JP2011080415A - Control circuit for electric assist supercharger and electric compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent deterioration of operation feeling by preventing occurrence of the so-called stepped feeling when temperature rises during operation restriction by a temperature switch for protecting a motor and an electric circuit in an electric assist supercharger. <P>SOLUTION: This circuit includes a motor applying torque to a compressor compressing air sucked from an exhaust manifold, a motor driver controlling operation of the motor, and a temperature sensor measuring temperature of the motor and the motor driver. The motor driver control motor output to an upper limit or lower in response to temperature increase of the motor and the motor driver according to a relation between temperature of the motor and the motor driver, and the upper limit of motor output stored as preset maps 3, 5, 6. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electric assist supercharger mainly used for a vehicle engine and an electric compressor control circuit for controlling an electric compressor constituting the electric assist supercharger.

  Conventionally, as described in Patent Document 1, a turbocharger that performs supercharging by using energy contained in exhaust gas is used in a vehicle engine such as an automobile engine. The supercharger is disposed on an exhaust manifold and an intake manifold, respectively, and two blade impellers (turbine and compressor) fixedly connected to each other by a shaft, and two blade impellers disposed around the blade impellers. And two volutes.

  The first impeller (turbine) obtains rotational force from the exhaust gas and transmits this rotational force to the second impeller (compressor). The second impeller (compressor) compresses the air in the intake manifold.

  In such a supercharger, an electric assist supercharger is proposed in which the rotational force of the turbine is assisted by a motor (electric motor). In such an electric assist supercharger, the operation is limited by a temperature switch in order to protect the motor and the electric circuit.

JP 2009-167827 A

  By the way, in an electric supercharging system using an electric assist supercharger or an electric compressor (hereinafter referred to as EBS (Electric Boosting System)), a motor and its driver are placed in the supercharger or in the engine room. Installed. For this reason, the motor and the motor driver are used in an extremely severe temperature environment. These motors and motor drivers are required to operate normally in an ambient temperature range of, for example, about −40 ° C. to about + 125 ° C. Furthermore, in recent years, operation at higher temperatures, for example, normal operation at about + 155 ° C. has been required.

  In such a use environment, it is assumed that the ambient temperature frequently reaches the upper limit temperature set for each device. The temperature of each device is determined not only by the rise in ambient temperature but also by the combination of the cooling conditions of each device and the temperature rise due to self-heating (self-loss) of each device.

  In such a use environment, when the operation is limited by the temperature switch, depending on the temperature switch setting temperature, the engine output decreases sharply, for example, 100% output suddenly becomes 0% output. This will cause a so-called stepped feeling, thus deteriorating driving feeling.

  Therefore, the present invention has been proposed in view of the above-described circumstances, and in an electric assist supercharger, a temperature rise has occurred when performing an operation restriction by a temperature switch for protection of a motor or an electric circuit. It is an object of the present invention to provide a control circuit for an electric assist supercharger and an electric compressor that can prevent a so-called stepped feeling and sometimes prevent deterioration in driving feeling.

  In order to solve the above-described problems and achieve the above object, the present invention has the following configuration.

[Configuration 1]
An electric assist supercharger according to the present invention includes a compressor that compresses air taken in from an exhaust manifold, a motor that applies rotational force to the compressor, a motor driver that controls the operation of the motor, and the temperatures of the motor and the motor driver. A motor sensor that measures the motor output according to the temperature rise of the motor and the motor driver according to the relationship between the temperature of the motor and the motor driver preset and stored as a map and the upper limit of the motor output. It is characterized by narrowing it below the upper limit.

[Configuration 2]
In the electric assist supercharger having the configuration 1, the relationship between the temperature of the motor and the motor driver and the upper limit of the motor output is as follows. The relationship is proportional to (large numerical value).

[Configuration 3]
An electric compressor control circuit according to the present invention is an electric compressor control circuit that controls an electric compressor that constitutes an electric assist supercharger, and a motor driver that controls the operation of a motor that applies a rotational force to the electric compressor; A temperature sensor for measuring the temperature of the motor and the motor driver, and the motor driver increases the temperature of the motor and the motor driver according to the relationship between the motor and motor driver temperature set in advance and stored as a map and the upper limit of the motor output Accordingly, the motor output is limited to the upper limit or less.

[Configuration 4]
In the control circuit of the electric compressor having the configuration 3, the relationship between the temperature of the motor and the motor driver and the upper limit of the motor output is as follows. The relationship is proportional to (large numerical value).

  In the control circuit for the electric assist supercharger and the electric compressor according to the present invention, the motor driver includes the motor and the motor driver according to the relationship between the temperature of the motor and the motor driver stored in advance as a map and the upper limit of the motor output. As the motor output is reduced to the upper limit or less according to the temperature rise, natural driving feeling can be realized while preventing overshoot of temperature rise regardless of the ambient temperature, cooling condition, operating condition, etc. .

  It is desirable to install the temperature sensor in each of the motor and the motor driver. In addition, it is desirable that the temperature sensor be installed in each case where the motor driver has a two-board configuration such as “a main circuit using an aluminum board” and “a control circuit using a resin board”.

