RU145150U1 - VOLTAGE FEEDBACK CONVERTER - Google Patents

Abstract

1. A voltage converter with fast feedback, comprising: a primary winding circuit of a first transformer, comprising: a power switch connected by a control terminal to a first terminal of a control device; secondary winding circuit of the first transformer; feedback circuit, including: a voltage divider connected to the output of the secondary circuit of the first transformer; a comparison device connected to the output of the voltage divider; serially connected to the output of the comparison device: the primary winding of the second transformer, the first diode and the first resistor connected to the secondary circuit of the first transformer, characterized in that the primary winding of the first transformer contains: a current sensor connected to the second output of the control device via a series connected second and third resistors; a first capacitor connected by one terminal to the second terminal of the control device, and the other to the third terminal of the control device and the second terminal of the current sensor; the terminals of the secondary winding of the second transformer connected directly to the terminals of the second resistor. 2. A voltage converter with high-speed feedback according to claim 1, characterized in that it is constructed according to the linear converter circuit and the first resistor is connected to one terminal of the secondary winding of the first transformer. A voltage converter with high-speed feedback according to claim 1, characterized in that it is constructed according to a flyback converter and the first transformer has an additional secondary winding, one terminal of which is connected�

Description

Technical field

The utility model relates to electrical engineering and can be used in pulsed sources of secondary power supply (IWEP) as a circuit for controlling the parameters of the output signal using a feedback circuit (OS).

State of the art

To stabilize the output voltage of the IWEP in the conditions of changing the load current, the OS is used according to the output voltage and the input or output current. The performance of the OS affects the quality of the output voltage, especially with a pulsed load of the power supply voltage.

When connecting a converter with an operating system in terms of output voltage and current to a pulsed load, for example, to an energy-intensive processor system having load fluctuations with a frequency much higher than the operating frequency of the converter, a sharp surge or load shedding is possible, which can lead to significant surges in the output voltage of the converter, leading to malfunctions processor systems. To avoid such phenomena, storage capacities are installed next to energy-intensive consumers, reaching several hundred thousand microfarads, which in turn requires a short-term operation in the short-circuit mode when power-consuming consumers are turned on, i.e. special requirements for converters appear.

It is possible to reduce the storage capacity of energy-intensive systems by increasing the speed of the converter OS.

A device is known (patent RU 2301438 "Secondary power source", priority of November 7, 2005, IPC G05F 1/571, H02M 3/335), in which the main goal is to create a secondary power source operating in a wide range of input voltage values, the formation of the total signal OS from the signals of the current sensor and the additional winding of the power transformer.

The disadvantages of this device are: low speed of the OS signal due to the significant size of the capacitance 10, which makes it impossible to track the output voltage in each conversion period and, as a result, low speed of the OS in terms of voltage and large total instability of the output voltage under the pulse load of the converter.

A device is known (patent US 4862339 "DC power supply with improved output stabilizing feedback", priority of 06/05/1987, IPC H02M 3/335, H02M 1/08), selected as a prototype (figure 1), the main purpose of which is to simplify the OS circuit without using an additional power source, obtain OS information in each conversion cycle according to the output voltage independent of the input voltage, and obtain OS information based on this principle when protecting against short-circuit and output overvoltages.

The principle of transmitting an analog signal through an isolation transformer in each converter cycle using the pulse signal of the secondary winding of the power transformer is used.

The disadvantages of this device are:

1. low speed of the OS signal due to:

- the use of a peak detector (diode 282 and capacitor 284) in the stabilization signal generating unit 28, the time constant of which depends on the capacitance of the capacitor 284 and the dynamic resistance and capacitance of the diode 282 (charge of the capacitance 284), resistance 286, and input resistance of the PWM controller 40 ( capacity discharge 284);

- increased inductance of the transformer windings 26, because it is necessary to overcome the voltage drop on the diode 282,

2. There is no OS for the input current, which can lead to failure of the transistor 14.

Brief Description of the Drawings

Figure 1 presents the prototype of the claimed utility model.

Figure 2 presents the voltage Converter with high-speed OS.

