RU2528565C2 - Single-step double flyback converter with improved dynamic properties - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: invention refers to electric engineering and can be used to control fast-response network transformer power sources with improved dynamic properties. The proposed device additionally comprises a relay stabiliser of magnetic state of an inductive element core and a logic element OR, the input of one key element is connected to the output of the relay magnetic state stabiliser and the input of the other key element - to the output of the OR element with the inputs of the latter being connected to the outputs of the relay voltage stabiliser and relay magnetic state stabiliser.

EFFECT: improvement of dynamic properties of a pulse power source based on a single-step double flyback converter.

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Description

The present invention relates to electrical engineering and can be used to control high-speed network transformerless power supplies with improved dynamic properties.

From the existing level of technology, a single-stroke dual flyback converter with a traditional control law is known [1, p. 79-83]. Closest to the claimed technical solution is an ultrasonic generator [2].

One of the main disadvantages of all pulse converters is the occurrence of an overshoot of the output voltage during a quick exit to the mode, as well as spikes and dips in the output voltage during sudden changes in the load parameters.

The problem to which the invention is directed, is to improve the dynamic properties of a switching power supply based on a single-stroke dual flyback converter.

This problem is solved due to the fact that a dual-circuit key element control system is used, which provides independent relay stabilization of the magnetic state of the core of the inductive element and voltage at the load.

The technical result provided by the given set of features is the absence of an overshoot of the output voltage during a quick exit to the mode, as well as surges and dips in the output voltage with abrupt changes in the load parameters.

The invention is illustrated by drawings, which depict:

Figure 1 - single-stroke dual flyback converter with two control loops;

Figure 2 - single-stroke dual flyback converter with two control loops and clocking.

The block diagram of a single-stroke dual flyback converter, in which a dual-circuit key element control system is used, which provides independent relay stabilization of the magnetic state of the core of the inductive element and voltage at the load, is shown in Fig. 1. The diagram indicates:

1, 2 - key elements,

3, 4 - switching diodes,

5 - source of supply voltage (rectified and filtered mains voltage is used in network converters),

6 - inductive element (in converters with direct coupling, a reactor is used, in converters with galvanic isolation - a transformer),

7 - flyback rectifier with a capacitive filter (a single-stroke dual converter can also work as a straight-through, if it uses a flyback rectifier with an LC filter),

8 - load, 9 - voltage setting,

10 - relay modulator circuit voltage stabilization,

11 - relay voltage stabilizer on the load,

12 - logical element OR,

13 - magnetic state sensor (The magnetic state of the core of a magnetic element in a flyback converter with galvanic isolation means the sum of the magnetomotive forces of all windings ∑w _i · i _{i of a} multi-winding transformer, where w _i and i _i are the number of turns and the instantaneous current value in the i-th A magnetic reactor in a flyback converter with direct coupling has only one winding, so a conventional current sensor can be used.),

14 - the setting of the magnetic state,

15 - relay modulator circuit stabilization of the magnetic state,

16 - relay stabilizer of a magnetic state.

Traditionally, such a converter uses a single control loop, and key elements open and close at the same time. In the flyback conversion mode, energy is accumulated in the core of the inductive element during the open state of the key elements and transferred to the load when they are locked. As in all pulse converters, here there is an overshoot of the output voltage during a quick exit to the mode, as well as surges and dips in the output voltage during abrupt changes in the load parameters.

In the diagram of Fig. 1 with two control loops, the upper and lower threshold levels of relay stabilizers (16, 11) are determined by the reference setpoint levels (14, 9) and the hysteresis width of the relay modulators (15, 10) in the corresponding channels.

The magnetic state stabilization circuit, which controls the two key elements 1 and 2, takes precedence over the output voltage stabilization circuit, which controls only one key element 1. Therefore, when the converter is turned on from zero initial conditions, the magnetic state is reached at the beginning - energy storage in the inductive element corresponding to the maximum output power. And only after that does the mode start on the voltage at the load.

It happens as follows:

Until the signal from the magnetic state sensor 13 has reached the upper threshold of the relay stabilizer of the magnetic state 16, a control signal is supplied to the control input of the key element 2 and through the OR element 12 to the control input of the key element 1 — a logical unit.

The unit at the input of the OR gate blocks the passage of the control signal from the voltage stabilization circuit to the control input of the key element 1.

Both key elements are open. There is an accumulation of energy in the magnetic field of the core of the inductive element.

