JP2021019423A - Rotary motor system - Google Patents

Abstract

To provide a rotary motor system that enables control of making current in both positive and negative directions flow through a field winding and has a simple configuration.SOLUTION: A rotary motor system 10 comprises: a rotary motor 30 comprising armature windings 32 and a field winding 34; a battery 14 that is a power source for the rotary motor 30; an inverter 26 for making current flow through the armature windings 32; a step-up converter 18 to which power is supplied from the battery 14, and making voltage between buses 28a, 28b of the inverter 26 be variable; a field converter 24 for making current flow through the field winding 34, and connected between the buses 28a, 28b of the inverter 26; and a controller 12. The field converter 24 includes an arm A1 including serially connected two switching elements S3, S4 controlled by the controller 12. The field winding 34 has one end connected to a middle point ap of the arm A1 of the field converter 24 and another end connected to a positive side bp of the battery 14.SELECTED DRAWING: Figure 1

Description

The present invention relates to a rotary motor system including armature windings and field windings.

Conventionally, there is known a rotary electric motor which includes an armature winding and a field winding and can change a rotational torque by a field magnetic flux generated by passing a field current through the field winding. Such a system of a rotary motor includes a driving device (hereinafter referred to as a field converter) for passing a field current through a field winding, and the field converter is configured to include a plurality of switching elements. .. The control device controls the on / off of each switching element of the field converter and controls the field current (see, for example, Patent Document 1).

JP-A-2018-85799

A rotary electric motor system having a simple structure is desired because it is possible to control both a positive current (strong field current) and a negative current (weak field current) to flow through the field winding.

An object of the present invention is to provide a rotary electric motor system capable of controlling a current flowing through a field winding in both positive and negative directions and having a simple configuration.

The rotary motor system of the present invention includes a rotary motor including an armor winding that generates a rotating magnetic field and a field winding that generates a field magnetic flux, a battery that is a power source of the rotary motor, and the armature winding. A field connected between an inverter that allows current to flow through a wire, a boost converter that is supplied with power from the battery and makes the voltage between the busbars of the inverter variable, and a field that is connected between the busbars of the inverter and allows current to flow through the field winding. A magnetic converter, the inverter, the field converter, and a control device for controlling the boost converter are provided, and the field converter has two switching elements controlled by the control device connected in series. One end of the field winding, including an arm, is connected between two switching elements of the arm of the field converter, and the other end of the field winding is connected to the positive side of the battery. , Characterized by.

Further, in the rotary electric motor system of the present invention, the boost converter includes a switching element, and the control device controls the voltage between the bus buses of the inverter by controlling the switching element of the boost converter. The apparatus generates a gate signal of the switching element of the boost converter by using a first carrier signal having a first period, and generates a gate signal of the switching element of the field converter by using a first carrier signal having a first period. It may be generated using a two-carrier signal, and the first cycle may be shorter than the second cycle.

Further, the rotary electric motor system of the present invention further includes a current sensor that detects a current flowing through the field winding as a field current detection value, the boost converter includes a switching element, and the control device is the control device. The voltage between the bus lines of the inverter is controlled by controlling the switching element of the boost converter, and the control device includes a feedback controller that proportionally integrates and controls the deviation between the field current command value and the field current detection value. A feedforward controller that outputs the duty ratio of the gate signal of the switching element of the boost converter as a feedforward value is included, and based on the output of the feedback controller and the output of the feedforward controller, the said The duty ratio of the gate signal of the switching element of the field converter may be controlled.

According to the present invention, it is possible to control the flow of current in both positive and negative directions through the field winding by the two switching elements of the field converter, and since the field converter contains few switching elements, the rotary motor system Can be a simple configuration.

It is a circuit diagram of a rotary electric motor system. It is a block block diagram of the field current control device. It is explanatory drawing about the generation of the gate signal of the switching element of the boost converter. It is explanatory drawing about the generation of the gate signal of the switching element of the field converter. It is explanatory drawing about the generation of the gate signal of the switching element of the boost converter. It is a circuit diagram of the rotary electric motor system of the prior art. It is a circuit diagram of another rotary electric motor system of the prior art.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings. The configuration described below is an example for explanation, and can be appropriately changed according to the specifications of the rotary motor system and the like. Similar elements are designated by the same reference numerals in all drawings, and duplicate description is omitted. In addition, when a plurality of embodiments and modifications are included in the following, it is assumed from the beginning that those characteristic portions are used in appropriate combinations.

