JP2024126775A - Angle detection device - Google Patents

Abstract

To provide an angle detection device capable of suppressing a detection error of angle information generated by disturbance magnetic flux of a dynamo-electric machine changed according to an operation state of the dynamo-electric machine.SOLUTION: An angle detection device includes: a resolver that includes a rotor fixed to a rotating shaft of a dynamo-electric machine and having a salient pole, and a stator having excitation winding and output winding; an excitation section that generates an AC voltage for excitation and applies an excitation voltage to the excitation winding according to the AC voltage for excitation; an angle information arithmetic section that computes angle information on the basis of an output signal of the output winding; and a state acquisition section that acquires an operation state of the dynamo-electric machine. The excitation section changes an amplitude of the AC voltage for excitation on the basis of the operation state of the dynamo-electric machine.SELECTED DRAWING: Figure 2

Description

This application relates to an angle detection device.

In the technology of Patent Document 1, a resolver is fixed to the rotating shaft of a rotating electric machine, and the rotating electric machine is controlled based on the angle information detected by the resolver.

In the technology of Patent Document 1, the resolver has an excitation winding and two output windings with different phases, and a sine wave excitation signal is input to the excitation winding to generate a magnetic field in the resolver, which generates output signals in the two output windings. In the technology of Patent Document 1, the phases of the two output signals are shifted, a phase modulation signal is generated by a combiner, and the rotation angle of the rotor is detected based on the phase difference between the phase modulation signal and the excitation signal.

JP 2020-101384 A

The magnetic flux generated by the field winding of the rotating electric machine flows through the rotating shaft of the rotating electric machine and interlinks with the excitation winding and output winding of the resolver. If the rotating shaft of the rotating electric machine becomes eccentric, the interlinked magnetic flux fluctuates with the rotation period, generating induced electromotive forces in the excitation winding and output winding, which become disturbance noise and cause errors in the detection angle.

In the technology of Patent Document 1, the two output signals are passed through a band-pass filter to attenuate disturbance noise, and the effect of fluctuations in the rotation speed of the rotating electric machine on disturbance noise is addressed by providing a separate gain adjustment circuit and adjusting the gain of the phase modulation signal as the rotation speed of the rotating electric machine increases.

However, when disturbance noise is superimposed on the excitation signal and the amplitude of the excitation signal is limited by the upper and lower limits of the possible output range, the voltage waveform of the excitation signal is distorted from a sine wave, and the waveforms of the two output signals are distorted. In this case, even if a bandpass filter is used as in the technology of Patent Document 1, the distortion of the waveforms of the two output signals cannot be removed, resulting in an angle detection error.

The disturbance magnetic flux generated by such a rotating electric machine changes depending on the operating state of the rotating electric machine. Therefore, the amount of fluctuation in the excitation signal and the output signal due to the disturbance magnetic flux changes depending on the operating state of the rotating electric machine, and when the amount of fluctuation is large, the angle detection error becomes large.

Therefore, the present application aims to provide an angle detection device that can suppress detection errors in angle information caused by disturbance magnetic flux of a rotating electric machine, which changes depending on the operating state of the rotating electric machine.

The angle detection device according to the present application comprises:
A resolver including a rotor fixed to a rotating shaft of a rotating electric machine and having salient poles, and a stator having an excitation winding and an output winding;
an excitation unit that generates an excitation AC voltage and applies an excitation voltage corresponding to the excitation AC voltage to the excitation winding;
an angle information calculation unit that calculates angle information based on an output signal of the output winding;
a state acquisition unit that acquires an operating state of the rotating electric machine,
The excitation unit changes the amplitude of the excitation AC voltage based on the operating state of the rotating electric machine.

When the operating state of the rotating electric machine changes, the disturbance magnetic flux of the rotating electric machine changes, and the effect on the excitation voltage and the output signal of the output winding changes. By changing the amplitude of the excitation AC voltage based on the operating state of the rotating electric machine, the range of change in the excitation signal and the output signal after fluctuation due to the disturbance magnetic flux can be prevented from becoming too large, and detection errors in the angle information can be suppressed.

1 is a schematic configuration diagram of a rotating electric machine, an angle detection device, and the like according to a first embodiment; 1 is a schematic configuration diagram of an angle detection device according to a first embodiment. 5 is a time chart illustrating behavior of an excitation voltage and an output signal according to the first embodiment. 1 is a schematic configuration diagram of a rotating electric machine and a power converter according to a first embodiment; 1 is a schematic block diagram of a control device according to a first embodiment. 5 is a time chart illustrating PWM control of an excitation unit according to the first embodiment. 1 is a schematic configuration diagram of an angle detection device according to a first embodiment. 5 is a schematic diagram for explaining disturbance magnetic flux according to the first embodiment. FIG. 5 is a time chart for explaining an excitation voltage when there is no disturbance magnetic flux according to the first embodiment. 5 is a time chart for explaining an excitation voltage when there is a disturbance magnetic flux according to the first embodiment. 5 is a time chart for explaining an excitation voltage when there is a disturbance magnetic flux according to the first embodiment. 5 is a diagram for explaining setting of a modulation factor K according to a current of a field winding according to the first embodiment. FIG. 5 is a diagram for explaining setting of a modulation rate K according to a rotation speed according to the first embodiment. FIG. 4 is a time chart for explaining the influence of a sudden change in modulation rate according to the first embodiment; 5 is a diagram for explaining setting of a modulation rate K according to a rotation speed according to the first embodiment. FIG.

1. First embodiment
An angle detection device 1 according to a first embodiment will be described with reference to the drawings. Fig. 1 is a schematic configuration diagram of the angle detection device 1. In this embodiment, the angle detection device 1 is incorporated in a control device 30 for a rotating electric machine (hereinafter, referred to as the control device 30).

1-1. Resolver 5
The angle detection device 1 includes a resolver 5. As shown in Fig. 2, the resolver 5 includes a resolver stator 55 and a resolver rotor 51. The resolver stator 55 has an excitation winding 52 and an output winding. As the output winding, a first output winding 53 and a second output winding 54 are provided.

The excitation winding 52, the first output winding 53, and the second output winding 54 are wound around a single resolver stator 55. The resolver rotor 51 is disposed radially inside the resolver stator 55. In this embodiment, the resolver rotor 51 is fixed to the rotating shaft 8 of the rotating electric machine. In this example, the resolver rotor 51 is fixed to the tip of the rotating shaft 8 of the rotating electric machine.

