SU1351524A3 - System for generating and distributing electric energy - Google Patents

Abstract

A control for an aircraft electrical generating and distribution system utilizes a plurality of interconnected microprocessors and comprises two engine-driven generators 15, 16 and an auxiliary power unit generator 26 with loads 20, 21 connected to the generators through circuit breakers 18, 19. A distribution bus 22 connected through tie breakers 23, 24, 27 interconnects the loads 20, 21 end the auxiliary generator 26 so that any one generator can power either or both loads. Each generator has a microprocessor control unit 30, 31, 32 responsive to the associated generator conditions to control generator operation. A microprocessor bus power control unit 42 is responsive to distribution circuit conditions and correlates information from the control units 30, 31, 32, to control the tie breakers and distribution of power from the generators to the loads. Serial data links between the control unit 42 and each control unit 30, 31, 32 provides for communication of input and control information and enables comparison of redundant circuit information enhancing reliability of the system operation. A generator voltage regulator uses the generator microprocessor control unit to develop an error voltage which is added to the average generator phase voltage, controlling the current. If phase failure occurs the control unit senses an abnormally high phase voltage, disables the average phase voltage circuit and the regulator continues to operate with the error voltage. <IMAGE>

Description

This invention relates to a control for a system for generating and distributing electrical energy.

 The purpose of the invention is to increase reliability.

Figure 1 shows a system diagram; Fig. 2 is a block diagram of a generator driven by an engine used in this system; Fig. 3 is a block diagram of a part of the generator control unit; Fig. 4 is a diagram showing current transducers in a system connected to a generator control unit and a bus power control unit; Fig. 5 is a block diagram, similar to Fig. 3, with additional details; in fig. 6 is a block diagram of a system, similar to FIG. 1, showing additional details of a bus power control unit and its internal connection with a distribution system; Fig. 7 is a block diagram of a generator voltage regulator; Fig. 8 is a block diagram illustrating the functions of a microprocessor associated with a voltage regulator.

The system for generating and distributing electrical energy is described in relation to a twin-engine atmospheric aircraft with an auxiliary power unit. The characteristic features of the control can be used in other systems for generating and distributing electrical energy for aospheric aircraft.

In the system (FIG. 1), one line may denote multiple connections between elements. The system contains generators 1 and 2, which have leads facing the common return wire or housing (ground) and connected through automatic switches 4 and 5 with loads 6 and 7, respectively. The electrical distribution bus 8 can be selectively connected to the loads -6 and 7 via the switches 9 and 10 of communication with the bus.

The auxiliary generator 11 also has a terminal facing the housing 3 and connected via an auxiliary power switch 12 to an electrical distribution bus 8. An external power source (not shown) can be connected to the electrical system when the atmospheric aircraft is on the ground through a contactor 13 .

Electrical system of atmospheric le-

performance apparatus is

is a three-phase system operating at a frequency of 400 Hz with a four-wire distribution system.

Accordingly, single-line connections and single-contact contactors are four wires and three-pole relays, with the neutral remaining uninterrupted.

Each of the generators has a control block 14-16. The generator control units monitor the operating states of the generators associated with them and control the operation of the sources 17-19 of the excitation currents and the generator control relays 20-22, respectively. The source current and generator control relays can be part of the control unit.

Arrows at each end of the lines interconnecting the generator control unit with the associated source of excitation current and

generator control relays indicate that the status and control information is transmitted in both directions. The lines with one dimensional arrow between the generator circuit and the switches with the bus and the generator control unit indicate that the state of the switch or state information represents the input signal to the control unit generator.

The bus power control unit 23 connects to transmit system state information, interconnects with each generator control unit and controls the operation of the bus switches with the bus in order to maintain an optimal distribution of energy from the sources available to loads 6 and 7 Each control unit uses a microprocessor to collect and organize information relating to the operation, the generator and the state of the circuit, and to isolate and distribute the corresponding control signals. According to another scheme of the electrical system of the atmospheric aircraft (figure 2), the engine 24 with

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drives a constant speed drive 25, which provides a torque input to the generator 26, which includes a permanent magnet generator 27, an excitation generator 28, and a three-phase power generator 29, the drive can be combined with the generator in one housing. Thus, the rotors of each generator (with permanent magnets, excitations and three-phase power) are mounted on a common shaft. held in rotation by a drive of 25 constant revolutions. A permanent magnet generator has an output that energizes the control units and a driver 28. The latter has fixed electromagnets and rotating measles, and the output current of the core is rectified and supplied to the rotating electromagnets of the power generator 29, which, in turn, has the output power removed from fixed windings. The excitation current for the driver 28 is provided by a permanent magnet generator through the contacts of the generator control relay 20-22 and the voltage regulator. The output of the generator is connected to the load circuit through three contacts of the automatic switch 4 (5, 12) of the generator.