FIG. 1 is a circuit diagram of the rotary electric motor system 10 according to the present embodiment. The rotary motor system 10 includes a battery 14 (also referred to as a DC power supply), capacitors 16 and 22, a boost converter 18, a field converter 24, an inverter 26, a rotary motor 30, and a control device 12. The rotary motor 30 includes a stator and a rotor, and the stator is an electric machine that passes a field winding 34 that flows a direct current that creates a field in the rotor and an AC current that generates torque in the rotor by interacting with the field. It includes a child winding 32 (three-phase winding). The field winding 34 generates a field magnetic flux, and the armature winding 32 generates a rotating magnetic field. Although it is assumed here that the stator is provided with the field winding 34, the rotor or a member around the rotor may be provided with the field winding 34.

As shown in FIG. 1, the capacitor 16, boost converter 18, capacitor 22, field converter 24, and inverter 26 are connected in parallel to the battery 14. The battery 14 is a power source for the rotary electric motor 30. The inverter 26 passes a current through the armature winding 32 of the rotary motor 30, and the boost converter 18 is supplied with electric power from the battery 14 to make the voltage between the bus lines 28a and 28b of the inverter 26 variable. The field converter 24 is connected between the bus lines 28a and 28b of the inverter 26, and a current is passed through the field winding 34. The control device 12 controls the boost converter 18, the field converter 24, and the inverter 26.

The boost converter 18 includes an arm A0 in which two switching elements S1 and S2 are connected in series, and a reactor 20. Diodes are connected in parallel to both ends of each switching element S1 and S2. The arm A0 of the boost converter 18 is connected between the bus lines 28a and 28b of the inverter 26, one end of the reactor 20 is connected to the midpoint cp of the arm A0, and the other end of the reactor 20 is the positive side (positive electrode) of the battery 14. It is connected to bp. The bus 28b on one side of the inverter 26 is connected to the negative side (negative electrode) of the battery 14. The control device 12 boosts the output voltage vb of the battery 14 by controlling the on / off of the two switching elements S1 and S2 of the boost converter 18, and applies the voltage vc between the bus bars 28a and 28b of the inverter 26. .. The ratio of the voltage vc to the voltage vb (boosting ratio) changes depending on the on / off period of the switching elements S1 and S2.

The field converter 24 is composed of an arm A1 in which two switching elements S3 and S4 are connected in series. Diodes are connected in parallel to both ends of the switching elements S3 and S4 so that a current in the direction opposite to the current direction of the switching elements S3 and S4 flows. The arm A1 of the field converter 24 is connected between the bus lines 28a and 28b of the inverter 26, and one end of the field winding 34 is connected between the switching elements S3 and S4 of the arm A1 (midpoint a). The other end of the magnetic winding 34 is connected to the positive side bp of the battery 14. The control device 12 controls the on / off of the two switching elements S3 and S4, and controls the direction and magnitude of the field current if flowing through the field winding 34 by changing the on / off period. A current sensor 40 is provided in the current path of the field current if. The detected value of the field current if detected by the current sensor 40 (hereinafter, also referred to as the field current detected value if) is transmitted to the control device 12.

The inverter 26 is a three-phase inverter. Specifically, the inverter 26 includes a U-phase arm B1, a V-phase arm B2, and a W-phase arm B3 connected in parallel. Two switching elements Sa and Sb are connected in series to each arm B1, B2 and B3, and a diode is connected to both ends of each switching element Sa and Sb so that a current in a direction opposite to the current direction of each switching element flows. Are connected in parallel. The armature winding 32 includes a U-phase winding through which a U-phase current flows, a V-phase winding through which a V-phase current flows, and a W-phase winding through which a W-phase current flows. In FIG. 1, the U-phase winding, the V-phase winding, and the W-phase winding are designated by u, v, and w, respectively. The control device 12 controls the current (three-phase current) of the armature winding 32 (three-phase winding) by controlling the on / off of each switching element of the inverter 26. In FIG. 1, the winding of each phase of the armature winding 32 (three-phase winding) is shown in a simplified manner, and only one is used for each phase. However, in reality, a plurality of windings are used for each phase. The wires are connected in series.