The resolver rotor 51 has salient poles. In this embodiment, the resolver rotor 51 has N salient poles (N is a natural number equal to or greater than 2). In this example, N is set to 4, and the shaft angle multiplier N is set to 4. Therefore, for every one rotation in mechanical angle, the resolver rotor 51 rotates four times in electrical angle. The resolver rotor 51 has N protrusions arranged evenly in the circumferential direction on the outer periphery. The protrusions generate salient poles. The radially outward protrusion height of the protrusions is formed so that the gap permeance between the resolver stator 55 and the resolver rotor 51 changes sinusoidally according to the rotation. In other words, the resolver 5 is a variable reluctance (VR) type resolver.

As shown in FIG. 3, when the rotor rotates while the excitation winding 52 is supplied with an excitation voltage Vex corresponding to the excitation AC voltage VR, the amplitude of the AC voltage S1 (hereinafter referred to as the first output signal S1) induced in the first output winding 53 changes in a sine wave shape according to the rotation angle (gap perminance) in electrical angle of the rotor, and the amplitude of the AC voltage S2 (hereinafter referred to as the second output signal S2) induced in the second output winding 54 changes in a cosine wave shape. The first output winding 53 and the second output winding 54 are wound around the circumferential position of the resolver stator 55 so that the amplitudes of the AC voltages differ from each other by 90 degrees in electrical angle.

For example, if the excitation AC voltage VR is a 10 kHz sine wave and the number of salient poles N is 4, the first output signal S1 oscillates at 10 kHz, while its amplitude changes sine-wave-like over four periods while the resolver rotor 51 rotates once in mechanical angle, and the second output signal S2 oscillates at 10 kHz, while its amplitude changes cosine-wave-like over four periods while the resolver rotor 51 rotates once, and the sine-wave amplitude of the first output signal S1 and the cosine-wave amplitude of the second output signal S2 differ in phase by π/2 in electrical angle.

1-2. Rotating electric machine 2 and power converter 6
As shown in Fig. 1, the rotating electric machine 2 includes a cylindrical stator 3 and a rotor 4 arranged radially inside the stator 3. As shown in Fig. 4, the stator 3 is provided with a multi-phase armature winding (in this example, three-phase armature windings Cu, Cv, and Cw of U-phase, V-phase, and W-phase). The rotor 4 is provided with a field winding 67 that generates magnetic flux in the rotor 4. A permanent magnet may be provided in the rotor 4 together with the field winding 67. The rotor 4 and the field winding 67 are of a claw pole type, and one end of the rotating shaft 8 is an N pole and the other end is an S pole. A resolver rotor 51 is fixed to one end or the other end of the rotating shaft 8.

The power converter 6 includes an inverter 63 that performs power conversion between the DC power source 61 and the armature winding, and a converter 64 that performs power conversion between the DC power source 61 and the field winding 67. The inverter 63 and the converter 64 are provided with switching elements SW. The inverter 63 is a three-phase bridge circuit, and the converter 64 is an H-bridge circuit. Various known elements may be used for the inverter 63 and the converter 64. Each switching element SW is turned on and off by the control device 30. The inverter 63 is provided with a current sensor 65 that detects the currents Iu, Iv, and Iw flowing through the armature winding, and the converter 64 is provided with a current sensor 66 that detects the current If flowing through the field winding 67.

1-3. Control device 30
1 and 2, the control device 30 (angle detection device 1) includes an excitation unit 31, an angle information calculation unit 32, and an information acquisition unit 33. The control device 30 also includes a rotating electric machine control unit .

The functions of the control device 30 are realized by processing circuits provided in the control device 30. Specifically, as shown in FIG. 5, the control device 30 includes, as processing circuits, a calculation processing device 90 (computer) such as a CPU (Central Processing Unit), a storage device 91 that exchanges data with the calculation processing device 90, an input circuit 92 that inputs external signals to the calculation processing device 90, an output circuit 93 that outputs signals from the calculation processing device 90 to the outside, and a communication circuit 94 that communicates data with external devices.

The arithmetic processing device 90 may be an ASIC (Application Specific Integrated Circuit), an IC (Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), various logic circuits, and various signal processing circuits. In addition, the arithmetic processing device 90 may be a plurality of the same or different types, and each process may be shared and executed. As the storage device 91, a RAM (Random Access Memory) configured to be able to read and write data from the arithmetic processing device 90, and a ROM (Read Only Memory) configured to be able to read data from the arithmetic processing device 90, etc. are provided. The first output winding 53, the second output winding 54, and the current sensors 65 and 66 are connected to the input circuit 92. The input circuit 92 is provided with an A/D converter and the like that inputs these signals to the arithmetic processing device 90. The output circuit 93 is connected to the excitation winding 52 and the power converter 6, and includes switching elements for driving these, a low-pass filter circuit 31b, an amplifier circuit 31, a gate drive circuit, and other drive circuits. The communication circuit 94 communicates with an external device 95.

The functions of the processing units 31 to 34 of the control unit 30 are realized by the arithmetic processing unit 90 executing software (programs) stored in a storage unit 91 such as a ROM, and working in cooperation with other hardware of the control unit 30 such as the storage unit 91, input circuit 92, output circuit 93, and communication circuit 94. Setting data such as the modulation rate K used by the processing units 31 to 34 is stored in the storage unit 91 such as a ROM as part of the software (programs). Each function of the control unit 30 will be described in detail below.

<Magnetic excitation unit 31>
The excitation unit 31 generates an excitation AC voltage VR and applies an excitation voltage Vex corresponding to the AC voltage VR to the excitation winding 52. As described below, the excitation unit 31 changes the amplitude of the excitation AC voltage VR based on the operating state of the rotating electric machine. The excitation unit 31 generates the excitation AC voltage VR by PWM control (Pulse Width Modulation). The PWM control period Tc is set shorter than the excitation period Tex of the excitation AC voltage VR.

For example, the excitation unit 31 calculates an excitation AC voltage command value Vin of a sine wave that oscillates with an excitation period Tex (excitation frequency fex). The excitation AC voltage command value Vin corresponds to the excitation AC voltage VR. The excitation unit 31 changes the excitation AC voltage command value Vin based on the operating state of the rotating electric machine.

As shown in FIG. 6, the excitation unit 31 generates a PWM signal that turns on and off a switching element for the excitation winding provided in the output circuit 93 based on the result of comparing the AC voltage command value Vin with the triangular wave Cex. The triangular wave Cex is a triangular wave that oscillates between 0 and the power supply voltage Vc at a PWM control period Tc. When the triangular wave Cex falls below the AC voltage command value Vin, the excitation unit 31 turns on the switching element and applies the power supply voltage Vc to the excitation winding 52 side, and when the triangular wave Cex exceeds the AC voltage command value Vin, the excitation unit 31 turns off the switching element and stops applying the power supply voltage Vc (applies 0 V to the excitation winding 52 side).

