RU2244998C1 - Generator voltage regulator - Google Patents

Abstract

FIELD: automotive electrical equipment; generator voltage regulation.

SUBSTANCE: proposed voltage regulator has power transistor switch, dropping diode, comparator, circuit of series-connected controlled current sources, and measuring element that generates control currents with antiphase ac component for controlled current sources. Newly introduced in device are temperature sensor protection unit, two controlled switches, regulated power supply, capacitor connected through one lead to comparator input and to point of connection of controlled current sources, its other lead being connected to output and common leads of regulated power supply.

EFFECT: enhanced reliability under abnormal operating conditions.

2 cl, 14 dwg

Description

The invention relates to the field of electrical engineering, and in particular to devices operating in conjunction with current generators and designed to maintain a constant voltage in the power supply network of cars, tractors and other autonomous objects.

Known devices for regulating the voltage of a valve generator, containing a measuring body, a power transistor switch, a comparator with upper and lower thresholds, a capacitor, stabilization circuits for switching frequency of the controller (1, 2).

The closest technical solution, selected as a prototype, is a generator voltage regulator containing a power transistor switch connected between the first power bus and the output terminal of the device, a measuring body connected between the first and second power buses and made with two outputs designed for generating antiphase on the variable component of the control currents, a comparator with upper and lower thresholds, connected by the output to the control input of the power transistor switch a, a quenching diode connecting the output terminal of the device to the third power bus, two controlled current sources, the first of which is connected to the first by the input, and the second to the second outputs of the measuring organ, the first and second controlled current sources being connected in series and forming a circuit, connected by one extreme terminal with the first power bus, another extreme terminal - with the second power bus, the connection point of the controlled current sources - with the input of the comparator and with one of the terminals of the capacitor connected to the other water with the first power rail.

Known voltage regulator has the disadvantage consisting in the following.

The abnormal temperature overloads of a generator set with an integrated voltage regulator (thermal shock) that arise during operation cause short-term excesses of the operating temperature limits of the voltage regulator circuit elements and, in particular, increase the probability of a power transistor switch failure due to breakdown or closing of its semiconductor junctions.

This circumstance significantly reduces the reliability of both the voltage regulator and the generator set as a whole.

The invention is aimed at improving the reliability of the voltage regulator in abnormal operating conditions of the device.

The specified technical result is achieved by the fact that in the voltage regulator of the generator, containing a power transistor switch connected between the first power bus and the output terminal of the device, designed to connect to the excitation winding of the generator, a quenching diode connecting the output terminal of the device with the second power bus, designed to connect to the generator rectifier, a comparator with upper and lower thresholds, connected by the output to the control input of the power transistor switch, a circuit from the first and second controlled current sources connected, connected by one extreme terminal to the first power bus, a capacitor connected by one terminal to the comparator input and the connection point of the first and second controlled current sources, a measuring body connected between the first and third power buses and equipped with two outputs intended for generating antiphase in the variable component of control currents, the first of which is connected to the signal input of the first, and to the second - the signal input of the second current sources, a temperature sensor, a protection unit, the first and second control keys, a stabilized power supply are introduced, in addition, each of the aforementioned controlled current sources is equipped with a parametric input, and the protection unit is connected by an input to the output of the temperature sensor, by an output to the input of the first and to the input of the second control keys connected respectively between the first power bus and the parametric inputs of the first and second controlled current sources, the stabilized power source is connected by a common a terminal with a first power bus, an input terminal with a third power bus, an output terminal with a fourth power bus, to which the circuit is connected to the other end terminal from a series of first and second controlled current sources, and the capacitor is connected to the output or common terminal by another terminal stabilized power source.

Figure 1 and 2 presents a functional diagram of the inventive device.

Figure 3, 4, 5 presents diagrams of voltages and currents, explaining the principle of operation of the voltage regulator in various operating modes.

The structure of the voltage regulator (figure 1) includes the following elements.

The power transistor switch 1 in the form of an n-p-n conductivity transistor connected between the first power bus 2 and the output terminal 3 of the device, designed to be connected to the excitation winding of the generator. A quenching diode 4 connected between the output terminal 3 of the device and the second power bus 5, intended for connection to the generator rectifier. Comparator 6 with upper and lower thresholds, connected by the output to the control input of the power transistor switch 1. A chain of serially connected first 7 and second 8 controlled current sources, connected by one extreme terminal to the first power bus 2. The measuring body 9, connected between the first 2 and third 10 power buses and equipped with two outputs, designed to generate antiphase in the variable component of the control currents, the first of which is connected to the signal input of the first 7, and to the second - the signal input of the second 8 controlled current sources. The protection node 11, connected by the input to the output of the temperature sensor 12. The first 13 and second 14 control keys connected respectively between the first power bus 2 and the parametric inputs of the first 7 and second 8 controlled current sources and connected by the inputs to the output of the protection node 11. Stable power supply 15, connected by a common terminal to a first power bus 2, an input terminal to a third power bus 10, an output terminal to a fourth power bus 16, to which a chain of series-connected first 7 th and 8 second controlled current sources. The capacitor 17, with one output connected to the input of the comparator 6 and the connection point of the first 7 and second 8 controlled current sources, the other output - with the output terminal of a stabilized power source 15.

