JP4269686B2 - Sensorless measurement method and position sensorless variable speed device for synchronous motor position, speed and voltage amplitude - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sensorless measurement method of position, speed, and voltage amplitude for measuring the rotor position, speed, and voltage amplitude of a synchronous motor using a permanent magnet as a field source without using a sensor, and a synchronous motor using this measurement. This relates to a sensorless variable speed device.
[0002]
[Prior art]
When a synchronous motor using a permanent magnet as a field source is idling, a speed electromotive force is generated at the synchronous motor terminal. Therefore, when starting with an inverter or the like, if the inverter outputs a zero voltage, the state becomes the same as the short circuit state of the synchronous motor terminal, and an excessive current is generated when the idling speed is high.
[0003]
In order to suppress this, it is necessary to continuously output a voltage having the same amplitude and the same phase as the speed-induced electromotive force from the inverter. However, if the electric motor is not provided with a position sensor or speed sensor, the voltage amplitude and phase cannot be set as the inverter output.
[0004]
Therefore, in the conventional start-up method, the output state of the inverter is set to a short-circuit state for a short time, and the pulse-like short-circuit current generated at that time is used in a phase that is exactly opposite to the phase of the induced electromotive force, An activation method has been proposed in which this is executed twice with a time interval, the speed is estimated from the time difference and the phase difference, and further the position (phase) is estimated (for example, see Non-Patent Document 1).
[0005]
5 and 6 show the current flow in a state where the terminals of the synchronous motor are short-circuited using the inverter. In FIG. 5, all the lower arm phases of the inverter are turned on, and in FIG. Is turned on and a pulsed short-circuit current flows. FIG. 7 is a time chart showing the principle of detecting the speed from the phase of the short-circuit current vector generated at that time. The rotational angular velocity ω _est of the motor is calculated from the phase difference θa (= θ0−θ1) measured with two pulses and the time difference Ta by the following equation. Further, it is possible to know the rotor position by the integral of the rotational angular velocity omega _est (phase), it is possible to know the rotational direction from the sign of the rotational angular velocity omega _est.
[0006]
[Expression 1]
ω _est = θa / Ta
[0007]
[Non-Patent Document 1]
1997 IEEJ Industrial Application Division National Conference No.135 Toba, Aihara, Yanase: “Position / Speed / Voltage Sensorless PM Motor Drive System Startup Method from Rotating State”
[0008]
[Problems to be solved by the invention]
The condition that enables measurement by the above-described conventional method is that the generation interval of the two short-circuit pulse currents is such that the idling rotor is less than 180 ° in electrical angle. This is because the phase measurement by the short-circuit pulse method can measure only the section of electric angle from −180 ° to + 180 °.
[0009]
Therefore, if the electric angle is rotated by 180 ° or more between two generations of pulses, the direction of rotation cannot be determined. Even if the rotation direction can be determined by another method, when the rotation is 360 ° or more, the number of rotations cannot be measured.
[0010]
Moreover, in the case of a multipolar synchronous motor, the frequency tends to increase. Further, in the case of a synchronous motor having a large inductance, there is little change in current even if a short circuit occurs, and a current amplitude sufficient to calculate an accurate phase will not occur unless the short circuit is performed for a certain period of time.
[0011]
Then, for a synchronous motor with a relatively high frequency exceeding 200 Hz, the rotor may rotate 180 ° or more during the time until a pulse current is generated and it once returns to zero. is there. For such a synchronous motor, the conventional method cannot be applied during high-speed rotation.
[0012]
As described above, in the condition where the rotational speed is high and the rotor rotates 180 degrees or more in electrical angle during the generation of the short-circuit pulse, it has been moved to its phase by multiple rotations or within one rotation. Cannot be determined. In addition, it is unclear whether the rotation direction has reached its phase by rotating forward or reverse. Therefore, an accurate speed could not be measured.
