Rotating electric machine control device

Abstract

To detect a rotational position of a resolver with accuracy by increasing opportunities for correcting an offset value of the resolver.SOLUTION: A device for controlling a rotary electric machine corrects an offset value of a resolver attached to a rotation shaft of a rotary electric machine driven by an inverter by using a power factor. Thereby, since the offset value can be corrected even when the rotary electric machine drives, opportunities for correcting the offset value of the resolver can be increased compared with a device that corrects the offset value only when a rotational speed of the resolver is constant, and thus, a rotational position of the resolver can be detected with accuracy.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a control device for a rotating electric machine, and more particularly to a control device for a rotating electric machine equipped with a resolver. [Background technology]

[0002] Conventionally, as a control device for this type of rotating electric machine, one has been proposed that calculates a correction parameter for the resolver based on rotational position data acquired at a plurality of specified time points when the rotational speed of the resolver is constant (for example, see Patent Document 1). In this control device, the correction parameter is calculated so as to be applicable to rotational position data of any value acquired when the resolver is rotating at any rotational speed and rotational position data of any value acquired when the resolver is stopped, thereby enabling the rotational position of the resolver to be detected with higher accuracy. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-008536 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned control device for a rotating electric machine, the correction parameters are calculated when the rotation speed of the resolver is constant, so in order to calculate the correction parameters accurately, it is necessary to keep the rotation speed of the resolver constant with high accuracy. For this reason, when the control device is mounted on an automobile or the like, the rotation speed of the resolver is seldom kept constant during normal use, and there are fewer opportunities to calculate the correction parameters accurately, which may result in the resolver rotation position not being detected with high accuracy.

[0005] A main object of the control device for a rotating electric machine of the present invention is to increase the opportunities for correcting the offset value of a resolver and to enable more accurate detection of the rotational position of the resolver. [Means for solving the problem]

[0006] The control device for a rotating electric machine according to the present invention employs the following means to achieve the above-mentioned main object.

[0007] The control device for a rotating electric machine of the present invention comprises: A control device for a rotating electric machine that corrects an offset value of a resolver attached to a rotating shaft of the rotating electric machine driven by an inverter, correcting the offset value of the resolver using a power factor; It is characterized by:

[0008] In the control device for a rotating electric machine of the present invention, the offset value is corrected using the power factor. Therefore, compared to a case where the offset value of the resolver is corrected when the rotation speed of the resolver is constant, the offset value of the resolver can be corrected more frequently. As a result, the rotational position of the resolver can be detected with higher accuracy. Here, the power factor is the cosine (cos(voltage phase-current phase)) of the difference between the voltage phase and the current phase.

[0009] In the control device for a rotating electric machine of the present invention, the offset value may be corrected so that the difference between a power factor command based on a torque command and a control power factor based on a measurement value becomes small. In this way, the offset value can be corrected more appropriately. Here, the power factor command is a power factor with respect to the torque command (power factor as a command value), and the control power factor is a power factor calculated from a measurement value.

[0010] In the control device for a rotating electric machine of the present invention, the power factor command may be acquired using a power factor command setting map in which the relationship between the torque command and the power factor command is predetermined. In this way, the power factor command can be obtained quickly and easily, and the offset value can be corrected quickly and easily. In this case, the power factor command setting map may be a map in which the relationship between the torque command and the power factor command is predetermined for at least one of the rotation speed of the rotating electric machine, the carrier frequency of the inverter, and the voltage of the DC power input to the inverter. In this way, the offset value can be corrected more appropriately.

[0011] In the control device for a rotating electric machine of the present invention, the control power factor may be calculated based on a current phase calculated based on a current flowing through the rotating electric machine and a signal from the resolver, and a voltage phase based on a d-axis voltage and a q-axis voltage obtained by current feedback control. [Brief description of the drawings]

[0012] [Figure 1] 1 is a diagram showing an outline of the configuration of a drive device 20 incorporating a control device 30 for a rotating electric machine as one embodiment of the present invention. [Diagram 2] 4 is an explanatory diagram for explaining an offset value OF of a resolver 28. FIG. [Diagram 3] 2 is a control block diagram showing an example of a functional block of a control device 30 when executing control for correcting an offset value of a resolver 28. FIG. [Figure 4] FIG. 4 is an explanatory diagram showing an example of a power factor command setting map; [Diagram 5] FIG. 13 is an explanatory diagram showing an example of a power factor command setting map according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Next, a mode for carrying out the present invention will be described using examples. EXAMPLES

[0014] 1 is a diagram showing an outline of the configuration of a drive device 20 incorporating a control device 30 for a rotating electric machine as one embodiment of the present invention. The drive device 20 includes a DC power supply 22, an inverter 24, a motor 26, a resolver 28, and a control device 30.

