JPS6130517B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric motor that detects the position of a rotor and sequentially switches energization to stator windings of each phase, and more specifically, a rotor that includes, for example, a permanent magnet; It has two-phase stator windings electrically shifted by 90 degrees from each other, which are formed by connecting multiple partial windings in series or in parallel, and a Hall element capable of converting a magnetic field into an electric signal is used to control the rotation of the rotor. The output signal of the Hall element is used to turn on and off a group of semiconductor switch elements for driving two-phase stator windings, thereby sequentially supplying current to the stator windings. The present invention relates to a brushless type (also referred to as electronic commutator type) electric motor configured to rotate a rotor.

Many brushless motors have been proposed in the past that use Hall elements to detect the rotational position of the rotor, and use the output to conduct a semiconductor switch element such as a transistor to drive the stator winding.
It has been put into practical use.

However, most of them are of a so-called half-wave drive type in which current is supplied to the stator winding in only one direction.

In general, a half-wave drive motor that supplies current to only one direction of the stator winding can easily configure its drive device, but a full-wave drive motor that supplies current to the stator winding in both directions. Compared to conventional electric motors, the stator windings have a lower utilization rate, are less efficient, and generate less torque.

Although the present invention has a simple configuration,
It is an object of the present invention to provide an electric motor having a full-wave drive type drive device that can achieve higher torque and higher efficiency than a half-wave drive type.

The present invention will be explained below.

The present invention utilizes two-phase Hall element outputs that detect the rotational position of a rotor containing permanent magnets to sequentially switch off the base command current of a group of transistors for driving stator windings in accordance with the rotation of the rotor. (In this case, the above signal is electrically switched sequentially by 90 degrees, and does not conduct two drive transistors at the same time), and the stator operates with the base command current of the above four phases. The main idea is that the two-phase stator windings are full-wave driven by a group of winding drive transistors. More specifically, the stator winding drive transistor group is composed of two sets of bridge circuits including four PNP transistors and four NPN transistors. stator windings are connected. Furthermore, in each of the two sets of bridge circuits, among the transistors forming each of the four sides, the collector output of the transistor of one polarity drives the base of the transistor of the opposite polarity on the opposite side, so that the opposite sides of the bridge are brought into conduction. ing.

That is, according to the present invention, one of the two bridge circuits is always controlled by the four-phase base command current described above.
Only the bridge circuit of the set is operated, and in the operating bridge circuit, only the two transistors on the opposite side are made conductive, so that the current-carrying phase and direction of the two-phase stator winding that forms the load of the bridge circuit are electrically controlled. The configuration is such that the angles are switched sequentially in 90° increments.

Furthermore, the present invention collects the current flowing through the bridge circuit in the two-phase stator windings into a common detection resistor, detects its magnitude, and feeds it back negatively to the stator winding current command circuit. The stator winding is configured to supply a required current proportional to the input command voltage to the stator winding.

Hereinafter, details of the present invention will be explained based on illustrated embodiments.

FIG. 1 is a circuit diagram of an embodiment of the present invention. In the figure, numerals 1 and 2 are Hall elements for detecting the rotational position of the rotor, which are connected in series as shown, and are supplied with a DC voltage E ₂ from a DC power source 11. Hall output voltage terminals 1a, 1b and 2 of the above two Hall elements 1 and 2
a and 2b are each connected to a differential amplifier constituting a signal processing means. In this embodiment, as the simplest example of the differential amplifier, a differential transistor circuit constituted by two transistors having a common emitter is adopted. Hall output terminals 1a and 1b of the Hall element 1 are connected to the bases of first differential transistors 4a and 4b, respectively. The emitters of the first transistors 4a and 4b are connected together and further connected to the output terminal of the voltage-current conversion circuit 12 (output current is defined as i). The voltage-current conversion circuit 12 ultimately becomes a current command source for the stator windings.

Furthermore, the collectors of the first differential transistors 4a, 4b are connected to the second and third differential transistors 5a,
5b and is connected to the common emitter of each of 6a and 6b.