FIG. 3 illustrates inputs to the distribution system and the main generator to the generator control unit. The output voltage of the generator for each of the three phases is taken at the control point, which can be the terminal of the automatic switch 4 (5, 12) of the generator. Phase voltages through the peak-limiting circuits 30 are supplied to an analog signal multiplexer 31.1 and a -31, 2 converter from analog to digital form. These phase voltages, together with the other input signals, are sequentially selected by the multiplexer, converted into digital information, and applied to the microprocessor 32 via the information bus and I / O windows.

Phase currents are sensed by current transformers (not shown in Fig. 3) and through peak limiting circuits 33, are fed to multiplexer 31.1 and converter 31.2 from ana. five

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den form to digital. The linear currents of the distribution circuit are also sensed by the current transformers and, together with the current generator signals, are supplied to the differential current comparator 34, which provides a corresponding input signal to the microprocessor in the case of 1Q over-current imbalance.

The output signal of the permanent magnet generator is sensed by detectors 35 and 36 of insufficient 5 and excess frequencies, which, if the frequency is outside the selected parameters, provide signals to the microprocessor. Alternatively, the output of the oscillator with permanent 20 magnets can be converted into a signal in digital form and fed directly to the microprocessors. An electromagnetic measuring transducer block, 25 associated with a 25 DC drive drive, provides a signal to the insufficient rotational speed detection circuit 37, which also provides input to the micro processor. Other signals of the generator state are provided by the generator turn on switch, the control board of the aircraft in the cockpit, which makes it possible for the generator control relay to function when the engine starts, and from the auxiliary switch of the generator switch and the switch. l contact with bus.

The output power of the permanent magnet generator is also used for the internal power sources of the generator control unit 38. These power sources are powered by an aircraft battery bus when the generator is not operating.

The phase voltages of the generator from the control point are supplied to the voltage regulator 39, in which the average voltage of the three phases is obtained, which is fed through a multiplexer and a converter from the analog one. digital forms to the microprocessor. The voltage error signal generated by the microprocessor is transmitted through

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45

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40 from digital to analog to voltage regulator. An adjustable excitation current for the exciter is fed through a generator control relay 41 to the excitation winding of the exciter 28. A short circuit detector 42 of a rotating rectifier connected to the excitation circuit provides an additional input signal to the microprocessor.

Phase currents at various points in the system are perceived, for example, by current transformers and supplied to the generator control units and the bus power control unit. These input signals regarding the system states and the generators to the control units provide the basis for the control functions and provide redundant information used in testing system. Figure 4 illustrates the arrangement of current transformers providing information on the state of the system and the generator for generator control unit 14 and bus control unit 23. T-oxides from the generator are measured by the generator current transformer 43 connected between the generator and the earth potential standard 3 The load current is measured by the current transformer 44 in the load feeder 45. These current input signals are supplied to the generator control unit 14. Current The communication bus 8 is sensed at the connection to the communication switch 9 with the bus by the current transformer 46. The current flowing in the feeder 47 between the bus coupler 9 and the connection to the load feeder 45 is sensed by the current transformer 48 connected to the bus power control unit 23.

Figure 5 shows the input and output signals of the control unit of the generator. Various analog. the signals representing the generator state are fed through multiplexer 31.1 and converter 31.2 from analog to digital form to microcomputer 49. These include the phase voltages of the control points, sprinkled peak limiting circuits 30, and the line and generator currents from the corresponding

current transformers perceived by peak limiting circuit 33. Revolution signal for drive 25 constant revolutions from electromagnetic

The transmitter is fed through a frequency to voltage converter 50. Similarly, the rotation speed signal from the permanent magnet generator 27 is supplied by

A frequency converter 51 to voltage cut. The temperature of the oil used in the drive for constant revolutions and for cooling the generator is perceived both at the inlet and

at the output of the common housing of the generator and drive. Analog temperature signals provide additional multiplexer units. Microcomputer controlled analog

multiplexer 31.1 sequentially scans the input signals of the state of the generator, and these signals through the analog-to-numeric converter 31.2 are fed to the input of this

microcomputer. The rotational speed signals from the electromagnetic measuring transducer unit and the permanent magnet generator can be converted directly into a digital form and fed to the microcomputer 49 (shown by dotted lines).

Digital input devices, such as switches, are connected

through input buffers 52 with a microcomputer 49. These input devices include auxiliary contacts on the generator control relay, automatic circuit breaker and bus switch. The generator enable switch located in the aircraft cockpit. This control provides discrete input signals as in

closed and open position. The oil pressure transducer provides another input signal indicating the availability of oil for

driving the constant speed drive and cooling the generator.

