JP2009089462A - Control system for turbocharger with motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the regenerating phenomena of a motor in a turbocharger with a motor, and also, achieve the higher efficiency and the miniaturization of the motor. <P>SOLUTION: The control system for the turbo charger with a motor, where the motor for assistance to be supplied with a drive signal by an inverter is coupled with the turbo charger annexed to an engine, includes an opening/closing switching means, which switches the opening/closing state of a drive signal line that connects the inverter with the motor, a rotational state grasping means, which grasps a rotating state value that shows the rotational state of the motor, and an opening/closing control means, which controls the above opening/closing switching means so that it may switch into an open state when the rotational state value grasped by the rotational state grasping means amounts to its preset set value of the rotational state. The set value of the rotational state is set to the rotational state value of the motor when the induced electromotive force of the motor accords with 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, in the motor free run state during the period from the stop of assist by the permanent magnet synchronous motor to the maximum rotation speed driven by the turbine alone, the induced electromotive force (EMF) of the permanent magnet synchronous motor is the DC of the inverter. A regenerative phenomenon in which the current flows backward from the permanent magnet synchronous motor to the inverter when the voltage exceeds the voltage (a phenomenon in which the permanent magnet synchronous motor acts as a generator and converts the rotational energy of the turbine into electrical energy and returns it to the inverter on the power supply side. ) Occurs, the brake is applied to the rotation of the turbine. 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 an open / close switching means for switching an open / close state of a drive signal line connecting the inverter and the electric motor, and a rotational state for grasping a rotational state value indicating the rotational state of the electric motor Grasping means and opening / closing control for controlling the opening / closing switching means to switch to an open state when the rotational state value grasped by the rotational state grasping means is equal to or greater than a preset rotational state setting value. And the rotational state set value is determined so that the induced electromotive force of the motor is equal to the DC voltage of the inverter. It is set in rotation value of the motor in the case of, characterized in that.

 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 open / close switching means switches the open / closed states of the drive signal lines of all phases connecting the inverter and the sensorless permanent magnet synchronous motor, and the rotation state grasping means includes the open / close switching means and the sensorless permanent magnet. A voltage detection means for detecting a voltage of at least one phase drive signal line; a current detection means for detecting a current flowing through each of at least two phase drive signal lines; and the voltage detection means. Rotation state detection means for detecting a rotation state value when the assist of the sensorless permanent magnet synchronous motor is stopped based on a voltage detected by the motor 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; and rotation state value detected by the rotation state detection means at the time of assist stop And the output selection means for selecting the rotation state value estimated by the rotation state estimation means and outputting it to the opening / closing control means and the host engine control device at the time of the assist.

 Further, as a fourth 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 open / close switching means switches the open / closed states of the drive signal lines of all phases connecting the inverter and the sensorless permanent magnet synchronous motor, and the rotation state grasping means includes the open / close switching means and the sensorless permanent magnet. A voltage detection unit that is provided between the synchronous motor and detects the voltage of at least one phase of the drive signal line, a power supply current detection unit that detects a power supply current supplied to the inverter, and the voltage detection unit detects A rotation state detecting means for detecting a rotation state value at the time of assist stop of the sensorless permanent magnet synchronous motor based on a voltage; The rotation state estimation means for estimating the 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, and the rotation state value detected by the rotation state detection means at the time of the assist stop And the output selection means for selecting the rotation state value estimated by the rotation state estimation means and outputting it to the opening / closing control means and the host engine control device at the time of the assist.

 Further, as a fifth solving means related 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 open / close switching means switches the open / closed states of the drive signal lines of all phases connecting the inverter and the sensorless permanent magnet synchronous motor, and the rotation state grasping means includes the open / close switching means and the sensorless permanent magnet. Voltage detection means provided between the synchronous motor and detecting the voltage of at least one phase drive signal line; arm current detection means for detecting an arm current flowing through the switch arm of the inverter; and the voltage detection means Rotation for detecting a rotation state value when the assist of the sensorless permanent magnet synchronous motor is stopped based on a voltage to be State detection means, rotation state estimation means for estimating a rotation state value during assist by the sensorless permanent magnet synchronous motor based on the arm current detected by the arm current detection means, and rotation state detection means when the assist is stopped An output selection unit that selects the detected rotation state value, and selects the rotation state value estimated by the rotation state estimation unit and outputs it to the opening / closing control unit and the host engine control device during the assist. It is characterized by.