[0015] The DC power supply 22 corresponds to a power storage device such as a battery, and may have a boost circuit that boosts and outputs the voltage of DC power from the battery.

[0016] The motor 26 corresponds to various three-phase AC motors such as a synchronous generator motor or an induction motor, and is driven by a three-phase current of uvw phases applied from the inverter 24. The inverter 24 is configured as a well-known inverter circuit.

[0017] The resolver 28 is configured as a known resolver having an elliptical rotor connected to the rotating shaft of the motor 26, and a stator 128 as a magnetic body incorporating an excitation coil to which an AC current is applied as an excitation signal from an oscillator circuit, and two output coils arranged electrically shifted by 90 degrees (so that the phase difference is 90 degrees). The resolver outputs a sine wave sine signal and a cosine wave cos signal detected by the two output coils as resolver signals.

[0018] The control device 30 is configured as a well-known microcomputer centered on a CPU (not shown), and includes a ROM storing programs and the like, a RAM for temporarily storing data, a flash memory, an input circuit, an output circuit, and the like (not shown) in addition to the CPU. The control device 30 receives a v-phase current Iv from a current sensor 25v attached to a v-phase power line of the three-phase current applied from the inverter 24 to the motor 26, a w-phase current Iw from a current sensor 25w attached to a w-phase power line, a resolver signal from a resolver 28, a motor torque command, and the like via an input circuit. The input circuit for the resolver signal is configured as a well-known resolver input circuit including an AD converter that converts a sine signal or a cosine signal into a digital signal, and an RD converter that calculates a resolver angle φ from the sine signal and the cosine signal from the AD converter. In addition, the control device 20 outputs a switching control signal for switching each switching element of the inverter 24 from an output circuit. In the control device 20, the u-phase current Iu flowing in the u-phase power line of the three-phase AC is calculated by Iu+Iv+Iw=0 using the v-phase current Iv and the w-phase current Iw. The control device 20 also calculates a corrected resolver angle φ using an offset value OF and an offset correction value F for the resolver angle φ, and uses this when generating a switching control signal for switching each switching element of the inverter 24 using a torque command. The offset value OF is a rotation angle error occurring in the d-axis and q-axis in terms of control due to manufacturing errors, installation errors, etc., as shown in Fig. 2.

[0019] Next, a control for correcting the offset value OF of the resolver 28 by the control device 30 of the drive device 20 configured as described above will be described. Fig. 3 is a control block diagram showing an example of a functional block of the control device 30 when executing control for correcting the offset value OF of the resolver 28. The control device 20 includes, as functional blocks, a power factor command calculation unit 32, a control power factor calculation unit 34, a subtractor 36, and a PI controller 38.

[0020] The power factor command calculation unit 32 calculates the power factor command Pf* using the torque command T*. In the embodiment, the calculation of the power factor command is performed by previously determining the relationship between the torque and the power factor and storing it as a power factor command setting map, and when the torque command T* is given, the torque command T* is applied to the map to derive the power factor, which is set as the power factor command Pf*. FIG. 4 shows an example of the power factor command setting map. In the power factor command setting map of FIG. 4, the power factor decreases as the torque increases. The power factor is the cosine (cos(voltage phase-current phase)) of the difference between the voltage phase and the current phase, and the power factor command Pf* is an ideal (target) power factor that should act on the motor 26. The power factor command setting map illustrated in FIG. 4 derives a power factor command excluding the dead time voltage, but may derive a power factor command including the dead time voltage. In this case, the power factor command setting map illustrated in FIG. 5 may be used. The power factor command setting map shown in Fig. 5 is a map in which the relationship between the rotation speed of the motor 26, the torque command T*, and the power factor command Pf* is obtained in advance. As the rotation speed of the motor 26 increases, the power factor command Pf* increases, albeit slightly. In addition, the relationship between the voltage Vh or carrier frequency input to the inverter 24, the torque, and the power factor may be obtained in advance to create the power factor command setting map. In this case, the power factor increases, albeit slightly, as the voltage Vh increases, and the power factor increases, albeit slightly, as the carrier frequency of the inverter 24 increases.

