 4, and the W-phase current sensor 5, respectively. Q-axis current detection value Iq and d-axis current in a two-dimensional coordinate system (coordinate system consisting of q-axis and d-axis) set on the armature of the permanent magnet synchronous motor 1a based on the drive currents Iu, Iv, Iw A detection value Id is generated,
The q-axis current detection value Iq is output to the q-axis current controller 6g, and the d-axis current detection value Id is output to the d-axis current controller 6f. More specifically, the three-phase / two-phase converter 6h performs a predetermined coordinate transformation on the motor driving currents Iu, Iv, Iw on the three-dimensional coordinate system composed of the U phase, the V phase, and the W phase, thereby performing the above described 2 A q-axis current detection value Iq and a d-axis current detection value Id on the dimensional coordinate system are obtained. The q axis is a coordinate axis set in the opposing direction of the S pole and the N pole of the permanent magnet on the rotating surface of the armature, and the d axis is a coordinate axis orthogonal to the q axis described above.

  The 2-phase / 3-phase converter (voltage manipulated variable generating means) 6i is inputted from the d-axis voltage command value Vd corresponding to the d-axis inputted from the d-axis current controller 6f and the q-axis current controller 6g. The q-axis voltage command value Vq corresponding to the q-axis is converted into a three-phase voltage manipulated variable Vu, Vv, Vw on a three-dimensional coordinate system composed of the U-phase, V-phase, and W-phase, and the three-phase voltage manipulated variable Vu, Vv, and Vw are output to the PWM signal generator 6j.

  The PWM signal generator (PWM signal generating means) 6j generates a PWM signal (inverter control signal) for switching the inverter 2d based on the three-phase voltage manipulated variables Vu, Vv, Vw and outputs the PWM signal to the inverter 2d. To do. The inverter control unit 6 operates based on a sine wave energization method. Therefore, the PWM signal generator 6j outputs a motor drive signal over the entire rotation angle (360 °) of the permanent magnet synchronous motor 1a by the inverter 2d. The PWM signal is output as follows.

  The speed calculator (speed calculation means) 7 differentiates the rotational position detection signal θ input from the rotational position sensor 1b, thereby calculating the angular speed as the rotational state value of the permanent magnet synchronous motor 1a, and the angular speed calculated value ωk. (DC voltage) is output to the subtractor 6a, the d-axis current command value generation unit 6e, and the ECU. The speed calculator 7 and the rotational position sensor 1b constitute rotational state grasping means in the present invention.

Here, the angular velocity set value ωs is set to an angular velocity (assist angular velocity) corresponding to the assist rotational speed that regulates the stop of assist by the permanent magnet synchronous motor 1a. Then, when the angular velocity of the permanent magnet synchronous motor 1a reaches the assist angular velocity, the permanent magnet synchronous motor 1a is set so that the induced electromotive force (EMF) of the permanent magnet synchronous motor 1a matches the DC voltage of the inverter 2d. Designed. The permanent magnet synchronous motor 1a can be designed in this way because it weakens the induced electromotive force of the permanent magnet synchronous motor 1a according to the rotational state of the permanent magnet synchronous motor 1a (angular velocity in this embodiment). This is because the inverter control unit 6 that generates a PWM signal for performing field control and outputs the PWM signal to the inverter 2d is provided. By designing in this way, the regeneration phenomenon of the permanent magnet synchronous motor 1a in the turbocharger 1 with an electric motor is prevented. In addition, the permanent magnet synchronous motor 1a can be made highly efficient and downsized. Hereinafter, the reason why such an effect is obtained will be described with reference to FIGS.

  In FIG. 2, the horizontal axis represents the motor rotation speed of the permanent magnet synchronous motor 1a, the vertical axis represents the induced electromotive force (EMF) of the permanent magnet synchronous motor 1a, and reference numeral 100 represents the motor rotation speed in the prior art. -EMF characteristics are shown, and reference numeral 200 indicates the motor rotation speed-EMF characteristics in the present embodiment. In FIG. 3, the horizontal axis indicates the motor drive current, the vertical axis indicates the motor loss (iron loss and copper loss) and the motor efficiency, the reference numeral 300 indicates the iron loss-motor drive current characteristic, and the reference numeral 400. Indicates a copper loss-motor driving current characteristic, and reference numeral 500 indicates a motor efficiency-motor driving current characteristic.

  As indicated by reference numeral 100 in FIG. 2, in the prior art, in the motor free run state during the period from the stop of assist by the permanent magnet synchronous motor until the maximum rotational speed is reached by driving only with the turbine alone, When the induced electromotive force (EMF) of the motor becomes higher than the DC voltage of the inverter, a regenerative phenomenon occurs in which current flows backward from the permanent magnet synchronous motor to the inverter. Therefore, the induced electromotive force of the permanent magnet synchronous motor is Therefore, it is necessary to design a permanent magnet synchronous motor so as not to exceed the direct current voltage. In this case, since the induced electromotive force is substantially proportional to the iron loss of the motor, as shown in FIG. 3, the iron loss (inductive electromotive force) is set so that the induced electromotive force at the maximum rotational speed is equal to or less than the DC voltage of the inverter. Is designed to increase the copper loss and increase the motor drive current. However, the permanent magnet synchronous motor designed with such a large current specification loses the balance between the iron loss and the copper loss, and the motor loss is biased toward the copper loss side, resulting in a significant reduction in motor efficiency. Since it is necessary to increase the number of windings in order to increase the size of the motor, there has been a problem that the motor itself is increased in size.

  On the other hand, in this embodiment, by providing the inverter control unit 6 that can perform field-weakening control according to the rotation speed (angular speed) of the permanent magnet synchronous motor 1a, the angular speed of the permanent magnet synchronous motor 1a is regenerated. When the angular velocity at which the phenomenon occurs, that is, the induced electromotive force of the permanent magnet synchronous motor 1a becomes equal to or higher than the angular velocity (angular velocity set value ωs) that matches the DC voltage of the inverter 2d, the induced electromotive force of the permanent magnet synchronous motor 1a. It is possible to generate a PWM signal for performing field-weakening control to weaken and to output to the inverter 2d. Thereby, since the motor drive signal which weakens the induced electromotive force of the permanent magnet synchronous motor 1a is supplied from the inverter 2d, the regeneration phenomenon of the permanent magnet synchronous motor 1a does not occur, and the design flexibility of the permanent magnet synchronous motor 1a increases. It will be.