The logical unit is removed from the output of the relay stabilizer 16 when the signal of the magnetic state sensor of the upper threshold level is reached. Key element 2 is locked. And the key element 1 begins to be controlled from the relay voltage regulator 11.

As long as the voltage at the load remains less than the upper threshold level of the stabilizer 11, its output signal corresponds to a logical zero - the key element 1 is locked. The energy stored in the core of the magnetic element enters the load. The filter capacitor is charging.

During the transfer of energy to the load, the energy reserve in the core of the magnetic element decreases and the signal from the magnetic state sensor decreases. As soon as this signal falls below the lower threshold level of the relay stabilizer 16, a logical unit will appear at its output. Both key elements 1 and 2 will open. Energy will be pumped into the core of the magnetic element. Then, the transfer of energy to the load will continue. Further similarly.

Thus, the output to the mode in a magnetic state is monotonous in nature, in output voltage - stepwise.

When the voltage at the load reaches the upper threshold of the relay stabilizer 11, a logical unit appears at its output, causing the key element 1 to open. The output of energy from the magnetic element to the load is stopped, except for overshoot on the load. The winding current of the magnetic element flows through the diode 4 and the key element 1. In this way, voltage surges are eliminated with an abrupt decrease in the load current.

The logical unit at the output of the relay stabilizer 11 and the open state of the key element 1 do not interfere with the work of the stabilization circuit of the magnetic state.

In the steady state, the voltage stabilization circuit monitors the voltage on the load with a given accuracy, and the magnetic state stabilization circuit monitors the energy supply in the core of the magnetic element with the specified accuracy. The stored energy and magnetic state of the core are connected by a quadratic dependence.

The energy reserve in the core of the magnetic element eliminates voltage dips during an abrupt increase in the load current, if this does not exceed the maximum allowable power. Exceeding the maximum allowable power will inevitably lead to voltage dips, however, this mode is emergency, although safe for this converter.

One of the drawbacks of the dual-circuit relay control system is a very wide range of changes in the switching frequency of key elements with changing load parameters. This disadvantage can be eliminated by introducing the timing of the relay stabilizers of figure 2.

Tactical D-flip-flops 17 and 18 are repeat triggers. They delay the signals from the relay elements 15 and 10 for no more than a period of the frequency of the clock generator 19 connected to the clock inputs of the triggers. In the presence of timing, the switching frequency of the key elements does not exceed the frequency of the clock generator.

A virtual experiment confirmed the operability of the proposed device. The prototype was tested for a power of 1.5 ... 1.8 kW.

Based on the foregoing, we can conclude that the use of the proposed device in high-speed power supplies with improved dynamic properties.

INFORMATION SOURCES

1. Rudyk S. D., Turchaninov V. B. One-stroke dual voltage converter for 500-700 watts. // Highly efficient sources and systems of secondary power supply REA. M: MDNTP them. F.E. Dzerzhinsky, 1983. S. 79-83.

2. Ryazanov B.P., Bystrova I.D., Kharlamenkov V.D., Fedorchenko V.V. The ultrasonic generator. Number of copyright certificate: 1121771. Date of publication: October 30, 1984.

Claims (2)

1. A single-stroke dual flyback converter, made in the form of a bridge, in which two opposite arms contain key elements connected by control inputs to the output of a voltage regulator, the other two arms are switching diodes, a power supply is included in one diagonal of the bridge, the polarity of which corresponds to the locked state diodes, in another - an inductive element with a flyback rectifier and a load, and the input of the relay voltage regulator is connected to the output of the rectifier, distinguishing be sure that the relay of the magnetic state stabilizer of the core of the inductive element and the OR logic element are introduced, the input of one key element being connected to the output of the relay stabilizer of the magnetic state, and the input of the other key element being connected to the output of the OR element, the inputs of which are connected to the outputs of the relay voltage stabilizer and relay stabilizer of a magnetic state. 2. The Converter according to claim 1, characterized in that it additionally introduces a clock generator and two clocked trigger-repeaters, each with two inputs (signal and clock), and the output of one trigger is connected to the interconnected inputs of the OR element and the key element, and its signal input is connected to the output of the relay stabilizer of the magnetic state, the output of another trigger is connected to the second input of the OR element, and its signal input is connected to the output of the relay voltage regulator, the inputs of both triggers are connected to the output of the clock generator.

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