[0021] The control power factor calculation unit 34 calculates the control power factor Pfc based on the measurement values. For example, the control power factor calculation unit 34 calculates the current phase based on the v-phase current Iv and the w-phase current Iw from the current sensors 25v and 25w, the resolver signal from the resolver 28, the offset value OF, and the like, calculates the voltage phase from the d-axis voltage Vd and the q-axis voltage Vq obtained by the current feedback control, and calculates the control power factor Pfc as the cosine (cos(voltage phase-current phase)) of the difference between the voltage phase and the current phase obtained by the calculation. Here, the calculation of the current phase and the voltage phase uses the corrected resolver angle φ corrected using the offset value OF and the offset correction value F. The voltage phase may be calculated by mapping the self-inductances Ld and Lq of the d-axis and q-axis inductances Ld and Lq in advance, and calculating the voltage phase according to the following formula (1) using the self-inductances Ld and Lq and the d-axis current id and the q-axis current iq of the armature current obtained from the phase currents. In equation (1), R is the armature resistance, ω is the angular velocity, p is the differential operator, and φ is the armature flux linkage due to the permanent magnet.

[0022]

number

[0023] The subtractor 36 calculates the difference (Pf*-Pfc) between the power factor command Pf* and the control power factor Pfc.

[0024] As shown in the following equation (2), the PI controller 38 calculates and outputs the sum of the proportional term and the integral term for the difference (Pf*-Pfc) between the power factor command Pf* and the control power factor Pfc as an offset correction value F. In equation (2), kp is the gain of the proportional term, and ki is the gain of the integral term.

[0025] F=kp(Pf*-Pfc)+∫ki(Pf*-Pfc)dt (2)

[0026] The offset correction value F thus obtained is used to correct the offset value OF when calculating the resolver angle φ, and a switching control signal to be output to the inverter 24 is generated based on the corrected resolver angle φ.

[0027] In the control device 30 incorporated in the drive device 20 of the embodiment, the offset correction value F is calculated so that the difference between the power factor command Pf* and the control power factor Pfc becomes small while the motor 26 is being driven. This increases the number of opportunities to calculate the offset correction value F of the resolver 28 compared to when the offset correction value F is calculated when the rotation speed of the resolver 28 is constant. As a result, the rotation position (resolver angle φ) of the resolver 28 can be detected with higher accuracy.

[0028] The control device 30 incorporated in the drive device 20 of the embodiment is configured to calculate an offset correction value F that corrects the offset value OF so as to reduce the difference between the power factor command Pf* and the control power factor Pfc while driving the motor 26. However, offset learning may be performed in which the offset correction value F is the offset value OF.

[0029] The correspondence between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem will be described below. In the embodiment, the inverter 24 corresponds to the "inverter", the motor 26 corresponds to the "rotating electric machine", the resolver 28 corresponds to the "resolver", and the control device 30 corresponds to the "control device".

[0030] The correspondence between the main elements of the Examples and the main elements of the invention described in the Summary of the Problem column does not limit the elements of the invention described in the Summary of the Problem column, since the Examples are examples for specifically explaining the mode for implementing the invention described in the Summary of the Problem column. In other words, the interpretation of the invention described in the Summary of the Problem column should be based on the description in that column, and the Examples are merely a specific example of the invention described in the Summary of the Problem column.

[0031] Although the form for carrying out the present invention has been described above using examples, the present invention is not limited to these examples in any way, and it goes without saying that the present invention can be carried out in various forms without departing from the scope of the gist of the present invention. [Industrial Applicability]

[0032] The present invention can be used in the manufacturing industry of control devices for rotating electrical machines. [Explanation of symbols]

[0033] 20 drive device, 22 DC power supply, 24 inverter, 25v, 25w current sensor, 26 motor, 28 resolver, 30 control device, 32 power factor command calculation unit, 34 control power factor calculation unit, 38 subtractor, 38 PI controller.

Claims

1. A control device for a rotating electric machine that uses a power factor to correct an offset value of a resolver attached to a rotating shaft of the rotating electric machine driven by an inverter, correcting the offset value so that a difference between a power factor command based on a torque command and a control power factor based on a measurement value becomes small; A control device for a rotating electric machine.

2. A control device for a rotating electric machine according to claim 1, obtaining the power factor command by using a power factor command setting map that defines a relationship between the torque command and the power factor command in advance; A control device for a rotating electric machine.

3. A control device for a rotating electric machine according to claim 2, the power factor command setting map is a map in which a relationship between at least one of a rotation speed of the rotating electric machine, a carrier frequency of the inverter, and a voltage of DC power input to the inverter, and between the torque command and the power factor command is determined in advance; A control device for a rotating electric machine.

4. A control device for a rotating electric machine according to any one of claims 1 to 3, The control power factor is calculated based on a current phase calculated based on a current flowing through the rotating electric machine and a signal from the resolver, and a voltage phase based on a d-axis voltage and a q-axis voltage obtained by current feedback control. A control device for a rotating electric machine.

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