SU1467732A1 - Self-sufficient diesel-electric set - Google Patents

Abstract

The invention relates to electrical engineering. The aim of the invention is to improve the quality of the generated electrical energy and economy. The installation contains an internal combustion engine 2, a generator 1, sensors of active power 9 and frequency 3, a functional converter 6 of the active power of the load into a signal proportional to the optimum engine speed, comparison device 8, limiter 10, actuator 4, organ control of fuel supply 5. Improved efficiency is provided by more accurate installation and support of optimal speeds corresponding to the load. 7 il.

Description

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The invention relates to electrical engineering and may find application in autonomous type electric power plants.

The purpose of the invention is to improve the quality of the generated electrical energy and efficiency.

Figure 1 shows the functional diagram of an autonomous diesel-electric installation; figure 2 is a functional diagram of the sensor active power; FIG. 3 shows the optimal speed characteristic of a diesel engine; FIG. 4 is a schematic diagram of a functional conversion of active load power into a signal proportional to the optimum rotational frequency, and a function setting indicator.

optimal control -, figure 5-20 | Tel 6 active power load

the design of the actuator j in FIG. 6 is the functional diagram of the amplifier-limiter j in FIG. 7, is static, the characteristic of the amplifier-limiter.

The autonomous diesel-electric installation contains an electric generator 1 (Fig. 1), mechanically connected to an internal combustion engine 2, a frequency sensor 3 connected to the engine 2 internal combustion engine, an executive organ 4 whose output is connected to an organ. 5 controls the fuel supply of the engine 2 internal combustion, functional converter 6 of the active power of the load into a signal proportional to the optimum engine rotational speed, connected by the first input to the setpoint 7 of the optimum control function, and Comparison 8, connected by the first input to the output of the functional transducer 6.

The device also includes an active power sensor 9 connected to the output of an electric generator 1, and a limiter amplifier 10, the input of which is connected to the code of the comparison device 8, and the output to the input of the executive body 4. The output of the active power sensor 9 is connected to the second functional input converter 6. The output of the rotational speed sensor 3 is connected to the second input of the comparison device 8. In this case, the linear segment (according to the input signal) of the characteristics of the limiter 10 is selected as the minimum permissible under the stability conditions. The active power sensor 9 consists (3) of three identical blocks 11-13 of instantaneous total power measurement. Each unit includes a sensor 14, an instantaneous phase current value, a sensor 15, an instantaneous phase voltage value, and an analog multiplicating unit 16. The outputs of blocks 11-13 are connected to the inputs of the adder 17, the output of which may include a filter 18.

The device works as follows.

In the steady state from the output of the sensor 9 of the active power (Fig.) To the input of the functional transform

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The signal is proportional to the optimum engine speed, a signal is received that is proportional to the current value of the active load power. The output signal of the functional converter 6, corresponding to the frequency of rotation of the diesel engine 2 that is optimal for a given load, is fed to the input of the comparison device 8. The second input of the comparator receives the voltage from the output of the rotational speed sensor 3, npot porhonsonalny the current value of the frequency of rotation of the shaft. In steady state, the output of the comparator is a static regulator error. The magnitude of this signal is within the linear portion of the static characteristic (Fig. 7) of the amplifier-limiter 10. Under the action of the output voltage of the amplifier-limiter, the rod of the actuator 4 and the fuel supply control body 5 associated with it are in a certain position corresponding to this established mode.

During load (discharge) load, the output signal of the sensor 9 of active power, and hence the output signal of the converter 6, begin to change. In the initial part of the transient time, the rate of change of voltage and current of the generator is significantly higher than the rate of change of rotational frequency, since the time of the generator and load is much less than the time of the internal combustion engine. For this reason, at the beginning of the transition process, an increase in the absolute value of the output is -. The signal 9 of the signal of the comparison device 8 will almost completely correspond to the change in the output voltage of the functional converter. As a result, the output signal of the comparator device in a short period of time will reach the level corresponding to the relay part of the static characteristic of the amplifier limiter 10. The output voltage of the amplifier limiter will become maximum (modulo). This will lead to the movement of the rod of the executive body 4 and the associated fuel control control unit to the extreme position corresponding to the maximum or minimum flow rate (depending on the sign of the output voltage of the limiter). The executive unit will be in the extreme position until the output signal of the comparator 8 due to a change in the rotational speed decreases to a level that corresponds to the linear portion of the static characteristic of the amplifier-limiter 10. Then, under the influence of this signal, the actuator stem will take the position , providing the value of the rotational speed close to optimal. Thus, in the device, regulation is carried out by setting and maintaining the maximum possible (t; e. Maximum or minimum) levels of fuel supply for a longer period of time of the transient process. This ensures the conversion of the internal combustion engine from one speed range to another for a minimum period of time.

In idle mode, when there is no load, the drive motor 2 operates at the minimum frequency, which ensures stability of the electrical unit at unexpected load surges. The value of this rotational speed is determined by the lower level of the signal coming from the function converter 6 at the zero signal at its input.

Improving the efficiency of the device due to a more accurate mouth

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and maintain optimal speeds corresponding to the load

The use in the device (for control action) of a signal proportional to the active power makes it possible to reduce the deviation of the actual value of the control action from the desired one. In this case, the magnitude of this deviation is determined only by the error of the active power sensor.

The presence in the device of the main negative feedback allows the drive motor to be controlled directly by the deviation of the rotational speed from the optimum value for the given load. As a result, the static system error is reduced.

Thus, reducing the error in the formation of a control action and improving the accuracy of its testing allows the device to significantly approximate the operating modes of the drive motor of a diesel-electric installation to the optimum one.

Reducing the time for a diesel-electric installation to go from one speed range to another as the load changes reduces the time of the transient over voltage. As a result, during the operation of a diesel-electric installation, the duration of time intervals during which the voltage does not correspond to the maximum permissible values is reduced. Thus, the quality of the generated electrical energy at the generator output of the installation is improved.

Claims (1)

Invention Formula An autonomous diesel-electric installation comprising an electric generator mechanically coupled to an internal combustion engine, a frequency sensor coupled to an internal combustion engine shaft, an actuator, the output of which is connected to an internal combustion engine fuel control, an active load power converter a signal proportional to the optimum engine speed, connected to the first input of the comparator, characterized in that. that, in order to improve the quality of the generated electrical energy and efficiency, an active power sensor is connected, connected to the output of the electric generator, and an amplifier-limiter, whose input is connected to the output of the comparator, and the output is connected to the input of the executive body, with input function (L U sixteen silt 15 An active load power converter into a signal proportional to the optimum engine rotational speed, the output of the rotational speed sensor is connected to the second input of the comparator, and the linear portion (of the input signal) of the amplifier-limiting characteristic is chosen to be minimally acceptable according to the stability conditions. Ia. l l l l N t v v y FT i-1 to; Mj) z cb -tl aa Tr //, J v v v / i Fig 5 H2 FIG. 6 0ife.7 / whether