SI9600152A - Three-phase electronically commutated dc electric motor - Google Patents

Abstract

In a three-phase electronically commutated brushless DC-electromotor the beginnings of stator windings (k) for individual phases are spatially distributed along the periphery with respect to each other so that the created magnetic field is shifted from phase to phase for 2/3 of the pole pitch T. The stator is provided with three rotor position sensors (6; OD1, OD2, OD3) situated above the rotor periphery, the angle spacing between them being equal to 2T/3. The rotor poles are permanent magnets (4) jutting out from the region of the stator plates (1) so that the rotor with its extended part directly influences the rotor position sensors (6; OD1, OD2, OD3) situated in the next vicinity of the rotor periphery. A control and regulation circuit (5) of the electromotor of the invention has a built-in pulse-width modulator (g), which, by means of the rest of the circuit, influences the chopping of the voltage for the excitation of the stator windings (k), the chopping being proportional to the input state.

Description

SPARK AUTO ELECTRICITY NOVA GORICA d.d.

Šempeter pri Gorici

Vrtojbenska c. 62

5290 Šempeter pri Gorici

Robert Žerjal, B.Sc. ing.

Stojan Markič, B.Sc. ing. Mag. Stanislav Solar, B.Sc. ing.

THREE-PHASE ELECTRONICLY COMMITTED ONE-DIRECT

ELECTRIC MOTOR

The subject of the invention is a three-phase, brushless, three-phase electric motor with electronic switching and speed control, which can be rotated or continuously rotated and thus the output power of the motor without the addition of conventional other control circuits, but this is already possible with the addition of one microswitch or potentiometer .

The invention belongs to the international patent classification in the field H 02 K 29/00.

A technical problem solved by the invention is such a design of a DC motor that makes it easy to switch on and off and to control the engine speed or output using a single microswitch or potentiometer, which is directly connected to the input of electronics on the motor so that start-up and rotation control and no additional weak or power control circuits are required, as well as the usual wiring of these, but at the same time the engine has no mechanically wearable parts other than the rotor bearings and therefore has a long service life, high operational reliability and quiet operation, performance however, it is compact and easy to manufacture.

There are many known solutions for electronically switched motors. The most widely used motors are in the center of electronic fans, which are massively used for cooling various systems, where DC supply of lower voltages is usually provided, usually from 12V to 24V as standard. These motors have at their center a stator with pronounced poles around which, as part of a vetym, is a rotating magnet forming an external rotor. The stator winding consists of two phases and is excited via electronics in the sense of simple switching without the possibility of regulating the rpm or controlling the start or stop of the motor.

Other widespread electronically commutated motors are servomotors, indicated by a separate control circuit that requires power connection of the motor windings and the connection of the rotor position encoders to the electronics for proper commutation of the motor windings. The disadvantage of these engines lies in the connection between electronics and motor.

According to the present invention, the problem of switching on - switching off the speed control and output power of the motor and connecting the electronics and the motor is solved by the implementation of an electric motor, which has only five main components in its assembly with the following solutions evident from Figure 1:

A stator made of laminated sheet metal (1) and three-phase winding (2), where the poles are unexpressed.

2. A rotor with a core (3) and permanent magnets (4) and the same number of poles as the stator winding when excited.

3. Front cover with bearing.

4. Rear bearing cover, and

5. Compact electronics with rotor position encoders (6), speed control and regulation circuit (5), and power output stage (7) for three-phase excitation.

The stator is constructed of laminated sheet metal (1) with evenly spaced grooves in which a three-phase winding is connected in a triangle or star, as is usual in stator alternators. In this case, the beginnings of the windings of the individual phases are so arranged that when the windings are excited, the field between the phases is locally displaced by 2/3 T, with T being the pole division as indicated in Figure 2.

The rotor is formed by a shaft with a core (3) of magnetically conductive material in the form of a cylinder and magnets (4) attached to the circumference of the cylinder with the same length and with such a radius that they fit as closely as possible to the surface of the core and thus allow a good magnetic coupling between adjacent magnetic opposite polarized poly. The length of the rotor or magnets is greater than the length of the stator package of laminated sheet metal, so that on the side where the position encoders of the rotor are located it extends from the area of the stator package.

Above this part of the peripheral surface of the rotor, there are three pantograph position pantographs that dictate the commutation of motor windings via an electronic circuit. Their condition is directly influenced by the magnetic rotor poles, so the motor does not have additional rotor position encoders.

The electronic circuit is described by the block diagram in Figure 3, and its operation provides several functions:

• Recognition of rotor position to provide basic commutation of motor windings with three rotor position pantographs.

• Limiting the current to the motor in case of overloading, starting the motor or blocking the rotor.

• Processing of signal leakage from position transducers.

• Pulse width modulation of the excitation of the windings by converting the control voltage into a pulse width modulated signal that provides continuous or stepped control of engine speed.

• Circuit or adjusting stage for controlling power transistors.

• Output transistors or modules as switches for switching windings.

• Power supply to the control circuit, which also performs the function of starting and stopping the motor.

The operation of the motor is conditioned by the correct arrangement of the rotor position pantographs (6), as shown in Figure 2.

The signal from the pantographs is first processed and eventually pulse width modulated, then transmitted via the adaptive stage to the individual transistors or modules in the output stage. These transistors are directly connected to the ends of the windings or the power source by switching the power supply of the windings between the plus and minus of the power source as switches in the correct rhythm.

All three phase voltages are therefore rectangular in shape due to the described arrangement of pantographs as in Fig. 2 and their electrical phase phase displacement is 120 °. The motor therefore acts as a three-phase synchronous motor in its basic principle, with the excitation frequency being variable and always synchronous with the rotation of the rotoi.

The rotational speed at a given supply voltage is conditioned by two parameters, the load on the rotoi shaft and the voltage at the analog input of the PWM modulator. The latter, in proportion to the input voltage, ensures the voltage is cut into the stator windings.

Claims (4)

PATENT APPLICATIONS A three-phase electronically commutated direct current motor in which the electronics, in addition to the basic function of switching stator windings, also enables switching, switching off and speed control, characterized in that it has a lamellar stator package (1) with uniformly distributed grooves in which each phase winding generates the same number of magnetic, unexpressed poles as there are on the rotor, and the beginning of the windings of the individual phases are so spaced apart from each other that the resulting field between phases is displaced by 2/3 T, with T being the pole division. A motor according to claim 1, characterized in that it has a rotor with permanent magnets (4) extending from the stator package region (1) with its length so as to have a direct effect on the condition with its extended part and the magnetic fields present. three pantograph position clients (6) in close proximity to the rotor circumference. An engine according to claim 1, characterized in that the three pantographs have rotor positions arranged above the periphery of the rotor with an angular distance of A = (n2T + 2T / 3), where T is a pole division on the rotor, and n can occupy an integer 0 , 1, 2, 3, ... Motor according to claim 1, characterized in that a pulse-width modulator with an input is installed in the controller and the control circuit (5), which influences, through the rest of the circuit, the voltage excitation for excitation of the motor stator windings, which is proportional to the state at the input. Mag.