In this embodiment, the excitation unit 31 includes a PWM signal generation unit 31a that generates the above-mentioned PWM signal, and an amplifier circuit 31c that converts the output signal of the low-pass filter circuit 31b into a current and supplies it to the excitation winding 52.

A sinusoidal voltage signal is generated by applying a low-pass filter to the PWM signal. If it is desired to steeply remove high-frequency components, the low-pass filter circuit 31b may be provided with a two or more stage primary filter. The amplifier circuit 31c converts the sinusoidal voltage signal into a sinusoidal current and supplies it to the excitation winding 52. The amplifier circuit 31c is a differential voltage input/differential current output circuit. The voltage input to the amplifier circuit 31c and the excitation voltage Vex output from the amplifier circuit 31c and applied to the excitation winding are in a linear function relationship having a preset gain and offset. The excitation voltage Vex output from the amplifier circuit 31c has an outputtable range of -Vmax to Vmax determined by the circuit performance, as described later. The excitation voltage Vex is limited by the upper and lower limits of the outputtable range, and a voltage exceeding the outputtable range cannot be applied to the excitation winding.

In a state where no disturbance magnetic flux is generated by the field winding described later, when the amplitude of the sine-wave excitation AC voltage command value Vin is Vc/2 or less, voltage saturation does not occur, and a sine-wave excitation AC voltage VR corresponding to the sine-wave excitation AC voltage command value Vin can be output to the excitation winding 52 side, and distortion of the excitation AC voltage VR from the sine wave can be suppressed. The value obtained by dividing the amplitude of the excitation AC voltage command value Vin by Vc/2 is defined as the modulation factor K. When the amplitude of the excitation AC voltage command value Vin is Vc/2, the modulation factor K is 1. On the other hand, in a state where disturbance magnetic flux is generated by the field winding, in order to suppress distortion of the excitation AC voltage VR from the sine wave due to the disturbance magnetic flux of the field winding, the amplitude of the excitation AC voltage command value Vin (modulation factor K, amplitude of the excitation AC voltage VR) is changed as described later. In this embodiment, when an excitation AC voltage command value Vin with a modulation rate K=1 is generated in a state where no disturbance magnetic flux is generated by the field winding, the amplitude of the excitation voltage Vex falls within the output possible range of -Vmax to Vmax.

<Angle information calculation unit 32>
The angle information calculation unit 32 calculates angle information based on the output signal of the output winding. The angle information calculation unit 32 calculates angle information from the first output signal S1 and the second output signal S2. For example, As in Patent No. 7186846, the ratio of the first output signal S1 and the second output signal S2 detected at the timing of the peaks and valleys of the first output signal S1 and the second output signal S2 oscillating with the excitation period Tex is The detected angle is calculated by calculating the arc tangent, and the rotation speed is calculated from the amount of change in the detected angle.

Alternatively, as in JP 2013-72867 A, the angle information calculation unit 32 may calculate the rotation speed from the resolver angular velocity obtained by feedback processing the first output signal S1 and the second output signal S2 detected at the timing of the peaks and valleys, and may calculate the detected angle by integrating the resolver angular velocity. As the angle information, only the detected angle or only the rotation speed may be calculated, as necessary.

As shown in FIG. 7, the angle information calculation unit 32 may have a bandpass filter 32a that removes disturbance noise from a rotating electric machine or the like from the output signal of the output winding. For example, the bandpass filter 32a may be configured as an active filter that can vary the amplification rate of the output signal, and the output signal may be amplified so that the A/D resolution does not decrease. Note that in cases where the frequency band during use is limited, a highpass filter may be used instead of the bandpass filter 32a.

<Rotating Electric Machine Control Unit 34>
The rotating electric machine control unit 34 controls the rotating electric machine via the power converter 6. The rotating electric machine control unit 34 calculates three-phase AC voltage command values for the armature winding based on an external operation command and angle information obtained from the angle information calculation unit 32, and turns on and off the switching elements of the power converter (inverter) by PWM control based on the three-phase voltage command values. The rotating electric machine control unit 34 calculates a voltage command value for the field winding based on an external operation command and angle information obtained from the angle information calculation unit 32, and turns on and off the switching elements of the power converter (converter) by PWM control based on the voltage command value. Examples of the external operation command include a torque command value or a rotation speed command value. Various known methods are used for the calculation method of each voltage command value and the PWM control.

For example, the rotating electric machine control unit 34 calculates a current command value for the field winding based on an external operation command, a DC voltage, and a rotation speed, and calculates a voltage command value for the field winding based on the current command value. A current sensor is provided to detect the current If flowing through the field winding, and the current If of the field winding is detected. It is preferable to perform feedback control in which the voltage command value is changed so that the current If of the field winding approaches the current command value of the field winding.

During power running, the rotating electric machine control unit 34 calculates a current command value for the armature winding based on an external operation command, a DC voltage, and a rotation speed, and calculates a voltage command value for the armature winding based on the current command value and angle information. A current sensor is provided to detect the current flowing through the armature winding, and the current in the armature winding is detected. It is preferable to perform feedback control in which the voltage command value is changed so that the current in the armature winding approaches the current command value for the armature winding. Note that a current sensor is not essential, and feedforward control may be performed.

During regenerative operation, if the rotation speed is low, the rotating electric machine control unit 34 calculates the current command value and the voltage command value and executes PWM control, similar to power running operation. If the rotation speed is high, the rotating electric machine control unit 34 executes diode rectification control, which turns off all switching elements of the power converter (inverter), or synchronous rectification control, which turns on switching elements through which a current generated by an induced voltage flows. For example, there is a method such as that described in JP 2016-195514 A. Note that during regenerative operation, only diode rectification control or synchronous rectification control may be executed without executing the same control as during power running operation. Alternatively, during regenerative operation, only control similar to that during power running may be executed without executing diode rectification control or synchronous rectification control.

<Necessity for changing the amplitude of the excitation AC voltage VR>
FIG. 8 shows a schematic diagram of magnetic flux when a current is applied to the field winding. The magnetic flux generated in the rotor 4 of the rotating electric machine passes through the rotating shaft 8 and reaches the resolver rotor 51 attached to the tip of the rotating shaft 8. The tip of the rotating shaft 8 to which the resolver rotor 51 is attached becomes a north pole or a south pole. At the tip of the rotating shaft 8, magnetic flux is generated that radiates from the center. When the rotating shaft 8 and the resolver rotor 51 are eccentric with respect to the center of rotation, the intensity of the interlinkage magnetic flux φn that interlinks with the excitation winding 52 changes at least once during one rotation of the rotating shaft 8. The interlinkage magnetic flux φn at this time is given by the formula (1) where the rotation speed of the rotating shaft is ωm. The amplitude φn0 of the interlinkage magnetic flux is larger as the amount of eccentricity is larger, and is larger as the magnetic flux generated by the field winding is larger. Although equation (1) is simplified and expressed only in terms of the first-order rotational component, the same effect can be obtained even if other harmonic components are present.

