DE112010005981T5 - Method for controlling the current of an engine and control unit of an engine - Google Patents

Abstract

The present invention is a controller of an engine for taking out a capacity of an engine as much as possible so as to achieve a high-speed, high-power performance thereof while ensuring stability, including: a power converter unit therefor is configured to rectify and smooth an AC voltage and output a main DC circuit voltage, an inverter unit configured to pass a current for driving the motor using the main circuit voltage, a current detector configured to conduct an armature current passing through passing the motor, a position detector disposed on the motor, the position detector configured to detect an engine speed, and a current control unit configured thereto upon receipt of a q-axis current command (Iqr) At kerstrom, which passes through the motor, by outputting a signal for driving the inverter unit, with the use of data from the current detector and data from the position detector.

Description

TECHNICAL AREA

The present invention relates to a control unit of an engine. More particularly, the present invention relates to a method of controlling a current of a motor and a controller of an engine to achieve high speed and high power performance thereof while ensuring its stability by passing a correspondingly controlled d-axis current through a dq -transformed armature of the motor.

GENERAL PRIOR ART

A motor is driven by applying a voltage across conductors to the motor so as to pass a current through an armature of the motor. On the other hand, when the motor is rotated, a counter electromotive voltage occurs. When the applied voltage is higher than the counter electromotive voltage, a current flows, so that the motor can be driven. As the speed of the motor increases, the counter electromotive voltage increases. Since there is an upper limit of the voltage to be applied, finally, a voltage saturation occurs in the armature of the motor, and thus the current can no longer flow. Thereby, due to the lack of torque, it becomes impossible to drive the motor.

In order to achieve greater torque, it is necessary to increase the voltage to be applied. However, it requires a large equipment that is expensive. Alternatively, it may be considered that the capacities of the motor and an inverter driving the motor are increased. However, this solution also requires high costs and is undesirable. As a result, recently, free methods of preventing the occurrence of the voltage saturation to produce a larger torque have been proposed.

As a method of preventing the occurrence of voltage saturation in an armature of an engine, there has been proposed a method of controlling a current that can achieve higher-speed, higher-power performance by passing a d-axis current through the armature, where d A-axis direction corresponds to a direction of a magnetic field in the motor, so as to reduce a back electromotive force that occurs when the motor is rotated, whereby a q-axis current for generating a torque can be increased (see, eg. JP9-84400A ).

In addition, as a method for achieving higher performance performance, a control method has been proposed which can increase an effective voltage in comparison with a general case in which each phase is supplied with a sinusoidal phase voltage by having one voltage waveform conductor to conductor to a rectangular or pseudo-rectangular waveform (see eg JP3939481B ).

Although that in JP9-84400A can not be said that the capacity of the motor is pulled out as far as possible, if a circuit of an inverter for driving the motor is sufficient. This is because a reactive current is controlled so as to be passed at a fixed speed close to a speed at which a voltage saturation occurs. On the other hand, since that in JP3939481B disclosed control method makes a voltage waveform conductor against conductor to a rectangular or pseudo-rectangular waveform, the capacity of the motor is pulled out as far as possible, if the circuit of an inverter for driving the motor is sufficient. However, this method lacks stability, and there is a possibility that the current control in the worst case becomes unstable.

BRIEF SUMMARY OF THE INVENTION

The object of the present invention is to provide a method of controlling a current and a controller therefor which can pull out a capacity of a motor as much as possible so as to achieve a high-speed, high-power performance while ensuring stability ,

In order to accomplish the aforementioned object, an engine control apparatus of the present invention for exhausting a capacity of an engine as much as possible so as to achieve high-speed, high-performance performance thereof while ensuring stability, includes: a power converter unit configured to rectify and smooth an AC voltage and output a main DC circuit voltage, an inverter unit configured to pass a current for driving the motor using the main circuit voltage, a current detector configured thereto; detecting an armature current passing through the motor, a position detector disposed on the motor, the position detector configured to detect an engine speed, and a current control unit therefor is configured, upon receipt of a q-axis current command (Iqr), to control the armature current passing through the motor, by outputting a signal to drive the inverter unit, using data from the current detector, and data from the position detector.