  Therefore, in the present embodiment, as indicated by reference numeral 200 in FIG. 2, the rotational speed (angular speed) of the permanent magnet synchronous motor 1a is set to the assist rotational speed (assist angular speed) that regulates the stop of the assist by the permanent magnet synchronous motor 1a. When reached, the permanent magnet synchronous motor 1a is designed so that the induced electromotive force of the permanent magnet synchronous motor 1a matches the DC voltage of the inverter 2d, and the angular velocity set value ωs is set to the assist angular velocity. That is, compared with the prior art (reference numeral 100), the present embodiment is designed to increase the induced electromotive force at the same rotational speed. Therefore, as shown in FIG. 3, in this embodiment, the permanent magnet synchronous motor 1a can be designed with a small current specification while increasing the iron loss while reducing the copper loss. Efficiency and miniaturization can be achieved.

Next, the operation of the turbocharger control system with an electric motor according to the first embodiment configured as described above will be described with reference to FIG.
<When assisting>
First, at the time of assist shown in FIG. 2, when the inverter control unit 6 receives an assist instruction from an operation instruction signal J input from an engine control unit (ECU), the inverter driving unit 6 operates the motor driving unit 2 to operate a permanent magnet synchronous motor. Drive 1a.

  Specifically, a motor drive signal is supplied from the inverter 2d to the permanent magnet synchronous motor 1a via the drive signal lines for each phase, and the permanent magnet synchronous motor 1a is rotationally driven. When the permanent magnet synchronous motor 1a rotates, the rotational position detection signal θ is output from the rotational position sensor 1b to the speed calculator 7, and the angular speed calculated value ωk is continuously subtracted from the speed calculator 7 by the subtractor 6a and the d-axis current command value. The data is output to the generation unit 6e and the ECU.

  The 3-phase / 2-phase converter 6h includes U-phase, V-phase, and W-phase motor drive currents Iu, Iv, detected by the U-phase current sensor 3, the V-phase current sensor 4, and the W-phase current sensor 5, respectively. A q-axis current detection value Iq and a d-axis current detection value Id are generated based on Iw, the d-axis current detection value Id is output to the d-axis current controller 6f, and the q-axis current detection value Iq is output to the q-axis current controller. Output to 6g.

  At this time, the d-axis current command value generation unit 6e outputs the q-axis current command value Iqs without performing field-weakening control because the calculated angular velocity value ωk is less than the preset angular velocity setting value. In addition, the switch 6d is controlled and a d-axis current command value Ids corresponding to the calculated angular velocity value ωk is output to the d-axis current controller 6f. Here, the d-axis current command value Ids is set to “0”.

Subtracter 6a outputs the calculated speed controller 6b the difference between the angular velocity calculation value ωk inputted from the angular velocity command value omega ₀ and the speed calculator 7 which is input from the ECU as a speed error [Delta] [omega. The speed controller 6b calculates a q-axis current command value Iqs corresponding to the speed error Δω by performing a predetermined proportional integral / differential calculation on the speed error Δω, and outputs the q-axis current command value Iqs to the switch 6d. The switch 6d outputs the q-axis current command value Iqs to the q-axis current controller 6g. Then, the d-axis current controller 6f calculates a d-axis voltage command value Vd corresponding to the d-axis current command value Ids based on the d-axis current command value Ids and the d-axis current detection value Id to obtain a two-phase / 3 It outputs to the phase converter 6i. On the other hand, the q-axis current controller 6g calculates a q-axis voltage command value Vq corresponding to the q-axis current command value Iqs based on the q-axis current command value Iqs and the q-axis current detection value Iq to obtain a two-phase / 3 It outputs to the phase converter 6i.

  The two-phase / three-phase converter 6i includes a d-axis voltage command value Vd corresponding to the d-axis input from the d-axis current controller 6f and a q corresponding to the q-axis input from the q-axis current controller 6g. The shaft voltage command value Vq is converted into a three-phase voltage manipulated variable Vu, Vv, Vw on a three-dimensional coordinate system composed of U phase, V phase, and W phase, and the three-phase voltage manipulated variable Vu, Vv, Vw is PWMed. The signal is output to the signal generator 6j. The PWM signal generator 6j generates a PWM signal for switching the inverter 2d based on the three-phase voltage manipulated variables Vu, Vv, Vw and outputs the PWM signal to the inverter 2d. As a result, the inverter 2d generates a motor drive signal and supplies it to the permanent magnet synchronous motor 1a, and the motor rotation speed of the permanent magnet synchronous motor 1a increases with time.

<When assist is stopped>
Then, as shown in FIG. 2, when the angular velocity calculation value ωk becomes equal to or larger than the angular velocity setting value ωs set as the assist angular velocity, the d-axis current command value generation unit 6e performs reference field control in order to perform field weakening control. The switch 6d is controlled so that the q-axis current command value Iqo is output, and the d-axis current of the armature in the permanent magnet synchronous motor 1a is induced by the induced electromotive force of the permanent magnet synchronous motor 1a using the following equation (1). A d-axis current command value Ids that flows in the direction of weakening (EMF) is calculated and output to the d-axis current controller 6f. In the following equation (1), φm is the number of armature flux linkages by permanent magnets, Ld is the d-axis inductance, Vom is the maximum induced electromotive force, and these are constants.
Ids = (− φm + Vom / ωk) / Ld (1)

  The d-axis current controller 6f is a d-axis voltage command corresponding to the d-axis current command value Ids based on the d-axis current command value Ids and the d-axis current detection value Id calculated using the calculation formula (1). The value Vd is calculated and output to the 2-phase / 3-phase converter 6i. On the other hand, the q-axis current controller 6g calculates the q-axis voltage command value Vq corresponding to the reference q-axis current command value Iqo (that is, zero) based on the reference q-axis current command value Iqo and the q-axis current detection value Iq. And output to the 2-phase / 3-phase converter 6i.

  The two-phase / three-phase converter 6i includes a d-axis voltage command value Vd corresponding to the d-axis input from the d-axis current controller 6f and a q corresponding to the q-axis input from the q-axis current controller 6g. The shaft voltage command value Vq is converted into a three-phase voltage manipulated variable Vu, Vv, Vw on a three-dimensional coordinate system composed of U phase, V phase, and W phase, and the three-phase voltage manipulated variable Vu, Vv, Vw is PWMed. The signal is output to the signal generator 6j. The PWM signal generator 6j generates a PWM signal for switching the inverter 2d based on the three-phase voltage manipulated variables Vu, Vv, Vw and outputs the PWM signal to the inverter 2d.

