JPH043486B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for detecting the phase error that occurs in an inductor type resolver in which, for example, an excitation winding and a detection winding are wound around a stator, and the rotor is made of only a magnetic material. The present invention relates to a device for compensating errors on the side. Inductive resolvers are brushless, simple machines consisting of only a core, windings, and insulation, and are highly reliable position and velocity sensors that can be used in any harsh environment where a motor can be used. There is no better sensor for mechatronic actuators. On the other hand, it has the disadvantage that it is structurally difficult to increase accuracy. Therefore, it is necessary to compensate for various errors using an external circuit. SUMMARY OF THE INVENTION An object of the present invention is to provide a phase error compensation device that performs compensating calculations on the output side of phase detection to compensate for the phase error of a resolver, thereby obtaining an output in which the phase error is eliminated. Now, the principle of the detection side compensation method will be described. Electrically, two-phase excitation winding with a phase difference of 90° w = winding and
Assuming that w〓 winding and detection winding w〓 are wound, excitation voltage e〓∝cosωt to w〓 winding, excitation voltage e〓∝sinωt to wβ winding (however, excitation angular frequency ω=
2π is the excitation frequency and t is the time), then the detected voltage e〓 is: e〓∝cos{ωt−(θ+(θ)}) Here, θ is the phase of the resolver, and (θ) is its phase error. When k is a constant of proportionality, (θ)≪θ, so ke〓≒cos(ωt−θ)+(θ)sin(ωt−θ)……(1
) can be expressed as Therefore, cos(ωt-θ)≒ke〓(θ)sin(ωt-θ)...From (2), −(ωt+π/2)・sin(ωt-θ) is the compensation voltage. If this compensation is successful, cos(ωt-θ) will be obtained near the zero cross. Instead, sin
It is necessary to know (ωt−θ). First, the detection winding is two-phase (for example, w〓〓 winding,
w = = winding). e′θ∝sin [ωt−(θ+(θ))] ke′θ≒sin(ωt−θ)−(θ)cos(ωt−θ)……
(3) Therefore, sin(ωt−θ)≒ke′θ+(θ)cos(ωt−θ)
...(4) Here, +(ωt)・cos(ωt−θ) is the compensation voltage. If equations (2) and (4) are considered as a pair, exact compensation is possible by mutually using the compensated voltages. That is, since this type of inductor type resolver has many harmonic phase errors, the Takamachi wave order is determined as i, δ _i is the i-th harmonic amplitude, and φ _i is the phase angle of the i-th harmonic. (θ)=δ _i cos(iθ+φ _i ), (ωt)
= δ _i
As cos(iωt+φ _i ), substituting equations (1) and (3) into the equations (2) and (4) where (θ) is set as (ωt), cos(ωt−θ)=cos(ωt− θ)+{(θ)−(
ωt+π/2)}sin(ωt−θ)……(5) sin(ωt−θ)=sin(ωt−θ)−{(θ)−(
ωt)}cos(ωt−θ)……(6) is obtained. At the zero cross of ωt=θ−π/2, the right side of equation (5) is cos(θ−π/2−θ)+δ _i [cos(iθ+φ _i )−cos
Since {i(θ−π/2 +π/2)+φ _i }]sin(θ−π/2−θ)=0, there is no error. At the zero cross of ωt=θ, the right side of equation (6) is sin(θ−θ)−δ _i {cos(iθ+φ _i )−cos(iθ+
φ _i )}・cos(θ−θ)=0, so there is no error here. In other words, if the above compensation voltage is applied to both detection windings, correct phase detection can be performed. Incidentally, the phase error (θ) is a mechanical value obtained through detection, and is a value that is difficult to handle in reality. The phase error (ωt) expressed by the excitation frequency rotating electrical angle ωt is a controllable value that is created according to the circuit configuration. Since this (ωt) is used in the phase error compensating means shown in FIGS. 2 and 3, which will be described later as an embodiment of the present invention, the error theory that logically holds true for (θ) also holds true for (ωt). In order to verify whether or not the equations (1) and (3) are substituted into the equations (2) and (4), where (θ) is set to (ωt), we performed an arithmetic operation. Next, when the voltage of the detection winding Wθα winding is a real number, and the voltage of the excitation winding Wθβ winding is an imaginary number, the exponential exp(jφ) = Since it is expressed as a complex number cosφ+jsinφ, the variable phase shifter is expressed as exp(jφ), but if φ〓1, exp(jφ)=1+jφ...(7) = 1/( 1−jφ) ...(8) There are the following two ways to realize these with a circuit. FIG. 1a is a first principle diagram of the present invention embodying equation (7), and FIG. 1b is a second principle diagram of the present invention displaying equation (8). 1 is a resolver output with uncompensated phase error, 2 is an adder, 3 is a compensated resolver output, 4 is a multiplier that multiplies the uncompensated output by φ, and 5 is a coefficient multiplier that multiplies j. This is expressed as an actual circuit in the block diagram shown in FIG. 2, which shows the configuration of an embodiment of the present invention. 21 is a resolver, 21 is an excitation voltage sinωt supply end,
22 is an excitation voltage cosωt supply end, 23 and 24 are adders, 25 and 26 are multipliers, and 27 is a compensated output
Output end of sin(ωt-θ), 28 is compensated output
The output terminal of cos (ωT-θ) and 29 are the input terminal of compensation (ωt). 30 within the dotted line frame forms a variable phase shifter. sinωt from the excitation voltage supply ends 21 and 22, respectively.