The current control unit includes: a boundary processing unit configured to calculate the q-axis current limit (Iqlimit) upon receipt of the q-axis current command (Iqr), using a maximum value (Imax) of a composite current of q -Axis and d-axis and the d-axis current command (Idr) described below to limit the q-axis current command (Iqr) such that Iqr does not become equal to or greater than a q-axis current limit (Iqlimit) q-axis current limit command value (Iqrl) to obtain and turn on a boundary mark, which instructs a higher-level control entity for controlling a rotational speed and so on the limitation of the q-axis current limit command when the q-axis current limit command is limited to Override the speed and so on to prevent a PI equalization unit configured to improve a gain, a VqLimit processing nonunit (for Vq) configured to limit a voltage command (Vq) output by the PI equalization unit to a limit imposed by a boundary of a device and so on used in the controller; and a VdLimit processing unit (for Vd), a two-phase three-phase conversion unit configured to supply a two-phase voltage (Vql and Vdl) output by the VqLimit processing unit and the VdLimit processing unit To convert a three-phase voltage to actually drive the motor, a PWM conversion unit configured to convert a signal output by the two-phase three-phase conversion unit into a pulse, a d-axis current command generating unit therefor is configured to Idr with the use of Vql, Vdl and the electrical angular frequency (ω) described below a current detection unit configured to convert a signal from the current detector to data that can be processed by the current control unit, a three-phase two-phase conversion unit configured to generate a three-phase current of respective phases by the current detection unit has been outputted to convert to a two-phase current, and a position detection unit configured to convert a signal from the position detector to data that can be processed by the current control unit.

According to the present invention, there can be provided a method of controlling a current and a controller therefor which can pull out a capacity of a motor as much as possible so as to achieve high-speed and high-power performance while ensuring stability.

BRIEF DESCRIPTION OF THE DRAWINGS

1 FIG. 12 is a block diagram of an example of the method of controlling a current and the control apparatus therefor according to the present invention; FIG.

2 FIG. 3 is a flowchart of a boundary processing unit; FIG.

3 is a block diagram of a PI equalization unit,

4 FIG. 10 is a flowchart of a d-axis current command generating unit; and FIG

5 FIG. 12 is a block diagram of the integrating step S406 of FIG 4 ,

MODES FOR CARRYING OUT THE INVENTION

Hereinafter, an example of the present invention will be described.

EXAMPLE 1

Example 1 of the method of controlling a current and the control apparatus therefor according to the present invention will be described with reference to FIG 1 described. 1 Fig. 10 is a block diagram showing Example 1 of the present invention. A power source in 1 shows an AC power source that provides an AC voltage. The block diagram shows the method of controlling a current and the controller therefor, wherein: the supplied AC voltage is through a power converter unit 1 is rectified and smoothed and a main circuit DC voltage is output, and for the main circuit DC voltage is an inverter unit 2 based on one of a power control unit 3 output signal is switched to a motor 5 drive. One by the power control unit 3 output limit flag informs a superordinate control unit for controlling a speed and so forth about the limitation of a q-axis current limit command to prevent oversteering of the speed and so on.

In the 1 shown current control unit 3 which controls an armature current passing through the motor will be described below.

Upon receipt of a q-axis current command (hereinafter referred to as "Iqr") from outside, a boundary processing unit calculates 301 from an expression √ (Imax ^ 2 - Idr ^ 2) with the use of a maximum value (Imax) of a composite current of q-axis and d-axis and the d-axis current command described below (hereinafter referred to as "Idr") a q Axial Current Limit (hereinafter referred to as "Iqlimit").

In turn, when Iqr is equal to or greater than 0 and greater than Iqlimit, a q-axis current limit command value (hereinafter referred to as "Iqrl") is limited to Iqlimit, and the boundary mark is turned on. If Iqr is equal to or greater than 0 and equal to or less than -Iqlimit, or if Iqr is less than 0 and equal to or greater than Iqlimit, Iqrl is made Iqr and the boundary marker is turned off. If Iqr is less than 0 and less than -Iqlimit, Iqrl is limited to -Imlimit, and the boundary marker is turned on. Iqrl is obtained as described above and is passed through the boundary processing unit 301 issued (see 2 for details).