  Based on the PWM signal, the inverter 2d generates a motor drive signal such that no q-axis current flows in the armature of the permanent magnet synchronous motor 1a, and only the d-axis current flows in a direction that weakens the induced electromotive force (EMF). To the permanent magnet synchronous motor 1a. Here, since the inverter 2d supplies only reactive power to the permanent magnet synchronous motor 1a, the permanent magnet synchronous motor 1a stops rotating (assist stop). As a result, when the assist is stopped, the permanent magnet synchronous motor 1a is subjected to field weakening control, and the induced electromotive force of the permanent magnet synchronous motor 1a does not become a value equal to or higher than the DC voltage of the inverter 2d. Does not occur.

 As described above, according to the turbocharger control system with an electric motor according to the first embodiment, the regeneration phenomenon of the permanent magnet synchronous motor 1a in the turbocharger with an electric motor is prevented, and the high efficiency and small size of the permanent magnet synchronous motor 1a are prevented. Can be achieved.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. FIG. 4 is a block diagram showing the configuration of the turbocharger control system with an electric motor according to the second embodiment. In FIG. 4, the same components as those in FIG.

  As shown in FIG. 4, the turbocharger control system with an electric motor according to the second embodiment is different from the first embodiment in that the rotational position sensor 1b, the W-phase current sensor 5 and the speed calculator 7 are deleted, and the inverter The control unit 6 is replaced with an inverter control unit 8 having a different configuration, and a rotation state estimation unit 9, a voltage sensor 10, a speed detection unit 11, and an output switch 12 are newly provided.

 The inverter controller 8 includes a subtracter 8a, a speed controller 8b, a reference q-axis current command value generator 8c, a switch 8d, a d-axis current command value generator 8e, a d-axis current controller 8f, and a q-axis current controller 8g. It comprises a 2-phase / 3-phase converter 8h and a PWM signal generator 8i.

The subtractor 8a is an angular velocity command value ω ₀ supplied from an engine control unit (ECU) that is a host controller, and an estimated angular velocity value ωe output from the rotor position / speed estimator 9b of the rotation state estimation unit 9. The difference is calculated as a speed error Δω and output to the speed controller 8b. Speed controller 8
b is a kind of PID controller, which calculates a q-axis current command value Iqs corresponding to the speed error Δω by performing a predetermined proportional integral / differential operation on the speed error Δω and outputs it to the switch 8d.

The reference q-axis current command value generation unit 8c generates a reference q-axis current command value Iqo such that the q-axis current of the armature in the permanent magnet synchronous motor 1a becomes zero and outputs it to the switch 8d. The switch 8d selectively outputs either the q-axis current command value Iqs or the reference q-axis current command value Iqo to the q-axis current controller 8g under the control of the d-axis current command value generation unit 8e. .

The d-axis current command value generation unit 8e receives the angular velocity signal ω output from the output switch 12, and performs field-weakening control when the angular velocity signal ω becomes equal to or greater than a preset angular velocity setting value ωs. In addition, the switch 8d is controlled so that the reference q-axis current command value Iqo is output, and the d-axis current of the armature in the permanent magnet synchronous motor 1a is determined by the permanent magnet synchronous motor 1a based on the above equation (1). A d-axis current command value Ids that flows in a direction that weakens the induced electromotive force (EMF) is calculated and output to the d-axis current controller 8f. Further, the d-axis current command value generation unit 8e does not perform field-weakening control and outputs the q-axis current command value Iqs when the angular velocity signal ω is less than a preset angular velocity setting value. The switch 8d is controlled, and the angular velocity signal ω, that is, the d-axis current command value Ids corresponding to the rotation state of the permanent magnet synchronous motor 1a is output to the d-axis current controller 8f.

  The d-axis current controller 8 f converts the d-axis current command value Ids input from the d-axis current command value generation unit 8 e and the d-axis current detection value Id input from the coordinate converter 9 a of the rotation state estimation unit 9. Based on this, a d-axis voltage command value Vd corresponding to the d-axis current command value Ids is calculated and output to the 2-phase / 3-phase converter 8h and the rotor position / speed estimator 9b of the rotation state estimation unit 9. Based on the q-axis current command value Iqs or the reference q-axis current command value Iqo input from the switch 8d and the q-axis current detection value Iq input from the coordinate converter 9a, the q-axis current controller 8g The q-axis voltage command value Vq corresponding to the shaft current command value Iqs or the reference q-axis current command value Iqo is calculated and output to the 2-phase / 3-phase converter 8h and the rotor position / speed estimator 9b. The d-axis current controller 8f and the q-axis current controller 8g are a kind of PID controller, and each voltage command value Vq, is obtained by subjecting each current command value Iqs, Ids to predetermined proportional integration / differentiation operations. Vd is generated.

  The two-phase / three-phase converter 8h includes an estimated rotation angle value θe output from the rotor position / speed estimator 9b, a d-axis voltage command value Vd output from the d-axis current controller 8f, and a q-axis current control. The q-axis voltage command value Vq output from the device 8g is input, and the d-axis voltage command value Vd and the q-axis voltage command value Vq are composed of the U phase, V phase, and W phase based on the estimated rotation angle θe. The three-phase voltage manipulated variables Vu, Vv, Vw on the three-dimensional coordinate system are converted, and the three-phase voltage manipulated variables Vu, Vv, Vw are output to the PWM signal generator 8i. The PWM signal generator 8i generates a PWM signal for switching the inverter 2d based on the three-phase voltage manipulated variables Vu, Vv, Vw and outputs the PWM signal to the inverter 2d.

  The rotation state estimation unit (rotation state estimation means) 9 includes a coordinate converter (armature shaft current detection means) 9a and a rotor position / speed estimator (estimation means) 9b. The coordinate converter 9a is configured to estimate the U-phase and V-phase motor drive currents Iu and Iv detected by the U-phase current sensor 3 and the V-phase current sensor 4, respectively, and the rotation angle estimation input from the rotor position / speed estimator 9b. Q-axis current detection value Iq and d-axis current detection value Id on a two-dimensional coordinate system (coordinate system consisting of q-axis and d-axis) set on the armature of permanent magnet synchronous motor 1a based on value θe The d-axis current detection value Id is output to the d-axis current controller 8f, the q-axis current detection value Iq is output to the q-axis current controller 8g, and the d-axis current detection value Id and the q-axis current detection are detected. The value Iq is output to the rotor position / speed estimator 9b. More specifically, the coordinate converter 9a obtains a W-phase motor drive current Iw by an internal calculation based on the motor drive currents Iu and Iv, on a three-dimensional coordinate system composed of a U-phase, a V-phase, and a W-phase. The current detection values Iq and Id are obtained by subjecting the motor drive currents Iu, Iv and Iw to predetermined coordinate transformation.