One end of the U-phase winding is connected to the midpoint between the switching elements Sa and Sb of the U-phase arm B1. One end of the V-phase winding is connected to the midpoint between the switching elements Sa and Sb of the V-phase arm B2. One end of the W-phase winding is connected to the midpoint between the switching elements Sa and Sb of the W-phase arm B3. The other ends of the U-phase winding, the V-phase winding and the W-phase winding are commonly connected at the neutral point G.

The current iu flowing in the U-phase winding is detected by the current sensor 38u, the detected value is transmitted to the control device 12, and the current iv flowing in the V-phase winding is detected by the current sensor 38v, and the detected value is controlled. It is transmitted to the device 12. Since the windings of each phase of the three-phase windings are commonly connected at the neutral point G, the sum of the currents iu, iv, and iw flowing through the windings of each phase becomes zero. Therefore, the control device 12 Can acquire the current iwa flowing through the W-phase winding from the detected values iu and iv.

The rotary electric motor 30 is provided with a rotation angle sensor 36 (for example, a resolver). The rotation angle position (hereinafter, also referred to as rotation angle) θe of the rotor detected by the rotation angle sensor 36 is transmitted to the control device 12.

The control device 12 has the gate signals GS1 and GS2 of the switching elements S1 and S2 of the boost converter 18 and the gate signals GS3 and S4 of the switching elements S3 and S4 of the field converter 24 based on the generated or input torque command value. The GS4 and the gate signal GI of the switching element of the inverter 26 (here, the gate signals of the six switching elements of the inverter 26 are collectively indicated by the code GI) are generated. The torque command value is derived from the accelerator opening degree and the vehicle speed by referring to a map or the like in the control device 12, for example, when the rotary electric motor system 10 is mounted on the vehicle.

The control device 12 controls the gate signals GS1 and GS2 of the switching elements S1 and S2 of the boost converter 18 based on the torque command value, and controls the voltage vc between the bus lines 28a and 28b of the inverter 26. Further, the control device 12 generates a field current command value irf from the torque command value so that the deviation between the field current command value irf and the field current detection value if (detection value of the current sensor 40) becomes zero. The feedback control is performed to generate the gate signals GS3 and GS4, and the field current if is controlled via the field converter 24. Further, the control device 12 generates dq-axis current command values ird and irq from the torque command value, and sets the current detection values iu, iv and iwa of each phase of the three-phase winding 32 by using the rotation angle θe of the rotor. The gate signal GI is generated by converting to the axis current detection values id and iq and performing feedback control so that the deviation between the dq axis current command values ird and irq and the dq axis current detection values id and iq becomes 0, and the inverter 26 The three-phase currents iu, iv, and iwa are controlled via. Since these controls are known, detailed description thereof will be omitted in the present specification. The field current control device 50 (see FIG. 2) applicable to the rotary motor system 10 of the present embodiment will be described later.

Next, the relationship between the on / off of the switching elements S3 and S4 of the field converter 24 and the field current if will be described. As described above, one end of the field winding 34 is connected to the midpoint a of the arm A1 of the field converter 24, and the other end of the field winding 34 is connected to the positive side bp of the battery 14. Has been done. Therefore, the potential of the other end of the field winding 34 (hereinafter, also referred to as bp point) is constant at vb, which is the output potential of the battery 14, while one end of the field winding 34 (hereinafter, ap point). The potential of (also referred to as) depends on the on / off state of the switching elements S3 and S4 and the magnitude of the voltage vc between the bus bars 28a and 28b of the inverter. Here, the voltage vc is higher than the voltage vb due to the function of the boost converter 18 (vc> vb).

When the switching element S3 is turned on and S4 is turned off, the potential at the ap point becomes vc, and the potential at the bp point is vb (<vc), so that the field current if flows from the ap point to the bp point. That is, since the potential at the ap point is higher than the potential at the bp point, the field current if flows in the positive direction (the direction indicated by the solid arrow of if shown in FIG. 1). On the other hand, when the switching element S3 is turned off and S4 is turned on, the potential at the ap point becomes 0V and the potential at the bp point is vb (> 0V), so that the field current if is from the bp point toward the ap point. It flows. That is, since the potential at the ap point is lower than the potential at the bp point, the field current if flows in the negative direction (the direction opposite to the direction indicated by the solid arrow of if shown in FIG. 1).