Further, the Hall output voltage terminals 2a, 2b of another Hall element 2 are connected to the bases of the second and third differential transistors 5a, 5b and 6a, 6b, respectively; in this case, the Hall output voltage terminals 2a is the differential transistor 5a and 6
Further, the Hall output voltage terminal 2b is connected to the bases of the differential transistors 5b and 6b, respectively.

7a, 7b, 7c, 7d and 8a, 8b, 8
c and 8d are stator winding drive transistors, among which transistors 7a, 7b, 8a, 8
b and transistors 7c, 7d, 8c, and 8d constitute each side of two sets of bridge circuits, and stator partial windings 3a,
Two sets of two-phase stator windings formed by connecting 3b, 3c, and 3d in series are connected.

The collector outputs (total of 4) of the second and third differential transistors are connected to 4 of each of the 2 sets of bridge circuits.
NPN type transistors 7a to 7d forming the sides and
Among the PNP transistors 8a to 8d, it is connected to the bases of the NPN transistors 7a to 7d. The remaining PNP transistors 8a, 8b, 8
The bases of c and 8d are respectively on the opposite side of the bridge.
It is connected to the collectors of NPN transistors 7b, 7a, 7d, and 7c via resistors 9a, 9b, 9c, and 9d. In addition, NPN type transistor 7
The emitters a to 7d are commonly connected and grounded via a common current detection resistor 10. moreover
The common emitter terminals of the NPN transistors 7a to 7d are connected to the inverting input terminal of the voltage-current conversion circuit 12 to provide negative feedback.

Note that the two sets of bridge circuits are connected to the DC power supply 14.
Power is now supplied from _E1 . In addition, the transistors 7a to 7d, 8a to 8d, and the resistor 9a
~9d, the current detection resistor 10 and the voltage-current conversion circuit 12 constitute control driving means.

FIG. 2 is a conceptual diagram of the configuration of the main part of the present invention, showing an example of a two-pole, two-phase winding. In the figure, Hall elements 1 and 2 are connected to the permanent magnet rotor 13 in order to detect the rotational position of the permanent magnet rotor 13.
They are placed 90° apart from each other in a magnetic field that changes with the rotation of the The stator partial windings 3a and 3b and 3c and 3d are respectively connected in series to form two-phase stator windings shifted by 90 degrees. In addition,
The permanent magnet rotor 13 is not limited to the external rotor type as shown in the figure, but may be of the internal rotor type, and the number of magnetized poles is not limited to two as shown in the figure, but may also be larger. Not even.

Next, the operation of the embodiment of the present invention will be explained with reference to FIG.

Figure 3 is a diagram showing the Hall output voltage waveform of the Hall element as the rotor rotates (rotation angle is θ), and Figure 3a shows the two outputs A, (however, A, respectively indicate the differential output voltages of the Hall output voltage terminals 1a and 1b). Figure 3b shows the two outputs B of the Hall element 2,
(However, B, indicates the differential output voltage of the Hall output voltage terminals 2a and 2b, respectively), and
As shown in the figure, there is a phase difference of 90° between them (with respect to A and B). As is clear from this figure, the Hall output voltage does not necessarily have to be sinusoidal, and may be trapezoidal or rectangular as shown.

Next, the outputs (collector output currents i _A and i _A ) of the first differential transistor operating in response to the Hall output voltage of the Hall element 1 are as shown in FIG. The currents i _A and i _A are given to the common emitters of the second and third differential transistors 5a, 5b and 6a, 6b, where they are further divided according to the Hall output voltage of the Hall element 2. The result will be as shown in the figure.

That is, among the second and third differential transistors that operate in response to the Hall output voltage of the Hall element 2, the common emitter current _iA is changed to _iAB and _iAB by the differential transistor composed of transistors 5a and 5b. The common emitter current i _A is distributed to i _AB and i _AB by a differential transistor composed of transistors 6a and 6b.
As a result, as shown in FIG. 5, four-phase collector output currents i _AB , i _AB , i _AB , i _AB are obtained that smoothly switch in sequence by 90 degrees in accordance with the rotation of the rotor.