As described above, in a state where no disturbance magnetic flux is acting on the excitation winding, the excitation voltage Vex is applied to the excitation winding so that a sinusoidal current of the excitation frequency fex flows, and the excitation voltage Vex can be given by the following equation (2), where G is the transfer function from the output voltage of the low-pass filter circuit 31b to the excitation voltage Vex: Here, K is the modulation factor obtained by dividing the amplitude of the excitation AC voltage command value Vin (the amplitude of the excitation AC voltage VR) by Vc/2.

When the outputtable range of the excitation voltage Vex of the excitation winding is -Vmax to Vmax, it is necessary to satisfy the formula (3) using a safety factor Sf of 1 or less. In this embodiment, the outputtable range is determined by the specifications of the amplifier circuit 31c. The safety factor Sf may be set in consideration of circuit variations. In a state where no disturbance noise due to disturbance magnetic flux is superimposed, the excitation voltage Vex of the excitation winding is within the outputtable range, so that the excitation voltage Vex becomes a sine wave of the excitation frequency fex as shown in FIG. 9.

However, when rotational period fluctuations (disturbance flux) of the interlinkage magnetic flux φn caused by the field winding, which are caused by eccentricity of the rotating shaft in formula (1), are introduced, the excitation voltage Vex applied to the excitation winding becomes as shown in formula (4) and has a waveform as shown in Fig. 10. The second term is the rotational period fluctuation component (disturbance noise) of the excitation voltage Vex caused by the disturbance magnetic flux, is the time differential value of the interlinkage magnetic flux φn, and is the induced electromotive force.

The amplitude of the second term in formula (4) increases as the amplitude φn0 of the interlinkage magnetic flux or the rotation speed ωm increases, so the amplitude of the excitation voltage Vex increases when the load and rotation speed are high. In particular, since the frequencies of the first and second terms in formula (4) are different, the amplitude of the excitation voltage Vex becomes maximum when the timing at which both amplitudes become maximum overlaps. In order to prevent the amplitude of the excitation voltage Vex from being limited by the upper and lower limits due to the possible output range -Vmax to Vmax, formula (5) needs to be satisfied.

In order to satisfy equation (5) over the entire operating range, if the amplitude φn0 of the linkage magnetic flux when the amount of eccentricity is the worst value (maximum value) of the tolerance and the current If flowing through the field winding is at its maximum value Ifmax is defined as φn0_max, and the maximum operable rotational speed of the rotating electric machine is defined as ωm_max, then equation (6) must be satisfied.

When the excitation voltage Vex deviates from the range of equation (6) and is limited to the outputtable range of -Vmax to Vmax, the peak value of the excitation voltage Vex is limited to the upper and lower limits as shown in Figure 11, and the waveform is distorted. In other words, if there is no eccentricity, a signal as expressed by equation (2) is obtained, but if there is eccentricity and the amplitude of the excitation voltage Vex exceeds the outputtable range, a distorted signal with a peak value limited to the upper and lower limits compared to equation (4) is obtained. If the excitation voltage Vex is distorted, the first output signal S1 and the second output signal S2 are distorted, and the effect of the waveform distortion appears as a detection angle error.

Furthermore, if the amplitude of the excitation voltage Vex is determined so as to satisfy equation (6) over the entire operating range, when the current flowing through the field winding is small or when the rotation speed is low, the second term of equation (4) becomes small, and the amplitude is reduced more than necessary. As a result, the amplitudes of the excitation voltage Vex, the first output signal S1, and the second output signal S2 become unnecessarily small, which leads to a deterioration in the S/N ratio and coarse resolution, leading to a deterioration in the accuracy of the detected angle.

<Change in Amplitude of Excitation AC Voltage VR According to Operation State of Rotating Electric Machine>
Therefore, in this embodiment, the information acquisition unit 33 acquires the operating state of the rotating electric machine, and the excitation unit 31 changes the amplitude (modulation rate K) of the excitation AC voltage VR based on the operating state of the rotating electric machine.

The resolver is disposed adjacent to the rotating electric machine and is therefore affected by disturbance magnetic flux generated by the rotating electric machine. When the operating state of the rotating electric machine changes, the disturbance magnetic flux of the rotating electric machine changes, and the effect on the excitation voltage Vex also changes. By changing the amplitude of the excitation AC voltage VR based on the operating state of the rotating electric machine, it is possible to prevent the range of change in the excitation voltage Vex after fluctuations due to the disturbance magnetic flux from becoming too large, and to suppress detection errors in the angle information.

In this embodiment, the rotating electric machine has a field winding, and the magnetic flux generated by the field winding is transmitted through the rotating shaft and interlinked with the excitation winding. When the rotating shaft becomes eccentric, the interlinkage magnetic flux φn fluctuates with the rotation period, and the excitation voltage Vex fluctuates depending on the time differential value of the interlinkage magnetic flux φn. The time differential value of the interlinkage magnetic flux φn fluctuates depending on the operating state of the rotating electric machine. By changing the amplitude (modulation rate K) of the excitation AC voltage VR based on the operating state of the rotating electric machine, the change range of the excitation voltage Vex after the fluctuation due to the interlinkage magnetic flux φn can be prevented from becoming too large, and detection errors of the angle information can be suppressed.

The excitation unit 31 changes the amplitude (modulation rate K) of the excitation AC voltage VR based on the operating state of the rotating electric machine so that the range of change in the excitation voltage Vex when disturbance noise caused by disturbance magnetic flux from the rotating electric machine is superimposed falls within the possible output range.

As described above, when the amplitude of the excitation voltage Vex is limited by the upper and lower limits of the possible output range -Vmax to Vmax due to the superposition of disturbance noise, the peak value of the excitation voltage Vex is limited by the upper and lower limits, the waveform of the excitation voltage Vex is distorted, the first output signal S1 and the second output signal S2 are distorted, and the effect of the waveform distortion appears as a detection angle error. With the above configuration, even when disturbance noise due to disturbance magnetic flux from the rotating electric machine is superimposed, the amplitude of the excitation voltage Vex can be prevented from being limited by the upper and lower limits of the possible output range -Vmax to Vmax, distortion of the excitation voltage Vex, the first output signal S1, and the second output signal S2 can be suppressed, and detection errors of angle information can be suppressed.

In this embodiment, the disturbance noise is assumed to be the rotational period fluctuation component of the excitation voltage Vex caused by the rotational period fluctuation of the interlinkage magnetic flux φn due to the eccentricity of the rotating shaft when the eccentricity amount is the worst value (maximum value) of the tolerance. The worst value of the eccentricity amount tolerance can be known in advance at the time of design, and the rotational period fluctuation component of the excitation voltage Vex in that case can also be known in advance at the time of design.