After that, this is done by the border processing unit 301 output Iqrl is reduced by a q-axis current (hereinafter referred to as "Iq") actually passing through the motor, and thereafter becomes a PI compensation unit 302a entered to increase a profit (see 3 for details). One through the PI compensation unit 302a output voltage command (hereinafter referred to as "Vq") becomes a VqLimit processing unit 303a configured to limit Vq to a limit that has been preset by limiting a device and so forth used in the controller.

The VqLimit processing unit 303a sets 1/2 of the main circuit DC voltage as a limit voltage VLimit (VLimit can be increased to the main circuit DC voltage / 2 × 1.15 with the use of a method in which the neutral point is moved to increase a phase voltage, so to increase a torque). If Vq is greater than VLimit, Vq is clamped to VLimit. Thereafter, a clamped q-axis voltage command (hereinafter referred to as "Vql") is output.

In addition, the Idr described below is reduced by a d-axis current (hereinafter referred to as "Id") that actually passes through the motor, and thereafter becomes a PI compensation unit 302b entered. One through the PI compensation unit 302b output voltage command (hereinafter referred to as "Vd") becomes a VdLimit processing unit 303b which is configured to limit Vd to a preset limit.

If Vd is greater than the VLimit described above, Vd is clamped to VLimit. Thereafter, a clamped d-axis voltage command (hereinafter referred to as "Vdl") is output.

A two-phase clamped voltage command (Vql and Vdl) generated by the VqLimit processing unit 303a and VdLimit processing unit 303b is output into a two-phase three-phase conversion unit 304 configured to convert the two-phase voltage command to a three-phase voltage to actually drive the motor (the content of the two-phase three-phase conversion unit) 304 is well known, and hence explanations thereof are omitted. See various documents for reference). A PWM conversion unit 305 configured by the two-phase three-phase conversion unit 304 converting the output signal to a pulse drives the inverter unit to drive the motor (the PWM conversion unit) 305 does not directly concern the present invention, and thus explanations thereof are omitted. See various documents for reference).

A current detection unit 307 which is configured to receive a signal from the current detector 4 to convert data generated by the power control unit 3 with the use of the two phase currents, the current of the remaining third phase is calculated from an expression Iv = - (Iu + Iw) and outputs these currents, as explained 1 , out. Alternatively, the current detection unit likes 307 only to convert data through the power control unit 3 can be processed, with current detectors are provided for three phases.

A three-phase two-phase conversion unit 308 configured to be detected by the current detection unit 307 output three-phase current from respective phases to a two-phase current outputs Iq and Id.

A position detection unit 305 configured to receive a signal from the position detector disposed on the motor 6 receive, converts a signal from the position detector 6 to data passing through the power control unit 3 can be processed, differentiates the data, calculates an electrical angular frequency (ω) of the motor and outputs it.

A d-axis current command generation unit 306 calculates VdVqerr from an expression VdVqerr = Vdl ^ 2 + Vql ^ 2 -Vlimit ^ 2 if Vql is equal to or greater than 0 and the above-described ω is equal to or less than 0, or else calculates VdVqerr from an expression VdVqerr = Vdl ^ 2 + -Vql ^ 2 ^ vlimit second

An integrator that has an integral constant ωi (see 5 ) performs an integral compensation (if a switch of 5 off) or a PI compensation (if the switch is from 5 one is) for VdVqerr and outputs Idri. As a method for turning on or off the switch of 5 There are some approaches: switching the switch depending on parameters or the like based on controllability, switching the switch in real time depending on programs or the like and so on.

If Idr is less than 0, Idr is made 0. If Idr is equal to or greater than 0 and greater than Idmax (Idmax is a constant value obtained in advance depending on the characteristics of the engine.) Idmax is usually the same as Imax, but can be found on some Imax engines distinguish), Idr is made Idmax. If Idr is equal to or greater than 0 and equal to or less than Idmax, Idr is made Idri (see 4 for details).