  The rotor position / speed estimator 9b includes a d-axis current detection value Id and a q-axis current detection value Iq input from the coordinate converter 9a, a d-axis voltage command value Vd input from the d-axis current controller 8f, The rotational state of the permanent magnet synchronous motor 1a is estimated based on the q-axis voltage command value Vq input from the q-axis current controller 8g. The rotor position / speed estimator 9b includes, for example, a motor model simulating a permanent magnet synchronous motor 1a inside, and the voltage command values Vq and Vd and current detection values Iq and Id are input to the motor model. The angular velocity estimated value ωe and the rotation angle estimated value θe are calculated. The rotor position / speed estimator 9b outputs the rotational angle estimated value θe estimated by such a method to the coordinate converter 9a and the 2-phase / 3-phase converter 8h, and the angular speed estimated value ωe to the subtractor 8a and Output to the output switch 12.

  In rotation control of a sensorless type permanent magnet synchronous motor, generally, the angular velocity and rotation angle of the motor are estimated by some method, and vector control or V / f control of the permanent magnet synchronous motor is performed based on the estimated values. . The estimation method of the angular velocity estimation value ωe and the rotation angle estimation value θe in the rotor position / speed estimator 9b is described in non-patent literature (Takaharu Takeshita et al .: “Sensorless brushless DC motor control based on current estimation error”, National Institute of Electrical Engineers of Japan, 1995 Although it is equivalent to the method described in the Conference Proceedings), other non-patent literature (Masashi Ichikawa: “IPMSM sensorless control by estimation of extended induced voltage in rotating coordinate system”, 2001 IEEJ National Conference Proceedings) (Hiroshi Osawa: “High Performance V / f Control of Embedded Magnet Type PM Motor”, Techno Frontier Symposium 2004 Motor Technology Symposium, Japan Management Association) and patent literature (Japanese Patent Laid-Open No. 2005) -137106 gazette) may be used.

  The voltage sensor (voltage detection means) 10 detects the voltage of the U-phase drive signal line and outputs it as a voltage detection value to the speed detection unit 11. When the inverter 2d does not supply the motor drive signal to the permanent magnet synchronous motor 1a when the assist is stopped, the U-phase drive signal line is subjected to electromagnetic induction between the U-phase stator winding and the rotor made of the permanent magnet. A sinusoidal induced voltage is generated. The voltage sensor 10 outputs such an induced voltage to the speed detection unit 11 as a voltage detection value.

  The speed detection unit (rotation state detection means) 11 includes a comparator 11a and an F / V converter 11b as shown in the figure. The comparator 11a compares the voltage detection value input from the voltage sensor 10 with the ground voltage to generate a pulse signal that makes a state transition at the zero cross point of the induced voltage, and outputs the pulse signal to the F / V converter 11b. The F / V converter 11b converts the pulse signal into a DC voltage corresponding to the frequency, and outputs it to the output switch 12 as an angular velocity detection value ωk.

    The output switch (output selection means) 12 is based on the operation instruction signal J supplied from the ECU, and the angular velocity estimation value ωe input from the rotor position / speed estimator 9b and the angular velocity detection value ωk input from the speed detector 11. Are output to the d-axis current command value generation unit 8e and the ECU as the angular velocity signal ω. The operation instruction signal J is used to instruct the inverter control unit 8 to assist with the permanent magnet synchronous motor 1a and to instruct the output switch 12 to switch the output between the angular velocity estimated value ωe and the detected angular velocity value ωk.

  The U-phase current sensor 3, the V-phase current sensor 4, the rotation state estimation unit 9, the voltage sensor 10, the speed detection unit 11, and the output switch 12 constitute rotation state grasping means in the present invention.

Next, the operation of the turbocharger control system with an electric motor according to the second embodiment configured as described above will be described.
<When assisting>
First, at the time of assist shown in FIG. 2, when the inverter control unit 8 receives an assist instruction from an operation instruction signal J input from an engine control unit (ECU), the inverter driving unit 8 operates the motor driving unit 2 to operate a permanent magnet synchronous motor. Drive 1a.

  Specifically, a motor drive signal is supplied from the inverter 2d to the permanent magnet synchronous motor 1a via the drive signal lines for each phase, and the permanent magnet synchronous motor 1a is rotationally driven. Here, since the inverter control unit 8 employs a sine wave energization method, a motor drive signal is always output from the inverter 2d to the permanent magnet synchronous motor 1a during assist, and as a result, an induction is generated in the drive signal line of each phase. No voltage is generated. Therefore, at the time of assist, the angular velocity detection value ωk is not output from the velocity detection unit 11, and the output switch 12 generates the ECU and d-axis current command value using the angular velocity estimation value ωe input from the rotation state estimation unit 9 as the angular velocity signal ω. To the unit 8e.

    The U-phase and V-phase motor drive currents Iu and Iv output from the U-phase current sensor 3 and the V-phase current sensor 4 are input to the coordinate converter 9a. The coordinate converter 9a calculates the motor driving current Iw of the other phase, that is, the W phase from the motor driving currents Iu and Iv of the U phase and the V phase, and the motor driving current of the three phases (U phase, V phase and W phase). Q-axis current detection in the q-axis-d-axis coordinate system unique to the permanent magnet synchronous motor 1a is performed by applying a coordinate conversion process to Iu, Iv, Iw using a conversion matrix comprising elements corresponding to the estimated rotation angle θe. A value Iq and a d-axis current detection value Id are generated.

  At this time, the d-axis current command value generation unit 8e does not perform field weakening control and outputs the q-axis current command value Iqs because the angular velocity signal ω is less than the preset angular velocity setting value. The switch 8d is controlled and a d-axis current command value Ids corresponding to the angular velocity signal ω is output to the d-axis current controller 8f. Here, the d-axis current command value Ids is set to “0”.

Subtracter 8a generates a speed error Δω by calculating the difference between the angular velocity estimate ωe input from the angular velocity command value omega ₀ input rotor position and speed estimator 9b from ECU, the speed controller 8b Calculates the q-axis current command value Iqs corresponding to the speed error Δω by performing proportional integral / differential processing on the speed error Δω, and outputs it to the switch 8d. The switch 8d outputs the q-axis current command value Iqs to the q-axis current controller 8g. Then, the d-axis current controller 8f calculates a d-axis voltage command value Vd corresponding to the d-axis current command value Ids based on the d-axis current command value Ids and the d-axis current detection value Id to obtain a two-phase / 3 Output to the phase converter 8h and the rotor position / speed estimator 9b. On the other hand, the q-axis current controller 8g calculates a q-axis voltage command value Vq corresponding to the q-axis current command value Iqs based on the q-axis current command value Iqs and the q-axis current detection value Iq to obtain a two-phase / 3 Output to the phase converter 8h and the rotor position / speed estimator 9b.

