RU2220322C2 - Method of and device for electric supply of electric plasma- jet rocker engine - Google Patents

Abstract

FIELD: rocketry. SUBSTANCE: according to proposed method, electric supply of electric plasma-jet rocket engine is provided by changing consumption of working medium so that value of consumed power at each moment should be maximum. For this purpose power pickup, extreme regulator, threshold device, second reference voltage source and switching element are introduced additionally into known engine thrust stabilizer. These devices make it possible to stabilize voltage and anode current at maximum tolerable levels when maximum tolerable input power of engine is less than power of primary electric supply source, or maintain consumed power maximum for said power of primary source if power of the latter is less than maximum tolerable input power of engine. EFFECT: increased efficiency of use of power of primary electric supply source. 3 cl, 3 dwg

Description

The proposed technical solution relates to electric rocket technology and can be used in conversion systems and control of electric rocket engines, as well as in plasma accelerator and generator sets.

A known method of power supply of an electric rocket plasma engine (ERPD) type stationary plasma engine (SPD) [1], which consists in the fact that at the same time stabilize the accelerating anode voltage and its anode current. Current stabilization is provided by changing the second flow rate of the working substance (RV) using a thermal throttle or electrovalves according to the signal from the anode current sensor, the value of which is proportional to the flow rate of the RV.

Is also known to supply IPA ERPD type [2], wherein the change in engine thrust stabilize RV flow so that the product value U _a I $\genfrac{}{}{0ex}{}{\text{2}}{\text{a}}$ remained stable in time, where I _a is the magnitude of the current flowing through the anode of the engine; U _a - the value of the anode voltage. Both methods stabilize a fixed amount of engine input power or power consumption from the primary power source and can be used when the power of the primary power source is greater than the stabilized engine input power. The disadvantage of these methods is the inability to adjust the input power of the engine in order to maximize the use of the primary power source that varies during the operation of the engine.

A device [3] is known that contains a stabilizing converter of the anode voltage (PN), a sensor for discharge (anode) current (DRT), an amplifier, a pressure regulator (stabilizer) in the supply system of the radioactive substances. This device is designed to stabilize at a fixed value of traction, the input power of the engine, regardless of changes in the power of the power source.

The purpose of the proposed technical solution is to increase the efficiency of using the power of the primary power source by adjusting the input power of the engine, providing its maximum value at each time point with a changing power of the primary power source. For this, in the electric power supply method of electric power supply, including stabilization of the anode voltage and changing the flow rate of the radioactive material, the flow rate is changed with the changing power of the primary power source so that the input power of the motor, proportional to the product I _a U _a , is the maximum possible at any time, where I _a is the magnitude of the current flowing through the anode; U _a - the value of the anode voltage.

The essence of the electric power supply method of electric propulsion diffraction follows from the ratio of the input engine power and the current-voltage characteristic (CVC) of the solar battery, which, as a rule, is the primary power source on the spacecraft.

The input power of the SPD is determined by the formula

where I _a is the current of the anode (discharge);

U _a is the voltage of the anode (discharge).

On the other hand, the input power is related to the power consumption from the primary power source by the following relationship:

P _in = P _rub η _p or P _rub = P _in / η _p ,

where P _consumption - power consumption;

η _p - the efficiency of the Converter, supplying SPD.

When η _n = const, it can be argued that P _I and P _tr are in direct proportion.

SB has a nonlinear CVC and is a source of limited power. The power of the SB during operation can vary within wide limits: when the temperature decreases, it increases, while the output voltage also increases significantly. With a decrease in the illumination of the SB (when the spacecraft is removed from the Sun), the power decreases, but due to a decrease in temperature, the voltage increases. During operation due to degradation processes, the power of the SB also decreases. Obviously, the input power of the engine, and therefore the power consumption can take different values.

In FIG. 1 shows the characteristics Sa: i _Sa = f (U _SB) and P _sb = f (U _SB) for different operating conditions, from which it follows that the SAT power, and hence the input power of the engine can be maximized only under specific operating conditions SB, at the optimal points of the CVC: a ₁ (I _SB1 , U _SB1 ), and ₂ (I _SB2 , U _SB2 ), and ₃ (U _SB3 , U _SB3 ).

The objective of the proposed technical solution is to ensure the operation of the engine at the above points of the CVC. This can be achieved by maintaining the maximum input power of the engine, which can be controlled by two parameters - I _a and U _a . However, in order to save PB flow U _as necessary to maintain the maximum, i.e., equal to the maximum permissible anode voltage of the motor

This follows from the expression for specific thrust:

- секундный расход РВ;Where

- RV second flow rate;

F is the thrust value, which according to [4] with a sufficient approximation is determined by the expression:

where U _a and I _a - voltage and current of the anode;

η _dv - engine efficiency.

In accordance with [3] in qualitatively designed and manufactured engines, the anode current is equal to the flow rate of the RV, expressed in current units:

Substituting equations (2) and (3) in (1), we obtain:

where k = 2η _dv αe / M is a constant coefficient.

