RU175601U1 - Bidirectional Switching Voltage Converter - Google Patents

Abstract

The utility model relates to electrical engineering and to pulsed electronics and is intended to be used as a unified module of a multifunctional pulsed converter of alternating and constant voltage for high-tech and highly reliable electrical systems with a modularly scalable architecture, in particular for electric power complexes of more (or fully) electrified aircraft. The main technical result of the proposal is to reduce heat loss and noise emissions from the device by ensuring the continuity of one of the external currents and “soft” switching of the switch keys. An additional result is the expansion of the functionality of the device due to reversible frequency conversion, as well as the regulation of the amplitude and phase shifts of two alternating voltages, in particular to triple the number of phases of alternating current. These results are ensured due to the fact that in a device containing two pairs of external terminals 1-2 and 3-4 for connecting a power source and loads, shunted by filter capacitors 5 and 6, a controlled electronic bridge switch, consisting of three two-arm branches with diode-key struts from 7-8 to 17-18 in the shoulders, the reactor 19 and the control unit 20 with feedback circuits 21, 22 and pulse-modulator outputs 23, all the terminal leads belong to the keys, and all the middle leads belong to the diodes; each switch arm is equipped with a snubber capacitor from 24 to 29, a damper inductor from 30 to 35, a charging diode from 36 to 41, and a two-diode discharge rack from 42 to 47. 2 ill.

Description

The utility model relates to electrical engineering and to pulsed electronics and is intended to be used as a unified module of a multifunctional pulse converter of variable and constant voltage for high-tech and highly reliable power systems with a modularly scalable architecture, in particular for power systems of more (or fully) electrified aircraft.

A bi-directional pulse voltage converter (analog) is known, comprising an input grounded filter capacitor, an output two-capacitor filter rack with a differential output, a two-winding storage-demodulator transreactor, two four-arm bridge switches with diode-key racks connected to each other by direct current through two transformer windings, as well as a shunting two-key rack and a control unit with pulse-modulator outputs (Reznikov SB, Bocharov VV, Lavrin HIV AV Kharchenko IA reversible converter of AC and DC voltages. A utility model patent RU №138899, Bull. №9 from 27.03.2014 city)

The disadvantages of the known device (analogue) include: low reliability and manufacturability of the device due to the lack of common grounding of the external terminals, which impedes three-phase execution with a grounded neutral, large switching heat losses and noise due to the “hard” switching of modulator keys (at non-zero currents and voltages) and due to the large internal reactive power determined by the inductance of the transformer rectifier windings.

Of the known devices, the closest in technical essence to the proposed one is a bi-directional pulse voltage converter (prototype), containing an input grounded filter capacitor, an output two-capacitor filter rack, a shunt differential voltage output with a grounded mid-potential output, a two-section storage-demodulator reactor, an electronic eight-arm bridge switch with diode-key racks and control unit with feedback circuits and impu alsno-modulatory output conclusions (Reznikov SB, Bocharov VV, Lavrinovich AV, Kharchenko IA Bidirectional rectifier-inverter converter with power factor correction. Utility model patent RU No. 143469, Bull. No. 20 dated July 20, 2014).

The disadvantages of this known device (prototype) include: narrow functionality due to the inability of the reversible conversion of constant-reversible and variable voltages with the ability to control and stabilize frequencies, amplitudes and mutual phase shifts, as well as large switching heat losses, overvoltages and noise emissions due to for “hard” switching of electronic keys (at non-zero currents and voltages).

The main technical result of the proposal is to reduce heat loss and noise emissions from the device by ensuring the continuity of one of the external currents and “soft” switching of the switch keys. An additional result is the expansion of the functionality of the device due to reversible frequency conversion, as well as the regulation of the amplitude and phase shifts of two alternating voltages, in particular to triple the number of phases of alternating current.