[0013]
An object of the present invention is to provide a method for measuring the rotor position and speed of a synchronous motor based on the time difference and phase difference of a short-circuit pulse current generated in the synchronous motor in the idling state of the synchronous motor using a permanent magnet as a field source. The position, speed, and voltage amplitude of a synchronous motor that can accurately measure the rotor position, speed, and voltage amplitude even when the rotor rotates 180 degrees or more in electrical angle during the occurrence of a short-circuit pulse current It is to provide a sensorless measurement method. Furthermore, this invention is providing the sensorless variable speed apparatus of the synchronous motor using this measuring method.
[0014]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a conventional sensorless measurement method for position / velocity, in which a short-circuit pulse current is generated three or more times at different time intervals, and the time difference and position of each measurement period of the short-circuit pulse current are measured. The phase difference is obtained, and the speed and phase are measured from the results of obtaining the differences.
[0015]
Further, according to the present invention, the phase advance angle of each measurement period is estimated by calculation from the speed measurement result, and based on this, the phase difference when the measurement phase is rotated multiple times is corrected.
[0016]
Furthermore, the present invention generates a short-circuit pulse current when the induced electromotive force of the synchronous motor exists on a phase shifted by 30 ° with respect to the three-phase winding axis, and the differential component of the current increase at that time, The differential component of the current decrease immediately after the end is measured, and the amplitude component of the induced electromotive force is obtained with the DC power supply voltage of the inverter as a constant.
[0017]
Therefore, the present invention is characterized by the following sensorless measurement method and sensorless variable speed apparatus.
[0018]
(Invention of sensorless measurement method)
(1) Rotor position / speed / voltage amplitude of synchronous motor based on time difference and phase difference of short-circuit pulse current generated in synchronous motor by gate control of inverter in synchronous motor with permanent magnet as field source A sensorless measurement method for the position, speed, and voltage amplitude of a synchronous motor that measures
The short-circuit pulse current is generated three or more times at intervals of different times t0, t1, and t2, and the phases θ0, θ1, and θ2 of the short-circuit pulse current are detected, and the time difference Ta (= t1−t0) of each time interval, Tb (= t2−t1) and phase differences θa (= θ1−θ0) and θb ( = θ2−θ1) are obtained, and the time difference ΔT (= Ta−) is further calculated from the time difference and the phase difference at each measurement time. Tb) and a phase difference Δθ (= θa−θb) are obtained, and the speed and phase are measured from the rotor angular velocity ω est of the synchronous motor obtained from the ratio Δθ / ΔT of these differences .
[0019]
(2) Estimating phase change amounts Θa ′ and Θb ′ in each measurement period from the product of the time difference signal Ta and the rotor angular velocity ω est and the product of the time difference signal Tb and the rotor angular velocity ω est , and the phase difference θa , Θb, the phase difference is corrected to a phase difference closest to Θa ′ and Θb ′ when the measurement phase is rotated many times , and the speed and phase are obtained.
[0020]
(3) The short-circuit pulse current is generated when the induced electromotive force of the synchronous motor is present on a phase shifted by 30 ° with respect to the three-phase winding axis. The differential component of the current decrease immediately after is measured, and the amplitude component of the induced electromotive force is obtained by using the DC power supply voltage of the inverter as a constant.
[0021]
(Invention of sensorless variable speed device)
(4) Rotor position / speed / voltage amplitude of the synchronous motor based on the time difference and phase difference of the short-circuit pulse current generated in the synchronous motor by gate control of the inverter in the idling state of the synchronous motor using the permanent magnet as the field source Is a sensorless variable speed device of a synchronous motor for starting and variable speed control of a synchronous motor based on these measurement results,
The inverter control device calculates a phase detector for detecting the phase signals θ0, θ1, and θ2 at least three times at different time intervals of t0, t1, and t2, and a rotor angular velocity signal. A speed calculation unit and calculation means for integrating the angular velocity signal calculated by the speed calculation unit to obtain a phase are provided, and the speed calculation unit calculates Ta (= t1-t0), Tb (= t2-) from the measurement time. Means for obtaining the phase difference of θa (= θ1-θ0), θb ( = θ2-θ1) from the time difference of t1) and the phase signal, and further each difference ΔT (= Ta−Tb) from the obtained time difference and phase difference And a phase difference Δθ (= θa−θb), and a means for obtaining the rotor angular velocity ω est from the difference ratio Δθ / ΔT.
