RU2797973C2 - Electromechanical power supply system - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: electromechanical power supply system contains an internal combustion engine with a shaft, a V-belt drive, a valve generator containing a contactless synchronous generator and a built-in rectifier, a storage battery. The V-belt drive connects the engine shaft to the generator shaft. The stator winding of the generator is connected to a built-in rectifier connected to the battery. The stator winding of the generator is divided into four groups of coils with an equal number of turns, shifted relative to each other in space by the same angle equal to 15°. The rectifier is made up of four sections connected in series. The groups of coils are connected to the corresponding sections of the rectifier, while the common positive and negative terminals of the rectifier sections are connected to the corresponding DC buses. There is also a voltage monitoring relay with normally closed contact. The battery has a discharge and charge circuit.

EFFECT: quality of the rectified voltage is improved.

1 cl, 1 dwg

Description

The invention relates to the field of electrical engineering and can be used as an electromechanical power supply system for mobile launchers.

An electromechanical power supply system is known, comprising an internal combustion engine with a protruding shaft, a V-belt drive, a valve generator, a battery, while the V-belt drive connects the shaft of the internal combustion engine to the shaft of the specified generator, the stator winding of the named generator is connected to a rectifier, the output of which is connected to the battery [1].

This system has found wide application in transport as a direct current system, it has a simple block diagram and is reliable, but the low quality of the rectified voltage limits its scope.

The required technical result is to improve the quality of the rectified voltage.

The specified technical result is achieved by the fact that in an electromechanical power supply system containing an internal combustion engine with a protruding shaft, a V-belt drive, a valve generator containing a contactless synchronous generator and a built-in rectifier, a battery, while the V-belt drive connects the internal combustion engine shaft to the shaft of the specified generator , the stator winding of the contactless synchronous generator is connected to a built-in rectifier, the output of which is connected to the battery, the stator winding of the contactless synchronous generator is divided into four groups of coils with an equal number of turns, shifted relative to each other in space by the same angle equal to 15 °; the rectifier is composed of four sections connected in series; said groups of coils are connected to the respective sections of the rectifier, while the common positive and common negative terminals of the rectifier sections are connected to the respective DC buses; a voltage monitoring relay with a closing contact was introduced, connected between the indicated tires; the battery is equipped with a discharge circuit and a charge circuit made of positive and negative wires, and the negative wire is common to both circuits, the positive wire of the discharge circuit connects the positive bus to the positive terminal of the battery through a separating diode, the positive wire of the charge circuit connects the positive bus to the positive terminal of the battery through the closing contact of the voltage control relay and a separating diode connected in series with it, connected in the opposite direction to the discharge circuit diode, a common negative wire connects the negative bus to the negative terminal of the battery.

The drawing shows a fragment of a diagram of an electromechanical power supply system.

The system contains an internal combustion engine (not shown) with a protruding shaft (not shown), a V-belt drive (not shown), a valve generator 1 containing a contactless synchronous generator and a built-in rectifier, the stator winding (not shown) of which is divided into the first group of coils 1- 1, a second group of coils 1-2, a third group of coils 1-3, and a fourth group of coils 1-4. These groups of coils have an equal number of turns, i.e.

where W _T.O. - the number of turns of the phase of the three-phase winding of the stator of the valve generator; W _K1 , W _K2 , W _K3 , W _K4 - the number of phase turns of the groups of coils: the first, second, third and fourth,

These groups of coils are displaced in space relative to each other by 15°, according to the rules for placing multiphase windings used in the theory and practice of electrical engineering [2]. The first group of coils 1-1 is connected to the first section of the rectifier 1-5, the second group of coils 1-2 is connected to the second section of the rectifier 1-6, the third group of coils 1-3 is connected to the third section of the rectifier 1-7, the fourth group of coils 1- 4 is connected to the fourth section of the rectifier 1-8, while the sections of the rectifier 1-5 ... 1-8 are made according to the Larionov scheme and are connected to each other in series, and the negative wire of the rectifier section 1-5 is connected to the negative DC bus 2, and the positive wire section of the rectifier 1-8 is connected to the positive DC bus 2. The stator winding is divided into four parts to significantly reduce the ripple coefficient of the rectified voltage K _P , which for a three-phase voltage system is determined by the formula

for one three-phase circuit. By increasing the number of phases with rectifiers from 3 to 12, we find

In order to determine the efficiency of increasing the number of phases, we divide equation (3) by equality (4) and find

that the ripple coefficient decreased by 16 times and became K _P2 \u003d 0.3%, therefore the requirement of DC consumers for the quality of the rectified voltage is fully met.

If the internal combustion engine will have low speed, then with a three-phase winding of the valve generator 1, the rectified voltage will be insignificant, so the consumers will not perform the specified functions, since the average value of the rectified voltage is small. An increase in the number of phases contributes to an increase in the average value of the rectified voltage, which predetermines an improvement in the operating conditions of consumers.