<Amplitude change due to field winding current If>
The information acquisition unit 33 acquires the current If flowing through the field winding as the operating state of the rotating electric machine. The field winding current If may be detected by a current sensor, or may be estimated based on a field winding voltage command value or a field winding current command value. The excitation unit 31 changes the amplitude (modulation factor K) of the excitation AC voltage VR based on the field winding current If.

As the field winding current If increases, the magnetic flux generated by the field winding increases, the amplitude φn0 of the interlinkage magnetic flux when eccentricity occurs increases, and the amount of fluctuation in the excitation voltage Vex increases. By changing the amplitude (modulation rate K) of the excitation AC voltage VR based on the field winding current If, it is possible to prevent the range of change in the excitation voltage Vex after fluctuation due to the interlinkage magnetic flux φn from becoming too large, and to suppress detection errors in the angle information.

In this embodiment, the excitation unit 31 reduces the amplitude (modulation rate K) of the excitation AC voltage VR as the current If in the field winding increases.

With this configuration, as the current If of the field winding increases and the amount of fluctuation in the excitation voltage Vex increases, the amplitude of the excitation AC voltage VR is reduced, preventing the range of change in the excitation voltage Vex after fluctuation due to the interlinkage magnetic flux φn from becoming too large, thereby suppressing detection errors in the angle information.

For example, as shown in FIG. 12, the modulation factor K may be set according to the field winding current If. The value obtained by multiplying the modulation factor K by half the power supply voltage Vc/2 becomes the amplitude of the excitation AC voltage VR. It is preferable to use map data in which the relationship between the field winding current If and the modulation factor K is preset.

Equation (6) is transformed so that the left side is the modulation factor K, and the modulation factor K is replaced with the minimum modulation factor Kmin to obtain equation (7). The minimum modulation factor Kmin, which is the modulation factor set when the current If of the field winding is the maximum value Ifmax of the current of the field winding, may be set so as to satisfy equation (7). Here, φn0_max is the amplitude φn0 of the interlinkage magnetic flux when the eccentricity amount is the worst value of the tolerance and the current If of the field winding is the maximum value Ifmax. ωm_max is the maximum rotation speed at which the rotating electric machine can be operated in power running. The minimum modulation factor Kmin is a modulation factor at which the amplitude of the excitation voltage Vex is not limited by the upper or lower limits of the output possible range -Vmax to Vmax when the eccentricity amount is the worst value of the tolerance, the rotation speed is the maximum rotation speed ωm_max at which power running is possible, and the current of the field winding is the maximum value Ifmax. In order to maximize the amplitude of the excitation voltage Vex and improve the S/N ratio and resolution, the maximum value of the minimum modulation factor Kmin that satisfies the formula (7) should be set. That is, the left and right sides of the formula (7) should be connected with an equal sign. There is no particular problem as long as an appropriate safety factor Sf is set.

Moreover, by transforming the formula (5) so that the left side becomes the amplitude φn0 of the linkage magnetic flux, setting the modulation factor K=1, and replacing the rotation speed ωm with the maximum rotation speed ωm_max capable of powering operation, formula (8) is obtained. The range of the amplitude φn0 of the linkage magnetic flux that satisfies formula (8) is the range in which the modulation factor K=1 can be set when the amount of eccentricity is the worst value of the tolerance and the rotation speed is the maximum rotation speed ωm_max capable of powering operation. The maximum amplitude φn1 of the linkage magnetic flux to be set to the modulation factor K=1 is set within the range of the amplitude φn0 of the linkage magnetic flux that can be set to the modulation factor K=1. Then, when the amount of eccentricity is the worst value of the tolerance and the rotation speed is the maximum rotation speed ωm_max capable of powering operation, the current If of the field winding that generates the maximum amplitude φn1 of the linkage magnetic flux is set to the maximum current If1 of the field winding that sets the modulation factor K=1. In order to maximize the amplitude of the excitation voltage Vex and improve the S/N ratio and resolution, it is sufficient to set the maximum current If1 of the field winding corresponding to the maximum value of the amplitude φn0 of the interlinkage magnetic flux that satisfies the formula (8). That is, the left side and the right side of the formula (8) should be connected with an equal sign. There is no particular problem as long as an appropriate safety factor Sf is set.

As shown in FIG. 12, the excitation unit 31 sets the modulation factor K to 1 when the field winding current If is in the range from 0 to the maximum field winding current If1 for which the modulation factor K is set to 1. The excitation unit 31 gradually decreases the modulation factor K from 1 to the minimum modulation factor Kmin as the field winding current If approaches the maximum field winding current Ifmax from the maximum field winding current If1 for which the modulation factor K is set to 1. In the example of FIG. 12, the lines are connected by straight lines, but they do not have to be straight lines.

<Amplitude change due to rotation speed ωm>
The information acquisition unit 33 acquires the rotation speed ωm of the rotating electric machine as the operating state of the rotating electric machine. The rotation speed ωm is calculated based on the angle information of the angle information calculation unit 32. The excitation unit 31 may change the amplitude (modulation rate K) of the excitation AC voltage VR based on the rotation speed ωm of the rotating electric machine.

As explained using equation (4), as the rotation speed ωm increases, the time differential value of the interlinkage magnetic flux φn, which fluctuates with the rotation period when eccentricity occurs, increases, and the amount of fluctuation in the excitation voltage Vex increases. By changing the amplitude (modulation rate K) of the excitation AC voltage VR based on the rotation speed ωm of the rotating electric machine, it is possible to prevent the change in the excitation voltage Vex after fluctuation due to the interlinkage magnetic flux φn from becoming too large, and to suppress detection errors in the angle information.

In this embodiment, the excitation unit 31 reduces the amplitude (modulation rate K) of the excitation AC voltage VR as the rotational speed ωm of the rotating electric machine increases.

With this configuration, as the rotation speed ωm of the rotating electric machine increases and the amount of fluctuation in the excitation voltage Vex increases, the amplitude of the excitation AC voltage VR is reduced, so that the range of change in the excitation voltage Vex after fluctuation due to the interlinkage magnetic flux φn does not become too large, thereby suppressing detection errors in the angle information.

For example, as shown in FIG. 13, the modulation rate K may be set according to the rotation speed ωm of the rotating electric machine. Map data in which the relationship between the rotation speed ωm and the modulation rate K is preset may be used.

When the rotation speed ωm is the maximum rotation speed ωm_max at which power operation is possible, the minimum modulation rate Kmin set for the modulation rate K is set as described using equation (7).