 Further, as a sixth solving means relating to the turbocharger control system with an electric motor, in any one of the third to fifth solving means, the voltage detecting means detects a voltage of a one-phase drive signal line, and The rotation state detection means detects a rotation 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 seventh solving means relating to the turbocharger control system with an electric motor, in any one of the third to fifth solving means, the voltage detecting means detects each voltage of the two-phase drive signal lines. The rotation state detecting 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.

 Further, as an eighth solving means relating to the turbocharger control system with an electric motor, in any one of the first to seventh solving means, an angular velocity is used as the rotation state value.

  According to the present invention, by providing an open / close switching means for switching the open / close state of the drive signal line connecting the inverter and the electric motor according to the rotational state of the electric motor, the rotational state value of the electric motor is a rotational state in which a regeneration phenomenon occurs. When the value, that is, the induced electromotive force of the motor becomes equal to or greater than the rotation state value (rotation state setting value) that matches the DC voltage of the inverter, the drive signal line is switched to the open state by controlling the open / close switching means. Is possible. As a result, since no current flows through the drive signal line, a regenerative phenomenon cannot occur, and the degree of freedom in designing the 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.
FIG. 1 is a block diagram showing the configuration of the turbocharger control system with an electric motor according to this embodiment. As shown in FIG. 1, a turbocharger control system with an electric motor according to this embodiment includes an electric turbocharger 1, a motor drive unit 2, an electromagnetic switch 3, a first current sensor 4, and a second current sensor 5. , A motor control unit 6, a voltage sensor 7, a speed detection unit 8, an output switch 9, and an opening / closing controller 10.

    The turbocharger 1 with an electric motor is composed of a permanent magnet synchronous motor 1a, a turbine 1b, and a compressor 1c, and the motor drive unit 2 is composed of a DC power source 2a, a booster circuit 2b, and an inverter 2c. 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 rotor, and is coaxial with the rotation shaft of the turbine 1b. The three-phase (U-phase, V-phase, and W-phase) motor drive signals connected to the inverter 2c are rotationally driven to assist (assist) the rotation of the turbine 1b. The turbine 1b and the compressor 1c are coaxially connected to form a turbocharger. By rotating the turbine 1b using exhaust energy of an engine (not shown), the compressor 1c 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 provided as necessary, boosts the DC power supply voltage supplied from the DC power supply 2a, and supplies it to the inverter 2c. The inverter 2c switches the DC power supply voltage supplied from the booster circuit 2b based on the PWM signal supplied from the motor control unit 6, thereby generating a three-phase motor drive signal composed of the U phase, the V phase, and the W phase. Generated and supplied to the permanent magnet synchronous motor 1a.

  The electromagnetic switch (open / close switching means) 3 connects the U-phase output terminal of the inverter 2c and the U-phase stator winding of the permanent magnet synchronous motor 1a in response to an open / close control signal input from the open / close controller 10. A U-phase drive signal line, a V-phase drive signal line connecting the V-phase output terminal of the inverter 2c and the V-phase stator winding of the permanent magnet synchronous motor 1a, a W-phase output terminal of the inverter 2c and the permanent magnet synchronous motor 1a. It is a switch for switching the open / close state of the W-phase drive signal line connecting the W-phase stator winding.

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

 As shown, the motor controller 6 includes a subtractor 6a, a speed controller 6b, a current controller 6c, a first coordinate converter 6d, a rotor position / speed estimator 6e, a second coordinate converter 6f, and a PWM ( Pulse Width Modulation) signal generator 6g. Among these components, the subtractor 6a, the speed controller 6b, the current controller 6c, the first coordinate converter 6d, and the rotor position / speed estimator 6e constitute a rotation state estimating means.