These results are ensured due to the fact that in a device containing two pairs of external terminals and for connecting a power source and loads shunted by filter capacitors, and a controllable electronic bridge switch, consisting of three two-arm branches with diode-key struts in the shoulders, a reactor and a control unit with feedback circuits and pulse-modulator leads, all the extreme leads of the branches belong to the keys, and all the middle leads belong to the diodes; at the same time, each switch arm is equipped with a snubber capacitor, a damper inductor, a charging diode and a two-diode discharge rack.

Experimental studies of the laboratory layout and computer simulation of the proposed device confirmed its efficiency and the feasibility of wide industrial use.

The drawing (Fig. 1) shows a circuit diagram and control channels of the proposed bidirectional pulse voltage Converter.

A bi-directional pulse voltage converter contains: two pairs of external terminals 1-2 and 3-4, including ground, for connecting a power source and loads with the possibility of energy recovery, shunted by the first and second filter capacitors 5 and 6, a controllable electronic bridge switch, consisting of three parallel-connected two-arm branches with diode-key racks from 7-8 to 17-18 in the shoulders, a reactor 19, shunting the extreme leads of these branches, and a control unit 20 with circuits 21, 22 of reverse ides for external currents and voltages and with pulse-modulator outputs 23.

Each arm of the bridge switch is equipped with a snubber capacitor from 24 to 29, a damper inductor from 30 to 35 in the circuit of this arm with a charging diode from 36 to 41, and a discharge and two-diode rack from 42 to 47.

The two-arm branches of the bridge switch are connected by their middle inter-arm terminals to the corresponding external terminals 1 (3), 2, and 4. The two-diode rack from 42 to 47 of each arm of the two-arm branches of the bridge switch is connected with its middle terminal along with the first terminal of the corresponding snubber capacitor from 24-29 to the middle terminal of the corresponding diode-key rack of this arm, and its extreme conclusions - to the extreme terminals of similar two-diode racks belonging to two other branches of the switch, and not being hsya adjacent to this shoulder.

The second output of the snubber capacitor from 24 to 29 is connected through a charging diode from 36 to 41 to the extreme key terminal of this diode-key rack.

The control unit 20 (Fig. 2) with its pulse-modulator terminals 23 is connected to the control terminals of the keys of the diode-key racks of the bridge switch.

As the keys of the diode-key racks of the bridge switch, key transistors or two-operation (lockable for control) thyristors are used.

Bidirectional pulse voltage Converter operates as follows. To external terminals 1-2 and 3-4 connect a power source and loads of constant (including reverse) or alternating voltage, in the general case, with the possibility of recovering electricity from the load into the source circuit and / or in the circuit of its other loads.

), некритичные к стабильности частоты (нагревательное, светотехническое и др. оборудование) или со стабильной частотой 400 Гц.A typical example of a power source with an unstable frequency and amplitude of an alternating voltage at terminals 1-2 can be the phase winding of the armature of an airborne electric machine starter-generator with rotating permanent magnets with an unstable angular velocity. A typical example of a DC voltage load (at terminals 3-4) is a unipolar DC link (270 V) in an airborne power supply system (with a grounded negative terminal). A typical example of an AC voltage load with a stable amplitude at terminals 3-4 is the airborne AC voltage consumer (with the phase voltage amplitude:

), non-critical to frequency stability (heating, lighting and other equipment) or with a stable frequency of 400 Hz.

In pulse-modulator 23 findings of the control unit 20 generates high-frequency width-modulated rectangular pulses with a constant period: T _PWM and adjustable pulse duration: t = γ _and ⋅T _{shim and} where γ _and - the relative duration (duty ratio) of a pulse.

At each arbitrary period: T _shim in the general case, three stages alternate:

a) the step of increasing the current of the reactor 19 (dI / dt> 0); b) the stage of approximate current conservation (dI / dt≈0); and c) the stage of partial (or full) current decrease (dI / dt <0).