  The map that narrows the output according to the temperature sets the temperature for each sensor, and calculates the output upper limit based on the temperature. Of these, the smallest output upper limit may be used for control. Note that the output restriction start temperature can be set to a higher temperature by selecting a smaller maximum current or a shorter continuous energization time.

  Since the maximum current and the continuous energization time are different between the power running operation and the regenerative operation, it is desirable to prepare separate maps for each.

  Further, the relationship between the motor and motor driver temperature and the upper limit of the motor output is such that the motor output is proportional to the a power of the temperature (where a is a numerical value greater than 1) above a predetermined temperature. It is desirable.

  That is, the present invention prevents the so-called stepped feeling from appearing when the temperature rises in the electric assist supercharger when the operation is limited by the temperature switch for protecting the motor and the electric circuit. Therefore, it is possible to provide a control circuit for an electric assist supercharger and an electric compressor that can prevent deterioration in driving feeling.

It is a block diagram which shows the structure (at the time of power running) of the control circuit of the electric compressor which concerns on this invention. 4 is a graph showing a map table used during control circuit powering in the electric compressor according to the present invention. It is a block diagram which shows the structure (at the time of regeneration) of the control circuit of the electric compressor which concerns on this invention. It is a graph which shows the map table used at the time of regeneration in the electric compressor which concerns on this invention. It is a figure explaining the calculation method of the map table in the electric compressor which concerns on this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The electric assist supercharger according to the present invention is a supercharger that performs supercharging using energy contained in exhaust gas mainly in a vehicle engine such as an automobile engine. The supercharger is disposed on an exhaust manifold and an intake manifold, respectively, and two blade impellers (turbine and compressor) fixedly connected to each other by a shaft, and two blade impellers disposed around the blade impellers. And two volutes.

  The first impeller (turbine) obtains rotational force from the exhaust gas and transmits this rotational force to the second impeller (compressor). The second impeller (compressor) compresses the air in the intake manifold.

  The supercharger is an electric assist supercharger that assists the rotational force of the turbine with a motor (electric motor). In this electric assist supercharger, a temperature sensor is installed in each of the motor and the motor driver. In addition, it is desirable that the temperature sensor be installed in each case where the motor driver has a two-board configuration such as “a main circuit using an aluminum board” and “a control circuit using a resin board”.

  The electric assist supercharger includes an electric compressor control circuit that limits the operation of the motor in accordance with the temperature in order to protect the motor and the electric circuit.

  FIG. 1 is a block diagram showing the configuration (during powering) of a control circuit for an electric compressor according to the present invention.

  The control circuit of this electric compressor has a selector circuit 1 as shown in FIG. When the electric assist supercharger is powered, a torque command value is input to the selector circuit 1 from the host ECU. In addition, a value (internal calculation value) indicating the turbo rotation speed is input to the selector circuit 1 via the map table 1. The map table will be described later.

  Further, the selector circuit 1 receives a difference signal obtained by subtracting the driver input power value (calculated value) from the power consumption limit value from the host ECU. A value indicating the temperature of the motor stator is input to the selector circuit 1 from the temperature sensor via the map table 3. A value indicating the temperature of the motor driver main circuit is input from the temperature sensor via the map table 5. Further, a value indicating the temperature of the motor driver control circuit is input from the temperature sensor via the map table 6. A value indicating the power supply voltage is input from the voltage sensor via the map table 9.

  In many cases, the motor driver is cooled by a forced air cooling method. In this case, the amount of cooling air changes depending on the vehicle speed, and the cooling capacity also changes. When the vehicle speed is 0 km / h, the cooling air is 0 m / s.

  The selector circuit 1 selects the smallest value from the input values and outputs it as a current command value to be supplied to the motor during power running. This current command value is a control command value.

  FIG. 2 is a graph showing a map table used during power running.

  As shown in FIG. 2, the map table is set for each temperature sensor. This map table shows the output limit value corresponding to the measured temperature, and the motor current is reduced in proportion to the square of the temperature above a predetermined output limit start temperature. Note that the motor output above the output restriction start temperature is not limited to the square of the temperature, but may be in a relationship proportional to the temperature a power (where a is a numerical value greater than 1).

  In such a map table, the temperature is set for each sensor, the output upper limit is calculated based on the measured temperature, and the smallest output upper limit is selected by the selector circuit 1 and used for motor control. . It should be noted that the output restriction start temperature can be set to a higher temperature by selecting a smaller maximum current or a shorter continuous energization time.

  In the electric assist supercharger according to the present invention, since the maximum current and the continuous energization time differ between the power running operation and the regenerative operation, it is desirable to prepare individual maps for each.

  FIG. 3 is a block diagram showing the configuration (during regeneration) of the control circuit of the electric compressor according to the present invention.

  That is, in the control circuit of the electric compressor, as shown in FIG. 3, when the electric assist supercharger is regenerated, a torque command value is input to the selector circuit 1 from the host ECU. Further, a value (internal calculation value) indicating the turbo rotation speed is input to the selector circuit 1 via the map table 2.