Equation (5) is transformed so that the left side becomes the rotation speed ωm, the modulation factor K is set to 1, and the amplitude φn0 of the interlinkage magnetic flux is replaced with the amplitude φn0_max of the interlinkage magnetic flux when the eccentricity amount is the worst value of the tolerance and the current If of the field winding is the maximum value Ifmax, to obtain Equation (9). The range of the rotation speed ωm where Equation (9) is satisfied is the range where the modulation factor K=1 can be set when the eccentricity amount is the worst value of the tolerance and the current If of the field winding is the maximum value Ifmax. The maximum rotation speed ωm1 where the modulation factor K=1 is set is set within the range of the rotation speed ωm where the modulation factor K=1 can be set. In order to maximize the amplitude of the excitation voltage Vex and improve the S/N ratio and resolution, it is sufficient to set the maximum value of the rotation speed ωm that satisfies Equation (9). That is, the left side and the right side of Equation (9) should be connected with an equal sign. There is no particular problem as long as an appropriate safety factor Sf is set.

As shown in FIG. 13, the excitation unit 31 sets the modulation factor K to 1 when the rotation speed ωm is in the range from 0 to the maximum rotation speed ωm1 for which the modulation factor K=1 is set. The excitation unit 31 gradually decreases the modulation factor K from 1 to the minimum modulation factor Kmin as the rotation speed ωm approaches the maximum rotation speed ωm_max at which powering operation is possible from the maximum rotation speed ωm1 for which the modulation factor K=1 is set. In the example of FIG. 13, the lines are connected by straight lines, but they do not have to be straight lines.

<Amplitude change due to field winding current If and rotation speed ωm>
Fig. 12 shows a setting example in which the modulation factor K is set according to the field winding current If, on the assumption that the rotation speed ωm is the maximum rotation speed ωm_max at which powering operation is possible. Fig. 13 shows a setting example in which the modulation factor K is set according to the rotation speed ωm, on the assumption that the field winding current If is the maximum value Ifmax. However, the amount of fluctuation in the excitation voltage Vex changes according to the field winding current If and the rotation speed ωm.

Therefore, the excitation unit 31 may change the amplitude (modulation rate K) of the excitation AC voltage VR based on the current If of the field winding and the rotational speed ωm of the rotating electric machine. In this case, the excitation unit 31 also reduces the amplitude (modulation rate K) of the excitation AC voltage VR as the current If of the field winding increases. Also, the excitation unit 31 reduces the amplitude (modulation rate K) of the excitation AC voltage VR as the rotational speed ωm of the rotating electric machine increases. Also, the excitation unit 31 changes the amplitude (modulation rate K) of the excitation AC voltage VR based on the current If of the field winding and the rotational speed ωm of the rotating electric machine so that the range of change of the excitation voltage Vex when disturbance noise due to disturbance magnetic flux from the rotating electric machine is superimposed is within the output possible range.

Equation (5) is transformed so that the left side is the modulation factor K, and equation (10) is obtained. Here, φn0 is the amplitude of the interlinkage magnetic flux when the eccentricity amount is the worst value of the tolerance and the field winding current If is each operating point. The range of modulation factor K that satisfies equation (10) is the range in which the amplitude of the excitation voltage Vex is not limited by the upper and lower limits of the output possible range -Vmax to Vmax at each operating point of the field winding current If and each operating point of the rotation speed ωm when the eccentricity amount is the worst value of the tolerance. In order to maximize the amplitude of the excitation voltage Vex and improve the S/N ratio and resolution, the maximum value of the modulation factor K that satisfies equation (10) should be set at each operating point of the field winding current If and each operating point of the rotation speed ωm. That is, the left side and the right side of equation (10) should be connected with an equal sign. There is no particular problem as long as an appropriate safety factor Sf is set. Since the maximum value of the modulation factor K that can be set is 1, the modulation factor K set by the equation (10) is limited to 1 as an upper limit.

The modulation factor K, which is set to satisfy the formula (10) at each operating point of the field winding current If and each operating point of the rotational speed ωm, may be preset in the map data. In other words, map data in which the relationship between the field winding current If, the rotational speed ωm, and the modulation factor K is preset may be used.

<Amplitude Change Using Output Possible Ranges of First Output Signal S1 and Second Output Signal>
So far, a method for setting the modulation rate K has been described in which the amplitude of the excitation voltage Vex is not limited by the upper or lower limits of the outputtable range -Vmax to Vmax. However, the first output signal S1 and the second output signal S2 also have an outputtable range. This outputtable range is determined by the voltage range that can be converted into digital form by the A/D converter. For example, as shown in equation (11), the first output signal S1 and the second output signal S2 are a value obtained by multiplying the excitation voltage Vex by a sine wave or cosine wave and a gain A, and adding an offset C to the result.

For example, if the maximum value of the output range of the first output signal S1 and the second output signal S2 is Vsmax, the modulation rate K can be set in a similar manner using an equation in which the following equation is substituted for Vmax in each of the above equations.

In addition to indirect fluctuations in the output signal due to fluctuations in the excitation voltage Vex caused by disturbance magnetic flux, direct fluctuations in the output signal due to disturbance magnetic flux may also be taken into consideration.

<Amplitude change according to maximum rotation speed during power running and maximum rotation speed during regenerative running>
During powering operation and during regenerative operation in a range where the rotational speed is low, when the voltage command value of the armature winding is calculated using the detected angle, the control accuracy of the output torque or output current of the rotating electric machine deteriorates due to a detected angle error. Therefore, it is desirable to suppress the detected angle error during these operations. On the other hand, during regenerative operation using diode rectification control or synchronous rectification control, even if the n-th rotation error contained in the detected angle increases due to a decrease in the S/N ratio, the rotational speed error becomes small when the rotational speed is high, and when the error is large, the rotational speed can be calculated through a low-pass filter. Therefore, the accuracy of the current command value generated using the rotational speed does not deteriorate significantly, so it is possible to obtain the desired output torque or output current.

Therefore, when the rotation speed ωm becomes greater than the maximum rotation speed ωm_max at which power operation is possible, the excitation unit 31 reduces the amplitude (modulation rate K) of the excitation AC voltage VR more than when the rotation speed ωm is equal to or less than the maximum rotation speed ωm_max at which power operation is possible.

According to this configuration, during powering operation when a detection angle is required, the amplitude of the excitation voltage Vex is increased, and the S/N ratio and resolution can be improved. For example, when the rotation speed ωm is equal to or less than the maximum rotation speed ωm_max at which powering operation is possible, the excitation unit 31 sets the modulation factor K to 1, and when the rotation speed ωm is greater than the maximum rotation speed ωm_max at which powering operation is possible, the excitation unit 31 sets the modulation factor K to less than 1. In this case, unlike the example of FIG. 13, each parameter on the right side of equation (7) is set so that the modulation factor K can be set to 1 at the maximum rotation speed ωm_max at which powering operation is possible.