Consider the following modes of operation of the device:

1) the rectification mode of the supply AC voltage (U _1-2 at the terminals 1-2) with the correction of the power factor and with the stabilization of the average value of the rectified voltage (U _3-4 at the terminals 3-4);

2) the inversion mode of the supply DC voltage (U _3-4 ) with its conversion to a sinusoidal voltage (U _1-2 );

3) the mode of frequency conversion and / or regulation of the amplitude and phase shift of the alternating voltage (from pins 1-2 to pins 3-4).

1. Rectification mode (U _1-2 → U _3-4 ):

la) polar repetitive undervoltage with steps:

a) dI / dt> 0) along the chain: 5-7-8-30-19-35-18-17-6-5;

b) dI / dt ~ 0 along the chain: 19-33-14-13-11-11-12-32-19;

c) dI / dt <0 along the chain: 19-35-18-17-6-11-12-32-19.

1b) polar repetitive voltage increase with the steps of:

a) dI / dt> 0 along the chain: 5-7-8-30-19-33-14-13-5;

b) see step "b" p. 1a;

c) dI / dt <0 along the chain: 19-35-18-17-6-5-7-8-30-19.

1c) polar-inverting lowering or increasing voltage with stages:

a) dI / dt> 0 along the chain: 5-11-12-32-19-31-10-9-5;

b) see step "b" p. 1a;

c) dI / dt <0 along the chain: 19-35-18-17-6-11-12-32-19.

2. Invert mode (U _3-4 → U _1-2 ) with the conversion of direct voltage to sinusoidal:

2a) polar repetitive undervoltage with steps:

a) dI / dt> 0 along the chain: 6-15-16-34-19-31-10-9-5-6;

b) see step "b" p. 1a;

c) dI / dt <0 along the chain: 19-31-10-9-5-11-12-32-19.

2b) polar repetitive voltage increase with the steps of:

a) dI / dt> 0 along the chain: 6-15-16-34-19-33-14-13-6;

b) see step "b" p. 1a;

c) dI / dt <0 along the chain: 19-31-10-9-5-6-15-16-34-19.

2c) polar-inverting lowering or increasing voltage with stages:

a) dI / dt> 0 along the chain: 6-15-16-34-19-33-14-13-6;

b) see step "b" p. 1a;

c) dI / dt <0 along the chain: 19-31-10-9-5-11-12-32-19.

3. The mode of frequency conversion and / or regulation of alternating voltage parameters (amplitude and phase shift).

In this mode, on the interval of the "positive" half-period of the output voltage: U _3-4 > 0 (when the potential of terminal 4 is positive with respect to ground), rectification modes are repeated (items 1a, 1b, 1c), and on the interval of the "negative" half-period: U _3-4 <0 (when the potential of output 4 is negative), we have the following cases:

3a) polar repetitive undervoltage with steps:

a) dI / dt> 0 along the chain: 5-6-15-16-34-19-31-10-9-5;

b) see step "b" p. 1a;

c) dI / dt <0 along the chain: 19-33-14-13-6-15-16-16-34-19.

3b) polar-repetitive increase in voltage with stages:

a) dI / dt> 0 along the chain: 5-11-12-32-19-31-10-9-5;

b) see step "b" p. 1a;

c) dI / dt <0 along the chain: 5-6-15-16-34-19-31-10-9-5.

3c) polar-inverting lowering or increasing voltage with stages:

a) dI / dt> 0 along the chain: 5-7-8-30-19-33-14-13-5;

b) see step "b" p. 1a;

c) dI / dt <0 along the chain: 19-33-14-13-6-15-16-16-34-19.

и, соответственно - входного тока - по синусоидальному закону:

совпадающему по временной фазе с функцией входного напряжения

При этом обеспечивается стабилизация среднего значения выпрямленного напряжения U_3-4, приложенного ко второму фильтровому конденсатору 6.In the rectification mode, the correction of the power consumption coefficient (i.e., the approximation of the power factor to unity) is ensured by generating the pulsating current of the reactor 19 according to the modular-sinus law:

and, accordingly, the input current, according to the sinusoidal law:

coinciding in phase with the input voltage function

This ensures stabilization of the average value of the rectified voltage U _3-4 applied to the second filter capacitor 6.