(5) the speed calculating section by Motoma' time difference signal Ta, enter the Tb and rotor angular velocity omega est, the time difference signal Ta and the rotor angular velocity omega est product, and the product of the time difference signal Tb and the rotor angular velocity omega est phase variation Θa of each measurement period ',? b' estimates the, and the phase difference .theta.a, phase variation Θa when measured phase from θb is multi-rotation ',? b' before Symbol rate measurement result closest to A phase difference correction unit that estimates the phase advance angle of each measurement period by calculation, calculates phase difference correction when the measurement phase is multi-rotation based on this, and outputs it to the speed calculation unit [0023]
(6) The inverter generates the short-circuit pulse current when the induced electromotive force of the synchronous motor exists on a phase shifted by 30 ° with respect to the three-phase winding axis,
The arithmetic means comprises means for measuring a differential component of current increase of each short-circuit pulse current and a differential component of current decrease immediately after the end of the short circuit, and obtaining an amplitude component of the induced electromotive force using the DC power supply voltage of the inverter as a constant. It is characterized by that.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
(Embodiment 1)
In the conventional method, when the rotation speed is high and the rotor rotates by 180 ° or more of the electrical angle during the generation period of the short-circuit pulse, it has been rotated multiple times and moved to the phase or within one rotation. Cannot be determined. In addition, it is unclear whether the rotation direction has reached its phase by rotating forward or reverse. Therefore, it was not possible to measure an accurate speed and rotation direction.
[0025]
In this embodiment, the phase between two short-circuit pulses is not directly used, but three short-circuit pulses are generated with different time differences, and the velocity and position are measured from these pulse time differences and phase differences, and these measurements are performed. The synchronous motor is started based on the value, and variable speed control is enabled.
[0026]
FIG. 1A shows the configuration of the main part of the position / speed sensorless variable speed device of this embodiment, and FIG. 1B shows the time chart of the main part of speed measurement.
[0027]
The variable speed device comprises a voltage type inverter 1, a control device 2, a current detector 3 as a digitized current detection means, and an A / D converter 4. The control device 2 is based on a current control system and a rotor phase. The synchronous motor 5 is activated and controlled at a variable speed with the coordinate conversion system. The variable speed control of this configuration is a known one, but there is also a configuration in which the device configuration is appropriately changed.
[0028]
Here, as means for realizing the position / velocity measurement method according to the present embodiment, a current phase detection unit 6, a speed calculation unit 7, and an integration unit 8 are provided.
[0029]
The current phase detector 6 is for detecting the phases θ0, θ1, and θ2 of the three short-circuit pulse currents to be generated in the synchronous motor 5, and the two-phase / 3-phase from the two-phase current detection signals of the synchronous motor 5 The three-phase current is detected by the conversion, and these are converted into an α-axis component and a β-axis component to obtain the phase of each short-circuit pulse current.
[0030]
When detecting the phase of the short-circuit pulse current, the control device 2 sets the gate signal of the inverter 1 for a short period of time during which the voltage is zero for a short period of time while the rotor of the motor is idling. In this embodiment, the generation of the short-circuit pulse current is repeated three times at times t0, t1, and t2, and the time difference between these time intervals (t1-t0, t2-t1) is made different. Perform gate signal control.
[0031]
With these controls, the current phase detector 6 can detect the three short-circuit pulse current phases θ0, θ1, and θ2 at times t0, t1, and t2 having different time intervals.
[0032]
As shown in FIG. 1 (b), the speed calculation unit 7 includes time differences Ta (t1-t0) and Tb (t2-t1) and phase differences θa (= θ1-θ0), θb (= θ2) in each measurement period. -Θ1) is obtained, and the speed ω _est is obtained from the result of taking the difference between them. The integrator 8 detects the phase (rotor position) by integrating the speed ω _est .
[0033]
The calculation in the speed calculation unit 7 will be described in more detail. Three short pulse currents are generated at different time intervals, and the phases of these current vectors are measured to measure the time intervals Ta and Tb of each measurement pulse. The phase intervals θa and θb are as follows.