Subtracter 6a is calculates the difference between the estimated angular velocity value ωe output from a higher-level controller engine control unit angular velocity target value omega ₀ supplied from (ECU) and the rotor position and speed estimator 6e as a speed error Δω Output to the speed controller 6b. The speed controller 6b is a kind of PID controller, and calculates a current manipulated variable Iqs corresponding to the speed error Δω by applying a predetermined proportional integral / derivative operation to the speed error Δω to the current controller 6c. Output.

  The current controller 6c determines the current operation amount Iqs, Ids based on the current operation amount Iqs, the current operation amount Ids supplied from the ECU, and the drive current detection amount Iq, Id input from the first coordinate converter 6d. The corresponding voltage operation amounts Vq and Vd are calculated and output to the rotor position / speed estimator 6e and the second coordinate converter 6f.

  The first coordinate converter 6d receives the U-phase and V-phase motor drive currents Iu and Iv detected by the first current sensor 4 and the second current sensor 5, respectively, and the rotor position / speed estimator 6e. Q-axis drive current detection amount Iq on a two-dimensional coordinate system (coordinate system consisting of q-axis and d-axis) set on the rotor of the permanent magnet synchronous motor 1a based on the estimated rotation angle θe And d-axis drive current detection amount Id is generated. More specifically, the first coordinate converter 6d obtains a W-phase motor drive current Iw by an internal calculation based on the motor drive currents Iu and Iv, and a three-dimensional coordinate system composed of a U-phase, a V-phase, and a W-phase. The drive current detection amounts Iq and Id are obtained by subjecting the motor drive currents Iu, Iv and Iw to predetermined coordinate transformation. The d axis is a coordinate axis set in the opposing direction of the S pole and the N pole of the permanent magnet on the rotation surface of the rotor, and the d axis is a coordinate axis orthogonal to the q axis described above.

  The rotor position / speed estimator 6e estimates the rotational state of the permanent magnet synchronous motor 1a based on the drive current detection amounts Iq and Id and the voltage operation amounts Vq and Vd. The rotor position / speed estimator 6e includes, for example, a motor model simulating a permanent magnet synchronous motor 1a inside, and the voltage manipulated variables Vq and Vd and the drive current detection quantities 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 6e outputs the rotational angle estimated value θe estimated by such a method to the first coordinate converter 6d and the second coordinate converter 6f, respectively, and the angular speed estimated value ωe as the subtractor. 6a and the output switch 9.

  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. . 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) is used to estimate the angular velocity estimated value ωe and the rotational angle estimated value θe in the rotor position / speed estimator 6e. 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 second coordinate converter 6f is a voltage manipulated variable Vq corresponding to the q-axis and d-axis input from the current controller 6c based on the estimated rotation angle θe input from the rotor position / speed estimator 6e. , Vd are converted into voltage manipulated variables Vu, Vv, Vw on a three-dimensional coordinate system composed of U phase, V phase and W phase, and the voltage manipulated variables Vu, Vv, Vw are output to the PWM signal generator 6g.

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

  The voltage sensor (voltage detection means) 7 is provided between the electromagnetic switch 3 and the permanent magnet synchronous motor 1a, detects the voltage of the U-phase drive signal line, and outputs it to the speed detector 8 as a voltage detection value. When the electromagnetic switch 3 is in an open state (the U-phase, V-phase, and W-phase drive signal lines are all open), the U-phase input end of the permanent magnet synchronous motor 1a is composed of a U-phase stator winding and a permanent magnet. A sinusoidal induced voltage is generated by electromagnetic induction with the rotor. The voltage sensor 7 outputs such an induced voltage to the speed detector 8 as a voltage detection value.

