SU744861A1 - Reversible power-diode electric motor - Google Patents

Description

The invention relates to electrical engineering, in particular, to adjustable electric drives and can be used in electric drives of machine tools. When creating medium power reverse transistor valve actuators, the main problem is to protect the inverter (switch) transistors from overvoltages caused by energy stored in the inductance of dissipation of the commutator phase from the load current. Known valve motors with a transistor inverter are known in which diodes 1 are connected in parallel with the opposite direction in order to protect the transistors from overvoltages. The disadvantage of such valve motor circuits is that they do not provide regenerative braking of the motor, since the transistor bridge operates in a rectifying mode and the uncontrolled diode and the open transistor short the two phases of the players. Also known is a valve motor with a transistor inverter, in which the energy stored in the section’s magnetic field is transferred via reverse diodes (reverse rectifying bridge) in a capacitor that is discharged into the resistors and partially used in control circuits a rotor, a stator with a winding core, the sections of which are connected to an adjustable source of EMF, consisting, for example, of a controlled rectifier equipped with a device for pulse-phase control and control speed and current torus, through an inverter on transistors, the basic circuits of which are connected via an inverter control device to the rotor position sensor of a synchronous machine, tachometer device, a reverse current bridge connected by alternating current terminals to the output terminals of an inverter, a DC terminal through transistor switches to the same terminals of the regulated EMF source AND. The main disadvantage of the known motor is that with an increase in the power of the motors and an increase in the starting currents, its mass and dimensions significantly increase due to the large dimensions of the capacitor and the discharge resistor. In addition, when operating at high speeds, it significantly (about 10%) decreases (its efficiency

The purpose of the invention is to increase the efficiency of a valve engine, reducing its weight and size.

The goal is achieved by additionally introducing a zero current sensor, OR logic elements, including: Black circuits between the inverter transistor control circuits and the inverter control unit, an engine operating mode detection unit (switching or braking), for example, of five logic elements, a meter alternating the phases and an amplifier of the resulting control signal, a blocking current device, for example, of six I-NOT logic elements, a relay element connected on the Tachometric device OUTPUT, moreover, the output of the engine operating detecting unit is connected to: the first input of the current blocking device, the second input of the current blocking device is connected to the output of the zero current sensor, the first output of the current blocking device is connected to the input of transistors to connect to inverting rectifier bridge inverter, and the second output of the current blocking device - to the second inputs of the logic elements OR, so that when the motor mode transistor the second output of the current blocking device was open and did not affect the operation of the logic elements of the IL during braking mode, the transistor switches were closed, and the output of all logical elements OR there was a signal that simultaneously opened all inverter transistors, the output of the relay element was connected to the third input of the current blocking device so that at the output of the current blocking device at low speed there were signals corresponding to the motor mode of operation.

Thanks to this connection of newly introduced elements in the motorized operation of the gate dvigatel transistor keys are open and the reverse rectifier bridge is connected parallel to the transistor inverter. Energy stored in the inductance of phase dissipation of the motor coming out of the rectifying rectifier bridge newly opened transistor and motor phase remaining in operation. Surge transistors are absent.

In the case of braking mode of the motor, the transistor switches are closed, the reverse rectifier bridge is turned off, and all the transistors of the inverter are opened by a constant signal from the OR logic elements. The transistor inverter operates as an ai-controlled rectifier, delivering engine braking energy through a DC link to the mains. Transistor overvoltages are also absent,

FIG. 1 is a schematic diagram of a reversing transistor valve motor; in fig. 2 - diagrams of operation of the main functional units.