Figure 14 shows the excitation voltage Vex when the modulation rate K is suddenly changed. Since the detection angle before and after the sudden change in modulation rate K is momentarily discontinuous, we want to smooth out the change in modulation rate K to eliminate the discontinuous points.

Therefore, as shown in FIG. 15, the excitation unit 31 sets the modulation rate K to 1 when the rotation speed ωm is in the range from 0 to the maximum rotation speed ωm_max at which powering operation is possible. The excitation unit 31 gradually reduces the modulation rate K from 1 as the rotation speed ωm approaches the maximum rotation speed ωm_max at which powering operation is possible from the maximum rotation speed ωm_maxgen at which regenerative operation is possible. In the example of FIG. 15, the modulation rate K is gradually reduced from 1 to the minimum modulation rate Kmin.

<Other embodiments>
In the above embodiment, the maximum setting value of the modulation factor K was 1, but since it only needs to be set to an optimal value taking into account the transfer function G and the output possible range of the excitation voltage Vex, it may be set to a value less than 1.

In the above embodiment, a rotating electric machine having a field winding on the rotor has been described, but a permanent magnet type rotating electric machine having a permanent magnet on the rotor may also be used. Even in this case, the fountain flux is generated through the rotating shaft, so the same effect can be obtained by changing the modulation factor K based on the rotation speed ωm. In particular, in the case of a consequent pole type rotating electric machine, the fountain flux tends to be large, so the improvement effect is greater.

In the above embodiment, the angle detection device 1 is incorporated in the control device 30 of the rotating electric machine, but the angle detection device 1 may be separate from the control device 30 of the rotating electric machine. In this case, the angle detection device 1 communicates with the control device 30 of the rotating electric machine and transmits angle information and the operating state of the rotating electric machine.

In the above embodiment, the excitation unit 31 includes the amplifier circuit 31c, but it may not include the amplifier circuit 31c and the output voltage of the low-pass filter circuit 31b may be supplied to the excitation winding 52. In this case, the excitation AC voltage VR becomes the excitation voltage Vex.

In the above embodiment, one set of excitation windings and output windings is provided, but multiple sets of excitation windings and output windings may be provided. In this case, the amplitude of the excitation AC voltage VR is changed for each set.

Summary of the various aspects of the present application
Various aspects of the present application are summarized below as appendices.
(Appendix 1)
A resolver including a rotor fixed to a rotating shaft of a rotating electric machine and having salient poles, and a stator having an excitation winding and an output winding;
an excitation unit that generates an excitation AC voltage and applies an excitation voltage corresponding to the excitation AC voltage to the excitation winding;
an angle information calculation unit that calculates angle information based on an output signal of the output winding;
a state acquisition unit that acquires an operating state of the rotating electric machine,
The excitation unit is an angle detection device that changes the amplitude of the excitation AC voltage based on the operating state of the rotating electric machine.

(Appendix 2)
2. The angle detection device according to claim 1, wherein the rotating electric machine is provided with a field winding.

(Appendix 3)
the state acquisition unit acquires a current flowing through the field winding as an operation state of the rotating electric machine;
3. The angle detection device according to claim 2, wherein the excitation unit changes an amplitude of the excitation AC voltage based on a current in the field winding.

(Appendix 4)
4. The angle detection device according to claim 3, wherein the excitation unit reduces an amplitude of the excitation AC voltage as a current in the field winding increases.

(Appendix 5)
the state acquisition unit acquires a rotation speed of the rotating electric machine as an operation state of the rotating electric machine;
5. The angle detection device according to claim 1, wherein the excitation unit changes an amplitude of the excitation AC voltage in accordance with a rotation speed of the rotating electric machine.

(Appendix 6)
6. The angle detection device according to claim 5, wherein the excitation unit reduces an amplitude of the excitation AC voltage as the rotation speed of the rotating electric machine increases.

(Appendix 7)
The rotating electric machine includes a field winding,
the state acquisition unit acquires a current flowing through the field winding and a rotation speed of the rotating electric machine;
2. The angle detection device according to claim 1, wherein the excitation unit changes an amplitude of the excitation AC voltage in response to a current in the field winding and a rotation speed of the rotating electric machine.

(Appendix 8)
8. The angle detection device according to claim 7, wherein the excitation unit reduces an amplitude of the excitation AC voltage as a current in the field winding increases, and reduces an amplitude of the excitation AC voltage as a rotational speed of the rotating electric machine increases.

(Appendix 9)
The angle detection device described in Appendix 5 or 6, wherein the excitation unit reduces the amplitude of the excitation AC voltage when the rotational speed of the rotating electric machine becomes higher than a maximum rotational speed at which the rotating electric machine can be operated in powered mode, compared to when the rotational speed of the rotating electric machine is equal to or lower than the maximum rotational speed at which the rotating electric machine can be operated in powered mode.

(Appendix 10)
The angle detection device according to any one of appendixes 5, 6, and 9, wherein the excitation unit gradually reduces the amplitude of the excitation AC voltage as the rotational speed of the rotating electric machine approaches a maximum rotational speed at which the rotating electric machine can be operated in a powered manner from a maximum rotational speed at which the rotating electric machine can be operated in a regenerative manner.

(Appendix 11)
The angle detection device according to claim 7 or 8, wherein the excitation unit reduces the amplitude of the excitation AC voltage when the rotational speed of the rotating electric machine becomes higher than a maximum rotational speed at which the rotating electric machine can be operated in powered mode, compared to when the rotational speed of the rotating electric machine is equal to or lower than the maximum rotational speed at which the rotating electric machine can be operated in powered mode.

(Appendix 12)
The angle detection device according to any one of appendices 7, 8, and 11, wherein the excitation unit gradually reduces the amplitude of the excitation AC voltage as the rotational speed of the rotating electric machine approaches a maximum rotational speed at which the rotating electric machine can be operated in a powered manner from a maximum rotational speed at which the rotating electric machine can be operated in a regenerative manner.

(Appendix 13)
13. The angle detection device according to claim 1, wherein the excitation unit generates an excitation AC voltage in the excitation winding by PWM control.

(Appendix 14)
14. The angle detection device according to any one of appendixes 1 to 13, wherein the excitation unit includes a PWM signal generation unit that generates a PWM signal, a low-pass filter circuit that performs low-pass filtering on the PWM signal, and an amplifier circuit that converts an output signal of the low-pass filter circuit into a current and supplies the current to the excitation winding.