  The speed detector (rotation state detection means) 8 includes a comparator 8a and an F / V converter 8b as shown in the figure. The comparator 8a compares the voltage detection value input from the voltage sensor 7 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 8b. The F / V converter 8b converts the pulse signal into a DC voltage corresponding to the frequency and outputs it to the output switch 9 as an angular velocity detection value ωk.

    The output switch (output selection means) 9 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 6e and the angular velocity detection value ωk input from the speed detector 8. Are selected and output to the ECU and the opening / closing controller 10 as an angular velocity signal ω. The operation instruction signal J instructs the motor controller 6 to assist the turbine 1b with the permanent magnet synchronous motor 1a, and instructs the output switch 9 to switch the output between the estimated angular velocity value ωe and the detected angular velocity value ωk. It is.

  The open / close controller (open / close control means) 10 is, for example, a differential amplifier, and controls open / close of a differential signal between the angular velocity signal ω input from the output switch 9 and a preset angular velocity set value ωs (DC voltage). It outputs to the electromagnetic switch 3 as a signal. Specifically, the switching controller 10 outputs a switching control signal that is a positive DC voltage to the electromagnetic switch 3 when the angular velocity signal ω input from the output switch 9 is smaller than the angular velocity setting value ωs. In this case, the electromagnetic switch 3 is closed (that is, the U-phase, V-phase, and W-phase drive signal lines are all conductive). Further, when the angular velocity signal ω input from the output switch 9 is greater than or equal to the angular velocity setting value ωs, the switching controller 10 outputs an opening / closing control signal that is a zero level or a negative DC voltage to the electromagnetic switch 3. In this case, the electromagnetic switch 3 is opened.

  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 2c. Designed. The permanent magnet synchronous motor 1a can be designed in this way because the drive signal lines of the U phase, V phase, and W phase according to the rotation state (angular velocity in the present embodiment) of the permanent magnet synchronous motor 1a. This is because the electromagnetic switch 3 for switching the open / close state of the motor is provided. By designing in this way, the regeneration of the permanent magnet synchronous motor 1a in the turbocharger 1 with an electric motor is prevented and the high efficiency of the permanent magnet synchronous motor 1a is prevented. And miniaturization can be achieved. Hereinafter, the reason why such an effect is obtained will be described with reference to FIG. 2 (a) and FIG.

  In FIG. 2A, the horizontal axis indicates the rotational speed of the permanent magnet synchronous motor 1a, the vertical axis indicates the induced electromotive force (EMF) of the permanent magnet synchronous motor 1a, and reference numeral 100 indicates the rotation in the prior art. The number-EMF characteristic is shown, and the reference numeral 200 shows the rotational speed-EMF characteristic 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 symbol 300 indicates the iron loss-motor drive current characteristic, and the symbol 400 indicates the copper. The loss-motor drive current characteristic is shown, and reference numeral 500 shows the motor efficiency-motor drive current characteristic.

  As indicated by reference numeral 100 in FIG. 2 (a), in the prior art, in the motor free run state during the period until the maximum rotation speed is reached by driving only with the turbine alone after the assist by the permanent magnet synchronous motor is stopped, When the induced electromotive force (EMF) of the permanent magnet synchronous motor becomes higher than the DC voltage of the inverter, a regenerative phenomenon occurs in which a current flows backward from the permanent magnet synchronous motor to the inverter. It is necessary to design a permanent magnet synchronous motor so that the electric power does not exceed the DC voltage of the inverter. 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.

  In contrast, in the present embodiment, an electromagnetic switch 3 is provided that switches the open / close states of the drive signal lines of the U phase, the V phase, and the W phase according to the rotation state (angular velocity in the present embodiment) of the permanent magnet synchronous motor 1a. Thus, the angular speed of the permanent magnet synchronous motor 1a is the angular speed at which the regenerative phenomenon occurs, that is, the angular speed at which the induced electromotive force of the permanent magnet synchronous motor 1a matches the DC voltage of the inverter 2c (in this embodiment, this angular speed is set as the angular speed set value). In this case, the electromagnetic switch 3 can be controlled to switch the U-phase, V-phase, and W-phase drive signal lines to the open state. As a result, no current flows through the U-phase, V-phase, and W-phase drive signal lines, so that no regenerative phenomenon occurs, and the degree of freedom in designing the permanent magnet synchronous motor 1a increases.