  The two-phase / three-phase converter 8h includes a d-axis voltage command value Vd corresponding to the d-axis input from the d-axis current controller 8f and a q corresponding to the q-axis input from the q-axis current controller 8g. The shaft voltage command value Vq is converted into a three-phase voltage manipulated variable Vu, Vv, Vw on a three-dimensional coordinate system composed of U phase, V phase, and W phase, and the three-phase voltage manipulated variable Vu, Vv, Vw is PWMed. It outputs to the signal generator 8i. The PWM signal generator 8i generates a PWM signal for switching the inverter 2d based on the three-phase voltage manipulated variables Vu, Vv, Vw and outputs the PWM signal to the inverter 2d. As a result, the inverter 2d generates a motor drive signal and supplies it to the permanent magnet synchronous motor 1a, and the motor rotation speed of the permanent magnet synchronous motor 1a increases with time.

<When assist is stopped>
As shown in FIG. 2, when the rotation speed (angular velocity estimated value ωe) of the permanent magnet synchronous motor 1a coincides with the assist rotation speed, an operation instruction signal J for instructing stop of the assist is input from the ECU, and the inverter control unit 8 stops the operation of the inverter 2d and stops the driving of the permanent magnet synchronous motor 1a. As described above, when the assist is stopped, the permanent magnet synchronous motor 1a enters a free-run state due to the rotation of the turbine 1c by the exhaust energy.

In this case, the drive signal lines for each phase are in a high impedance state, and the permanent magnet synchronous motor 1a.
A sinusoidal induced voltage is generated in each drive signal line between the two by a magnetic induction between the stator winding and the armature. Since this induced voltage is induced by electromagnetic induction between the stator winding and the armature of the permanent magnet synchronous motor 1a, the ground potential (zero potential) is set as the center potential and the rotation period (angular velocity) of the armature is supported. AC voltage with angular frequency.

The voltage sensor 10 detects the induced voltage of the U-phase drive signal line and outputs it as a voltage detection value to the comparator 11a of the speed detection unit 11. This voltage detection value is converted to a pulse signal that makes a state transition at a zero cross point (a point that crosses the ground potential) by being compared with the ground potential by the comparator 11a. This pulse signal is a signal synchronized with the rotation period of the armature,
The F / V converter 11b converts the voltage into a DC voltage corresponding to the angular velocity of the armature, and outputs it to the output switch 12 as the angular velocity detection value ωk. When the assist is stopped, the output switch 12 outputs the angular velocity detection value ωk as the angular velocity signal ω to the ECU and the d-axis current command value generation unit 8e.

As described above, when the assist is stopped, the angular velocity detection value ωk is generated based on the pulse signal that makes a state transition at the zero crossing point of the induced voltage of the permanent magnet synchronous motor 1a. Even when the amplitude fluctuates, a highly accurate angular velocity can be detected without being affected by the fluctuation.

  Since the angular velocity signal ω is equal to or greater than the angular velocity setting value ωs set to the assist angular velocity, the d-axis current command value generation unit 8e has the reference q-axis current command value Iqo to perform field weakening control. The switch 8d is controlled so as to be output, and, similarly to the first embodiment, the d-axis current of the armature in the permanent magnet synchronous motor 1a is induced by the permanent magnet synchronous motor 1a using the above equation (1). The d-axis current command value Ids that flows in the direction of weakening the electric power (EMF) is calculated and output to the d-axis current controller 8f.

  The d-axis current controller 8f is a d-axis voltage command corresponding to the d-axis current command value Ids based on the d-axis current command value Ids and the d-axis current detection value Id calculated by using the arithmetic expression (1). The value Vd is calculated and output to the 2-phase / 3-phase converter 8h. On the other hand, the q-axis current controller 8g calculates the q-axis voltage command value Vq corresponding to the reference q-axis current command value Iqo (that is, zero) based on the reference q-axis current command value Iqo and the q-axis current detection value Iq. And output to the 2-phase / 3-phase converter 8h.

  The two-phase / three-phase converter 8h includes a d-axis voltage command value Vd corresponding to the d-axis input from the d-axis current controller 8f and a q corresponding to the q-axis input from the q-axis current controller 8g. The shaft voltage command value Vq is converted into a three-phase voltage manipulated variable Vu, Vv, Vw on a three-dimensional coordinate system composed of U phase, V phase, and W phase, and the three-phase voltage manipulated variable Vu, Vv, Vw is PWMed. It outputs to the signal generator 8i. The PWM signal generator 8i generates a PWM signal for switching the inverter 2d based on the three-phase voltage manipulated variables Vu, Vv, Vw and outputs the PWM signal to the inverter 2d.

  As a result, as in the first embodiment, when the assist is stopped, the permanent magnet synchronous motor 1a is subjected to field weakening control, and the induced electromotive force of the permanent magnet synchronous motor 1a is greater than the DC voltage of the inverter 2d. As a result, no regenerative phenomenon occurs.

As explained above, the turbocharger control system with motor according to the second embodiment is different from the first embodiment in the means for grasping the rotation state of the permanent magnet synchronous motor 1a.
In addition to preventing the regeneration phenomenon of the permanent magnet synchronous motor 1a in the turbocharger with electric motor, it is possible to increase the efficiency and size of the permanent magnet synchronous motor 1a.

    In addition, this invention is not limited to the said embodiment, For example, the following modifications can be considered.

(1) In the first and second embodiments, when the rotational speed (angular velocity) of the permanent magnet synchronous motor 1a reaches the assist angular velocity that defines the stop of the assist by the permanent magnet synchronous motor 1a, the permanent magnet synchronous motor The permanent magnet synchronous motor 1a was designed so that the induced electromotive force of 1a coincided with the DC voltage of the inverter 2d, and the angular velocity set value ωs was set to the assist angular velocity. This is because, as can be seen from FIG. 3, by designing in this way, the effects of high efficiency and miniaturization can be obtained to the maximum. On the other hand, although the effects of high efficiency and downsizing are reduced, for example, an angular speed corresponding to a predetermined rotational speed between the assist rotational speed and the maximum rotational speed in FIG. 2 is set as the angular speed set value ωs, and the permanent magnet synchronous motor When the rotational speed (angular velocity) of 1a reaches the angular velocity set value ωs set in this way, the permanent magnet synchronous motor 1a is set so that the induced electromotive force of the permanent magnet synchronous motor 1a matches the DC voltage of the inverter 2d. You may design.