(Appendix 15)
The angle detection device according to any one of appendixes 1 to 14, wherein the excitation unit changes the amplitude of the excitation AC voltage based on the operating state of the rotating electric machine so that the range of change in the excitation voltage or the output signal of the output winding when disturbance noise due to disturbance magnetic flux from the rotating electric machine is superimposed is within an output possible range.

(Appendix 16)
15. The angle detection device according to any one of claims 1 to 14, wherein the angle information calculation unit has a high-pass filter that removes disturbance noise from the rotating electric machine from the output signal of the output winding.

(Appendix 17)
15. The angle detection device according to any one of claims 1 to 14, wherein the angle information calculation unit has a bandpass filter that removes disturbance noise from the rotating electric machine from the output signal of the output winding.

(Appendix 18)
16. The angle detection device according to claim 15, wherein the angle information calculation unit has a high-pass filter that removes disturbance noise from the rotating electric machine from the output signal of the output winding.

(Appendix 19)
16. The angle detection device according to claim 15, wherein the angle information calculation unit has a bandpass filter that removes disturbance noise from the rotating electric machine from the output signal of the output winding.

Although the present application describes exemplary embodiments, the various features, aspects, and functions described in the embodiments are not limited to application to a particular embodiment, but may be applied to the embodiments alone or in various combinations. Thus, countless variations not illustrated are anticipated within the scope of the technology disclosed in the present application specification. For example, this includes modifying, adding, or omitting at least one component.

1: Angle detection device, 2: Rotating electric machine, 5: Resolver, 8: Rotating shaft, 31: Excitation unit, 31a: PWM signal generation unit, 31b: Low-pass filter circuit, 31c: Amplifier circuit, 32: Angle information calculation unit, 32a: Band-pass filter, 33: Information acquisition unit, 34: Rotating electric machine control unit, 51: Resolver rotor, 52: Excitation winding, 53: First output winding, 54: Second output winding, 55: Resolver stator, VR: AC voltage for excitation, Vex: Excitation voltage, ωm: Rotation speed, ωm_max: Maximum rotation speed at which power operation is possible, ωm_maxgen: Maximum rotation speed at which regenerative operation is possible

Claims (19)

A resolver including a rotor fixed to a rotating shaft of a rotating electric machine and having salient poles, and a stator having an excitation winding and an output winding;
an excitation unit that generates an excitation AC voltage and applies an excitation voltage corresponding to the excitation AC voltage to the excitation winding;
an angle information calculation unit that calculates angle information based on an output signal of the output winding;
a state acquisition unit that acquires an operating state of the rotating electric machine,
The excitation unit is an angle detection device that changes the amplitude of the excitation AC voltage based on the operating state of the rotating electric machine. The angle detection device according to claim 1, wherein the rotating electric machine is provided with a field winding. the state acquisition unit acquires a current flowing through the field winding as an operation state of the rotating electric machine;
The angle detection device according to claim 2 , wherein the excitation section changes an amplitude of the excitation AC voltage based on a current in the field winding. The angle detection device according to claim 3, wherein the excitation unit reduces the amplitude of the excitation AC voltage as the current in the field winding increases. the state acquisition unit acquires a rotation speed of the rotating electric machine as an operation state of the rotating electric machine;
The angle detection device according to claim 1 , wherein the excitation section changes an amplitude of the excitation AC voltage in accordance with a rotation speed of the rotating electric machine. The angle detection device according to claim 5, wherein the excitation unit reduces the amplitude of the excitation AC voltage as the rotation speed of the rotating electric machine increases. The rotating electric machine includes a field winding,
the state acquisition unit acquires a current flowing through the field winding and a rotation speed of the rotating electric machine;
The angle detection device according to claim 1 , wherein the excitation section changes an amplitude of the excitation AC voltage in response to a current in the field winding and a rotation speed of the rotating electric machine. The angle detection device according to claim 7, wherein the excitation unit reduces the amplitude of the excitation AC voltage as the current in the field winding increases, and reduces the amplitude of the excitation AC voltage as the rotation speed of the rotating electric machine increases. The angle detection device according to claim 5, wherein the excitation unit reduces the amplitude of the excitation AC voltage when the rotational speed of the rotating electric machine becomes higher than the maximum rotational speed at which the rotating electric machine can be operated in powered mode, more than when the rotational speed of the rotating electric machine is equal to or lower than the maximum rotational speed at which the rotating electric machine can be operated in powered mode. The angle detection device according to claim 5, wherein the excitation unit gradually reduces the amplitude of the excitation AC voltage as the rotational speed of the rotating electric machine approaches the maximum rotational speed at which the rotating electric machine can be operated in regenerative mode from the maximum rotational speed at which the rotating electric machine can be operated in power mode. The angle detection device according to claim 7, wherein the excitation unit reduces the amplitude of the excitation AC voltage when the rotational speed of the rotating electric machine becomes higher than the maximum rotational speed at which the rotating electric machine can be operated in powered mode, more than when the rotational speed of the rotating electric machine is equal to or lower than the maximum rotational speed at which the rotating electric machine can be operated in powered mode. The angle detection device according to claim 7, wherein the excitation unit gradually reduces the amplitude of the excitation AC voltage as the rotational speed of the rotating electric machine approaches the maximum rotational speed at which the rotating electric machine can be operated in regenerative mode from the maximum rotational speed at which the rotating electric machine can be operated in power mode. The angle detection device according to any one of claims 1 to 12, wherein the excitation unit generates an excitation AC voltage for the excitation winding by PWM control. The angle detection device according to any one of claims 1 to 12, wherein the excitation unit includes a PWM signal generation unit that generates a PWM signal, a low-pass filter circuit that applies a low-pass filter to the PWM signal, and an amplifier circuit that converts the output signal of the low-pass filter circuit into a current and supplies it to the excitation winding. The angle detection device according to any one of claims 1 to 12, wherein the excitation unit changes the amplitude of the excitation AC voltage based on the operating state of the rotating electric machine so that the range of change of the excitation voltage or the output signal of the output winding when disturbance noise due to disturbance magnetic flux from the rotating electric machine is superimposed is within the possible output range. The angle detection device according to any one of claims 1 to 12, wherein the angle information calculation unit has a high-pass filter that removes disturbance noise from the rotating electric machine from the output signal of the output winding. The angle detection device according to any one of claims 1 to 12, wherein the angle information calculation unit has a bandpass filter that removes disturbance noise from the rotating electric machine from the output signal of the output winding. The angle detection device according to claim 15, wherein the angle information calculation unit has a high-pass filter that removes disturbance noise from the rotating electric machine from the output signal of the output winding. The angle detection device according to claim 15, wherein the angle information calculation unit has a bandpass filter that removes disturbance noise from the rotating electric machine from the output signal of the output winding.

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