  Therefore, in the present embodiment, as indicated by reference numeral 200 in FIG. 2 (a), the rotation speed (angular velocity) of the permanent magnet synchronous motor 1a determines the assist rotation speed (assist The permanent magnet synchronous motor 1a is designed so that the induced electromotive force of the permanent magnet synchronous motor 1a coincides with the DC voltage of the inverter 2c when the angular velocity) is reached, 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 configured as described above will be described in detail with reference to FIGS. 2 (a) and 2 (b).
<When assisting>
First, at the time of assist shown in FIGS. 2 (a) and 2 (b), the motor control unit 6 operates the motor drive unit 2 when receiving an assist instruction by an operation instruction signal J input from an engine control unit (ECU). By doing so, the permanent magnet synchronous motor 1a is driven.

  Specifically, a motor drive signal is supplied from the inverter 2c 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 motor control unit 6 employs a sine wave energization method, a motor drive signal is always output from the inverter 2c to the permanent magnet synchronous motor 1a during assist, and as a result, induced 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 detector 8, and the output switch 9 outputs the angular velocity estimation value ωe input from the motor control unit 6 to the opening / closing controller 10 and the ECU as the angular velocity signal ω. .

    The U-phase and V-phase motor drive currents Iu and Iv output from the first current sensor 4 and the second current sensor 5 are input to the first coordinate converter 6d. The first coordinate converter 6d 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 calculates three phases (U phase, V phase and W phase). By subjecting the motor drive currents Iu, Iv, and Iw to a coordinate conversion process using a conversion matrix composed of elements corresponding to the estimated rotation angle θe, q in the q-axis-d-axis coordinate system inherent to the permanent magnet synchronous motor 1a. An axis drive current detection amount Iq and a d-axis drive current detection amount Id are generated.

On the other hand, the angular velocity target value ω ₀ is input from the ECU to the subtractor 6a, and the current operation amount Ids corresponding to the target value of the drive current detection amount Id is also input from the ECU to the current controller 6c. Here, the current manipulated variable Ids is set to “0”.

The subtractor 6a generates a speed error Δω by calculating a difference between the angular speed target value ω ₀ and the angular speed estimated value ωe of the permanent magnet synchronous motor 1a input from the rotor position / speed estimator 6e, and speed control is performed. The device 6b generates a current operation amount Iqs corresponding to the drive current detection amount Iq by subjecting the speed error Δω to proportional integration / differentiation processing. Then, the current controller 6c generates the voltage manipulated variables Vq and Vd corresponding to the drive voltage to be applied to the permanent magnet synchronous motor 1a by performing proportional integral / differential calculations on the current manipulated variables Iqs and Ids, respectively. To do.

    The rotor position / speed estimator 6e then detects the q-axis drive current detection amount Iq, the voltage operation amount Vq, and the d-axis drive in the q-axis-d-axis coordinate system fixedly set on the rotor of the permanent magnet synchronous motor 1a. The angular velocity estimation value ωe and the rotation angle estimation value θe are estimated using the current detection amount Id and the voltage operation amount Vd as input signals.

    That is, the rotor position / speed estimator 6e detects the drive current detection amounts Iq and Id indicating the drive current supplied from the inverter 2c to the permanent magnet synchronous motor 1a and the estimated rotation angle θe of the permanent magnet synchronous motor 1a estimated by itself. Angular velocity estimation using the drive current detection amounts Iq and Id generated based on the above and the voltage manipulated variables Vq and Vd that are generated based on the angular velocity estimated value ωe estimated by the driver and that regulate the generation of the PMW signal. Since the value ωe and the estimated rotation angle θe are estimated, the estimated angular velocity value ωe and the estimated rotation angle θe are values that accurately indicate the rotation state of the permanent magnet synchronous motor 1a.