(2) In the first embodiment, the U-phase, V-phase, and W-phase motor drive currents Iu, Iv, and Iw detected by the U-phase current sensor 3, the V-phase current sensor 4, and the W-phase current sensor 5, respectively. The q-axis-d-axis coordinate system specific to the armature of the permanent magnet synchronous motor 1a is detected by supplying the motor drive currents Iu, Iv, Iw to the inverter control unit 6 (3-phase / 2-phase converter 6h). The q-axis current detection value Iq and the d-axis current detection value Id are calculated in place of the power supply current Ip supplied from the booster circuit 2b to the inverter 2d as shown in FIG. The q-axis current detection value Iq and the d-axis current detection value Id may be calculated by detecting the power supply current Ip to the inverter control unit 6A.

   In this case, the inverter control unit 6A has a configuration in which a phase current reproducer (current conversion means) 6k is added to the inverter control unit 6 as shown in FIG. The phase current reproducer 6k converts the power supply current Ip into three-phase motor drive currents Iu, Iv, and Iw based on the PWM signal supplied from the PWM signal generator 6j. Although FIG. 5 shows the case where the current sensor 20 is provided on the + side of the power supply to detect the power supply current Ip, the current sensor 20 may be provided on the − side of the power supply to detect the power supply current Ip. good. Such a current detection method can be similarly used in the second embodiment.

 (3) FIG. 7 is a block diagram showing a modification of FIG. As shown in this figure, since the inverter 2d drives a permanent magnet synchronous motor 1a which is a three-phase motor, three switch arms 30 to 32 corresponding to each phase (U phase, V phase and W phase) are provided. I have. In FIG. 5, the power supply current Ip supplied from the booster circuit 2b to the inverter 2d is detected, but in this modification, the arm current Ia flowing through the switch arms 30 to 32 is detected by the current sensor (arm current detecting means) 21. It supplies to the inverter control part 6A mentioned above. In FIG. 7, the current sensor 21 is provided in the U-phase switch arm 30, but may be provided in other phases, that is, the V-phase or W-phase switch arms 31 and 32. Such a current detection method can be similarly used in the second embodiment.

  (4) In the second embodiment, for example, as shown in FIG. 8, in addition to the voltage sensor 10, a voltage sensor 10A for detecting the voltage of the V-phase drive signal line is provided, and the voltages of the U-phase and V-phase drive signal lines are provided. May be supplied to the speed detection unit 11A, and the two voltages may be compared by a comparator to generate a pulse signal that changes state at the timing when the magnitude relationship between the two voltages is reversed. Since both voltages have a phase difference of 120 °, the magnitude relationship is reversed twice during one period. Note that the voltage supplied to the speed detector 11A is not limited to the U-phase and V-phase drive signal lines, and any two of the three phases (U-phase, V-phase, and W-phase) may be selected.

(5) In the first and second embodiments, since the DC power source 2a is used, the booster circuit 2b is a DC / DC converter. However, the present invention is not limited to this, and when an AC power source is used, the booster circuit 2b is used. An AC / DC converter may be used.

  (6) In the first embodiment, the rotational position sensor 1b that outputs a pulse signal of one pulse by one rotation of the permanent magnet synchronous motor 1a is used. However, the present invention is not limited to this. A rotational position sensor that outputs a plurality of pulses in one rotation may be used, and the output of the rotational position sensor may be input to the speed calculator 7.

  (7) Although the rotational position sensor 1b in the first embodiment uses a Hall element as a detection element, the present invention is not limited to this. The rotational position sensor 1b may use a detection element (for example, a magnetoresistive element) other than the Hall element.

(8) Furthermore, in the first and second embodiments, the d-axis current command value Ids is set to “0” during assist, but this is generally performed in vector control. However, the present invention is not limited to this. A constant other than “0” may be set in the d-axis current command value Ids as necessary.

  (9) In the second embodiment, the speed detection unit 11 including the comparator 11a and the F / V converter 11b is used. However, the configuration of the speed detection unit 11 is not limited to this. Any other configuration may be used as long as it converts the fluctuation cycle of the voltage detected by the voltage sensor 10 into a DC voltage. As other configuration examples, for example, a configuration using a PLL (Phas Locked Loop) circuit or a software processing using a microcomputer can be considered.

(10) In the second embodiment, the estimated angular velocity value ωe and the detected angular velocity value ωk are output to the ECU as the switching angular velocity signal ω based on the operation instruction signal J supplied from the ECU. Then, the operation instruction signal J may be generated in the inverter control unit 8. Since the angular velocity command value ω ₀ is supplied from the ECU to the inverter control unit 8 only at the time of assist, the inverter control unit 8 determines whether or not to supply the angular velocity command value ω ₀ , and an operation instruction signal based on the determination result J is generated.

(11) In the first and second embodiments, the angular velocity is used as the rotation state value indicating the rotation state of the permanent magnet synchronous motor 1a. However, the present invention is not limited to this, and the rotation number or the like may be used as the rotation state value.

1 is a configuration block diagram of a turbocharger control system with an electric motor according to a first embodiment of the present invention. It is explanatory drawing regarding operation | movement of the turbocharger control system with an electric motor which concerns on 1st Embodiment of this invention. It is explanatory drawing regarding the design method of the permanent-magnet synchronous motor 1a in the turbocharger control system with an electric motor which concerns on 1st Embodiment of this invention. It is a block diagram of a turbocharger control system with an electric motor according to a second embodiment of the present invention. It is a 1st modification of the turbocharger control system with an electric motor which concerns on 1st Embodiment of this invention. It is detailed explanatory drawing regarding the 1st modification of the turbocharger control system with an electric motor which concerns on 1st Embodiment of this invention. It is a 2nd modification of the turbocharger control system with an electric motor which concerns on 1st Embodiment of this invention. It is a modification of the turbocharger control system with an electric motor which concerns on 2nd Embodiment of this invention.