[0034]
[Expression 2]
Ta = t1-t0
Tb = t2-t1
[0035]
[Equation 3]
θa = θ1 θ1
θb = θ2−θ1
Then, when the difference ΔT, Δθ between these time difference and phase difference is taken, the following equation is obtained.
[0036]
[Expression 4]
ΔT = Ta-Tb
Δθ = θa and θb
The rotor angular velocity ω _est can be obtained from the difference ratio Δθ / ΔT by the following equation.
[0037]
ω _est = Δθ / ΔT
However, as a restriction, the time difference of ΔT is set to such an extent that the rotor does not idle more than 180 ° during this time difference. Even if the pulse interval itself cannot be shortened, the time difference can be set freely. Therefore, the difference between the two time differences to be measured can be set to a short time difference. The present embodiment utilizes this feature.
[0038]
In the conventional method, there is a condition that the time difference between the two measurement sections is less than 180 ° of the electrical angle of the rotor. In the measurement method of the present embodiment, the rotor is rotated by 180 ° or more of the electrical angle. In this case, the rotor position / speed can be measured. In addition, the absence of this time limit eliminates the need for shortening the measurement period when rotating at high speed, and in turn, the short-circuit period can be lengthened, so that the pulsed current amplitude to be measured can be increased, and current detection is performed. Accurate measurement with reduced influence of errors and the like is possible, and as a result, variable speed control with high accuracy becomes possible.
[0039]
Note that the number of occurrences of the short-circuit pulse current is three or more at different time intervals, and the speed and phase can be obtained from the averaging process or the like.
[0040]
(Embodiment 2)
In the first embodiment, the speed / phase detection is performed by simply taking the phase difference difference. However, the phase difference Δθ used for detecting the final speed and the phase is limited to 180 ° or less. Therefore, it is easily affected by the phase detection error, and the accuracy of the detected speed is lowered.
[0041]
Here, if the approximate speed and direction of rotation are known by the speed detection method of the first embodiment, it is possible to estimate the number of times of multi-rotation even for a phase that has undergone multiple rotations of 360 ° or more. . In this way, the phase difference used for speed measurement can be increased, and the accuracy of the estimated speed and phase is greatly improved.
[0042]
Therefore, in the present embodiment, the phase change amounts Θa ′ and Θb ′ in the periods of Ta and Tb are estimated from the following equations from the speed and the measurement period measured by the method of the first embodiment.
[0043]
[Equation 5]
Θa '= ω _est * Ta
Θb ′ = ω _est * Tb
Further, the phase difference in the case of multiple rotations is estimated from the measured phase differences θa and θb. Here, an example of correcting θa is shown.
[0044]
One electrical rotation or less: θa ′ = θa + 0 * 360 °
Within 1 to 2 rotations in electrical angle: θa ′ = θa + 1 * 360 °
Within 2 to 3 rotations in electrical angle: θa ′ = θa + 2 * 360 °
Even if the rotation is 360 degrees or more by selecting the one closest to the phase differences Θa ′ and Θb ′ estimated from the speed from the phase differences assuming the above multiple rotations. The phase difference can be corrected. If the speed is calculated from the phase difference and time difference corrected for multiple rotations, more accurate speed detection is possible.
[0045]
In the present embodiment, the above estimation and phase difference correction are realized by the phase difference correction unit 9 shown in FIG. Then, the speed calculation unit 7 obtains a corrected speed ω _est using the corrected phase differences θa ′ and θb ′.
[0046]
(Embodiment 3)
The speed estimation during the idling of the synchronous motor using the permanent magnet as the field source may use the first or second embodiment. Further, since not only the speed but also the phase and its time are known, the phase of the time at which the inverter is started and the operation is started can be predicted by calculation. However, when starting an idling motor, voltage amplitude information is also required.
[0047]
If the speed can be detected in the first and second embodiments and the magnetic flux of the permanent magnet is known, it is easy to calculate the speed-induced electromotive force. However, the residual magnetic flux of the permanent magnet varies depending on the temperature of the magnet. For this reason, the magnetic flux changes depending on the temperature of the synchronous motor, and an accurate speed-induced electromotive force cannot be calculated. Therefore, it is possible to start more stably when the voltage can be directly measured than when the induced electromotive force is indirectly calculated from the speed and the magnetic flux.