In this case, the battery 3 begins to discharge through the discharge circuit, however, if the speed of the motor shaft increases, then the voltage on the DC buses 2 will increase so that the voltage control relay 4 will operate and close its NO contact 4-1 and the battery will be recharged. The battery discharge circuit 3 is formed by wire 3-1 (positive) with a separating diode 5 and wire 3-2, which is common to both circuits. The charge circuit of the battery 4 is formed by a wire 3-3 with a closing contact 4-1 of the control relay 4 and an isolating diode 6, which is in antiphase with the isolating diode 5 of the named battery discharge circuit.

The system works as follows.

In statics, until the internal combustion engine starts, its shaft is stationary (not shown), the V-belt transmission (not shown) is stationary, the valve generator does not rotate, the stator winding (not shown) is de-energized and in its coils 1-1, 1-2, 1- 3 and 1-4 no EMF, rectifier sections 1-5 ... 1-8 are de-energized, there is no voltage on common DC buses 2; voltage monitoring relay 4 is de-energized and NO contact 4-1 is open; battery 3 is charged, discharge circuits 3-1 and 3-2 and charge circuits 3-3 and 3-2 are de-energized, while rectifier sections 1-5…1-8 are de-energized.

When the internal combustion engine is started, its shaft begins to rotate, which is carried out by the V-belt transmission on the rotor of the valve generator 1 and the rotor begins to rotate, in which the magnetic field of the permanent magnets also begins to rotate. When the magnetic field rotates, its lines of force cross the turns of the coils 1-1, 1-2, 1-3 and 1-4 of the stator winding of the valve generator and the EMF is induced in the coils:

where E _1-1 - EMF of the first group of coils; ƒ - voltage frequency (EMF), depending on the frequency of rotation of the internal combustion engine shaft n, i.e.

W _1-1 - the number of phase turns of the first group of coils; K ₀₁ - winding coefficient of the first group of coils; Ф - induced main magnetic flux.

Since the number of turns of the groups are equal, and the flow is the same, we can assume that

and by analogy (2), we have

where E _TO is the EMF of a three-phase winding.

The EMF of the coil groups is supplied to the corresponding sections of the rectifier 1-5, 1-6, 1-7, 1-8, where the alternating current is converted to direct current and voltage appears on the positive 2-1 and negative 2-2 bus 2, which allows you to start working consumers 7 and 8. At low speeds, EMF E _TO will be less than the calculated value, so diode 5 will be open and battery 3 will be discharged through the discharge circuit 3-1 and 3-2. However, at high speeds of the internal combustion engine, the voltage of the common DC buses 2 will be higher than the calculated one and the voltage control relay 4 will work, so its contact 4-1 will close, forming a battery charge circuit along wires 3-3 and 3-2; the battery will be recharged every time

where n _D - the actual frequency of rotation of the rotor shaft; n _R - design frequency of rotation of the rotor shaft of the valve generator.

In other cases, the operation of the system does not change the mechanism of action.

Thus, the quality of the rectified voltage has improved significantly by increasing the phase of the stator winding.

Sources taken into account:

[1]. Lipai B.R., Solomin A.N., Tyrichev P.A. Electromechanical systems. M., MPEI, 2008, fig. 9.2, page 33.

[2]. Radin V.I., Zagorsky A.E., Belonovsky V.A. Electromechanical frequency stabilization devices. M., Energoizdat, 1981, 168 p.

Claims (1)

An electromechanical power supply system containing an internal combustion engine with a protruding shaft, a V-belt drive, a valve generator containing a contactless synchronous generator and a built-in rectifier, a battery, while the V-belt drive connects the shaft of the internal combustion engine with the shaft of the specified generator, the stator winding of the contactless synchronous generator is connected to built-in rectifier, the output of which is connected to the battery, characterized in that the stator winding of the contactless synchronous generator is divided into four groups of coils with an equal number of turns, shifted relative to each other in space by the same angle equal to 15 °; the rectifier is composed of four sections connected in series; said groups of coils are connected to the respective sections of the rectifier, while the common positive and common negative terminals of the rectifier sections are connected to the respective DC buses; a voltage monitoring relay with a closing contact was introduced, connected between the indicated tires; the battery is equipped with a discharge circuit and a charge circuit made of positive and negative wires, and the negative wire is common to both circuits, the positive wire of the discharge circuit connects the positive bus to the positive terminal of the battery through a separating diode, the positive wire of the charge circuit connects the positive bus to the positive terminal of the battery through the closing contact of the voltage control relay and a separating diode connected in series with it, connected in the opposite direction to the discharge circuit diode, a common negative wire connects the negative bus to the negative terminal of the battery.

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