The average phase voltage of the generator (figure 5) is formed in the circuit

53 reading the average value and through the filter 54 is fed to the analog multiplexer. Mismatch signal through converter 40 of

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The digital form is fed to analog to summing junction 55, where it is summed with the average phase voltage, and this sum is fed to pulse width modulator 56, which controls the output amplifier 57, which provides the excitation current to the excitation winding of the driver. The excitation circuit energy is supplied by a permanent magnet generator through a generator control relay 41. The output signals of the digital-to-analog converter 40 and the output amplifier 57 are fed to the inputs of the analog multiplexer 31.1 and compared by the microcomputer 49 with the desired values in the case of testing the system. A short-circuit detector 42 senses a diode failure and provides an input to the microcomputer to drive the generator control relay 41.

The output signals from microcomputer 49 are provided via output buffers 58. The main output signals include signals controlling the operation of the generator control relay and the closing and opening of the circuit breakers of the generator control unit and the bus connection. The output signal Turn off the light signal provides a visual indication in the cockpit of the state in which the generator should turn off. If it is necessary to perform additional checks on the operation of the system, the signals of the output buffers are fed through a multicore cable 59 to the input multiplexer 31.1 of analog signals.

Communication with the power control unit in the bus is provided through an intermediate communication device 60 and a serial data transmission channel 61 (data bus), which may comprise a two-wire twisted pair. When data is transmitted between control units in a sequential manner, only a two-wire line is needed, even if the data can represent many different system states or control signals. In a three-generator system, the power control unit in the bus can have a cycle period of 4 ms. During

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each cycle, the system information is exchanged and verified through a data link. J-Internal clock synchronizing generator (not shown) provides synchronization for the microcomputer multiplexer and de-multiplexer and other sync circuits of the device. Synchronization signals transmitted via the information bus 61 from the power control unit in the bus coordinate the operation of the control units.

15 system. These synchronization signals are considered to establish exact synchronization periods, which may have a common initial moment of time, or a trigger period.

20 Interrelation of the power control unit 23 in the tire with this system, illustrating the mutual exchange of data with the generator control units 14 and 15 and entering from

25 matic switches 4 and 5 of the generators and switches 9 and 10 for communication with the bus are illustrated in FIG. For the left generator 1, the auxiliary contact of the automatic switch 4 provides input to the power control unit in the bus. Another auxiliary contact provides input to the left generator control unit 14, and this automatic

the switch is controlled

the generator control unit. The communication switch with the bus has auxiliary contacts that provide inputs to the control unit 14 of the left generator and the power control unit 23 in the bus, and the automatic circuit breaker is controlled by the control unit of the left generator according to

4g by the mation formed in the control unit of the left generator and the information received from the power control unit in the bus. Similar circuits are provided for the generator circuit breaker 5 and the bus connection switch 10 for the right generator 2. The generator control units 14 and 15 are connected via data buses 61 and 62 respectively to the unit

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55

tire performance.

The state of the auxiliary contacts, —connected to the generator control and regulation units

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bus power provides redundant information, which is checked for accuracy by control units over data transmission channels. The measurement of voltages and currents adds additional levels of redundant information.

The auxiliary generator 26 is connected to the communication bus through the auxiliary power switch 12, which has auxiliary contacts providing inputs to the bus power control unit 23 and the auxiliary generator control unit 16. This auxiliary power switch is controlled by the output of block 16 of the auxiliary generator control. Serial information bus 63 provides communication between the auxiliary generator control unit 16 and the bus power control unit 23.

An external energy source 64 may be used when the atmospheric vehicle is in the ground state. This energy source is connected via the external energy contactor 13 to the bus line 8. The auxiliary contact on the external energy contactor provides input to the power control unit 23 in the tire, and this control unit, in turn, controls the external energy contactor. The phase voltages of the external energy source provide an additional input signal in the bus power control unit

Other inputs for the power control unit in the tire include: 1. controls in the cockpit, representing the tire transfer switch, switch, external power source, and automatic bus connection switches. The output signals, in addition to the information transmitted to the auxiliary control units via the information buses and controlling the external energy contactor 13, include signals from the cockpit showing the bus system failure and the availability of external energy. When necessary, other output signals from the cockpit can be provided.

When the atmospheric flight apparatus is in a mundane

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five

0

five

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ten

In a state, the electrical energy is provided from an external source 64 of energy or from an auxiliary generator 11. When external energy is supplied to the system, the external energy contactor 13 and the bus switches 9 and 10 are closed, supplying energy through loads 6 and 7 (FIG. 1) . When an auxiliary generator 11 is used, the auxiliary power switch 12 and the bus switches 9 and 10 are closed.