Explanation of symbols

     DESCRIPTION OF SYMBOLS 1 ... Turbocharger with an electric motor, 1a ... Permanent magnet synchronous motor, 1b ... Rotary position sensor, 1c ... Turbine, 1d ... Compressor, 2 ... Motor drive part, 2a ... DC power supply, 2b ... Booster circuit, 2c ... Smoothing capacitor, 2d Inverter, 3 U phase current sensor, 4 V phase current sensor, 5 W phase current sensor, 6 8 inverter control unit, 7 speed calculator, 9 rotational state estimation unit, 10 voltage sensor, 11 ... speed detector, 12 ... output switch

Claims (12)

A control system for a turbocharger with an electric motor, in which an assist electric motor to which a drive signal is supplied by an inverter is connected to a turbocharger attached to an engine,
Rotation state grasping means for grasping a rotation state value indicating the rotation state of the electric motor;
Generates an inverter control signal for performing field-weakening control to weaken the induced electromotive force of the motor when the rotational state value grasped by the rotational state grasping means becomes a value equal to or larger than a preset rotational state set value. Control means for outputting to the inverter;
Comprising
The rotational state set value is set to the rotational state value of the motor when the induced electromotive force of the motor matches the DC voltage of the inverter.
A turbocharger control system with an electric motor.   The motor is designed so that the induced electromotive force of the motor matches the DC voltage of the inverter when the rotation state value of the motor reaches an assist rotation state value that defines the stop of assist by the motor. The turbocharger control system with an electric motor according to claim 1, wherein the rotation state set value is set to the assist rotation state value. The electric motor is a sensorless permanent magnet synchronous motor that is driven by receiving a supply of a three-phase drive signal,
The rotation state grasping means is
A rotational position detecting means for detecting a rotational position of a rotor of the sensorless permanent magnet synchronous motor and outputting a rotational position detection signal indicating the rotational position;
Speed calculating means for calculating an angular velocity as a rotation state value of the sensorless permanent magnet synchronous motor by differentiating the rotational position detection signal;
The control means includes
When the angular velocity calculated by the velocity calculating means becomes equal to or greater than a preset angular velocity setting value, the q-axis current of the armature in the motor becomes zero, and the d-axis current becomes the induction of the motor. Generating the inverter control signal so as to flow in the direction of weakening the power and outputting it to the inverter;
The turbocharger control system with an electric motor according to claim 1 or 2. Current detection means for detecting a current flowing in each of at least two-phase drive signal lines;
The control means includes
Speed control means for generating a q-axis current command value based on a difference value between an angular velocity command value input from a host controller and an angular speed calculation value input from the speed calculation means;
Reference q-axis current command value generating means for generating a reference q-axis current command value such that the q-axis current becomes zero;
A switch that selectively outputs one of the q-axis current command value generated by the speed control unit and the reference q-axis current command value generated by the reference q-axis current command value generation unit;
Armature shaft current detection means for detecting the q-axis current and the d-axis current based on the current detected by the current detection means;
When the angular velocity calculation value input from the velocity calculation means becomes a value equal to or higher than the angular velocity setting value,
The d-axis current command value that generates the d-axis current command value that controls the switch so that the reference q-axis current command value is output, and that the d-axis current flows in a direction that weakens the induced electromotive force of the motor. Generating means;
A d-axis voltage command value for the armature is generated based on the d-axis current command value generated by the d-axis current command value generation unit and the d-axis current detection value output from the armature shaft current detection unit. D-axis current control means,
A q-axis voltage command value for the armature is generated based on a q-axis current command value or a reference q-axis current command value output from the switch and a q-axis current detection value output from the armature shaft current detection means. Q-axis current control means for
Voltage manipulated variable generating means for generating a three-phase voltage manipulated variable of the electric motor based on the d-axis voltage command value and the q-axis voltage command value;
PWM signal generation means for generating a PWM signal for controlling switching of the inverter as the inverter control signal based on the three-phase voltage operation amount, and outputting the PWM signal to the inverter;
The turbocharger control system with an electric motor according to claim 3, further comprising: The electric motor is a sensorless permanent magnet synchronous motor that is driven by receiving a supply of a three-phase drive signal,
The rotation state grasping means is
Voltage detection means for detecting the voltage of at least one phase of the drive signal line;
Current detection means for detecting a current flowing in each of at least two-phase drive signal lines;
Rotation state detection means for detecting a rotation state value at the time of assist stop of the sensorless permanent magnet synchronous motor based on the voltage detected by the voltage detection means;
Rotation state estimation means for estimating a rotation state value at the time of assist by the sensorless permanent magnet synchronous motor based on the current detected by the current detection means;
An output selection means for selecting and outputting the rotation state value estimated by the rotation state estimation means during the assist, while selecting the rotation state value detected by the rotation state detection means when the assist is stopped;
The control means includes
When the rotation state value output from the output selection means becomes a value greater than or equal to a preset rotation state setting value, the q-axis current of the armature in the motor becomes zero, and the d-axis current becomes equal to that of the motor. Generating the inverter control signal so as to flow in the direction of weakening the induced electromotive force and outputting it to the inverter;
The turbocharger control system with an electric motor according to claim 1 or 2. The electric motor is a sensorless permanent magnet synchronous motor that is driven by receiving a supply of a three-phase drive signal,
The rotation state grasping means is
Voltage detection means for detecting the voltage of at least one phase of the drive signal line;
Power supply current detection means for detecting a power supply current supplied to the inverter;
Rotation state detection means for detecting a rotation state value at the time of assist stop of the sensorless permanent magnet synchronous motor based on the voltage detected by the voltage detection means;
Rotation state estimation means for estimating a rotation state value at the time of assist by the sensorless permanent magnet synchronous motor based on the power supply current detected by the power supply current detection means;
An output selection means for selecting and outputting the rotation state value estimated by the rotation state estimation means during the assist, while selecting the rotation state value detected by the rotation state detection means when the assist is stopped;
The control means includes
When the rotation state value output from the output selection means becomes a value greater than or equal to a preset rotation state setting value, the q-axis current of the armature in the motor becomes zero, and the d-axis current becomes equal to that of the motor. Generating the inverter control signal so as to flow in the direction of weakening the induced electromotive force and outputting it to the inverter;
The turbocharger control system with an electric motor according to claim 1 or 2. The electric motor is a sensorless permanent magnet synchronous motor that is driven by receiving a supply of a three-phase drive signal,
The rotation state grasping means is
Voltage detection means for detecting the voltage of at least one phase of the drive signal line;
Arm current detection means for detecting an arm current flowing in the switch arm of the inverter;
Rotation state detection means for detecting a rotation state value at the time of assist stop of the sensorless permanent magnet synchronous motor based on the voltage detected by the voltage detection means;
Rotation state estimation means for estimating a rotation state value at the time of assist by the sensorless permanent magnet synchronous motor based on the arm current detected by the arm current detection means;
An output selection means for selecting and outputting the rotation state value estimated by the rotation state estimation means during the assist, while selecting the rotation state value detected by the rotation state detection means when the assist is stopped;