The device operates as follows.

When the ignition switch is turned on and the generator is stopped, the power transistor switch 1 opens and connects the switched output of the generator field winding to the first power bus 2. Since the voltage between the supply lines 2 and 10 is set below the adjustment level of the voltage regulator, the measuring body 9 generates a current at the second output, which reduces the internal resistance of the second controlled current source through the signal input and accelerates the charging process of the capacitor 17 to a voltage close to the output voltage stabilized power source 15. In this case, the voltage at the input of the comparator 6 is set slightly less than the level of the lower threshold U.p. In this state, when the voltage at the input of the comparator is low, and the power transistor switch 1 is open, the voltage regulator circuit can be arbitrarily long.

When starting the engine and increasing the generator speed, the adjustable voltage Ureg., Continuously increasing, approaches the value of the adjusting level of the regulator. When the regulated voltage enters the error tube and further increases within it (Fig. 3, a; 0-t ₁ ), the current in the signal input circuit of the first 7 controlled current source generated by the measuring body 9 at the first output increases, and the current in the circuit the signal input of the second 8 controlled current source generated by the measuring body 9 on the second output is reduced. Due to the decrease in the internal resistance of the first 7 controlled current source and the drag of the internal resistance of the second 8 controlled current source, the discharge current of the capacitor 17 increases, and its charging current decreases. The voltage at the input of the comparator 6 increases to the value of the upper threshold Uv.p. (Fig. 3, b; t ₁ ), as a result of which its output voltage decreases to a value close to zero (Fig. 3, c; t ₁ ). In this case, the threshold of the comparator 6 is switched to the lower level U.p., and the power transistor switch 1 is closed (Fig.3, d; t ₁ ).

After closing the power transistor switch 1, the current in the generator field winding circuit begins to decrease exponentially, closing through the quenching diode 4 (Fig. 3, d; t ₁ -t ₂ ), which causes a corresponding decrease in the regulated voltage Ureg. (figure 3, a; t ₁ -t ₂ ). Reducing the voltage between the supply lines 10, 2 leads to the fact that the current in the signal input circuit of the first 7 controlled source generated by the measuring body 9 at the first output is reduced, and the current in the signal input circuit of the second 8 managed source of power generated by the measuring body 9 second exit increases. Correspondingly, the discharge current decreases and the charging current of the capacitor 17 increases, as a result of which the input voltage of the comparator 6 decreases to the level of the lower operation threshold Uн.п. (Fig. 3, b; t ₂ ). Comparator 6 switches the response threshold from the lower level U.p. to the upper level Uvp, increases the output voltage to the upper value (Fig.3, c; t ₂ ) and opens the power transistor switch 1 (Fig.3, d; t ₂ ). After opening the power transistor switch 1, the current in the field circuit of the field winding begins to increase (Fig. 3, d; t ₂ -t ₃ ), which causes a corresponding increase in the regulated voltage Ureg. (Fig.3, g; t ₂ -t ₃ ).

Further, the control process proceeds similarly to the above, as a result of which the output voltage of the generator is maintained at a nominal level with high accuracy. In the process of regulation, the switching frequency of the voltage regulator practically does not change in the operating range of changes in load currents and generator rotation speeds due to the generation by the measuring body of signals that are out of phase with the variable component, which control the charging and discharging currents of the capacitor 17.

In the abnormal mode of exceeding the maximum permissible value for the voltage regulator of the positive ambient temperature the functioning algorithm of the device is as follows.