When the engines of an atmospheric aircraft are started up in preparation for take-off, generators 1 and 2 provide the system with energy after reaching the appropriate engine speed. At this point in time, electrical loads from an external energy source or an auxiliary generator to the generator-driven motors are transmitted by opening switches 9 and 10 to the bus and closing the automatic switches 4 and 5 of the generators. In the event of an engine or generator failure in flight, all loads can be supplied with energy from one of the alternators driven by an engine or from a combination of one generator driven by an engine and an auxiliary generator 11 by appropriate manipulation. circuit breakers with bus and automatic generator breakers.

Consider the combination of processing an analog signal and a microprocessor signal in a voltage controller. Nag1r 7keni three phases A, B and C

(Fig. 7) is fed to the read-a-. circuit. 53 is of no mean value, and the analog average signal is fed through a 65 nil filter often, the filter 54 and the analog-to-digital converter 31.2 to the microcomputer. For normal control of generators (FIG. 8), the average voltage of the three phases is compared with the reference voltage of the transition 66v. The difference is integrated in the integrator 67, providing a voltage error supplied through the logical circuit 68, the converter 40. from digital to analog and analog switch 69 to summing input

thirty

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40

50

55

eleven

55. The average phase voltage from filter 65 through analog switch 70 to another input of summing junction 55. The output of summing junction 55 through filter 71 is connected to pulse width modulator 56 and output amplifier 57 (FIG. 5), so that to provide an adjustable current to the excitation winding of the exciter.

This microcomputer has additional inputs, representing the largest phase current 72, the highest phase voltage 73 and the lowest phase voltage 74, which provide the possibility of additional voltage regulator modes of operation to cope with abnormal conditions. The large phase current and the function of the highest phase voltage, set by the functional unit 75, are summed at junction 76, providing the excitation winding current limit.

In the event of a single phase failure in the generator, the average phase signal from the filter 65 includes harmonics that should not be supplied to the excitation current controller. This state also results in a large phase current detected by the comparator 77, which provides a mode control signal to open the analog switch 70. This removes the average voltage input signal from the summing junction 55. The system continues to function when the voltage error signal from the summing transition 76 regulating the excitation current.

In the event that the voltage of a single phase is low, the regulator will attempt to establish an excessive excitation current. This state is perceived by comparing the highest phase voltage with the reference voltage in summing junction 78, providing a C1 signal to the logic circuit 68 and limiting the control signal to the excitation winding of the driver.

The highest and lowest phase voltages are compared in summation transition 79. When the difference is redundant, and the output of comparator 80 opens analog switch 69, reducing the force for the error signal

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voltage by connecting resistor 81 to this circuit. This prevents the regulator from trying to set an excessive excitation current.

The control units of the generator and the power control in the microprocessor-based bus more fully and more accurately correlate the information

10 relating to the state of the generator and distribution system than to. practice with control on hardwired wired circuits. As a result, the electrical system is operated with a smaller cyclical operation of the switches and fewer interruptions in operation than was achieved using known systems.

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Claims (1)

Invention Formula A system for generating and distributing electrical energy, including at least two generators, in the circuit of at least one generator, has a load circuit and a generator switch for connecting the load circuit to the generator, 30 busbar and bus switch for connecting the load circuit via bus to another generator, control unit for each of the generators, circuit connection means - (- each of the generators with the inputs of the control unit for determining the operating conditions of the generator, the means for connecting the outputs of the block for each of the generators for 40 controlling the operation of the corresponding generator, as well as generator and bus switches, characterized in that, in order to increase reliability, a microprocessor unit is used as a control unit for each generator, and the system is equipped with a bus power supply microprocessor control unit Q input-to-microprocessor bus power control unit with a power distribution system to determine the operating conditions of the distribution system, information buses for g providing microprocessor bus power control unit interaction with each of the microprocessor generator control blocks to transmit information about the conditions 13 . 1351524 1 operation of the generator and the distribution system for correlating the operation of these divisions and output signals of the control unit. FIG. 2 (ffJ2) From measure milHlll telno leprevozra / le lriboda pic / pa other oUapomoB 32 From - shi / 4- SJfepo 8 muses seHepgmof "G5; //) - PU) - (PU2.3 L / 5 lam 7,15,16 srig.5 front ev in (rig 8 Compiled by K.Fotin Editor V.Petrash Tehred A.Kravchuk Proofreader N, King Order 5302/59 Circulation 618 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, Projecto st., 4