Next, the control of the switching elements S3 and S4 by the control device 12 will be described. The potential vap at the ap point is expressed by the following equation (1).

vap = df × vc ・ ・ ・ (1)

In the above equation (1), df is the duty ratio of the gate signals GS3 and GS4 of the switching elements S3 and S4. Specifically, the duty ratio df is the ratio of the period t1 in which S3 is on and S4 is off to the period t2 in which S3 is off and S4 is on, and is expressed by the following equation (2).

df = t1 / t2 ... (2)

Here, when the potential vap at the ap point is set to vb (battery potential) (vap = vb), the potential vbp at the bp point is constant at vb (battery potential) (vbp = vb), so the field current if is 0A. It becomes. Substituting vap = vb for which the field current if = 0A into the above equation (1) yields df = (vb / vc). Therefore, it can be seen that the field current if can be set to 0A by controlling the periods t1 and t2 (switching of S3 and S4) so that the control device 12 has df = (vb / vc). Further, the control device 12 can flow the field current if in the positive direction by controlling the periods t1 and t2 so that df> (vb / vc), and df <(vb / vc). By controlling the periods t1 and t2 in this way, the field current if can flow in the negative direction.

According to the rotary motor system 10 described above, although the field converter 24 has only two switching elements S3 and S4, the field winding 34 has a positive current (strong field current). ) And the current in the negative direction (field weakening current) can be controlled. Since the field current if can be controlled to flow in both the positive and negative directions in this way, the current responsiveness of the field current if can be increased when the torque command value is increased or decreased. For example, when the field current if is flowing in the positive direction with a relatively large current value, when the field current if is reduced to 0 (A) according to the torque command value, the field current according to the present embodiment is used. Since it is possible to control the flow of the if in the negative direction, the field current if can be changed to 0 (A) in a short time. Further, according to the rotary motor system 10 described above, since the field converter 24 has a simple configuration, the rotary motor system 10 or a power control unit (a unit including the field converter 24 and the inverter 26). It is also advantageous in terms of cost (also called PCU).

Note that FIG. 6 is a circuit diagram of a conventional rotary electric motor system. The rotary electric motor system 110 of the prior art also includes a field converter 124, and the field converter 124 is composed of an arm A11 in which two switching elements S13 and S14 are connected in series. The arm A11 is connected between the busbars of the inverter 26, one end of the field winding 34 is connected to the midpoint a (ap point) of the arm A11, and the other end of the field winding 34 is the busbar on one side of the inverter 26. It is connected to (bp point). In this conventional rotary electric motor system 110, the field converter 124 is also composed of two switching elements S13 and S14. However, the ap point of the field converter 124 can output only the same or higher potential as the bp point, and only the current in the positive direction can flow through the field winding 34.

Further, FIG. 7 is a circuit diagram of another rotary electric motor system according to the prior art. This conventional rotary electric motor system 210 also includes a field converter 224, and the field converter 224 is composed of a first arm A21 and a second arm A22 connected in parallel. Two switching elements S23 and S24 and switching elements S25 and S26 are connected in series to the first and second arms A21 and A22, respectively. The first and second arms A21 and A22 are connected between the busbars of the inverter 26, one end of the field winding 34 is connected to the midpoint a of the arm A21, and the other end of the field winding 34 is inside the arm A22. Connected to point bp. The rotary electric motor system 210 of the prior art can pass a current in both positive and negative directions through the field winding 34, and has four switching elements of the field converter 224.

From the above, the rotary motor system 10 of the present embodiment is more advantageous than the conventional rotary motor systems 110 and 210 (FIGS. 6 and 7) from the viewpoint of controlling the field current if and the circuit configuration. It is easy to understand that.

Next, the control of the field converter 24 applicable to the rotary electric motor system 10 of the present embodiment will be described. As can be seen from the above equation (1), the potential vap at the ap point (see FIG. 1) of the field converter 24 changes depending on the voltage vc between the bus 28a and 28b of the inverter 26. Here, the voltage vc can be expressed by the following equation (3).

vc = du × vb ・ ・ ・ (3)

In the above equation (3), du is the duty ratio of the gate signals GS1 and GS2 of the switching elements S1 and S2 of the boost converter 18. Specifically, the duty ratio du is the ratio of the period t3 in which S1 is off and S2 is on to the period t4 in which S1 is on and S2 is off, and can be expressed by the following equation (4).

du = t3 / t4 ... (4)

The control device 12 controls the voltage vc to a desired voltage value by controlling the duty ratio du. Here, the duty ratio du affects the potential vap at the ap point of the field converter 24 via the voltage vc, and the potential vap at the ap point affects the field current if. That is, the duty ratio du affects the field current if. Therefore, in the control of the field converter 24 described here (control of the field current if), the duty ratio du of the boost converter 18 is used as a control factor.