Figure 3 shows a voltage converter with a high-speed operating system for input current and output voltage made according to: a) a flyback circuit with a transformer current sensor; b) a forward-flow circuit with a transformer current sensor; c) flyback circuit with a resistive current sensor; d) a forward-flow circuit with a resistive current sensor.

Figure 4 shows the timing diagrams of the proposed voltage Converter: a) the voltage of the current sensor; b) the total voltage of the current sensor and the OS by the output voltage at the connection point of the resistors R2 and R3; c) the total voltage at the input CS of the PWM controller; d) gate pulses of the transistor VT1.

Figure 5 shows the timing diagrams of the output voltage for: a) surge and b) load shedding.

Utility Model Essence

The goal is the formation in each conversion step of a high-speed total operating system according to the input current and output voltage to reduce the duration of transients during load surge / discharge, as well as to reduce the amplitude of the output voltage ripple while maintaining a high accuracy of output voltage stabilization.

This goal is achieved by simplifying the OS voltage circuit and reducing the inductance of the windings of the isolation transformer.

The voltage Converter with a high-speed OS (figure 2) contains: the primary circuit 1 of the first transformer 2, including: a power switch 1.1 connected by a control terminal to the first output of the control device 1.2; secondary circuit 3 of the first transformer 2; OS circuit, including: a voltage divider 4, connected to the output of the secondary circuit 3 of the first transformer 2; a comparison device 5 connected to the output of the voltage divider 4; connected in series with the output of the comparison device 5: the primary winding of the second transformer 6, the first diode 11 and the first resistor 10 connected to the secondary circuit 3 of the first transformer 2, and the primary winding circuit 1 of the first transformer 2 contains: a current sensor 1.3 connected to the first output to the second output of the control device 1.2 through series-connected second 9 and third 8 resistors; a first capacitor 7 connected by one terminal to the second terminal of the control device 1.2, and the other to the third terminal of the control device 1.2 and the second terminal of the current sensor 1.3; the conclusions of the secondary winding of the second transformer 6 connected to the terminals of the second resistor 9 directly.

Figures 3a-3g show embodiments of a utility model.

A possible option (figa and 3b), in which the voltage Converter with a high-speed operating system is constructed according to the linear converter and the first resistor is connected to one terminal of the secondary winding of the first transformer.

A variant is possible (Figs. 3c and 3d), in which the voltage converter with a high-speed OS is built according to the flyback converter and the first transformer has an additional secondary winding, one output of which is connected to the first resistor, the other is connected to the current return circuit of the secondary winding of the first transformer.

The current sensor can be either resistive (R5 figv and 3d) and transformer (T1, R5 figa and 3b). The comparison device D1 can be performed, for example, on a chip TL431 (controlled zener diode).

Comparative analysis with the prototype (Fig. 1) shows that the inventive voltage converter with a high-speed operating system is characterized by the absence of a rectifier 282 and a capacitance 284 in the secondary circuit of the second transformer and the presence of a current sensor included in the input voltage circuit that provides a signal with information about the input current of the IEDS , which is summed with the signal OS voltage from the secondary winding of the second transformer in each conversion cycle, Thus, the claimed device meets the criterion of "novelty."

In accordance with a preferred embodiment of the utility model (figa and 3b), the device operates as follows.

After turning on the transistor VT1 (Fig. 4d), the current flowing through the primary winding of the current transformer T1.1 causes a current in the secondary winding T1.2, which creates a voltage across the resistor R5, which generates an OS current signal (Fig. 4a).

At the same time, the voltage increases on the winding of the transformer T2.2 (Fig.3a) or on the secondary winding of the transformer T2 (Fig.3b), the current of which passes through the resistor R1 and diode VD1 along the primary winding of the isolation transformer T3. The current flowing through the primary winding of the transformer T3 depends on the degree of opening of the output transistor of the chip D1, which depends on the output voltage Uout coming from the divider R6, R7. The principle of transmitting an analog signal through an isolation transformer in each conversion cycle using pulses of the secondary winding of the power transformer is described in detail in the prototype.

If the output voltage Uout is less than the stabilization voltage of the converter, then the output transistor of the D1 chip is closed and the current through the primary winding of the transformer T3 is zero, the OS voltage on the secondary winding of the transformer T3 is not generated and does not stand out on the resistor R3, the OS voltage on the input current of the resistor R5 controls the operation transducer in each conversion cycle.