cosωt is given to the β wire w〓 and the α winding w〓, and due to the rotation of the rotor of the resolver 20, that is, from the excitation rotation electrical angle ωt, the phase error (θ) is generated from the detection winding w〓〓.
The output sin {ωt−θ−(θ)} containing
An output cos {ωt−θ−(θ)} is output from the detection winding w〓〓. Here, since the phase error (θ) can be measured and known in advance, an excitation rotating electrical angle (ωt) equivalent to the phase error (θ), that is, a signal synchronized with the phase error, is applied from the input terminal 29. Here, a description will be given of how to equivalently convert the mechanical phase error (θ) into a phase error (ωt) expressed in excitation frequency electrical angle. For example, an inductive resolver whose rotor is directly connected to a common shaft with an optical encoder is installed so that the rotation angle corresponding to the mechanical rotation position outputs an accurate detected value with its own error corrected. The rotational frequency electrical angle ωt that excites the inductive resolver
For example, by applying a voltage of
The value of the output voltage (peak value) of the inductive resolver is detected, and the mechanical angle of 0°, 1°, where the common axis is rotated by 1° mechanical angle is detected.
Corresponding to 2°, ...359°, the positive and negative error voltages of the output voltage of the inductive resolver can be found as the difference voltage between the two. The phase error curve (θ) of the inductive resolver with the rotation angle of the common axis as the horizontal axis and the detected voltage as the vertical axis has now been measured. ) is written in memory , where ω=2πf, f=ω/(2π), 1/f=2π/ω
=T, T/360°=Δt=(2π/ω)/360°, then
If this data is sequentially read out from the previous memory at a period Δt [frequency f=360 (ω/2π)], the phase error (ωt) can be obtained as a time series. The same technical means is detailed in Japanese Patent Application No. 19339/1982 (Japanese Unexamined Patent Publication No. 148556/1983), which was filed earlier than the present invention (filing date: February 8, 1982), which will be described later. The value obtained by multiplying the output of the adder 23 and (ωt) by the multiplier 25 is the output cos {ωt−θ− of the detection winding w〓〓
(θ)}, and add the value obtained by multiplying the output of the adder 24 and (ωt) by the multiplier 26 to the output sin {ωt−θ−θ−(θ)} of the detection winding w〓〓 . In this way, the output terminals 27 and 28 output sin(ωt−θ) and cos with the phase error (θ) compensated.
(ωt−θ) is output. FIG. 3 is a block diagram showing the configuration of another embodiment of the present invention. This other embodiment is a simple compensation circuit when the detection winding w has only one phase. 31 is an adder, 32 is a phase compensated output end,
33 is an arithmetic unit that integrates the output of the adder 31 _and multiplies it by ω, and 34 is a multiplier. This circuit corresponds to the phase error (θ) (ωt
+π/2) is input to the multiplier 34. In other words, this circuit integrates cos(ωt−θ) and
sin(ωt−θ), and since there is no detection winding w〓〓,
This supplements this. As a compensation phase,
Since (ωt+π/d) is used, the zero-crossing phase error when ωt=θ−=π/2 can be made zero for all i. Although the embodiment of FIG. 2 is constructed from the principle diagram of FIG. 1b, it can also be displayed based on FIG. 1a. The same applies to the other embodiments shown in FIG. Therefore, the present invention can be described as follows. In the present invention, when a resolver is used as a phase modulator, a variable phase shifter is provided in series on the detection side of the resolver, and the phase error of the resolver is (θ)= 〓 ⁱ δ _i cos (i ωt + φ _i ) When expressed as (ωt) = 〓 ⁱ δ _i cos (i ωt + φ _i or (ωt + π/2) = 〓 ⁱ δ _i cos (i ωt + φ _i ), a signal synchronized with the phase error generated by this resolver is expressed as This is a phase error compensating device for a resolver on the detection side that controls the phase of the variable phase shifter.Thus, according to the present invention, the following effects are recognized: B. This phase error compensating device for a resolver is Means for compensating the phase error on the excitation side [Japanese Patent Application No. 58-19339 (Japanese Patent Application Laid-open No. 148-14856), which was separately studied and filed by the present inventor (filing date: February 8, 1982)] It can be used to remove residual errors on the detection side, or to selectively remove specific harmonic errors. ○B Linear resolvers become unbalanced due to end effects, so A phase error occurs.This can be removed by devising the structure of the resolver body.