The control device 12 includes a field current control device that generates gate signals GS3 and GS4 of the switching elements S3 and S4 of the field converter 24. FIG. 2 is a block configuration diagram of the field current control device 50. The field current controller 50 includes a feedback controller 52, a feedforward controller 58, a limiter 60, and a PWM 62. The feedback controller 52 is proportional to the adder 55 that calculates the deviation (= irf-if) between the field current command value irf and the field current detection value if, and the deviation calculated by the adder 55 so as to approach zero. Includes a proportional integral controller 56 that performs integral control (PI control). The feedforward controller 58 outputs the duty ratio du of the gate signals GS1 and GS2 of the switching elements S1 and S2 of the boost converter 18 as a feedforward value. The output of the feedback controller 52 and the output of the feedforward controller 58 are added by the adder 59, and the output signal of the adder 59 is input to the PWM 62 after passing through the limiter 60. The PWM 62 generates the gate signals GS3 and GS4 of the switching elements S3 and S4 of the field converter 24 according to the input signal from the limiter 60. According to this configuration, the field current controller 50 is based on the output of the feedback controller 52 and the output of the feedforward controller 58, and the gate signals GS3 and GS4 of the switching elements S3 and S4 of the field converter 24. Duty ratio df is controlled. When the torque command value increases or decreases, the field current command value irf may be changed, the duty ratio du of the boost converter 18 may be changed, and the field current if may be adjusted. At this time, according to the above-mentioned field current control device 50, in addition to the feedback control according to the field current command value irf, the feed forward control according to the duty ratio du of the boost converter 18 is performed, so that the field current is obtained. The if can quickly move to the field current command value irf. That is, the responsiveness (followability) of the field current if to the field current command value irf can be improved.

Next, a carrier signal applicable to the rotary motor system 10 of the present embodiment will be described. FIG. 3 is an explanatory diagram for generating gate signals GS1 and GS2 of the switching elements S1 and S2 of the boost converter 18. The control device 12 generates the gate signals GS1 and GS2 by comparing the threshold value BCth set based on the torque command value with the signal value of the first carrier signal CS1. In FIG. 3, when the threshold BCth is larger than the signal value of the first carrier signal CS1, GS1 is set to High (on), GS2 is set to Low (off), and the threshold BCth is equal to or less than the signal value of the first carrier signal CS1. The state in which GS1 and GS2 are generated is shown so that GS1 is set to Low (off) and GS2 is set to High (on). Further, FIG. 3 shows a current iL (hereinafter, also referred to as a reactor current iL) flowing through the reactor 20 (see FIG. 1) when the on / off of the switching elements S1 and S2 of the boost converter 18 is controlled according to the GS1 and GS2. It is shown.

As shown in FIG. 3, a ripple of amplitude α may appear in the reactor current iL, and the magnitude of the amplitude α depends on the period Tc1 (also referred to as the first period Tc1) of the first carrier signal CS1. As shown in FIG. 5, the larger the period Tc1 of the first carrier signal CS1, the larger the amplitude α. When the reactor current iL having a ripple having a large amplitude α is input to the battery 14, the deterioration of the battery 14 may progress. Therefore, in order to suppress the deterioration of the battery 14, it is desirable to reduce the amplitude α by reducing the period Tc1 of the first carrier signal CS1 as shown in FIG.

FIG. 4 is an explanatory diagram for generating gate signals GS3 and GS4 of the switching elements S3 and S4 of the field converter 24. Similar to the gate signals S1 and S2 of the boost converter 18, the control device 12 (field current control device) compares the threshold value FCth set based on the torque command value with the signal value of the second carrier signal CS2. As a result, the gate signals GS3 and GS4 of the field converter 24 are generated. In FIG. 4, when the threshold FCth is larger than the signal value of the second carrier signal CS2, GS3 is set to High (on), GS4 is set to Low (off), and the threshold FCth is equal to or less than the signal value of the second carrier signal CS2. The state in which GS3 and GS4 are generated is shown so that GS3 is set to Low (off) and GS4 is set to High (on). Further, FIG. 4 shows a field current if when the on / off of the switching elements S3 and S4 of the field converter 24 is controlled according to the GS3 and GS4.