[0048]
Therefore, in this embodiment, in addition to the measurement data of the current change during the period in which the short-circuit pulse current is generated in the synchronous motor, the change in current when the inductance current attenuates when the short-circuit is released is also used for synchronization. The present invention proposes a measurement method for estimating the terminal voltage (voltage amplitude) of an electric motor and a variable speed device using the same.
[0049]
Here, it is assumed that the DC power supply voltage Vdc of the inverter 1 in FIG. 1 is known by other voltage sensors. Actually, it is intended for a three-phase motor, but for the sake of simplicity, the measurement principle will be described below using a one-phase model.
[0050]
As shown in FIG. 2 (a), a short-circuit pulse current can be generated in the synchronous motor by short-circuiting the terminal of the idle synchronous motor only for a short period by gate control of the inverter.
[0051]
The equivalent circuit at this time is a current proportional to E0 because the voltage of the induced electromotive force E0 is added to the inductance L of the synchronous motor when the gate of the lower arm in the single-phase model is turned on as shown in FIG. Change occurs. Thereafter, when the gate of the lower arm is turned OFF to stop the short circuit, this time, as shown in FIG. 2C, the current is commutated to the current loop for regenerating the power source through the diode of the upper arm of the inverter.
[0052]
Accordingly, the amount of change in the current flowing through the inductance L satisfies the following relationship using the DC power supply voltage Vdc and the induced electromotive force E0 when the power is regenerated through the diode after the short circuit and after the short circuit.
[0053]
[Formula 6]
−E0 = (di _L / dt) L
(Vdc−E0) = (di _H / dt) L
Here, (di _L / dt) represents the current differentiation at the time of short circuit in the period of FIG. 2B, and (di _H / dt) represents the current differentiation after the short circuit in the period of FIG.
[0054]
Since these current differentials are proportional to the voltage applied to the inductance L, the ratio of the terminal voltage of the synchronous motor to the induced electromotive force can be estimated by measuring the amount of current change (current differential value). Can be requested.
[0055]
Therefore, as shown below, the induced electromotive force E0 can be derived from the following relational expression using the current change amount ratio K.
[0056]
[Expression 7]
K = (di _L / dt) / (di _H / dt)
K = −E0 / (Vdc−E0)
K (Vdc−E ₀ ) = − E0
K ・ Vdc = K ・ E0−E0
E0 = K · Vdc / (K−1)
Therefore, it is possible to directly measure the voltage from the current differential component and the power supply voltage Vdc when the synchronous motor is short-circuited and immediately after that.
[0057]
Here, in the case of a three-phase synchronous motor, the induced electromotive force has a three-phase AC waveform, and therefore the three-phase voltage varies depending on the phase of the rotor. In the short-circuit period, the current changes in proportion to the induced electromotive force of each phase, but only two potentials at both the P and N terminals of the DC power supply are used to regenerate the inductance energy after the short-circuit to the DC power supply. Is applied to the terminal according to the current polarity of the inductance, the three-phase terminal voltage is different from the ratio of the induced electromotive force. Therefore, since the ratio of the current rise in the short-circuit period and the current fall in the regeneration period immediately after that is different for all three phases, the above equation cannot be applied.
[0058]
Therefore, measurement is performed when the induced electromotive force coincides with the axis of the three-phase winding. Induced electromotive force of the three-phase alternating current skin type e _u shown in FIG. 3, e _v, of e _w, at the timing when the two-phase components are identical, since only the induced electromotive force also binary three phases does not exist, just The same model as single phase can be applied.
[0059]
In order to perform measurement when this phase is reached, the measurement phases θ0, θ1, θ2 and times t0, t1, t2 and the calculated speed ω _{est of} Embodiment 1 and Embodiment 2, and the corrected speed ω _{Since the} rotational phase is predicted from _est, it is possible to measure the amplitude component of the induced electromotive force at the timing when the two-phase components match from this prediction.
