JP7619122B2 - Rotating electric machine control device - Google Patents

Description

The present invention relates to a control device for a rotating electric machine, and more specifically, to a control device for a rotating electric machine equipped with a resolver.

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

JP 2009-008536 A

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

The main purpose of the rotating electric machine control device of the present invention is to increase the opportunities to correct the resolver offset value and to detect the resolver rotational position with greater accuracy.

The rotating electric machine control device of the present invention employs the following means to achieve the above-mentioned main objective.

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:

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 correction when the rotation speed of the resolver is constant, it is possible to increase the opportunities to correct the offset value of the resolver. As a result, it is possible to detect the rotational position of the resolver with greater accuracy. Here, the power factor is the cosine (cos(voltage phase - current phase)) of the difference between the voltage phase and the current phase.

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

In the control device for a rotating electric machine of the present invention, the power factor command may be obtained using a power factor command setting map in which the relationship between the torque command and the power factor command is predefined. 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 predefined 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.

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

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 according to an embodiment of the present invention; 4 is an explanatory diagram for explaining an offset value OF of a resolver 28. FIG. 2 is a control block diagram showing an example of a functional block of a control device 30 when executing control to correct an offset value of a resolver 28. FIG. FIG. 4 is an explanatory diagram showing an example of a power factor command setting map; FIG. 13 is an explanatory diagram showing an example of a power factor command setting map according to a modified example.

Next, we will explain how to implement the present invention using examples.

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

The DC power source 22 may be a power storage device such as a battery, and may have a boost circuit that boosts and outputs the voltage of the DC power from the battery.

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

The resolver 28 is configured as a well-known resolver having an elliptical rotor connected to the rotating shaft of the motor 26, and a stator 128 as a magnetic body that incorporates an excitation coil to which an AC current is applied as an excitation signal from an oscillator circuit, and two output coils arranged electrically offset 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.

The control device 30 is configured as a well-known microcomputer centered on a CPU (not shown), and includes a ROM in which programs and the like are stored, 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 the v-phase current Iv from the current sensor 25v attached to the v-phase power line of the three-phase current applied from the inverter 24 to the motor 26, the w-phase current Iw from the current sensor 25w attached to the w-phase power line, a resolver signal from the 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 through the u-phase power line of the three-phase AC is calculated using the v-phase current Iv and the w-phase current Iw by Iu + Iv + Iw = 0. In addition, the control device 20 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 switching control signals that switch each switching element of the inverter 24 using a torque command. As shown in Figure 2, the offset value OF is a rotation angle error that occurs in the d-axis and q-axis in terms of control due to manufacturing errors, installation errors, etc.

Next, the control for correcting the offset value OF of the resolver 28 by the control device 30 of the drive device 20 configured in this manner will be described. FIG. 3 is a control block diagram showing an example of the functional blocks 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.

The power factor command calculation unit 32 calculates the power factor command Pf* using the torque command T*. In the embodiment, the power factor command is calculated by determining the relationship between the torque and the power factor in advance 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 then set as the power factor command Pf*. FIG. 4 shows an example of a 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 the ideal (target) power factor that should act on the motor 26. The power factor command setting map shown 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 shown 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 determined 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 and the carrier frequency input to the inverter 24, the torque, and the power factor may be determined in advance to create a power factor command setting map. In this case, the power factor increases slightly as the voltage Vh increases, and the power factor increases slightly as the carrier frequency of the inverter 24 increases.

The control power factor calculation unit 34 calculates the control power factor Pfc based on the measured values. For example, the current phase is calculated based on the v-phase current Iv and w-phase current Iw from the current sensors 25v and 25w, the resolver signal from the resolver 28, the offset value OF, etc., the voltage phase is calculated from the d-axis voltage Vd and the q-axis voltage Vq obtained by current feedback control, and the control power factor Pfc is calculated 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 corrected resolver angle φ corrected using the offset value OF and the offset correction value F is used for the calculation of the current phase and the voltage phase. Note that 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 it according to the following formula (1) using the self-inductances Ld and Lq and the d-axis current id and 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.

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

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 the offset correction value F, as shown in the following equation (2). In equation (2), kp is the gain of the proportional term, and ki is the gain of the integral term.

F=kp(Pf*-Pfc)+∫ki(Pf*-Pfc)dt (2)

The offset correction value F thus obtained is used to correct the offset value OF when calculating the resolver angle φ, and the corrected modified resolver angle φ is used to generate a switching control signal to be output to the inverter 24.

The control device 30 incorporated in the drive device 20 of the embodiment calculates the offset correction value F 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 rotational speed of the resolver 28 is constant. As a result, the rotational position (resolver angle φ) of the resolver 28 can be detected with greater accuracy.

The control device 30 incorporated in the drive device 20 of the embodiment calculates an offset correction value F that corrects the offset value OF so that the difference between the power factor command Pf* and the control power factor Pfc becomes smaller while the motor 26 is being driven. However, offset learning may be performed in which the offset correction value F is the offset value OF.

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 explained. 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".

The correspondence between the main elements of the Examples and the main elements of the invention described in the Means for Solving the Problem column does not limit the elements of the invention described in the Means for Solving the Problem column, since the Examples are examples for specifically explaining the form for implementing the invention described in the Means for Solving the Problem column. In other words, the interpretation of the invention described in the Means for Solving 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 Means for Solving the Problem column.

The above describes the form for carrying out the present invention using examples, but 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 invention.

The present invention can be used in the manufacturing industry of control devices for rotating electrical machines, etc.

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 (4)

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. The 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. The 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. 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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