Similar to the reactor current iL, as shown in FIG. 4, a ripple of amplitude β may appear in the field current if, and the magnitude of the amplitude β is determined by the period Tc2 of the second carrier signal CS2 (second period Tc2). Also called). As the period Tc2 of the second carrier signal CS2 becomes larger, the amplitude β can become larger. However, since the inductance of the field winding 34 is several to several hundred times larger than that of the reactor 20 of the boost converter 18, even if the period Tc2 of the second carrier signal CS2 is increased, the field current if The amplitude β does not become as large as the amplitude α of the reactor current iL. If the period Tc2 of the second carrier signal CS2 is increased, the number of switchings of the switching elements S3 and S4 of the field converter 24 is reduced, so that deterioration of the switching elements S3 and S4 can be suppressed. Therefore, as shown in FIG. 4, it is desirable to increase the period Tc2 of the second carrier signal CS2.

Therefore, in the rotary motor system 10 of the present embodiment, the control device 12 assumes that the period Tc1 of the first carrier signal CS1 of the boost converter 18 is shorter than the period Tc2 of the second carrier signal CS2 of the field converter 24. May be good. In this way, it is possible to suppress both the deterioration of the battery 14 and the deterioration of the switching elements S3 and S4 of the field converter 24.

10,110,210 Revolving motor system, 12 controller, 14 battery, 16,22 capacitor, 18 boost converter, 20 reactor, 24,124,224 field converter, 26 inverter, 28a, 28b bus, 30 revolving motor, 32 armature winding (three-phase winding), 34 field winding, 36 rotation angle sensor, 38u, 38v, 40 current sensor, 50 field current controller, 52 feedback controller, 55 adder, 56 proportional integration Controller (PI controller), 58 feed forward controller, 59 adder, 60 limiter, 62 PWM, CS1 1st carrier signal, CS2 2nd carrier signal, S1, S2, S3, S4, S13, S14, S23, S24, S25, S26, Sa, Sb switching element, A0, A1, A11 arm, A21 first arm, A22 second arm, B1 U phase arm, B2 V phase arm, B3 W phase arm, if field current detection value (Field current), irf field current command value, iL reactor current.

Claims (3)

A rotating motor equipped with an armature winding that generates a rotating magnetic field and a field winding that generates a field magnetic flux,
The battery, which is the power source for the rotary motor,
An inverter that allows current to flow through the armature winding,
A boost converter that is powered by the battery and variable the voltage between the busbars of the inverter.
A field converter connected between the busbars of the inverter and passing a current through the field winding,
A control device for controlling the inverter, the field converter, and the boost converter is provided.
The field converter includes an arm in which two switching elements controlled by the control device are connected in series.
One end of the field winding is connected between two switching elements of the arm of the field converter, and the other end of the field winding is connected to the positive side of the battery.
A rotary motor system that features this. The rotary electric motor system according to claim 1.
The boost converter includes a switching element, and the control device controls the voltage between the bus buses of the inverter by controlling the switching element of the boost converter.
The control device generates a gate signal of the switching element of the boost converter by using a first carrier signal having a first period, and generates a gate signal of the switching element of the field converter by using a first carrier signal having a first period. Generated using the second carrier signal that has
The first cycle is shorter than the second cycle.
A rotary motor system that features this. The rotary electric motor system according to claim 1.
A current sensor that detects the current flowing through the field winding as a field current detection value is further provided.
The boost converter includes a switching element, and the control device controls the voltage between the bus buses of the inverter by controlling the switching element of the boost converter.
The control device is
A feedback controller that proportionally integrates and controls the deviation between the field current command value and the field current detection value, and a feedforward controller that outputs the duty ratio of the gate signal of the switching element of the boost converter as a feedforward value. , Including,
The duty ratio of the gate signal of the switching element of the field converter is controlled based on the output of the feedback controller and the output of the feedforward controller.
A rotary motor system that features this.