[0060]
(Embodiment 4)
In the third embodiment, the induced electromotive force measurement is performed under the condition that the components of the two phases out of the three phases coincide with each other. However, the same result can be obtained even if measurement is performed under the condition where only one phase does not flow current. .
[0061]
Therefore, in this embodiment, as shown in FIG. 4, it is proposed to measure at the time when the voltage of one phase is zero.
[0062]
The phase where the induced electromotive force is zero corresponds to the intermediate voltage of the other two phases. For this reason, the current also remains zero due to the balanced input and output components. If it does so, the measurement equivalent to a single phase model can be implemented, and the amplitude component of an induced electromotive force can be measured.
[0063]
Note that the measurement timing in the present embodiment and the third embodiment is when the induced electromotive force exists on a phase shifted by exactly 30 ° with respect to the three-phase winding axis.
[0064]
【The invention's effect】
When a synchronous motor using a permanent magnet as a field source is idling, if the amplitude, phase, and speed of the induced electromotive force of the rotor are known, the induced electromotive force is generated when starting operation during idling. The output can be started from the balanced voltage, and stable start-up is possible without a sudden change in current.
[0065]
Among them, in order to measure the phase and speed, the current component generated by the induced electromotive force of the synchronous motor is measured by turning on the gate of the inverter for a short period of time under the condition of zero voltage. The phase and speed of the induced electromotive force are measured by utilizing the fact that the space vector of the measured current exists in a phase opposite to the induced electromotive force vector by 180 °. At this time, in the conventional method, there is a condition that the time difference between the two short-circuit pulse currents is less than 180 ° of each rotor.
[0066]
On the other hand, according to the measurement method and the variable speed device of the first and second embodiments of the present invention, there is no time limit for measurement, and it is not necessary to shorten the measurement period when rotating at high speed. As a result, since the short-circuit period can be made longer, the amplitude of the short-circuit pulse current to be measured can be increased, so that the influence of current detection error and the like can be reduced.
[0067]
In the conventional method, the speed and phase can be measured, but the amplitude of the induced electromotive force cannot be measured. If the inductance value is known, the voltage can be estimated from the differentiation of the current. If the residual magnetic flux is known, the induced electromotive force can be calculated from the speed. Both of these methods have the problem of requiring a constant for the synchronous motor. Therefore, when the constant changes depending on the temperature, or when the individual variations of the synchronous motors are large, an error occurs in the estimated value of the induced electromotive force.
[0068]
On the other hand, in the measurement method and the variable speed device of the third and fourth embodiments of the present invention, the voltage amplitude component is directly estimated from the differential component of the current and the DC voltage based on the measurement method of the first and second embodiments. Therefore, accurate voltage amplitude measurement and variable speed control are possible.
[Brief description of the drawings]
FIG. 1 is a time chart of a variable speed device and speed / phase measurement according to first and second embodiments of the present invention.
FIG. 2 is a diagram illustrating a measurement principle according to a third embodiment of the present invention.
FIG. 3 is an explanatory diagram of the measurement timing of the induced electromotive force in the third embodiment.
FIG. 4 is an explanatory diagram of measurement timing of induced electromotive force in the fourth embodiment.
FIG. 5 is a short-circuit mode in which all lower arm gates are turned ON when a short-circuit pulse current is generated.
FIG. 6 is a short-circuit mode in which all upper arms are gated ON when a short-circuit pulse current is generated.
