JPS61191291A - Position detector of commutatorless dc motor - Google Patents

Abstract

PURPOSE:To improve the maximum torque capable of rotating a motor by connecting the secondary filters with armature windings, comparing the two of the outputs, and controlling a semiconductor commutator by the outputs. CONSTITUTION:The secondary filters 14-16 are connected with armature windings of a commutatorless motork and the outputs of the filters 14-16 are input to comparators 17-19 to be compared. A semiconductor switching element of a semiconductor commutator is turned ON by the outputs of the comparators 17-19. The energization of the armature winding of the motor is controlled by the commutator.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is a non-commutated motor which detects a relative device between a magnet rotor and an armature winding by a back electromotive force induced in the armature winding. This invention relates to a position detection circuit for a secondary DC motor.

BACKGROUND OF THE INVENTION In recent years, commutatorless DC motors have been used in various fields because they have a high i-factor and can easily control the rotation speed by changing the applied voltage. However, in general, since a non-commutated DC motor is operated by controlling the operation timing and time of semiconductor switching elements, a position detection sensor such as a Hall element is required to detect the position of the magnet rotor. However, when it is desired to use a non-commutated DC motor in a place where the operating environment is very bad, such as in an electric compressor, there is a problem in the reliability of the position detection sensor. Therefore, in recent years, various methods have been proposed for detecting the relative position of the magnet rotor from the back electromotive force of the armature winding.

An example of the conventional position detection circuit for the above-mentioned commutatorless motor will be described below with reference to the drawings.

FIG. 4 shows the overall circuit of a commutatorless motor that rotates the magnet rotor by using a complementary device of the magnet rotor from the back electromotive force of the armature winding. 1 is a DC power supply, and 2 is a semiconductor commutator device formed by connecting six semiconductor switching elements S-8 in a three-phase bridge connection. 3 is armature winding 4
This is a commutatorless DC motor with a magnet rotor 6.

Reference numeral 6 denotes a control circuit which inputs back electromotive voltages vA, VB, and vc of the armature winding 3 and page wires 4 and generates signals for controlling the semiconductor switching elements S1 to S6 of the semiconductor commutator device 2.

In the above configuration, the control circuit 6 detects the relative position of the magnet rotor 5 from the back electromotive force vA, VB, and vc of the armature winding 4, controls the semiconductor switching elements 81 to S6 of the semiconductor commutator device 2, and controls the magnet rotor 5. Rotator 5 is rotated. However, since no back electromotive force is generated in the armature winding 4 when the motor is started, a separate starting circuit (for example, low frequency synchronous starting) is required. FIG. 6 shows a conventional position detection circuit for a non-commutated motor. In FIG. 5, reference numerals 7 to 9 are primary filters to which the back electromotive voltages vA, VB, and c of the electric machine prewinding a4 are respectively input. 1o is a neutral point synthesis circuit that creates neutral points of the outputs of the primary filters 7-9.

Comparators 11 to 13 compare the outputs of the primary filters 7 to 9 and the output of the neutral point synthesis circuit 10, respectively.
The operation of the position detection circuit for a commutatorless DC motor configured as described above will be described below.

First, the back electromotive voltages A, VB, and C of the armature winding 4 are converted into triangular wave signals having a phase relationship of about 900 by passing through primary filters 7 to 9. By comparing each triangular wave signal and the output of the neutral point synthesis circuit 4, the magnet rotor 5
The relative position of can be detected.

Problems to be Solved by the Invention However, in the above configuration, the components of the spike voltage vs as shown in FIG. ing. The width of this spike voltage ■s increases as the load torque of the non-commutated DC motor 3 increases, and due to this influence, the width of the spike voltage ■s increases.
The output phase of .about.13 advances as shown in FIG. 3A with respect to the originally desired signal. In other words, the commutatorless motor operates in a phase leading to the normal commutation timing. As the load torque increases further, the phase advances more and more, and when the load torque exceeds TA, the phase exceeds 30° and the commutatorless DC motor stops. Therefore, there was a problem in that the commutatorless DC motor could not be rotated with a load torque of 5 pages or more than TA.

In view of the above problems, the present invention provides a position detection circuit for a non-commutated DC motor that can rotate the non-commutated DC motor to a higher load torque with a simple circuit configuration.

Means for Solving the Problems In order to solve the above problems, the position detection circuit for a non-commutated DC motor of the present invention includes a secondary filter connected to the armature winding, and an output signal of the secondary filter. Each of these comparators is configured to compare two outputs.

In the above-described configuration, the present invention makes use of the good high-frequency shielding properties of the secondary filter, making it possible to rotate to high torque with less phase shift and less influence from spike voltage. .

Example Below Regarding the position detection circuit of a non-commutator motor according to an embodiment of the present invention, the entire circuit of the non-commutator motor is the same as 6 bezos, and only the position detection circuit is different, so only the different points will be explained. .

FIG. 1 shows a position detection circuit for a commutatorless motor in an embodiment of the present invention. 14 to 16 in Figure 1
17 is a comparator that compares the output of the secondary filter 14 and the output of the secondary filter 15, and 18 is the output of the secondary filter 15 and the secondary filter. a comparator 19 for comparing the output of the filter 16;
is a comparator that compares the output of the secondary filter 16 and the output of the secondary filter 14.

The operation of the position detection circuit for a commutatorless motor constructed as described above will be explained below with reference to FIGS. 2 and 3.

First, FIG. 2 shows the operating waveforms at points (al to li) of the circuit in FIG. Figure 2 (al~(cl) o
(Al~(cl voltage is set to the secondary filter 14~1 in Fig.
6, a sinusoidal signal with a phase of approximately 180° is obtained from the original waveform as shown in Figure 2 (dl~(fl).ofql is fdl and fel, fhl is ( e+ is a comparison of the potentials of (fl and fdl, respectively. Based on the signal of (g+~(il),
As shown in FIG. 2, the commutatorless DC motor 3 rotates by turning on the semiconductor switching elements 81 to S6.

Here, the second-order filter has better high-frequency shielding properties than the first-order filter and is less susceptible to the effects of high frequency components such as the spike voltage s shown in Figure 2 (al). Therefore, as shown in Figure 3B, The load torque can be applied in the -F direction up to TB.

As described above, according to this embodiment, the secondary filters 14 to 16 connected to the armature winding 4 and the secondary filters 14 to 16
By providing comparators 17 to 19 that compare the outputs of the two, it is possible to improve the maximum torque that can be rotated.

Effects of the Invention As described above, the present invention reduces the influence of spike voltage by providing a secondary filter connected to the armature winding and a comparator that compares two outputs of each of the secondary filters. The maximum torque that can be rotated by the commutatorless motor can be improved.

[Brief explanation of drawings]

Figure 1 shows a position detection circuit for a non-commutated DC motor according to an embodiment of the present invention, Figure 2 shows the operating waveforms of each part in Figure 1, Figure 13 shows the relationship between load torque and phase, and Figure 13 shows the relationship between load torque and phase. FIG. 4 shows the overall circuit of a non-commutated DC motor, and FIG. 6 shows a position detection circuit of a conventional non-commutated DC motor. 2... Semiconductor commutator device, 4...
・Armature winding, 6... Magnet rotor, 14-16
...Secondary filter, 17-19...Comparator. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] It has an armature winding with a neutral point non-grounded, a semiconductor commutator device formed by connecting six semiconductor switching elements in a three-phase bridge, and a magnet rotor, and each of the armature windings has a magnet rotor. 1. A position detection circuit for a commutatorless DC motor, comprising a connected secondary filter and a comparator for comparing two outputs of each of the secondary filters.