The power control unit 3 executes the method described above.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 9-84400 A [0004, 0006]
• JP 3939481 B [0005, 0006]

Claims (4)

A method of controlling a current of an engine so as to extend a capacity of an engine as much as possible so as to achieve a high speed, high power performance thereof while ensuring its stability, the engine including: a power converter unit configured to rectify and smooth an AC voltage and output a main DC circuit voltage, an inverter unit configured to pass a current to drive the motor using the main circuit voltage; a current detector configured to sense an armature current passing through the motor, a position detector disposed on the engine, wherein the position detector is configured to detect an engine speed, and a current control unit configured to control the armature current passing through the motor upon receipt of a q-axis current command (Iqr), outputting a signal for driving the inverter unit, using data from the current detector, and Data from the position detector. A method of controlling a current of an engine according to claim 1, wherein the power control unit includes: a boundary processing unit configured to calculate the q-axis current limit (Iqlimit) upon receipt of the q-axis current command (Iqr) using a maximum value (Imax) of a composite current of q-axis and d-axis and the d-axis current command (Idr) described below to limit the q-axis current command (Iqr) such that Iqr does not become equal to or greater than a q-axis current limit (Iqlimit) to provide a q-axis current limit command ( Iqrl), and to turn on a boundary mark instructing a higher-level control instance to control a speed and so on by limiting the q-axis current limit command when the q-axis current limit command is limited, to override the speed, and so on to prevent, a PI equalization unit to improve a profit a VqLimit processing unit (for Vq) configured to limit a voltage command (Vq) output by the PI equalization unit to a limit imposed by a limitation of a device and so forth in a controller is used, has been preset and a VdLimit processing unit (for Vd), a two-phase three-phase conversion unit configured to convert a two-phase voltage (Vql and Vdl) output by the VqLimit processing unit and the VdLimit processing unit to a three-phase voltage to actually drive the motor; a PWM conversion unit configured to convert a signal output by the two-phase three-phase conversion unit to a pulse; a d-axis current command generation unit configured to obtain Idr with the use of Vql, Vdl and the electrical angular frequency (ω) described below, a current detection unit configured to convert a signal from the current detector to data that can be processed by the current control unit, a three-phase two-phase conversion unit configured to convert a three-phase current of respective phases output by the current detection unit into a two-phase current, and a position detection unit configured to convert a signal from the position detector to data that can be processed by the power control unit. An engine control apparatus for taking out a capacity of the engine as much as possible so as to achieve a high speed, high power performance thereof while ensuring stability, wherein the engine control unit includes: a power converter unit configured to rectify and smooth an AC voltage and output a main DC circuit voltage, an inverter unit configured to pass a current to drive the motor using the main circuit voltage; a current detector configured to sense an armature current passing through the motor, a position detector disposed on the engine, wherein the position detector is configured to detect an engine speed, and a current control unit configured to control the armature current passing through the motor upon receipt of a q-axis current command (Iqr), outputting a signal for driving the inverter unit, using data from the current detector, and Data from the position detector. 3. The motor controller of claim 3, wherein the current control unit includes: a boundary processing unit configured to calculate the q-axis current limit (Iqlimit) upon receipt of the q-axis current command (Iqr), using a maximum value ( Imax) of a composite stream of q-axis and d-axis and the d-axis current command (Idr) described below, to limit the q-axis current command (Iqr) such that Iqr is not equal to a q-axis current limit (Iqlimit) or becomes larger than the same in order to obtain a q-axis current limit command value (Iqrl) and turn on a boundary flag instructing a higher-level control instance to control a rotational speed and so on through the limitation of the q-axis current limit command when the q-axis current Limited limit to prevent overdriving the speed and so on, a PI compensation unit to improve a profit, a VqLimit processing unit (for Vq) configured to limit a voltage command (Vq) output by the PI equalization unit to a limit imposed by a limitation of a device and so forth in a controller and a VdLimit processing unit (for Vd), a two-phase three-phase conversion unit configured to have a two-phase voltage (Vql and Vdl) outputted by the VqLimit processing unit and the VdLimit processing unit is to convert to a three-phase voltage to actually drive the motor, a PWM conversion unit configured to convert a signal output by the two-phase three-phase conversion unit to a pulse, a d-axis current command generating unit Idr configured with the use of Vql, Vdl and the electrical described below n angular frequency (ω), a current detection unit configured to convert a signal from the current detector to data that can be processed by the current control unit, a three-phase two-phase conversion unit configured to generate a three-phase current from respective ones Phase converted by the current detection unit to a two-phase current, and a position detection unit configured to convert a signal from the position detector to data that can be processed by the current control unit.

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