Very difficult. In such cases, this electrical compensation method is very effective. ○C The resolver structure can be simple, which reduces costs. A vernier resolver can be made using the core of a stepping motor. Since the phase error is compensated by an external circuit, there is no need to change the design of the resolver body. ○D In practical applications, the output of the air gap magnetic flux sensor used for vector control of induction machines includes slot pulsation, so it is necessary to remove this, but in such cases, the excitation side compensation mentioned earlier cannot be done. .
The amplitude is less important since it is necessary to know the location of the air gap flux. Therefore, it is possible to modulate the magnetic flux signal with a carrier wave and then apply this phase error compensation to remove the pulsation component.

[Brief explanation of drawings]

FIGS. 1a and 1b are basic configuration diagrams of the present invention, and FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention.
FIG. 3 is a block diagram of another embodiment of the invention. 1... Resolver output without phase error compensation, 2, 2
3, 24, 31... Adder, 3, 27, 28, 3
2... Resolver output (output end) with phase error compensated, 4, 25, 26, 34... Multiplier, 5...
Coefficient unit, 20... Resolver, 21, 22... Excitation voltage input terminal, 29... Compensation voltage input terminal, 30...
Variable phase shifter, 33... Arithmetic unit.

Claims (1)

[Claims] 1. 2 wound at positions separated by an electrical angle of 90° from each other.
Phase excitation winding wβ, excitation winding wα, and two-phase detection windings wound at positions separated by an electrical angle of 90° from each other.
In an inductor resolver in which wθβ and a detection winding wθα are respectively installed on a stator and a rotor made of ferromagnetic material via air, θ is the electrical angle of the resolver rotor, ω=2πf, and f is the excitation When the frequency, t is time, (θ) is the phase error regarding the detected rotor phase θ, and (ωt) is the phase error expressed in the excitation rotational electrical angle corresponding to the phase error (θ), the detection The phase signal sin{ωt− detected from the winding wθβ
θ−(θ)} and the phase signal cos{ωt detected from the detection winding wθα
−θ−(θ)} is introduced into a variable phase shifter, and this variable phase shifter receives the corrected phase output sin(ωt -θ) by the phase error (ωt), and the corrected phase output cos(ωt-θ) of the other adder 24 into which the phase signal cos{ωt-θ-(θ)} is input. )
The other multiplier 26 multiplies by the phase error (ωt)
is connected so as to add the output of the other multiplier 26 to one adder 23 and subtract the output of one multiplier 25 from the other adder 24, and the output of one adder 23 and the addition of the other Vessel 2
A phase error compensating device for a resolver on a detection side, characterized in that the outputs of No. 4 are respectively corrected two-phase phase outputs. 2 2 wires wound at positions separated by an electrical angle of 90° from each other
In an inductor resolver in which the phase excitation winding wβ, the excitation winding wα, and the one-phase detection winding wθ are installed on the stator through a rotor made of ferromagnetic material, θ is the electricity of the resolver rotor. angle, ω = 2πf, where f is the excitation frequency, t is the time, (θ) is the phase error of the detected rotor phase θ, and (ωt) is the excitation rotating electrical angle corresponding to the phase error (θ). When the phase error is expressed by This adder 31 outputs a corrected phase output cos(ωt-θ), and an integrator 33 inputs this corrected phase output cos(ωt-θ), integrates it over time t, and multiplies it by ω. A multiplier 34 is provided to multiply the output of the integrator by (ωt+π/2), and the output of the multiplier 34 is applied to the adder 31 to obtain a phase signal cos{ωt− θ−
(θ)}, and the output of the adder 31 is used as a corrected phase output.