  The switching controller 10 outputs a difference signal between the angular velocity signal ω (angular velocity estimation value ωe) obtained as described above and the angular velocity setting value ωs set to the assist angular velocity to the electromagnetic switch 3 as an opening / closing control signal. To do. Here, at the time of assist, that is, during a period when the angular velocity of the permanent magnet synchronous motor 1a does not reach the assist angular velocity, the open / close control signal becomes a positive DC voltage signal, and as shown in FIG. Closed (ON). That is, the U-phase, V-phase, and W-phase drive signal lines are all conductive, and the motor drive signal generated by the inverter 2c is normally supplied to the permanent magnet synchronous motor 1a.

<When assist is stopped>
As shown in FIG. 2A, when the angular velocity signal ω (angular velocity estimation value ωe) matches the angular velocity setting value ωs set to the assist angular velocity, the switching controller 10 sends a zero-level switching control signal to the electromagnetic Output to the switch 3. In this case, as shown in FIG. 2B, the electromagnetic switch 3 is in an open state (OFF). That is, the U-phase, V-phase, and W-phase drive signal lines are all open. On the other hand, the motor control unit 6 receives an operation instruction signal J instructing stop of assist from the ECU, and the motor control unit 6 stops the operation of the motor driving unit 2 and stops the driving of the permanent magnet synchronous motor 1a. . Thus, in a state where the motor drive unit 2 has stopped operating, the permanent magnet synchronous motor 1a enters a free-run state due to the rotation of the turbine 1b by the exhaust energy.

In this case, the drive signal lines for each phase are in a high impedance state, and each drive signal line between the electromagnetic switch 3 and the permanent magnet synchronous motor 1a has a sinusoidal shape due to electromagnetic induction between the stator winding and the rotor. An induced voltage is generated. Since this induced voltage is induced by electromagnetic induction between the stator winding and the rotor of the permanent magnet synchronous motor 1a, the ground potential (zero potential) is set as the center potential and corresponds to the rotation period (angular velocity) of the rotor. AC voltage with angular frequency.

The voltage sensor 7 detects the induced voltage of the U-phase drive signal line and detects the induced voltage detected value (precisely U
(Phase induced voltage detection value) is output to the comparator 8a of the speed detector 8. This induced 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 8a. This pulse signal is a signal synchronized with the rotation period of the rotor, and is converted into a DC voltage corresponding to the angular velocity of the rotor by being input to the F / V converter 8b.

That is, the detected angular velocity value ωk output from the F / V converter 8b to the output switch 9 is U
The detection signal is generated based on the phase induced voltage detection value and is a detection signal indicating the angular velocity of the permanent magnet synchronous motor 1a. When the assist is stopped, the output switch 9 outputs the angular velocity detection value ωk as the angular velocity signal ω to the opening / closing controller 10 and the ECU.

  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.

When the angular velocity signal ω (angular velocity detection value ωk) exceeds the angular velocity setting value ωs set to the assist angular velocity, the switching controller 10 outputs an opening / closing control signal that is a negative DC voltage signal to the electromagnetic switch 3. The electromagnetic switch 3 is maintained in the open state (OFF). Thus, when the assist is stopped, no current flows through the drive signal lines of the U phase, the V phase, and the W phase, so that no regenerative phenomenon occurs. When the angular velocity (angular velocity detection value ωk) of the permanent magnet synchronous motor 1a becomes lower than the angular velocity setting value ωs when the assist is stopped, the electromagnetic switch 3 is switched to the closed state (ON).
An assist start instruction is output again from the ECU, and a motor drive signal is supplied from the inverter 2c to the permanent magnet synchronous motor 1a to assist the turbine 1b.