Next, the obtained four-phase collector output current i _AB ,
i _AB , i _AB , i _AB become the base command currents of the two-phase stator winding drive transistors 7a, 7b, 7c, and 7d as they are, and the four NPN transistors 7a to 7d and the four PNP transistors 8.
Of the two sets of bridge circuits each configured as one side by a to 8d, only one set of bridge circuits is always operated, and when the bridge circuit is in operation, only the two transistors on the opposite sides are 90
Conductivity is maintained for a period of ゜.

As a result, 2
Among the stator windings of the phases, the current-carrying phases to which current is supplied and the current-carrying direction are sequentially switched by 90 degrees.

For example, a current i _AB is supplied to the base of the stator winding driving transistor 7a, and the transistor 7a is supplied with a current i AB.
When transistor a becomes conductive, the base of PNP transistor 8b, which forms the opposite side of the bridge, is connected to the collector of transistor 7a via resistor 9b. Base current flows and transistor 8b is also turned on. As a result, the stator windings 3a and 3b have a
A drive current Ia is supplied in the direction. The situation is schematically shown in FIG. 6a.

Similarly, depending on the rotation angle θ of the rotor,
Stator winding drive transistors 7b, 7c, 7d
When base currents i _AB , i _AB , i _AB are supplied to the stator windings, the stator windings have the following values, b, c, and d, respectively.
As shown, 3d → 3c, 3a → 3b, 3c
→The drive current Ia is supplied in the direction of 3d for each period of 90°. As a result, a rotational force in a fixed direction is generated in the permanent magnet rotor 13.

As is clear from FIG. 6, in the present invention, two PNP transistors and two
Of the two bridge circuits each side of which is made up of NPN transistors, only one bridge circuit is always in operation. In an operating bridge circuit, the output of the transistor supplied with the base command current makes the transistor on the opposite side of the bridge completely conductive, so that only the two transistors on the opposite side of the bridge are always in a conductive state, while the other The two transistors on opposite sides of are in a cut-off state.

As a result, due to the action of the two sets of bridge circuits, one of the two-phase stator windings is always energized, and the current-carrying phase of the stator winding is always energized by 90 degrees in electrical angle. , and the current direction of the stator windings are sequentially switched according to the rotational position of the rotor.

Also, in an operating bridge circuit, of the two transistors that are conducting, the PNP transistor is used as a mere switching means, so it is completely conducting, and the other NPN transistor is also connected to the stator winding. This will control the current flowing to the Therefore, a PNP transistor used as a simple switching means has the advantage that a comparatively small capacitance transistor can be used since the amount of heat generated is small.

In addition, in the PNP type transistors 7a to 7d for stator winding drive, even if the magnitude of each base command current i _AB , i _AB , i _AB , i _AB is constant, the current amplification factor of each transistor is The four currents flowing through the stator windings have different magnitudes due to variations, but the voltage across the current detection resistor 10
If the base command current is controlled by applying negative feedback to the inverting input terminal of the voltage-current conversion circuit 12 using Ve, the two-phase stator winding can be driven with a constant magnitude without variation. In addition to being able to supply the current Ia, it is also possible to supply the required current proportional to the command voltage Ec input to the non-inverting input terminal of the voltage-current conversion circuit 12 to the two-phase stator windings. .

FIG. 7 is a circuit diagram showing another embodiment of the present invention. The embodiment shown in FIG. 7 uses a transistor circuit using NPN transistors as a differential amplifier, and the four collector outputs obtained from the differential transistors drive two-phase stator windings. Of the eight PNP type and NPN type transistors 7a to 7d and 8a to 8d forming each side of the two sets of bridge circuits for
The power is supplied to the bases of type transistors 7a to 7d, respectively. Note that, in FIG. 7, the same reference numerals are given to those having the same functions as those explained in FIG. 1. Further, since the circuit operation of the embodiment shown in FIG. 7 is essentially the same as the circuit operation of the embodiment shown in FIG. 1, a description thereof will be omitted here.