The valve motor contains a controlled rectifying bridge 1, an uncontrolled reverse current bridge 2, transistor switches 3 and 4,

designed to connect the rectifier bridge 1 valves parallel to the inverter transistors 5-10 during motor operation, uncontrolled gates 11-16 to protect the transistors from reverse voltages, zero current sensor 17, to monitor the presence of current in the converter's power circuit, synchronous machine 18, sensor 19 position of the rotor of the synchronous machine,

designed to issue signals for switching the inverter transistors as a function of the rotor position, tachogenerator 20, rectifier pulse-phase control system 21, current motor and valve motor speed regulator 22, rotation direction setting unit 23 similar to the logic unit of separate control of converter sets in reversible

a direct current drive for zero current switching of signals from the sensor 19 of the position of the rotor and matching the reverse outputs of the speed and current regulator 22 with

by non-reversible input of system 21, when changing the sign of the resulting control signal (dUU Ui, .UTr), the unit for determining the operating mode of a synchronous machine (motor or brake), consisting of amplifier 24, used as a null organ, logical elements IS-25 25 29 and a phase rotation meter 30 for determining the direction of rotation of the rotor of a synchronous machine;

current blocking, consisting of logical elements AND-NOT 31-36 and intended to prohibit the switching of the state of the power elements of the converter corresponding to the motor mode, to the state corresponding to the braking state, if there is a current in the main circuit (at zero signal of the current sensor 2) , logic elements OR 37 (their number is equal to the number of transistors of the inverter), an inverter transistor control device 38 for switching signals with a rotor position sensor when changing the sign of the resulting signal control, relay element 39, designed to highlight a zone of low braking speeds, where the natural switching of the current of the phases of a synchronous machine is difficult due to the small value of the EMF of rotation.

All logic elements are made on transistors. Conductance. The useful signal that opens the transistor switches is the zero signal.

In the initial state of the circuit, the voltage setting of the speed UZOD is zero, the voltage at the output of rectifier 1 is absent and the current through the sections of the synchronous machine does not flow. Engine speed is zero. At the output of the device 39 and the inputs of logic elements AND-NOT 32-36 zero signal. At the same time, at the first output of the current blocking device (logic element 33), the zero signal, and at the second output (logic element 34), is single, not affecting the operation of logic elements OR 3 from signals from the rotor position sensor 19. In this case, a zero signal from the logic element 33 transistor switches 3 and 4 are open. Two inverter transistors are also opened by a signal from the position sensor 19 in accordance with the motor rotation direction set by block 23.

The signal at the output of the phase rotation meter 30 and the output of the engine operating mode determination unit (logic element 26) at the first moment is not defined. However, due to the presence of the device 39, the signals at the output of the current blocking device (logic elements 33 and 34) correspond to the motor operation of the valve motor.

When the driving voltage UjoA is applied, a signal appears at the output of the regulator 22, the control angles of the system 21 decrease, and a voltage appears at the output of the rectifier bridge 1. At the same time, the signal from the unit 23 specifying the direction of rotation, the angles at the output of the device 38 are set to the corresponding motor operating mode (f, 0) for a given direction of rotation, the two inverter trazistors are open and current flows through two sections of the motor, creating torque. When the rotor is rotated at an angle of 60 electrical degrees, a signal appears at the output of the position sensor to switch the motor section, the transistor section, for example, A (transistor 5) closes, and transistor 6 section

in opens. The dissipation inductance energy of section A going out of work is discharged through uncontrolled rectifier 2, open transistor of key 4, inverter transistor and phase C remaining in operation.

Further, the described process is repeated every 60 electrical degrees of rotor rotation. The resulting signal is 1) UioA, - U-rr at the input of amplifier 24 has such a magnitude and sign that amplifier 24 is in saturation mode and the maximum signal is set at its output corresponding to a logical unit. At the output of the measured 5 phase interleaved bodies 30, after the arrival of the second pulse, a single signal is established from the rotor position sensor. As the motor speed increases above the dead zone of the nonlinear element 39, a single signal is established at its output, and later it does not affect the operation of the circuit.

Further signal changes

5 at the outputs of the current blocking device are possible as functions of the signals from the mode detection unit (from logic element 26) at zero current in the power circuit (single

0 signal on the output of the sensor 17 current).