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

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

(1) In the above embodiment, when the rotational speed (angular speed) of the permanent magnet synchronous motor 1a reaches the assist rotational speed (assist angular speed) that regulates 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 2c, 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 effect of high efficiency and downsizing is reduced, for example, the angular velocity corresponding to a predetermined rotational speed between the assist rotational speed and the maximum rotational speed in FIG. When the rotational speed (angular speed) of the magnet synchronous motor 1a reaches the angular speed set value ωs set as described above, the permanent magnet is set so that the induced electromotive force of the permanent magnet synchronous motor 1a matches the DC voltage of the inverter 2c. The synchronous motor 1a may be designed.

(2) In the above embodiment, the motor drive currents Iu and Iv are detected by the first current sensor 4 and the second current sensor 5, and the motor drive currents Iu and Iv are supplied to the motor control unit 6 to be permanent. The drive current detection amounts Iq and Id in the q-axis / d-axis coordinate system specific to the rotor of the magnet synchronous motor 1a are calculated. Instead, they are supplied from the booster circuit 2b to the inverter 2c as shown in FIG. The drive current detection amounts Iq and Id may be calculated by detecting the power supply current Ip detected by the third current sensor (power supply current detection means) 20 and supplying the power supply current Ip to the motor controller 6A. . Further, instead of calculating the drive current detection amounts Iq and Id, the motor drive currents Iu and Iv, the motor drive currents Iv and Iw, the motor drive currents Iu and Iw, or the motor drive currents Iu, Iv, Iw may be calculated.

  In this case, the motor control unit 6A has a configuration in which a phase current reproducer 6h is added to the motor control unit 6 as shown in FIG. The phase current reproducer 6h converts the power supply current Ip into a three-phase motor drive current Iu based on the PWM signal supplied from the PWM signal generator 6g and the rotation angle estimated value θe supplied from the rotor position / speed estimator 6e. , Iv, Iw. In the motor controller 6, the first coordinate converter 6d calculates the W-phase motor drive current Iw from the U-phase and V-phase motor drive currents Iu and Iv. Since the W-phase motor drive current Iw is generated in the reproducer 6h, the first coordinate converter 6d ′ performs only the coordinate conversion process. FIG. 4 shows the case where the third current sensor 20 is provided on the positive side of the power source to detect the power source current Ip, but the third current sensor 20 is provided on the negative side of the power source and the power source current Ip is detected. You may make it detect.

(3) FIG. 6 is a block diagram showing a modification of FIG. As shown in this figure, since the inverter 2c 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. 4, the power supply current Ip supplied from the booster circuit 1b to the inverter 2c is detected. In this modification, the arm current Ia flowing through the switch arms 30 to 32 is detected by the fourth current sensor 21, and the motor described above. This is supplied to the control unit 6A. In FIG. 6, the fourth 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.

(4) Further, for example, as shown in FIG. 7, in addition to the voltage sensor 7, a voltage sensor 7A for detecting the voltage of the V-phase drive signal line is provided, and the voltage of the U-phase and V-phase drive signal lines is detected by the speed detector 8A. And a pulse signal that makes a state transition at a timing at which the magnitude relationship between the two voltages is reversed may be generated by comparing the two voltages with a comparator. Since both voltages have a phase difference of 120 °, the magnitude relationship is reversed twice during one period. The voltage supplied to the speed detector 8A 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 above embodiment, the speed detector 8 including the comparator 8a and the F / V converter 8b is used. However, the configuration of the speed detector 8 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 7 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.

(6) In the above embodiment, the angular velocity estimated 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. The instruction signal J may be generated in the motor control unit 6. Since the angular velocity target value ω ₀ and the current operation amount Ids are supplied from the ECU to the motor control unit 6 only at the time of assist, the motor control unit 6 determines whether the angular velocity target value ω ₀ or the current operation amount Ids is supplied / not supplied. The operation instruction signal J is generated based on the determination result.

  (7) Furthermore, in the above embodiment, the current operation amount Ids is set to “0”, 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 current operation amount Ids as necessary. Further, the current control amount Ids may be generated by the motor control unit 6 itself.