FIG. 7 is a diagram illustrating the principle of performing speed measurement from the generation timing and measurement phase of a short-circuit current in a conventional method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Inverter 2 ... Control apparatus 3 ... Current detector 4 ... A / D converter 5 ... Synchronous motor 6 ... Current phase detection part 7 ... Speed calculation part 8 ... Integration part 9 ... Phase difference correction part

Claims (6)

In the idling state of a synchronous motor with a permanent magnet as a field source, the rotor position, speed, and voltage amplitude of the synchronous motor are measured based on the time difference and phase difference of the short circuit pulse current generated in the synchronous motor by gate control of the inverter. A sensorless measurement method for the position, speed, and voltage amplitude of a synchronous motor,
The short-circuit pulse current is generated three or more times at intervals of different times t0, t1, and t2, and the phases θ0, θ1, and θ2 of the short-circuit pulse current are detected, and the time difference Ta (= t1−t0) of each time interval, Tb (= t2−t1) and phase differences θa (= θ1−θ0) and θb ( = θ2−θ1) are obtained, and the time difference ΔT (= Ta−) is further calculated from the time difference and the phase difference at each measurement time. Tb) and a phase difference Δθ (= θa−θb) are obtained, and the speed and phase are measured from the rotor angular velocity ω est of the synchronous motor obtained from the ratio Δθ / ΔT of these differences. Sensorless measurement method for motor position, speed, and voltage amplitude. Phase change amounts Θa ′ and Θb ′ in each measurement period are estimated from the product of the time difference signal Ta and the rotor angular velocity ω est , and the product of the time difference signal Tb and the rotor angular velocity ω est , and from the phase differences θa and θb. The position / speed / position of the synchronous motor according to claim 1, wherein the speed and phase are obtained by correcting to a phase difference closest to the phase change amounts Θa ′ and Θb ′ when the measurement phase is rotated many times. Sensorless measurement method of voltage amplitude.   The short-circuit pulse current is generated when the induced electromotive force of the synchronous motor exists on a phase shifted by 30 ° with respect to the three-phase winding axis, and the differential component of the current increase at that time and the current immediately after the end of the short-circuit 3. The sensorless measurement of the position / speed / voltage amplitude of the synchronous motor according to claim 1, wherein a differential component of the decrease is measured, and an amplitude component of the induced electromotive force is obtained by using a DC power supply voltage of the inverter as a constant. Method. In the idling state of a synchronous motor using a permanent magnet as a field source, the rotor position, speed, and voltage amplitude of the synchronous motor are measured based on the time difference and phase difference of the short circuit pulse current generated in the synchronous motor by gate control of the inverter. , A sensorless variable speed device of a synchronous motor for starting and variable speed control of the synchronous motor based on these measurement results, wherein the inverter control device includes a time interval in which the phases of the short-circuit pulse currents are different at t0, t1, and t2. The phase detector that detects the phase signals θ0, θ1, and θ2 three times or more, the speed calculator that calculates the rotor angular velocity signal, and the calculation that obtains the phase by integrating the angular velocity signals calculated by the velocity calculator In addition to providing the means, the speed calculation unit calculates the time difference of Ta (= t1−t0) and Tb (= t2−t1) from the measurement time and θa (= θ1−θ0), θ from the phase signal. Means for determining a phase difference (= θ2-θ1), further from the determined time difference and the phase difference each difference △ T (= Ta-Tb) and phase difference △ theta seeking (= θa-θb), the ratio of these differences A sensorless variable speed device for a synchronous motor, comprising means for obtaining a rotor angular velocity ω est from Δθ / ΔT . The time difference signals Ta and Tb obtained by the speed calculation unit and the rotor angular velocity ω est are input , and each measurement period is calculated from the product of the time difference signal Ta and the rotor angular velocity ω est and the product of the time difference signal Tb and the rotor angular velocity ω est. phase variation Θa of ',? b' estimates the, and the phase difference .theta.a, phase variation Θa when measured phase from θb is multi-rotation ',? b' each measurement from the result closest prior Symbol rate measured A phase difference correction unit that estimates a phase advance angle of a period by calculation, calculates a phase difference correction when the measurement phase is rotated multiple times based on this, and outputs the phase difference correction unit to the speed calculation unit is provided. A sensorless variable speed device for a synchronous motor according to claim 4. The inverter generates the short-circuit pulse current when the induced electromotive force of the synchronous motor exists on a phase shifted by 30 ° with respect to the three-phase winding axis,
The arithmetic means comprises means for measuring a differential component of current increase of each short-circuit pulse current and a differential component of current decrease immediately after the end of the short circuit, and obtaining an amplitude component of the induced electromotive force using the DC power supply voltage of the inverter as a constant. 6. The sensorless variable speed device for a synchronous motor according to claim 4, wherein the variable speed device is a synchronous motor.

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