By reducing the reference voltage Uzad or changing its polarity, the polarity at the input of the amplifier 24 changes. At the same time, the signal at its output

5 is reduced from maximum to zero, and the signal from the meter 30 phase alternation remains the same and equal to unity. When the signals from the amplifier 24i with the meter 3Q of phase alternation do not match, the signal from the output of the engine operating mode determination unit becomes zero, since single signals are set at the outputs of logic elements 25, 28 and 39, which corresponds to the braking mode

5 valve operation: a new engine. However, as long as a current flows at the output of current sensor 2 in the power circuit of the converter, a zero signal is set, which goes to the second

0 input current blocking device and no switching in the power circuit does not occur. Switches do not occur in the speed and current controllers. When changing the resulting control signal, the converter control angles are reduced to the minimum and the rectifier 1 goes into the inverter mode. The current in the power circuit is reduced to zero.

0 After that, the prohibition on switching from the current sensor 2 is removed (a logical unit appears at its output) and the signal at the output of logic element 33 becomes unity, and at the output of element 34, zero.

Claims (2)

5 which leads to the closure of the transistor switches 3 and 4 and the opening of all the transistors of the inverter. The engine operates in the braking mode, delivering energy through the rectifier 1 to the supply network. Overvoltages on the inverter transistors are absent in this mode, since they are fully open, and the switching of the current of the phases is due to the emf of the phases of the synchronous machine. Switching the motor from the brake mode to the motor mode occurs as follows: With an increase in the driving voltage, the UjdA signals at the output of the amplifier 24 and the phase rotation meter 30 become the same, which leads to the appearance of a single signal at the output of the logic element 26. However, changing characters at the output of logic elements 33 and 34, the opening of transistors 3 and 4 and the closing of the inverter transistors occur after the motor current decreases to zero and the output of the sensor 17 is zero current of a single signal. It is only after this that the output of the logic (31) appears a zero signal, causing the switching of the static trigger on the logic elements 32 and 33 and the change of characters on the output of the logic elements 33 and 34. Thus, the inverter transistors are closed without current H overvoltage They are absent at this moment in Fig. 2jj is the motor speed and} 01D.the driving voltage, the current in the DC link U, 33 31 2 the voltage at the input U2J,, Uj of the corresponding circuit elements. allows for exclusion to reduce the cumulative overvoltage protection unit of the inverter transistors, reduce its weight and dimensions, and increase the efficiency of the valve motor.The calculations show that when switching the rated current of the phases of the three-phase synchronous machine at the rated frequency of rotation with the value of the short-circuit inductive resistance of the phase OD of the relative unit and inductance of the smoothing choke in the DC link, five times higher than the inductance of the phase short-circuit of the synchronous machine The power output of external devices (resistors, surge suppressors) is s 0.0874 of the rated motor power. The invention of the reversible valve motor containing a rotor, a stator with a winding crust, the sections of which are connected to an adjustable source of electromotive force, for example, a controlled rectifier equipped with a device for pulse-phase control and a speed and current controller, through an inverter using transistors , the basic circuits of which are connected via an inverter control device to the rotor position sensor of a synchronous machine, a tachometer device, a reverse current bridge connected by alternating current terminals On the output terminals of the inverter, and on the DC terminals, via transistor switches to the like terminals of an adjustable EMF source, characterized in that, in order to increase the efficiency of the valve motor, reduce its mass and size, a zero-current sensor is added, logic elements OR, connected between the inverter transistor control circuits and the inverter control unit, an engine operating mode determination unit, consisting, for example, of the AND-NOT five logic elements, is measured Either alternating phases and a resultant control signal amplifier, a current blocking device, consisting, for example, of six NAND logic elements, a relay element connected to the output of a tachometric device, the output of the engine operation mode determination unit connected to the first input of the current blocking device, the output of the zero current sensor is connected to the second input of the current blocking device, the first output of the current blocking device is connected to the input of the transistor switches, and the second output of the current device oh lock - to the second inputs of OR gates, the output relay element is connected to the third input of the current blocking device. Sources of information taken into account in the examination 1. A. Arakel and others. Valve electric drive with synchronous motor and dependent inverter. M., Energie, 1977, p. 8-13. 2. Japanese Patent No. 51-14687, cl. 55 C 2, 1976. Uifl v