It follows that the higher the anode voltage of the motor, the greater the specific thrust, the more economical the consumption of the radioactive substances.

Therefore, it is possible to maintain the input power of the motor that corresponds to the optimal I – V characteristic only by the anode current — by changing the second flow rate of the propellant with a thermo-throttle or an electrovalve according to the signal from the anode current sensor, which is proportional to the flow rate of the propellant, while the anode voltage of the electric propulsion must be maintained at the maximum permissible value. Depending on the power value of the primary power source, two options are possible:

1. The power of the primary power source exceeds the maximum allowable input power of the engine. In this case, the voltage and current of the anode stabilize at the maximum permissible values for the motor.

2. The power of the primary power source is less than the maximum allowable input power of the engine. In this case, the anode voltage is stabilized at the maximum permissible value for the motor, and the anode current is regulated by the flow rate of the PB, which is changed so that the power consumption from the power source is maximum.

The power supply according to the first embodiment is presented on the characteristics of SB i _SB1 = f (U _SB1 ) and P _SB1 = f (U _SB1 ), where the maximum power of SB P _{M1 is} greater than the maximum allowable input power P _MDOS and corresponds to the operating point a _1P on CVC i _CB1 = f (U _СБ1 ) with parameters I _СБ1Р and U _СБ1Р . Due to degradation processes, as mentioned above, the power of the SB decreases and becomes less than the maximum allowable input power of the electric propulsion system, and the motor is powered by the second option. The operating points in this case are a ₂ and a ₃ on the I – V characteristic i _SB2 = f (U _SB2 ) and i _SB3 = f (U _SB3 ), respectively.

To implement the method of power supply of the electric propulsion voltage in a known device containing a stabilizing voltage converter, the input of which is connected to a power source, and the output terminals are connected to the motor electrodes, the anode current sensor (DTA), the reference voltage source connected to the anode current circuit of the engine, the comparison unit, the first the input of which is connected to the output of the DTA, and the output through the mismatch amplifier - with the control supply regulator RV installed in the supply path RV between the input to the engine and the XP system RV, additionally introduced a power sensor included in the power supply circuit of a stabilizing voltage converter, an extreme regulator (ER), a switching element (CE), a threshold device (PU) and a second reference voltage source, the value of which corresponds to the maximum allowable input motor power, while the input of the ER is connected to the output of the power sensor (DM), the second input of the comparison unit (BS) through the switching element is connected either to the output of the ER, or to the first source of the reference voltage, the value of which It corresponds to the maximum permissible value of the current of the anode of the motor, the first input of the control unit is connected to the output of the DM, the second input to the output of the second source of the reference voltage, and the output of the control panel to the input of the FE. Switching the FE is performed according to the signal from the control panel. In the absence of a signal, when the output voltage of the DM, proportional to the power consumption, is equal to the voltage of the second source of the reference voltage, the FE connects the second input of the BS to the first source of the reference voltage, and if there is a signal at the output of the PU, when the output voltage of the DM is less than the voltage of the second source of the reference voltage, The FE connects the second input of the BS to the FE.

Figure 2 shows a structural diagram of a device for implementing the proposed method of power supply ERPD.

рабочего вещества.The device contains a stabilizing voltage converter 1, the input terminals of which are connected through the power sensor 2 to the primary power supply U _pit , the output terminals of the converter through the anode current sensor 3 are connected to the electrodes of the motor 4, a comparison unit 5, the first input of which is connected to the DTA output, and the output through the amplifier 6 voltage mismatch is connected to the regulator 7 flow rate RV storage system RV 8, the extreme regulator 9 and the switching element 10, while the input ER is connected to the output DM, the second input BS through the FE connected either to the output of the ER, or to the source 11 of the reference voltage, the value of which corresponds to the maximum allowable current value of the anode, the threshold device 12 and the second source 13 of the reference voltage, the value of which corresponds to the maximum allowable input power of the motor, while the first input of the control unit is connected to DM output, the second input of the PU with the second source of the reference voltage, and the input of the threshold device is connected to the input of the FE. As a regulator of the flow of RV can be used a thermal reactor or an electrovalve, including between the engine and the storage system 8 RV. Regulator 7 is the executive body that controls the flow.

working substance.

A device for implementing the proposed method of power supply ERPD works as follows.

When applying the output voltage converter 1 appears stabilized voltage equal to the maximum allowable value of the anode _{and the} motor voltage U that is applied to the motor 4. After the start (ignition) of the engine in the motor supply circuit occurs, the discharge current (anode) I _a. The signal proportional to the anode current from the current sensor 3 is fed to the first input of the comparison unit 5. The power sensor included in the device, processing information about the voltage and current of the primary power source, generates a voltage proportional to the current value of the consumed power at its output. This voltage is supplied to the input of the extreme controller and the threshold device 12.