The control means includes
When the rotation state value output from the output selection means becomes a value greater than or equal to a preset rotation state setting value, the q-axis current of the armature in the motor becomes zero, and the d-axis current becomes equal to that of the motor. Generating the inverter control signal so as to flow in the direction of weakening the induced electromotive force and outputting it to the inverter;
The turbocharger control system with an electric motor according to claim 1 or 2. The rotational state estimating means includes
Armature shaft current detection means for detecting the q-axis current and the d-axis current based on the current detected by the current detection means;
Estimating means for estimating the rotational state value based on a q-axis current detection value and a d-axis current detection value output from the armature shaft current detection means;
With
The control means includes
Speed control means for generating a q-axis current command value based on a difference value between the rotation state command value input from the host controller and the rotation state value output from the estimation means;
Reference q-axis current command value generating means for generating a reference q-axis current command value such that the q-axis current becomes zero;
A switch that selectively outputs one of the q-axis current command value generated by the speed control unit and the reference q-axis current command value generated by the reference q-axis current command value generation unit;
When the rotation state value output from the output selection means is a value greater than or equal to the rotation state set value,
The d-axis current command value that generates the d-axis current command value that controls the switch so that the reference q-axis current command value is output, and that the d-axis current flows in a direction that weakens the induced electromotive force of the motor. Generating means;
A d-axis voltage command value for the armature is generated based on the d-axis current command value generated by the d-axis current command value generation unit and the d-axis current detection value output from the armature shaft current detection unit. D-axis current control means,
A q-axis voltage command value for the armature is generated based on a q-axis current command value or a reference q-axis current command value output from the switch and a q-axis current detection value output from the armature shaft current detection means. Q-axis current control means for
Voltage manipulated variable generating means for generating a three-phase voltage manipulated variable of the electric motor based on the d-axis voltage command value and the q-axis voltage command value;
PWM signal generation means for generating a PWM signal for controlling switching of the inverter as the inverter control signal based on the three-phase voltage operation amount, and outputting the PWM signal to the inverter;
The turbocharger control system with an electric motor according to claim 5, comprising: The rotational state estimating means includes
Current conversion means for converting the power supply current detected by the power supply current detection means into a current flowing in each of at least two-phase drive signal lines;
Armature shaft current detection means for detecting the q-axis current and the d-axis current based on the current converted by the current conversion means;
Estimating means for estimating the rotational state value based on a q-axis current detection value and a d-axis current detection value output from the armature shaft current detection means;
With
The control means includes
Speed control means for generating a q-axis current command value based on a difference value between the rotation state command value input from the host controller and the rotation state value output from the estimation means;
Reference q-axis current command value generating means for generating a reference q-axis current command value such that the q-axis current becomes zero;
A switch that selectively outputs one of the q-axis current command value generated by the speed control unit and the reference q-axis current command value generated by the reference q-axis current command value generation unit;
When the rotation state value output from the output selection means is a value greater than or equal to the rotation state set value,
The d-axis current command value that generates the d-axis current command value that controls the switch so that the reference q-axis current command value is output, and that the d-axis current flows in a direction that weakens the induced electromotive force of the motor. Generating means;
A d-axis voltage command value for the armature is generated based on the d-axis current command value generated by the d-axis current command value generation unit and the d-axis current detection value output from the armature shaft current detection unit. D-axis current control means,
A q-axis voltage command value for the armature is generated based on a q-axis current command value or a reference q-axis current command value output from the switch and a q-axis current detection value output from the armature shaft current detection means. Q-axis current control means for
Voltage manipulated variable generating means for generating a three-phase voltage manipulated variable of the electric motor based on the d-axis voltage command value and the q-axis voltage command value;
PWM signal generation means for generating a PWM signal for controlling switching of the inverter as the inverter control signal based on the three-phase voltage operation amount, and outputting the PWM signal to the inverter;
The turbocharger control system with an electric motor according to claim 6, further comprising: The rotational state estimating means includes
Current converting means for converting the arm current detected by the arm current detecting means into a current flowing in each of at least two-phase drive signal lines;
Armature shaft current detection means for detecting the q-axis current and the d-axis current based on the current converted by the current conversion means;
Estimating means for estimating the rotational state value based on a q-axis current detection value and a d-axis current detection value output from the armature shaft current detection means;
With
The control means includes
Speed control means for generating a q-axis current command value based on a difference value between the rotation state command value input from the host controller and the rotation state value output from the estimation means;
Reference q-axis current command value generating means for generating a reference q-axis current command value such that the q-axis current becomes zero;
A switch that selectively outputs one of the q-axis current command value generated by the speed control unit and the reference q-axis current command value generated by the reference q-axis current command value generation unit;
When the rotation state value output from the output selection means is a value greater than or equal to the rotation state set value,
The d-axis current command value that generates the d-axis current command value that controls the switch so that the reference q-axis current command value is output, and that the d-axis current flows in a direction that weakens the induced electromotive force of the motor. Generating means;
A d-axis voltage command value for the armature is generated based on the d-axis current command value generated by the d-axis current command value generation unit and the d-axis current detection value output from the armature shaft current detection unit. D-axis current control means,
A q-axis voltage command value for the armature is generated based on a q-axis current command value or a reference q-axis current command value output from the switch and a q-axis current detection value output from the armature shaft current detection means. Q-axis current control means for
Voltage manipulated variable generating means for generating a three-phase voltage manipulated variable of the electric motor based on the d-axis voltage command value and the q-axis voltage command value;
PWM signal generation means for generating a PWM signal for controlling switching of the inverter as the inverter control signal based on the three-phase voltage operation amount, and outputting the PWM signal to the inverter;
The turbocharger control system with an electric motor according to claim 7, comprising: The voltage detecting means detects a voltage of a one-phase drive signal line,
The rotation state detection means detects a rotation state value of the sensorless permanent magnet synchronous motor based on a zero cross point of a voltage of the one-phase drive signal line;
The turbocharger control system with an electric motor according to any one of claims 5 to 10. The voltage detection means detects the voltage of each of the two-phase drive signal lines,
The rotation state detection means detects a rotation state value of the sensorless permanent magnet synchronous motor based on a voltage difference between the two-phase drive signal lines;
The turbocharger control system with an electric motor according to any one of claims 5 to 10.

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