JPS5917892A - Phase detector for commutatorless motor - Google Patents

Abstract

PURPOSE:To gain stable commutation in a commutatorless motor by calculating the phase variation due to armature reaction from an armature current reference value or an actual armature current value, adding them to a phase deviation to compare continuously in phase. CONSTITUTION:An armature reaction arithmetic circuit 102 calculates the phase variation component of the motor voltage from the current value applied from a current value arithmetic circut 101 which calculates the actual current value by the current reference value I* from a speed controller, not shown. This calculated output and the phase deviation output obtained through a motor voltage detector, a 3-phase/2-phase converter 7, a phase difference calculating circuit 8 and a deviation amplifier 10 are added by an adder 103, and inputted to a V/F converter 11. The analog signal from the converter 11 is converted to the phase theta of digital amount by the counter 12, inputted to an ROM13 and an effective commutation leading angle setter, not shown, and the sinusoidal signal corresponding to the phase theta outputted from the ROM13 is inputted through a D/A converter 9 into the phase difference calculating circuit 8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a phase detection device for determining commutation timing based on the induced voltage phase of a commutatorless motor.

[Technical background of the invention]

Generally, commutatorless motors drive the rotor by converter operation based on natural commutation, so the device configuration is 1 to 4.
Because it is simple and highly reliable, it is widely used as an AC variable speed electric motor. Conventionally, in this device, one of the following types of rotor position detection methods has been used to determine the energized phase of the motor current. One is to install a mechanical position detector to detect the relative position of the rotor and stator of the motor, and the other is to detect the position using the armature voltage phase or magnetic flux phase of the electric motor. This method detects the position from

All of the above methods are publicly known, but the latter automatically corrects the armature reaction due to the load size and maintains the power factor of the electric rfJJJ approximately regardless of the load condition, considering the drive characteristics of the motor. Since it can be kept constant, efficiency,
It has many advantages in terms of characteristics, such as overload tolerance and reduced torque pulsation.

Phase detection methods for detecting the armature voltage of the motor and determining the energized phase of the motor current include a method of shaping the detected voltage with a filter, and a method of correcting the motor's leakage inductance and resistivity drop from the instantaneous current value. There is a method of shaping, or a method of treating the detected voltage as a vector-like quantity and performing continuous phase comparison so that the phase deviation from the λ-phase sine wave is as small as possible. The present invention relates to a phase detection device using the above method of continuously performing phase comparison (hereinafter referred to as "continuous phase comparison method").

With reference to FIG. 1, the configuration and operation of a phase detection device using a conventional continuous phase comparison method will be described using a three-phase non-commutator motor as an example. Forward converter/DC converter. In addition, the 'unpleasant pressure detector B detects a three-phase signal from the armature voltage and supplies it to the three-phase/two-phase converter 7. The 3-phase/2-phase converter 7 is
Convert this three-phase signal to a λ-phase signal with a 90 degree phase difference and feed it to the phase difference calculation circuit r. The phase difference calculation circuit g uses a triangular formula to convert the sine wave signal converted from -C digital to analog by the D/A converter and the co-phase signal given from the three-phase/two-phase converter 7. Compare and calculate the phase deviation Δθ
is generated and applied to the deviation amplifier 10. Deviation amplifier/
θ is calculated by amplifying this phase deviation Δθ using a built-in proportional-integral circuit, etc., and converting it into a voltage/frequency converter (rV/F
(referred to as "converter")//.

The analog quantity signal emitted from the V/F converter l/ is converted into a digital quantity phase θ by a counter saw, and the phase θ is equal to the read-only memory (hereinafter referred to as oMJ) /3 and the effective commutation progress. Angle β setting circuit (hereinafter referred to as "β setting circuit")/Hiroto. Here, ROM/
3 has a sine wave signal with a qo degree difference written in advance, and a sine wave signal corresponding to the phase θ is output.

This sine wave signal is applied to a D/A converter and converted into a digital signal. In addition, the phase θ given to the β setting circuit/≠ becomes a reference for determining the commutation timing, and the signal emitted from the β setting circuit/Hiroshi is ・ζ pulse amplifier circuit/! 5 and applied to the main circuit≠.

In this way, the phase detection device/6 continuously compares the detected phase from the motor voltage with the sine wave signal given via the ROM/J, and operates in a closed loop so that the phase deviation is as close to zero as possible. There is.

[Problems with background technology]

In such a conventional device, when the motor current changes, the fundamental wave phase of the terminal voltage changes as seen from one point on the rotor due to armature reaction. The speed and magnitude of this change greatly affect the electrical constants of the motor regarding the windings, field windings, etc. of the motor. Therefore, when the response of the phase detection device is slow compared to the armature reaction, the detected phase will be transiently different from the actual phase. The motor commutation timing is determined based on this detected phase, but if the detected phase differs from the actual phase due to a detection delay, it may not be possible to secure the specified commutation margin angle, and the commutation It may even lead to failure. Furthermore, the commutation margin angle becomes large, the linearity of the torque characteristic with respect to the current breaks down, and the control characteristic deteriorates.

[Purpose of the invention]

The present invention has been made in view of the point -F, and provides a phase detection device for a commutatorless motor that can compensate for phase changes caused by armature reaction of the motor when the armature current changes. The purpose is to provide.