If the voltages at the output of the power sensor 2 and the reference voltage source 13 are equal, that is, when the power consumption from the power source and the maximum allowable input motor power are equal, there is no signal at the output of the threshold device - a switched element connects the second input of the comparison unit to the reference voltage source 11, the value of which corresponds to the maximum permissible value of the anode current. The voltage converter due to the feedback loop on the current of the anode of the engine, containing the anode current sensor, a comparison unit, a voltage mismatch amplifier and a flow regulator, stabilizes the anode current at a given level. If the voltage at the output of the anode current sensor remains more or less than the reference voltage, then the voltage of the corresponding sign will appear at the input of the comparison unit. The mismatch voltage amplified by the amplifier through the control device acts on the thermo-throttle (electrovalve), decreasing or increasing the second flow rate of RV, which is equivalent to a change in the discharge (anode) current I _a . Thus, if the value of the power generated by the SB exceeds the maximum permissible engine power, the device provides the SB at a point _1P BAX. At the same time, power equal to the maximum allowable engine power is consumed from the SB. With a decrease in the power generated by the SB, the voltage at the output of the DM decreases. A signal appears at the output of the threshold device, by which the FE switches the second input of the comparison unit to the output of the extreme controller, the output voltage of which is proportional to the power consumption and, accordingly, to the current of the motor anode, which the voltage converter must support at the moment. The output voltage of the extreme controller is the reference for the comparison unit. The voltage Converter due to the above-described feedback loop on the current of the anode of the motor stabilizes the current at a given level at a given time. If the voltage at the output of the anode current sensor turns out to be more or less than the reference voltage at the output of the extreme regulator, then the voltage of the corresponding sign will appear at the input of the comparison unit. The mismatch voltage amplified by the amplifier through the control device acts on the thermo-throttle (electrovalve), decreasing or increasing the anode flow rate of the PB, which is equivalent to a change in the discharge (anode) current I _a .

The extreme regulator (Fig. 3) works as follows. According to the signal from the ER synchronization circuit 14, the value of the engine power consumption is currently stored in the storage device 15. Then, according to the signal from the synchronization circuit, the correcting device 16 changes in a certain direction (in the direction of increasing or decreasing) the value of the output voltage of the ER, thereby changing the value of the current of the anode of the motor, which must be stabilized. The voltage converter switches to stabilization of the new value of the anode current. Input power, and therefore power consumption, is changing. The newly measured value of the power consumption is compared by the comparison device 17 with the previous value stored in the storage device 15.

Depending on the result of the comparison, the direction of the next change in the output voltage of the ER changes or does not change. With increasing power consumption, the direction of the search for the maximum power consumption does not change and, accordingly, with a decrease in power consumption, the direction of the search changes to the opposite. Thus, a step-by-step search of the current value of the anode of the motor is carried out, at which the power consumption from the primary power source will be maximum.

The proposed method of power supply ERPD with maximum power consumption and a device for its implementation can significantly increase the efficiency of using the power of the primary power source.

Sources of information

1. Leferov EV and others. Prospects for the use of stationary electro-reactive plasma engines for controlling spacecraft. Proceedings of the All-Union Research Institute of Electromechanics. T.83. Development and research of electromechanical systems of spacecraft for meteorological and natural resource purposes. M., 1987, p. 45.

2. Pat. 2044926 RF. A method for stabilizing the thrust of an electric rocket plasma engine and a device for its implementation (N.M. Katasonov). Inventions, 1995, No. 27.

3. Development of a stationary plasma engine and its testing on the satellite "Meteor" / L.A. Artsimovich, I.M. Andronov, Yu.V. Yesenchuk et al. USSR Academy of Sciences. Space Research, vol. XII, issue 3, 1974, pp. 451-459.

4. Glibitsky M.M. Power systems and control of electric rocket engines. M .: Mechanical Engineering, 1981.

Claims (2)

1. The method of power supply of an electric rocket plasma engine, including stabilizing the anode voltage and changing the flow rate of the working substance, characterized in that when the power of the power supply exceeds the maximum allowable input power of the engine, the flow rate of the working substance is changed so that the current of the anode of the engine is equal to the maximum allowable value, and when the power of the power source is less than the maximum allowable value of the input power of the engine, the flow rate of the working substance change so that the power consumption from the power source is maximum, while in both cases, the voltage of the anode is stabilized at the maximum acceptable level. 2. The power supply device of an electric rocket plasma engine containing a stabilized converter of the anode voltage of the engine, the input of which is connected to a power source, and the output terminals are connected to the engine electrodes, a reference voltage source, the value of which corresponds to the maximum allowable current of the anode, anode current sensor included in the power supply circuit engine, a comparison unit, the first input of which is connected to the output of the anode current sensor, and the output through the signal matching amplifier alov - with a controlled regulator of the supply of the working substance, characterized in that an additional power sensor, an extreme regulator, a switching element, a threshold device and a second reference voltage source are added to the voltage converter’s power supply circuit, the value of which corresponds to the maximum allowable input motor power, while the input extremal controller is connected to the output of the power sensor, the second input of the comparison unit through the switching element is connected or to the output of the ext cial controller, or to a second reference voltage source.

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