If the output voltage Uout is greater than the stabilization voltage of the converter, then the output transistor of the D1 chip is open and the current through the primary winding of the transformer T3 is maximum, the OS voltage on the secondary winding of the transformer T3 is allocated to the resistor R3, summing up with the OS voltage for the input current of the resistor R5, controls the operation of the converter in each conversion step.

The operation of the converter in each conversion cycle is controlled as follows: the total voltage of the operating system according to the output voltage and input current (Fig. 4, beam 2) in each conversion cycle passes through an integrating chain R2, C1 with a time constant of 0.1 · T conversion to suppress pulse interference (Fig. 4, beam 3) and is fed to the input of the OS by current (CS) of the PWM PWM controller. When the voltage threshold value is reached, the PWM PWM controller turns off the transistor VT1 (Fig. 4, beam 4), forming an output voltage with a precision accuracy of ± 0.2 ... 0.3% at the converter output.

When a load surge occurs, the voltage at the output instantly drops, the operating voltage restores the output voltage due to its high speed for several conversion clocks (Fig. 5a). When a load shedding occurs, the output voltage instantly increases, the operating voltage voltage restores the output voltage due to its high speed for several conversion clocks (Fig. 5b).

The difference in the recovery time of the output voltage during surge and load shedding is due to the absence of discharge currents of capacitor C1 through transformer T3 when a load shedding occurs, i.e. its energy is pumped in case of a load surge by the high current of transformer T3 with the output transistor of the D1 chip open, and its energy is dumped through resistors R3, R5, the total value of which is relatively large.

The inductance of the T3 transformer also affects the OS time constant over voltage. In the prototype circuit (Fig. 1), there is a diode 282, the voltage drop on which causes the output voltage of the transformer T3 to increase and, as a result, the inductance of the secondary winding of the isolation transformer T3 increases, which in turn leads to an increase in the overall dimensions of the ferromagnetic core of the transformer T3 and to increase the energy transmitted through it. The exclusion of diode 282 from the proposed circuit allowed not only to increase the operating speed of the OS in terms of voltage, but also to reduce the inductance of the secondary winding, and as a result, the overall dimensions of the isolation transformer T3.

The experimental data obtained in the manufacture of voltage converters, according to the proposed structure are shown on the oscillograms (figure 4 and 5), there was a reduction in price and a decrease in the overall dimensions of the converter itself. Storage capacities of energy-intensive consumers decreased by 4 ... 5 times, which in turn led to a decrease in the volume of the power system by 10-12%.

The proposed voltage converter with a high-speed operating system is made of standard elements that are commercially available from the industry. It is assembled by typical installation operations using standard equipment and does not require adjustment, which is especially important in serial production. Therefore, the proposed device meets the criterion of "industrial applicability".

Claims (3)

1. A voltage converter with fast feedback, comprising: a primary winding circuit of a first transformer, comprising: a power switch connected by a control terminal to a first terminal of a control device; secondary winding circuit of the first transformer; feedback circuit, including: a voltage divider connected to the output of the secondary circuit of the first transformer; a comparison device connected to the output of the voltage divider; serially connected to the output of the comparison device: the primary winding of the second transformer, the first diode and the first resistor connected to the secondary circuit of the first transformer, characterized in that the primary winding of the first transformer contains: a current sensor connected to the second output of the control device via a series connected second and third resistors; a first capacitor connected by one terminal to the second terminal of the control device, and the other to the third terminal of the control device and the second terminal of the current sensor; the terminals of the secondary winding of the second transformer connected directly to the terminals of the second resistor. 2. A voltage converter with high-speed feedback according to claim 1, characterized in that it is constructed according to the linear converter circuit and the first resistor is connected to one terminal of the secondary winding of the first transformer. 3. The voltage converter with high-speed feedback according to claim 1, characterized in that it is constructed according to a flyback converter and the first transformer has an additional secondary winding, one output of which is connected to the first resistor, the other is connected to the current return circuit of the secondary winding of the first transformer.