  Furthermore, a value indicating the temperature of the motor stator is input to the selector circuit 1 from the temperature sensor via the map table 4. In addition, a value indicating the temperature of the motor driver main circuit is input from the temperature sensor via the map table 7. Further, a value indicating the temperature of the motor driver control circuit is input from the temperature sensor via the map table 8. Further, a value indicating the power supply voltage from the voltage sensor and a generated voltage command value from the host ECU are input via the map table 10.

  The selector circuit 1 selects the smallest value from the input values and outputs it as a current command value to be supplied to the motor during power running. This current command value is a control command value.

  FIG. 4 is a graph showing a map table used during regeneration.

  Even during regeneration, the map table is set for each temperature sensor as shown in FIG. This map table shows the output limit value corresponding to the measured temperature, and the motor current is reduced in proportion to the square of the temperature above a predetermined output limit start temperature. Note that the motor output above the output restriction start temperature is not limited to the square of the temperature, but may be in a relationship proportional to the temperature a power (where a is a numerical value greater than 1).

  In such a map table, the temperature is set for each sensor, the output upper limit is calculated based on the measured temperature, and the smallest output upper limit is selected by the selector circuit 1 and used for motor control. .

  As a specific example of the map table, consider a case where output restriction is started at 85 ° C. and the output is 0% at 115 ° C. Further, it is assumed that the EBS is operated while climbing while towing (towing) a slope with a high slope.

  In such a case, the engine load is large, the vehicle speed is slow, and the outside air (cooling air) that enters the engine room decreases, so the temperature in the engine room rises and the cooling air volume of the motor driver also increases. Decrease. Then, the heat dissipation of the motor driver is lowered and the temperature starts to rise.

  And if the temperature of a motor driver exceeds 85 degreeC, the output limitation of a motor will be started and a loss will be reduced. At this time, the temperature of the motor driver is settled to a temperature where the reduced heat dissipation amount and the reduced loss are balanced.

  Here, consider a case where the temperature continues to rise to 100 ° C. (that is, between 85 ° C. and 115 ° C.). The current limit value is about 0.7 times (1 / √2 times) that of the unlimited case. Since the loss is proportional to the square of the current, it means that the motor torque proportional to the motor current is reduced by about 0.7 times while the loss is reduced to ½.

  In this way, in this electric assist supercharger, although the motor torque is reduced, the rate of decrease is moderate, so that a natural driving feeling can be realized.

  FIG. 5 is a diagram for explaining a map table calculation method in the electric compressor according to the present invention.

  The map table calculation method described above will be described with reference to FIG.

As shown in A in FIG. 5, at a temperature T _1, the motor output is 120% of the rated, at a temperature T _2, consider the case where the motor output is 0%. First, as shown by B in FIG. 5, the motor output is set to be (120 / √2)% at a temperature {(T ₁ + T ₂ ) / 2} between temperatures T ₁ and T _2. . When the horizontal axis (x-axis) is the temperature and the vertical axis (y-axis) is the motor output (%), as shown by C in FIG. 5, (T ₁ , 120), ({(T ₁ + T ₂ ) / 2}, (120 / √2)) and (T ₂ , 0), assuming a quadratic curve [y = ax ² + bx + c], the coefficients a and b , C can be defined.

120 = aT ₁ ² + bT ₁ + c
(120 / √2) = a {(T ₁ + T ₂ ) / 2} ² + b {(T ₁ + T ₂ ) / 2} + c
0 = aT ₂ ² + bT ₂ + c
An approximate expression may be used instead of the quadratic curve.

  The present invention is mainly applied to an electric assist supercharger used for a vehicle engine and an electric compressor control circuit for controlling an electric compressor constituting the electric assist supercharger.

    1 Selector circuit

Claims (4)

A compressor that compresses the air drawn from the exhaust manifold;
A motor for applying a rotational force to the compressor;
A motor driver for controlling the operation of the motor;
A temperature sensor for measuring the temperature of the motor and the motor driver,
The motor driver sets the motor output to the upper limit according to a temperature increase of the motor and the motor driver according to a relationship between the temperature of the motor and the motor driver stored in advance as a map and an upper limit of the motor output. An electric assist supercharger characterized by focusing on: The relationship between the temperature of the motor and the motor driver and the upper limit of the motor output is that the motor output is proportional to the a power of the temperature (where a is a numerical value greater than 1) above a predetermined temperature. The electric assist supercharger according to claim 1, wherein the relationship is a relationship. An electric compressor control circuit for controlling an electric compressor constituting the electric assist supercharger,
A motor driver that controls the operation of a motor that applies rotational force to the electric compressor;
A temperature sensor for measuring the temperature of the motor and the motor driver,
The motor driver sets the motor output to the upper limit according to a temperature increase of the motor and the motor driver according to a relationship between the temperature of the motor and the motor driver stored in advance as a map and an upper limit of the motor output. An electric compressor control circuit characterized by the following. The relationship between the temperature of the motor and the motor driver and the upper limit of the motor output is that the motor output is proportional to the a power of the temperature (where a is a numerical value greater than 1) above a predetermined temperature. The control circuit for an electric compressor according to claim 3, wherein the relationship is a relationship.

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