In the inverter mode, the formation of a modular sinusoidal current law of the reactor 19 (amplitude modulation with pulsating flux linkage) and the corresponding sinusoidal output current (demodulation) are also used.

In the frequency conversion mode, an output voltage is generated with the amplitude and phase angle parameters determined by the reference sinusoidal signal (using the feedback circuits 21 and 22 of the control unit 20).

на величину 2π/3(120°), то получим трехфазную систему из трех линейных напряжений: U_1-2, U_3-4, U_2-4, взаимосдвинутых по временной фазе на 2π/3(120°) («треугольник» векторов напряжений). Это соответствует функции утроения частоты переменного тока.If the frequency of the output single-phase voltage U _3-4 (t) is preserved, but this voltage is shifted relative to U _1-2 (t) in the time phase

by 2π / 3 (120 °), then we obtain a three-phase system of three linear voltages: U _1-2 , U _3-4 , U _2-4 , mutually shifted by the time phase by 2π / 3 (120 °) (“triangle” stress vectors). This corresponds to the triple function of the AC frequency.

In all of the above modes, “soft” switching of the switch keys is provided (without simultaneous surges in current and voltage). The increase in current in the key is controlled by the damper choke from 30 to 35, and the increase in voltage on the key is controlled by the snubber capacitor from 24 to 29, which is completely discharged before the key is turned off, transmitting the energy accumulated by it to the reactor 19 for use in the load.

Damper chokes and snubber capacitors form the so-called “non-scattering damper-snubber chains”. An example of a circuit for completely discharging a snubber capacitor is the circuit: 24-8-30-19-33-14-45-24 and 24-8-30-19-35-18-47-24, depending on which key pairs 14 and 18 are included with key 8.

The indicated “soft” switching provides a reduction in heat and switching losses (increased efficiency) and interference emissions (improved electromagnetic compatibility). In addition, an increase in efficiency (reduction of heat loss) is ensured by the choice of the most energy-efficient modulation modes with continuous one of the external currents: polar repetitive modes of lowering or increasing voltage.

Thus, in comparison with the prototype, the proposed device provides the main technical result: reducing heat loss and noise emissions from the device by ensuring the continuity of one of the external currents and “soft” switching of the switch keys, and in addition, an additional result: expanding the functionality of the device due to reversible frequency conversion, as well as regulation of the amplitude and phase shifts of two alternating voltages, in particular - to triple the number of phases of alternating current.

Claims (1)

Bi-directional pulse voltage converter containing two pairs of external terminals, including ground, for connecting a power source and loads with the possibility of energy recovery, shunted by filter capacitors, controlled electronic bridge switch, consisting of three parallel two-arm branches with unidirectional diode-key racks in the shoulders, reactor shunting the extreme terminals of these branches, and a control unit with feedback circuits for external currents and voltages and impu by modular-modular outputs connected to the control terminal of the keys of the indicated branches, connected by their middle inter-arm outputs to the corresponding external terminals, characterized in that all the extreme terminals of the two-arm branches belong to the keys, and all the middle inter-shoulder outputs belong to diodes; each arm of the bridge switch is equipped with a snubber capacitor, a damper inductor, a charging diode and a two-diode discharge rack, with the damper inductor connected in series with the corresponding diode-key rack of this arm, the snubber capacitor bypasses the power leads of the key of this arm through the charging diode, and the discharge two-diode rack with its middle output it is connected to the common terminals of the snubber capacitor of this key, and with its extreme terminals it is connected to the extreme terminals of the discharge two diode struts of the shoulders belonging to two other branches and not adjacent to this shoulder.

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