On the time interval t ₀ -t ₁ (figure 4, a), when the positive ambient temperature does not exceed the maximum permissible value, the principle of operation of the device is similar to the principle described above for the normal temperature mode of operation of the voltage regulator. In the time interval t ₁ -t ₂ (Fig. 4, a), when the ambient temperature exceeds the maximum permissible value, a signal is generated at the output of the protection unit 11 at the output of the temperature sensor 12, which opens the control keys 13, 14. By connecting the control keys 13 , 14, respectively, between the first power bus 2 and the parametric inputs of the first 7 and second 8 controlled current sources, the latter abruptly change their internal resistances regardless of the values of the currents generated by the first and second outputs of the measuring org Ana 9. In this case, the internal resistance of the first 7 controlled current source takes the minimum possible value, and the internal resistance of the second 8 controlled current source takes the maximum possible. As a result, the input voltage Uin.comp. comparator 6 jumps up to the level of the upper threshold Uv.p. (figure 4, b; t ₁ ), and its output voltage Uout.comp. decreases to zero (figure 4, c; t ₁ ). This causes the power transistor switch 1 to be locked (Fig. 4, d; t ₁ ), and in this state the controller can remain arbitrarily long until the ambient temperature drops below the maximum permissible value (Fig. 4, a; t ₂ ). In this case, the temperature sensor 12 generates a signal that interrupts the current generation by the protection unit 11. At the same time, the control keys 13, 14 are closed, and from time t ₂ charging of the capacitor 17 begins, causing a decrease in the input voltage Uin.comp. comparator 6 to the value of the lower threshold Un.p. Output voltage Uout.comp. the comparator 6 jumps up to the upper value (Fig. 4, c), the power transistor switch 1 opens (Fig. 4, d), and then the regulation process is carried out similarly to the above, as a result of which the regulated voltage is maintained at a nominal level.

Thus, due to the locking of the power transistor switch 1 in the time interval t ₁ -t ₂ (Fig. 4, d) of an abnormal excess of the ambient temperature, the voltage regulator is prevented from failing due to overheating of its radio elements, in particular, overheating of the power transistor switch 1.

The functional diagram of the voltage regulator presented in figure 2, according to the principle of operation in normal operating modes, is similar to the circuit of figure 1 and differs from the latter:

- the implementation of the protection node 11, equipped with a second input for connecting to the output terminal of the voltage regulator and an output for realizing permission to produce the specified node of the output current;

- the implementation of the comparator 6, equipped with a second output for generating strobe pulses;

- connecting a capacitor 17 between the connection point of the controlled current sources 7, 8 and the common output of the stabilized power source 15.

In normal operating modes of the voltage regulator, made according to the scheme of figure 2, the elements 11 ... 14 of the device do not have any effect on its performance.

In the current overload mode of the power transistor switch 1, for example, due to the closure of the excitation winding of the generator, the controller circuit (figure 2) works as follows.

Let at time t ₁ open state of the power transistor switch 1 (Fig.5, c) there was a short circuit of the excitation winding of the generator. At the same time, the power transistor switch 1 switches to linear mode, due to which the voltage between the output terminal 3 of the controller and the first 2 power bus jumps up to a value exceeding the reference voltage Uo. node protection 11. In the presence of a gating pulse as a result of comparing the output voltage of the controller with the reference voltage Uop. the protection unit 11 generates a current that opens the control keys 13, 14. Since the control keys 13, 14 are connected between the first power bus 2 and the parametric inputs of the first 7 and second 8 controlled current sources, the latter change their internal resistances irregularly regardless of the values of the currents generated on the first and second outputs of the measuring body 9. In this case, the internal resistance of the first 7 controlled current source takes the minimum possible value, and the internal resistance of the second 8 controlled source ka current - the maximum possible value. As a result, the capacitor 17 is fully charged, and the input voltage of the comparator 6 jumps up to the level of the upper threshold Uv.p. (figure 5, a; t ₂ ). Output voltage Uout.comp. (Fig. 5, b) and the voltage of the gate pulse generated by the comparator 6 is reduced to zero. The power transistor switch 1 is closed, and the current generation by the protection unit 11 is stopped. The control switches 13, 14 are closed, and the internal resistances of the first 7 and second 8 controlled current sources come into correspondence with the current and first outputs produced by the measuring body 9 for the case when adjustable voltage is less than the adjustment level of the voltage regulator. Due to the fact that at the previous stage, the capacitor 17 was forcibly fully charged, the process of discharging it accordingly lengthens, and this corresponds to an increase in the closed time of the power transistor switch 1. After the capacitor 17 is discharged to the lower threshold Un.p. (Fig. 5 , а; t ₃ ), the comparator 6 switches to the upper threshold U.v.p. and at its outputs a gating pulse and voltage are formed, opening the power transistor switch 1 (Fig. 5, b; t ₃ -t ₄ ). In the circuit of the power transistor switch 1 there is a short-term current pulse Is.cl., Exceeding the nominal value (Fig. 5, c; t ₃ -t ₄ ), and again the power transistor switch 1 switches to the linear mode of operation, at which the voltage between the output terminal device and bus 2 power exceeds the reference voltage Uo. protection node 11. As a result, a current is generated at the output of the protection node 11, which opens the control keys 13, 14. Next, the process is repeated as described above, as a result of which the voltage regulator switches to the mode of operation of the relaxation generator with a large duty cycle of current pulses in the circuit of the power transistor switch 1, for example, 100 or more. With this duty cycle, the power transistor switch 1 overheats with respect to the ambient temperature by only (2-3) ° C, which does not affect its performance.