As is clear from the above description, the present invention can realize a high efficiency, high torque electric motor with a relatively simple configuration, and its effects are very large.

[Brief explanation of the drawing]

Fig. 1 is a circuit configuration diagram of an embodiment of the present invention;
The figure is a schematic configuration diagram of the main part of the embodiment of the present invention, Figures 3a and 3b are output voltage waveform diagrams of the Hall element, and Figure 4
5 and 5 are signal waveform diagrams of various parts to explain the circuit operation of FIG. 1, and FIG. FIG. 7 is a circuit configuration diagram showing another embodiment of the present invention. 1, 2...Hall element, 3a-3d...Stator partial winding, 4a, 4b, 5a, 5b, 6a, 6
b, 7a-7d, 8a-8d...transistor,
9a, 9b, 9c, 9d...Resistor, 10...Current detection resistor, 11, 14...DC power supply, 12...Voltage-current converter, 13...Permanent magnet rotor.

Claims (1)

[Claims] 1. A plurality of Hall elements are used to detect the rotational position of the rotor, and the output signals of the Hall elements are used to sequentially conduct semiconductor switching means to energize the stator windings. It is a brushless electric motor that
A current command source for the stator winding, a plurality of Hall elements disposed within a magnetic field whose magnetic field changes according to the rotation of the permanent magnet rotor, and outputs of the plurality of Hall elements to input terminals, respectively. One or two connected differential amplifiers are provided for each Hall element, and the difference between two predetermined differential amplifiers to which an input current is supplied from the current command source among the differential amplifiers is provided. A signal processing means configured to use the dynamic output current as the input current of the remaining differential amplifiers, and an NPN type (or PNP type) configured to use the differential output current of the remaining differential amplifiers as the base command current. 2) A circuit in which the emitter-collector path of a PNP type (or NPN type) transistor is connected in series with a transistor whose base is connected to the collector of the NPN type (or PNP type) transistor on the opposite side of the bridge through a resistor, respectively. The emitters of the PNP type transistors are connected together in parallel and connected to one terminal of the DC power supply, and the emitters of the NPN type transistors are connected together and connected to the other terminal of the DC power supply. The corresponding phase is fixed between the connection point between the collector of the NPN transistor and the collector of the PNP transistor in one set and the connection point between the collector of the NPN transistor and the collector of the PNP transistor in the other set. The control drive means includes m sets (where m is the number of phases) of bridge circuits configured to connect child windings, and uses the differential output current to sequentially drive one of the m sets of bridge circuits. An electric motor characterized in that only one set of bridge circuits is operated and the current flowing through each stator winding is controlled by controlling the current command source. 2. Two Hall elements are used as a current command source for the stator windings and a Hall element that detects the rotational position of the rotor.One Hall element operates with its Hall output voltage as a base input, and from the current command source, A first differential amplifier to which an emitter current is supplied is connected, and the other Hall element is connected to second and third differential amplifiers that operate with the Hall output voltage as a base input. 2 of differential amplifier
the two collectors to output the differential output current respectively to the second
and the emitter current of the third differential amplifier, and the NPN type (or PNP type) in which the base command current is the collector differential output current of the second and third differential amplifiers. ) transistor and a PNP whose base is interconnected through a resistor to the collector of the NPN (or PNP) transistor on the opposite side of the bridge.
type (or NPN type) transistor emitter
Two sets of circuits in which collector paths are connected in series are connected in parallel, each emitter of the PNP type transistor is connected together and connected to one terminal of a DC power supply, and the
The emitters of the NPN transistors are connected together and connected to the other terminal of the DC power supply, and the connection point between the collectors of the NPN transistors of one set and the collectors of the PNP transistors is connected to the collector of the NPN transistor of the other set.
A patent comprising a control drive means consisting of two sets of bridge circuits configured such that stator windings of corresponding phases are connected between the connection points of the collector of the NPN transistor and the collector of the PNP transistor. The electric motor according to claim 1. 3. The control drive means includes means for detecting a current flowing through the bridge circuit in the stator winding and providing negative feedback to the signal processing means. The electric motor according to item 1 or 2.