KR100560259B1 - IPM motor controller - Google Patents

Abstract

The present invention discloses an IPM motor controller that ensures stability of control even in the presence of a non-linearly changing inductance component by implementing an IPM motor in a cross coupling control method using a proportional integral controller.

The present invention provides a proportional integral current control of the d-axis and q-axis current commands output from the current command generator and the current supplied to the IPM motor to control the coupling term of the IPM motor. IPM by generating a d-axis voltage and a q-axis voltage for driving an IPM motor in consideration of the change of inductance component in the cross-coupling method using a proportional integral controller by providing a coupling compensation means for generating a plurality of control values to compensate. The stability of the motor control is secured.

Description

IPM motor controller

1 is a block diagram of a conventional IPM motor controller

2 is a block diagram showing a preferred embodiment of the IPM motor controller according to the present invention.

3 is a flow chart illustrating the operation of the current command generator of FIG.

4A and 4B are graphs comparing the stabilization state of the d-axis current and the q-axis current of the conventional IPM motor controller of the present invention.

The present invention relates to an IPM motor controller, and more particularly, to implement an IPM motor in a cross-coupling control method using a proportional integral controller to secure control stability even in a non-linearly varying inductance component. It relates to a motor controller.

IPM (Interior Permanent Magnat) motor is a motor in which permanent magnets are embedded in the rotor, and since the permanent magnets are embedded in the structure, they are structurally robust and are advantageous for high speed rotation. In addition, IPM motors have a leakage path between the magnetic poles and the magnetic poles structurally, but the torque is slightly smaller than that of the SPM (Surface Permanent Magnat) motors of the same size. It is advantageous in terms of mechanical reliability and efficiency of the rotor.

The above-described IPM motor is applied to a hybrid electric vehicle.

The controller of the above-described conventional IPM motor is implemented in a feedforward manner, and the voltage equations for the d-axis and the q-axis are expressed by Equation 1 below.

[Equation 1]

In the above, Vd is a d-axis voltage and Vq is a q-axis voltage.

The controller of the IPA motor implementing the control in consideration of Equation 1 is implemented as shown in FIG. 1.

Referring to FIG. 1, when a torque command is inputted to the current command generator 10, the current command generator 10 generates a d-axis current command and a q-axis current command in proportion to each other by referring to the speed ωr fed back. Inputs are made to the integral current controllers 12 and 14, respectively.

The proportional integral current controller 12 provides a control signal obtained by proportionally integrating the d-axis current i _d outputted from the coordinate converter 16 and the d-axis current command to the d-axis voltage command generator 16, and proportionally integrated. The current controller 14 provides the q-axis voltage command generator 20 with a control signal obtained by proportionally integrating the q-axis current i _q and the q-axis current command outputted from the coordinate converter 16.

Meanwhile, a compensator 22 for compensating ωL _d i _d for the q axis and a compensator 24 for compensating ω L _q i _q for the d axis are configured, and the proportional integral current controller 12 includes a coordinate converter ( The control signal obtained by proportionally integrating the d-axis current (i _d ) output from 16) is provided to the d-axis voltage command generator 18, and the proportional integral current controller 14 outputs the q-axis output from the coordinate converter 16. The control signal obtained by proportionally integrating the current i _{q is} provided to the q-axis voltage command generator 20.

Accordingly, the d-axis voltage command generator 18 outputs the d-axis voltage command as a control signal provided from the proportional integral current controller 12 and the compensator 24, and the q-axis voltage command generator 20 outputs the proportional integral current controller. A q-axis voltage command is output as a control signal provided from (14) and the compensator (22).

The coordinate converter 26 operates to convert a two-phase voltage into a three-phase voltage. Accordingly, the d-axis voltage command and the q-axis voltage command are converted into three phases and output as voltages Vu, Vv, and Vw. The phase voltage is converted into a three phase current in the pulse width modulated inverter 28 and provided to the motor 30.

Conventional IPM motor controller is difficult to control the greater the amount of coupling as the control at high speed. In order to solve the above problems, the IPM motor is configured to compensate the coupling term (Coupling Term) by the feed forward method by configuring the compensators 22, 24 as shown in FIG.

However, in the above-described feedforward method, the coupling amount is calculated one step slowly, and since the inductance components Ld and Lq of the d-axis and q-axis are nonlinear, it is difficult to accurately predict the parameters.

Therefore, the problem that the control stability of an IPM motor controller falls.

An object of the present invention is to secure the stability of the IPM motor control by generating the d-axis voltage and the q-axis voltage for driving the IPM motor in consideration of the change in inductance component in a cross coupling method.

