JPS59172099A - Improvement in accuracy of resolver - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention corrects the phase distortion of the output of a resolver used as a position detector when vector controlling an induction motor or a synchronous motor, thereby achieving highly accurate control. The present invention relates to a method for improving the accuracy of a resolver.

[Background technology]

Vector control using an induction motor involves making the main magnetic flux in a DC machine correspond to the rotor vector and the armature current to the rotor secondary current hector, and by controlling these vectors, a torque equivalent to that of a DC machine can be obtained. This is what I did.

This vector control uses a resolver as a means for detecting the position of the rotor.

There are two types of resolvers: inductor type and vernier type two-turn transformer type, but unlike the latter, the former two do not have a winding on their rotor.

Figure 1 shows the configuration and arrangement of a 72-pole vernier resolver, in which the 32-slot stator core (1) has an α-phase excitation winding (2) and a β-phase excitation winding (3) at electrical angles. They are wound every 4 slots with a 90° phase shift, and 2
A detection winding (4) is wound around each slot, and a 36-pole rotor (5) constitutes a two-pole harmonics resolver. The same figure (bl, (C1, (dl is α phase,
This represents the connection of the β-phase excitation winding and the θ-phase detection winding.

However, in this case, since the detection winding (4) is placed in the stator slot in which the excitation winding +2L (31) is placed, the leakage magnetic flux generated by the excitation winding in the detection winding (for example, the leakage magnetic flux in the slot, the coil end part leakage magnetic flux, etc.), and a residual voltage with the same frequency as the excitation frequency is generated. Figure 2 shows the voltage waveform, where the α-phase excitation voltage Uσ and β
The residual voltage UθR having the same frequency as the excitation frequency of the phase excitation voltage uB has a phase difference of θ0 from the α phase voltage,
The residual voltage of the maximum value ■ is superimposed on the detected voltage.

The generated residual voltage causes electrical phase errors and reduces resolver accuracy, but there remains a fundamental problem unique to inductor-type and vernier-type resolvers for which there is no satisfactory solution.Recent 72 As the precision of vernier-type resolvers increases, it has been found that the residual voltage can be reduced by changing the relative positions of the excitation winding and detection winding placed in the slots, but this is considerably difficult in terms of production technology. There is a problem.

[Purpose of the invention]

The object of the present invention is to connect a correction winding for removing residual voltage to a vernier-type twister produced using a conventional manufacturing method, thereby improving the characteristics.

[Structure of the invention]

The present invention arranges an excitation winding and a detection winding in slots provided in the stator of a resolver, and by exciting the excitation winding, an electrical signal that changes with the rotational position of the rotor is transmitted to the detection winding. In an inductor type or vernier type resolver taken out from a wire, the excitation winding and the detection winding are wound around an iron core, and the voltage induced in the detection winding by the magnetic flux induced in the iron core by the excitation current flowing in the excitation winding is detected. The present invention relates to a method for improving accuracy of a resolver, which is characterized by correcting a phase error occurring in a detection winding by superimposing it on a voltage.

[Detailed description of the invention]

The phase relationship of the residual voltage generated in the detection winding is as shown in Fig. 2, where the α-phase excitation voltage is 'IJ(1), the β-phase excitation voltage is 'ttB, and υ(1=Vsinωt, υβ−V c.
If osωt, the residual voltage υθR generated in the detection winding is
is as shown below.

U(IR=VθRsin (ωt-θ0) ---
Although the amplitude and phase angle of the generated residual voltage vary considerably even among the same models, it can be canceled by applying a voltage of opposite polarity to the detection winding.

FIG. 3 shows an example of a configuration in which a voltage of opposite polarity to the residual voltage is applied to the detection winding. In this figure, (al is the conventional configuration without a correction winding, (bl is the configuration example of the present invention. In the figure, 00) is the resolver, (61 is the iron core, (7) is α
The phase correction winding (8) is a β phase correction winding, and (9) is a detection correction winding.

Determination of the number of turns of the correction winding connected to each winding of the generator and adjustment of the degree of magnetic coupling between each correction winding are performed according to the principles and procedures described below.

In the configuration example of the correction winding shown in FIG. 4, the winding f71
．． Voltage for each +81? / tcc= V animals s inωt −−−−−−
Second formula 'J8C= Vsc cosω1----
--When the third equation is applied, the composite magnetic flux created by each winding interlinks with the winding (9), and the voltage expressed by the following equation is applied to the winding (9).
9). However, it is assumed that there is no leakage flux in each winding.

'LfeC=Vec sjn (ωt-φ) -song----1 4th formula% formula%) φ-jan-' (VBCnoc/Var: n
B) 1 Equation 5 As is clear from the 4th and 5th equations, the amplitude of the induced voltage is determined by the number of turns of the winding and the applied voltage,
It can be seen that the phase angle φ is determined by the number of turns of the windings (71, (81) and the applied voltage, regardless of the winding (9).

Therefore, in order to make the fourth equation equal to the first equation, the relationship between each winding and the applied voltage may be determined based on the following equation.

VθR=Vθc −−−−−−−One side−−=Mountain−
6th formula θ0−φ −−−−−One mountain one・−1−−−−
−−−−−−−−−−−−−− Equation 7 For each winding determined in this way, winding (7) is connected to the α-phase excitation winding (2) of the detector, and winding (8 ) is connected to the β-phase excitation winding (3), the residual voltage becomes zero.

When considering the leakage reactance created by each winding, the amplitude and phase change by adjusting the positional relationship between the windings.

Although FIG. 4 shows a bar-shaped iron core (6), it is also possible to miniaturize the device by making it ring-shaped so that the magnetic path of the magnetic flux is closed.

〔Effect of the invention〕

As described above, according to the present invention, the residual voltage inherent in an inductor type or vernier type resolver can be easily removed by the correction winding without making any modification to the conventional manufacturing process, and accuracy can be improved. This has the effect that it can be applied as a position detector for vector control, etc., which requires high accuracy.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the configuration of a 72-pole vernier resolver, Fig. 2 is a waveform diagram showing the phase relationship between excitation voltage and residual voltage, and Fig. 3 is a conventional detection method and a correction winding according to the present invention. FIG. 4 is an explanatory diagram showing the structure of the correction winding. (1): Stator winding (2): α-phase excitation winding (3): β-phase excitation winding (4) Second detection winding (5): Rotor (6): Iron core (7): α Phase correction winding (8): β-phase correction winding (9): Detection correction winding 00): Resolha patent applicant Yaskawa Electric Co., Ltd. Representative Masu Kodo (2 persons) Figure 1 (a) βi θ10−
Figure 2 Figure 4

Claims (1)

[Claims] 1. An excitation winding and a detection winding are arranged in slots provided in the stator of the resolver, and by exciting the excitation winding, an electric current that changes with the rotational position of the rotor is generated. In an inductor-type or vernier-type resolver in which No. 4g is taken out from a detection winding, the excitation winding and the detection winding are wound around an iron core, and the excitation current flowing through the excitation winding is induced into the detection winding by the magnetic flux induced in the iron core. A method for improving accuracy of a resolver, characterized in that a phase error occurring in a detection winding is corrected by superimposing a voltage applied to the detection voltage on the detection voltage.