[Summary of the invention]

In order to achieve the above object, the present invention provides an armature reaction calculation circuit in a phase detection device using a conventional continuous phase comparison method, and calculates the current value that should flow through the armature or the actual current value that actually flows through the armature reaction. The present invention provides a phase detection device for a commutatorless motor that can calculate a phase change, add it to a phase deviation Δθ, and perform continuous phase comparison.

[Embodiments of the invention]

The present invention will be described in detail with reference to FIGS. 2 and 3.

Figure 2 shows an example of a configuration that calculates the current value that should flow through the armature and calculates the phase change due to the stain reaction.The same elements as the example of the configuration of the conventional device shown in Figure 1 are the same. Indicated by the symbol. The current value calculation circuit 10/ calculates the actual current value that should actually flow based on the current reference value (2) given from a speed control circuit (not shown). Here, the current reference value 9 is set manually from the outside and instructs the magnitude of the current flowing through the motor. The current value calculation circuit 10/ can be constituted by a first-order lag circuit having a response comparable to that of a current control circuit of a non-illustrated commutatorless motor device. The armature reaction calculation circuit 10.2 calculates the phase change of the motor voltage based on the current value given by the current value calculation circuit 10, and provides this to the adder 103. That is, the armature reaction calculation circuit 70.2 outputs a change in the voltage phase due to the armature reaction that occurs with an approximately first-order lag due to the motor constant with respect to the motor current, that is, a change in the load angle, as a change in the angular frequency. For example, the circuit can be configured by a combination of a -order lag and a differential element. The output of the armature reaction calculation circuit 102 and the output of the deviation amplifier 10 are added by an adder 103 and provided to the V/F converter //.

In this way, according to the embodiment of FIG. 2, the current reference value I
The actual current equivalent is calculated from the actual current, the phase change due to armature reaction is calculated, and this is added to the closed loop of the phase detection device to compensate. It is possible to prevent the inconvenience that the voltage phases of the two voltages differ greatly.

FIG. 3 shows an embodiment of a configuration for determining the phase change due to armature reaction from the actual current value flowing through the armature. Elements that are the same as the configuration example of the conventional device shown in FIG. 1 are designated by the same reference numerals. The conventional device is provided with an armature reaction calculation circuit 102, and its output is provided to an adder 103.

Output of armature reaction calculation circuit 70.2 and deviation amplifier 10
The outputs of are added by adder 103 and given to V/F converter //. Here, 'dL machine reaction calculation circuit 7
The DC current work given to 0 is the current that actually flows through the motor converted into DC.

In this way, according to the embodiment shown in Fig. 3, the phase change due to the armature reaction is calculated from the DC conversion of the actual current, and this is added to the closed loop of the phase detection device/B to compensate. It is possible to prevent the inconvenience that the detected phase and the actual phase differ greatly due to load fluctuations or the like.

The configuration of the armature reaction calculation circuit 10.2 is as follows:
The simplest method is to use a combination of first-order delay and differential elements as described above, but in order to more accurately compensate for the armature reaction, K may be configured in a circuit that takes into account various constants of the motor. That is, the d-axis (direction of the magnetic pole), the q-axis (
The compensation circuit may take into consideration the damper constant and the field winding constant in the direction of the d-axis and the electrical direction (Oo).

Furthermore, although the above description has been made regarding the case where the speed of the motor is constant, compensation of the phase detection circuit against changes in speed can also be achieved by adding the speed detection signal to the human power of the V/F converter.

〔Effect of the invention〕

As described above, according to the present invention, by providing the armature reaction calculation circuit and the adder Xt in the conventional phase detection device, it is possible to close-loop compensate for the phase change caused by the armature reaction when there is a fast current change. Because it is possible to
It becomes possible to reduce the phase detection ml difference due to armature reaction by 7, and even if there is a sudden load change, accurate phase detection and stable commutation can be ensured. In addition, the commutation margin angle, which is important for commutation, can take a desired value, improving the efficiency and power factor of the motor, and is a phase detection device for commutatorless motors that is applied to applications that require fast response. can be realized.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of the configuration of a conventional device, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG. 3 is a block diagram showing another embodiment of the present invention. ri...Digital/analog converter, /3...Read-only memory, 103...Adder. Applicant's agent Kiyoshi Inomata Figure 1 Figure 3

Claims (1)

[Claims] /, the phase detected from the armature voltage and the reference phase for determining the commutation timing are continuously compared to continuously calculate the phase deviation, and this phase deviation is used as the In a phase detection device for a commutatorless motor that performs closed-loop control by converting the phase to a reference phase that determines timing and thereby minimizing this phase deviation as much as possible, the actual current value flowing through the armature is calculated by converting the phase change due to armature reaction. A commutatorless motor, comprising: an armature reaction calculation circuit that calculates the phase deviation; and a circuit that adds this phase change to the phase deviation and then converts it into a phase that becomes a reference for determining commutation timing. Phase detection device. E. The electron reaction calculation circuit is configured to calculate the phase change due to the armature reaction based on the current value that should flow through the armature obtained by converting the current reference value manually set from the outside. A phase detection device for a commutatorless KwJ machine according to claim 1.