An IPM motor controller according to the present invention includes a current command generator for generating d-axis and q-axis current commands with reference to a torque command and a speed fed back from the IPM motor; A plurality of control values for compensating coupling term of the IPM motor by proportionally integral current control of the d-axis and q-axis current command and the feedback of the current supplied to the IPM motor and the d-axis and q-axis current Coupling compensation means for generating a; A d-axis voltage command generator that generates a d-axis voltage command by mixing a value of Ld of the d-axis and a value of the coupling term of the q-axis among the control values output from the coupling compensation means; A q-axis voltage command generator for generating a q-axis voltage command by mixing a value of Lq of the q-axis and a value of the coupling term of the d-axis thereof among the control values output from the coupling compensation means; A first coordinate converter which coordinate-converts the d-axis voltage command and the q-axis voltage command, respectively, and outputs the voltage in three phases; A pulse width modulation inverter converting the voltage of the three phases into a three phase current and providing the voltage to the IPM motor; And a second coordinate converter for converting the three-phase current output from the pulse width modulation inverter to provide the feedback d-axis current and q-axis current to the coupling compensation means.

Here, the coupling compensation means includes: a first mixer for extracting a difference between the d-axis current command and the fed back d-axis current; A second mixer for extracting a difference between the q-axis current command and the feedback q-axis current; A first proportional integral current controller that generates and outputs a value for Ld of a d-axis as a value output from the first mixer; A second proportional integral current controller configured to generate and output a value for a coupling term of d-axis as a value output from the first mixer; A third proportional integral current controller configured to generate and output a value for Lq of the q-axis as a value output from the second mixer; And a fourth proportional integral current controller which generates and outputs a value for the coupling term of the q-axis as a value output from the second mixer.

Hereinafter, a preferred embodiment of the IPM motor controller according to the present invention will be described in detail with reference to the accompanying drawings.

The embodiment according to the present invention is a q-axis proportional integral current controller and a d-axis proportional integral current controller cross-coupled to the d-axis proportional integral current controller and the q-axis proportional integral current controller, respectively, to control the nonlinear change. By controlling the IPM motor by having a configuration that employs.

2, an embodiment includes a starter 40 for generating a start torque command. The starting unit 40 is a mixing unit 48 for extracting the difference between the input speed command and the feedback speed (ωr) for the speed control at start-up, and the starting torque command as the speed difference extracted from the mixing unit 48 And a speed controller 50 for outputting.

The current command generator 52 is configured to input the starting torque command, the torque command for torque control in the normal driving state, and the speed ωr fed back.

According to the above configuration, the current command generator 52 generates the d-axis current command and the q-axis current command as the speed (ωr) fed back from the starting torque command in the starting state, respectively, and the torque command and the speed ( ωr) generates a d-axis current command and a q-axis current command, respectively.

Detailed operation of the current command generator 52 will be described later with reference to FIG.

On the other hand, the d-axis current command output from the current command generator 52 is input to the mixer 56, and the q-axis command is input to the mixer 58.

The IPM motor 42 is driven by three-phase currents ius, ivs and iws, and the three-phase currents ius, ivs and iws supplied to the IPM motor 42 are currents corresponding to the d-axis and q-axis by the coordinate converter 54. Is converted to.

The phase transformation performed by the coordinate transformer 54 applies dynamic modeling of the w-axis or dq theory if the power supply is equilibrium three phase, so that the coordinate transformer 54 removes time-varying parameters for the current input into the three phases. Variables and parameters are expressed as orthogonal or separated direct axis (d axis) and quadrature axis (q axis).

For reference, in the static coordinate system, the reference d-axis and the q-axis are fixed to the stator. On the other hand, in the rotation coordinate system, these reference axes rotate. Rotational coordinates can be fixed on the rotor or move at synchronous speed. The model of the coordinate system rotating at the synchronous speed has the advantage of representing the direct current of the variables in the steady state in the case of a sine wave power source, so that it can be easily used for control.

In order to realize this, the coordinate converter 54 has a map for representing two phases, and the data of the map can have a value obtained by applying torque and velocity conditions through a dynamo experiment or a finite element electromagnetic analysis (FEA). have.

The mixer 56 extracts the difference between the d-axis current command id * outputted from the current command generator 52 and the d-axis current id outputted from the coordinate converter 54 described above, and supplies them to the proportional integral current controllers 60 and 66. Output In addition, the mixer 58 extracts the difference between the q-axis current command iq * output from the current command generator 52 and the q-axis current iq output from the coordinate converter 54 described above. )

As described above, the proportional integral current controllers 62 and 66 are configured for cross coupling, and q is represented by d-axis current i _d and q-axis current i _q corresponding to the coupling term L _d , Lq. It is the configuration to compensate the voltage command of axis and d axis.

By the above-described configuration for compensating, the mixer 68 outputs the d-axis voltage command V _sd corresponding to the difference between the proportional integral current controller 60 and the proportional integral current controller 62, and the mixer 70 is proportional. The q-axis voltage command V _sq corresponding to the difference between the integral current controller 64 and the proportional integral current controller 66 plus ωΨ _F in consideration of Equation 1 is output. That is, the mixer 68 performs the function of the d-axis voltage command generator, and the mixer 70 performs the function of the q-axis voltage command generator.