After eliminating the short circuit of the excitation winding of the generator (Fig. 5; t ₅ ), the voltage regulator is switched on automatically.

The principle of operation of the voltage regulator circuit of FIG. 2 in an abnormal mode of exceeding the maximum permissible ambient temperature is similar to the above-described principle of operation of this circuit in the short circuit mode of the generator excitation winding and differs from the latter in that the amplitude of the current pulses in the circuit of the power transistor switch 1 is limited by the impedance the excitation winding of the generator and has a significantly lower value than in the short circuit mode of the excitation winding of the generator. As a result, in the indicated anomalous mode, the overheating of the power transistor switch 1 with respect to the ambient temperature is almost close to zero.

When implementing a voltage regulator according to the schemes of figures 1, 2 in an integrated version, for example, the following well-known solutions of functional elements can be used:

- measuring body - in the form of a differential amplifier with two outputs or using a Norton amplifier;

- controlled current source - in the form of a controlled current stabilizer with an additional input for setting a fixed current value;

- comparator - in the form of a comparison device using two Schmitt triggers;

- protection node - in the form of a comparator with or without implementation of the “OR” logical function in the input circuit;

- control key - using one or two-stage key amplifiers;

- stabilized power source - in the form of a transistor parametric voltage stabilizer;

- temperature sensor - in the form of several series-connected pn junctions.

Thus, the introduction of a temperature sensor, a protection unit, the first and second control keys, a stabilized power supply into the device, the implementation of the first and second controlled current sources with signal and parametric inputs, the connection of the protection unit with an input to the output of the temperature sensor, an output - to the input of the first and to the input of the second controlled keys, respectively connected between the first power bus and the parametric inputs of the first and second controlled current sources, connecting a stabilized source power supply with a common output to the first power bus, input output to the third power bus, output output to the fourth power bus, to which the other end pin connects a circuit from the first and second controlled current sources connected in series, as well as connecting the capacitor with another output to the common or the output terminals of the stabilized power source favorably distinguishes the claimed device from the known, as it can significantly increase the reliability of the voltage regulator in abnormal operating conditions.

Laboratory and operational tests conducted by Avtoelektronika OJSC together with ZIT OJSC showed high reliability of the controller in abnormal operating conditions, complete with a 94.3701 generator and its modifications.

Sources of information

1. RU Patent No. 2115220, Cl. H 02 P 9/30, 1988, Bull. No. 19.

2. RU Application No. 20011134869/09, IPC 7 H 02 P 9/30, 2001.

Claims (2)

1. The voltage regulator of the generator, containing a power transistor switch connected between the first power bus and the output terminal of the device, designed to connect to the field winding, a damping diode connecting the output terminal of the device to the second power bus, designed to connect to the generator rectifier, a comparator with the upper and lower thresholds of operation, connected by the output to the control input of the power transistor switch, a chain of series-connected first and second controlled sources of current sources connected by one extreme terminal to the first power bus, a capacitor connected by one terminal to the comparator input and to the connection point of the first and second controlled current sources, a measuring organ connected between the first and third power buses and equipped with two outputs designed for generating antiphase on the variable component of the control currents, the first of which is connected to the signal input of the first, and to the second - the signal input of the second controlled current sources, characterized in that s temperature sensor, protection unit, first and second control keys, stabilized power supply, in addition, each of the aforementioned controlled current sources is equipped with a parametric input, the protection unit is connected by an input to the output of the temperature sensor, by an output - to the input of the first and to the input of the second control keys connected respectively between the first power bus and the parametric inputs of the first and second controlled current sources, a stabilized power source connected by a common output to the first power bus, input th output - to the third bus power, output terminal - a fourth power bus to which other extreme terminal connected chain of serially connected first and second controlled current sources, the other terminal of the capacitor connected to the output terminal or a common regulated power supply. 2. The voltage regulator according to claim 1, characterized in that the comparator is equipped with a second output intended for generating strobe pulses, and the protection unit is equipped with a second input connected to the output terminal of the device and an additional output connected to the second output of the comparator.

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