(8) The current operation amount Ids is set as a constant, and the operation instruction signal J can be generated in the motor control unit 6 based on the angular velocity target value ω _0. 6 or the signal supplied to the output switch 9 may be the angular velocity target value ω ₀ only. Further, by providing the speed controller 6b on the ECU side, the current target value I ₀ may be supplied to the motor control unit 6 instead of the angular speed target value ω ₀ .

  (9) In the above embodiment, 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 an embodiment of the present invention. It is explanatory drawing regarding operation | movement of the turbocharger control system with an electric motor which concerns on one 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 one Embodiment of this invention. It is a 1st modification of the turbocharger control system with an electric motor which concerns on one 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 one Embodiment of this invention. It is a 2nd modification of the turbocharger control system with an electric motor which concerns on one Embodiment of this invention. It is a 3rd modification of the turbocharger control system with an electric motor which concerns on one Embodiment of this invention.

Explanation of symbols

      DESCRIPTION OF SYMBOLS 1 ... Turbocharger with an electric motor, 1a ... Permanent magnet synchronous motor, 1b ... Turbine, 1c ... Compressor, 2 ... Motor drive part, 2a ... DC power supply, 2b ... Booster circuit, 2c ... Inverter, 3 ... Electromagnetic switch, 4 ... 1st current sensor, 5 ... 2nd current sensor, 6 ... Motor control unit, 7 ... Voltage sensor, 8 ... Speed detection unit, 9 ... Output switch, 10 ... Opening / closing controller, 6a ... Subtractor, 6b ... Speed Controller, 6c ... Current controller, 6d ... First coordinate converter, 6e ... Rotor position / speed estimator, 6f ... Second coordinate converter, 6g ... PWM signal generator

Claims (8)

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,
Open / close switching means for switching an open / close state of a drive signal line connecting the inverter and the electric motor;
Rotation state grasping means for grasping a rotation state value indicating the rotation state of the electric motor;
An opening / closing control means for controlling the opening / closing switching means to switch to an open state when the rotation state value grasped by the rotation state grasping means becomes a value equal to or larger than a preset rotation state setting value;
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 open / close switching means switches the open / close states of the drive signal lines of all phases connecting the inverter and the sensorless permanent magnet synchronous motor,
The rotation state grasping means is
A voltage detecting means provided between the open / close switching means and the sensorless permanent magnet synchronous motor for detecting a 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 during assist by the sensorless permanent magnet synchronous motor based on the current detected by the current detection means;
While the assist state is stopped, the rotation state value detected by the rotation state detection unit is selected, and at the assist time, the rotation state value estimated by the rotation state estimation unit is selected and output to the opening / closing control unit and the host engine control device. Output selection means for
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 open / close switching means switches the open / close states of the drive signal lines of all phases connecting the inverter and the sensorless permanent magnet synchronous motor,
The rotation state grasping means is
A voltage detecting means provided between the open / close switching means and the sensorless permanent magnet synchronous motor 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 during assist by the sensorless permanent magnet synchronous motor based on the power supply current detected by the power supply current detection means;
While the assist state is stopped, the rotation state value detected by the rotation state detection unit is selected, and at the assist time, the rotation state value estimated by the rotation state estimation unit is selected and output to the opening / closing control unit and the host engine control device. Output selection means for
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 open / close switching means switches the open / close states of the drive signal lines of all phases connecting the inverter and the sensorless permanent magnet synchronous motor,
The rotation state grasping means is
A voltage detecting means provided between the open / close switching means and the sensorless permanent magnet synchronous motor for detecting a 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;
While the assist state is stopped, the rotation state value detected by the rotation state detection unit is selected, and at the assist time, the rotation state value estimated by the rotation state estimation unit is selected and output to the opening / closing control unit and the host engine control device. Output selection means for
The turbocharger control system with an electric motor according to claim 1 or 2. 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 3 to 5. 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 3 to 5. An angular velocity is used as the rotation state value.
The turbocharger control system with an electric motor according to any one of claims 1 to 7.

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