The voltage command of the d-axis and the q-axis is input to the coordinate converter 72, and the coordinate converter 72 performs the inverse function of the above-described coordinate converter 54 to convert the two-phase voltage input to the three-phase voltages V _us , V _vs. , V _ws Of course, like the coordinate converter 54, it has a map for converting the input value of two phases into three phases.

The three-phase voltages V _us , V _vs , V _ws output as described above are input to the pulse width inverter 74, and the pulse width inverter 74 generates three-phase current three-phase currents ius, ivs, iws to generate an IPM motor. Provided by 42.

In the configuration of the embodiment of the present invention configured as described above, the current command generator 52 receives the torque and the speed as shown in FIG. 3 and utilizes a map having data corresponding to each axis to calculate the d-axis current and the q-axis current. Create and print each one.

Referring to FIG. 3, the current command generator 52 receives the torque and the speed (S10), and calculates the speed index i and the torque index j (S12).

The process of generating the d-axis current command and the q-axis current command is performed in parallel with reference to the speed index i and the torque index j calculated as described above.

First, the d-axis current command generation process, with reference to the speed index (i) and torque index (j) calculated as described above, extracts the four point values on the d-axis two-dimensional map (S14). This extracts the four-point values D (i, j), D (i + 1, j), D (i, j + 1), and D (i + 1, j + 1) for the d-axis. Linear interpolation is performed based on the point (S16). The d-axis current command is generated in accordance with the linear interpolation S16 (S18).

Then, the q-axis current command generation process, with reference to the speed index (i) and torque index (j) calculated as described above, extracts the four point values on the q-axis two-dimensional map (S20). This extracts the four-point values D (i, j), D (i + 1, j), D (i, j + 1), and D (i + 1, j + 1) for the q-axis, Linear interpolation is performed based on the point (S22). The q-axis current command is generated according to the linear interpolation S22 described above (S24).

In general, since the torque generated from the IPM motor has a non-linear characteristic compared to the current, the current command generator 52 inevitably generates a torque control error when a current is simply applied in proportion to the torque, and the exact torque due to the magnetic flux saturation phenomenon. Since control is difficult, it is difficult to apply general control loops.

In order to solve this problem, the d-axis and q-axis commands that have been selected in advance are stored in MAP form through experiments on all torque and full-speed ranges, and when the torque command and motor speed are input, the d-axis and q The axis command is configured to generate precise torque control through two independent two-dimensional maps.

As described above, according to the embodiment of the present invention, the d-axis current i _d , q corresponding to the coupling term L _d , Lq by configuring the proportional integral current controllers 62 and 66 for cross coupling. The axis current i _q compensates for the voltage command on the q and d axes.

Therefore, parameter prediction of the IPM motor can be made possible, and stability of control of the IPM motor controller can be ensured.

For reference, in case of applying the conventional technology, d-axis current i _d and q-axis current i _q have low stability as shown in FIG. 4A, but as a result of improving IPM motor control by applying the present invention, d-axis current i _d as shown in FIG. 4B. , q-axis current i _q is controlled stably.

Therefore, according to the present invention, the stability of the IPM motor control is secured by generating the d-axis voltage and the q-axis voltage for driving the IPM motor in consideration of the change of the inductance component by the cross coupling method using the proportional integral controller. .

Claims (2)

A current command generator for generating d-axis and q-axis current commands with reference to the torque command and the speed fed back from the IPM motor; A plurality of control values for compensating coupling term of the IPM motor by proportionally integral current control of the d-axis and q-axis current command and the feedback of the current supplied to the IPM motor and the d-axis and q-axis current Coupling compensation means for generating a; A d-axis voltage command generator that generates a d-axis voltage command by mixing a value of Ld of the d-axis and a value of the coupling term of the q-axis among the control values output from the coupling compensation means; A q-axis voltage command generator for generating a q-axis voltage command by mixing a value of Lq of the q-axis and a value of the coupling term of the d-axis thereof among the control values output from the coupling compensation means; A first coordinate converter which coordinate-converts the d-axis voltage command and the q-axis voltage command, respectively, and outputs the voltage in three phases; A pulse width modulation inverter converting the voltage of the three phases into a three phase current and providing the voltage to the IPM motor; And And a second coordinate converter for converting the three-phase current output from the pulse width modulation inverter to provide the feedback d-axis current and q-axis current to the coupling compensation means. The method of claim 1, wherein the coupling compensation means, A first mixer for extracting a difference between the d-axis current command and the fed back d-axis current; A second mixer for extracting a difference between the q-axis current command and the feedback q-axis current; A first proportional integral current controller that generates and outputs a value for Ld of a d-axis as a value output from the first mixer; A second proportional integral current controller configured to generate and output a value for a coupling term of d-axis as a value output from the first mixer; A third proportional integral current controller configured to generate and output a value for Lq of the q-axis as a value output from the second mixer; And And a fourth proportional integral current controller for generating and outputting a value for the coupling term of the q-axis as a value output from the second mixer.

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