CN203883677U - Direct-current DC-DC sectionalizer based on phase-shift power flow control - Google Patents

Abstract

The utility model provides a direct-current DC-DC sectionalizer based on phase-shift power flow control, and the sectionalizer is characterized in that the sectionalizer consists of full-bridge transverters (1, 2), a high-frequency transformer (3), and resonant capacitors (4, 5); the upper and lower ends of four bridge arms of each of the full-bridge transverters (1, 2) are connected together, and are connected with two-side direct-current buses (6, 7); the upper bus is a positive bus, and the lower bus is a negative bus; a direct-current capacitor is connected between the positive and negative buses according to the capacitor polarity; and the output ends of the full-bridge transverters (1, 2) are respectively connected with the primary and secondary sides of the high-frequency transformer (3) through the resonant capacitors (4, 5). The sectionalizer is advantageous in that the sectionalizer is simple in control; the remarkable superiority is reflected in electric isolation of a direct-current microgrid, power control, and the connection of buses with different stages of voltage; a fault bus of the direct-current microgrid is quickly isolated during fault; the range of power failure is reduces; and the system reliability is improved.

Description

Direct current DC-DC sectionalizer based on shift power current control

Technical field

The utility model relates to micro-electric power network technique field, be specially a kind of based on shift power current control direct current DC-DC sectionalizer.

Background technology

DC micro-electric net, as a kind of micro-electrical network form that connects distributed power source and major network, can be brought into play value and the benefit of distributed power source efficiently, effectively isolates the various fault effectses in intermittent power disturbance, power quality problem and the major network of micro-electrical network inside.Therefore, domestic and international research institution launches research and the engineering practice of DC micro-electric net correlation theory in succession.Yet; direct current system needs jumbo electric capacity to eliminate voltage ripple; during short trouble, electric capacity instantaneous discharge causes that transient current may cause device damage or switch malfunction, causes the power-off of selective protection disabler, a large amount of loads and protects the problems such as equipment room coordination ability deterioration.Meanwhile, DC high-power solid circuit breaker cost costliness, control complexity and reliability are queried, so be difficult to extensive use in DC micro-electric net.

The utility model provides a kind of direct current DC-DC sectionalizer, is the direct current sectionalizer (being called for short direct current DC/DC sectionalizer) configuring in DC micro-electric net topology, is two full-bridge topologies, adopts shift power current control, can replace solid circuit breaker.This direct current DC-DC sectionalizer, aspect electrical isolation, the reliable disjunction of fault, power flow control electric pressures different from contact, with respect to traditional DC high-power solid circuit breaker, has significant superiority.

Summary of the invention

The purpose of this utility model is to provide a kind of direct current DC-DC sectionalizer, replaces solid circuit breaker, connects different DC buss, DC micro-electric net is formed cut apart, the power supply general layout of multi-joint network more.When system is normally moved, the random fluctuation of drawing power according to micro-source input power and load, control bus voltage regulation and power stream, while breaking down, carry out fast detecting and the isolated fault bus of fault.Direct current DC-DC sectionalizer can be optimized the protection and control of DC micro-electric net, i.e. the performance of the aspects such as the reliable disjunction of fault, electrical isolation, power flow control and the different electric pressures of contact.

Direct current DC-DC sectionalizer adopts two full-bridge topologies, full-bridge converter (1,2), high frequency transformer (3), resonant capacitance (4,5), consists of; The upper and lower side of four brachium pontis of each full-bridge converter (1,2) is connected respectively to together, is connected with both sides DC bus (6,7), and upper end bus is positive electrode bus, and lower end bus is negative pole bus; DC capacitor is connected between two ends positive electrode bus and negative pole bus according to electric capacity polarity; The output of full-bridge converter (1,2) is connected with secondary with the former limit of high frequency transformer (3) through resonant capacitance (5,6) respectively, as shown in Figure 1.Each full-bridge converter (1,2), forms by 4 branch roads containing IGBT device, and each IGBT device of route and backward diode, RC buffer circuit compose in parallel; Each brachium pontis of full-bridge inverter is in series up and down by two above-mentioned branch roads, and the tie point of two IGBT devices is brachium pontis output.

When system is normally moved, direct current DC-DC sectionalizer adopts full control phase shifting control strategy, and its turn-on and turn-off are controlled by master signal, realizes the adjusting of control to exchanging power between different electric pressure buses, active and passive busbar voltage.The DC bus 1 of take is example to DC bus 2 transferring energies, respectively the VT1 of H bridge, VT3 and VT2, VT4 being applied to pulsewidth is 50%, the driving signal of phase phasic difference α, the control signal of the VT5 of locking simultaneously, VT6, VT7, VT8, obtains driving voltage and output voltage waveforms as shown in Figure 2.

H bridge output voltage is:

$V_i=\left\{\begin{array}{cc}\mathrm{Vdc}& \mathrm{\θ}\∈(0,\mathrm{\π}-\mathrm{\α}]\\ 0& \mathrm{\θ}\∈(\mathrm{\π}-\mathrm{\α},\mathrm{\π}]\\ -\mathrm{Vdc}& \mathrm{\θ}\∈(\mathrm{\π},2\mathrm{\π}-\mathrm{\α}]\\ 0& \mathrm{\θ}\∈(\mathrm{\π},2\mathrm{\π}-\mathrm{\α}]\end{array}\right.$

Above formula is carried out to Fourier decomposition, and expansion is:

$V_i=\underset{k=1}{\overset{\∞}{\mathrm{\Σ}}}\frac{{4V}_{\mathrm{dc}}}{\mathrm{k\π}}\cos \left(\frac{\mathrm{k\α}}{2}\right)\sin (\mathrm{k\θ}+\frac{\mathrm{k\α}}{2}),\mathrm{\θ}=\mathrm{\ωt}-\frac{\mathrm{\α}}{2}$

Due to the effect of building-out capacitor, there is series resonance in former limit circuit at fundamental frequency place

$C_1=\frac{1}{{\mathrm{\ω}}^2{L}_{\mathrm{\σ}1}},C_2=\frac{1}{{\mathrm{\ω}}^2{L}_{\mathrm{\σ}2}}$

The high-order component of Voltage-output can be ignored, and H bridge output voltage is approximately fundametal compoment

$V_i=\frac{{4V}_{\mathrm{dc}}}{\mathrm{\π}}\cos \left(\frac{\mathrm{\α}}{2}\right)\sin \mathrm{\ωt}$

The no-load voltage ratio of transformer is N, and loss of voltage rate is η, V _s' be the value that the input voltage of secondary diode rectification is converted former limit

$\mathrm{\η}=\frac{{V_s}^{\′}}{V_i}$

The input current of H bridge is

$I_i=\frac{\mathrm{Vi}-{\mathrm{Vs}}^{\′}}{R_L+\mathrm{j\ω}{L}_L}=\frac{{4V}_{\mathrm{dc}}}{\mathrm{\π}}\·\frac{1-m}{R_L+\mathrm{j\ω}{L}_L}\·\cos \left(\frac{\mathrm{\α}}{2}\right)\sin \left(\mathrm{\ωt}\right)$

The power factor of diode rectifier circuit is cos φ=1, and the power of secondary input direct-current bus is all real component, obtains the meritorious expression formula about phase shifting angle α of input direct-current bus

$P_s=\cos \mathrm{\φ}\·I_{\mathrm{i\; rms}}{V_{\mathrm{s\; rms}}}^{\′}=\frac{{{8V}_{\mathrm{dc}}}^2}{{\mathrm{\π}}^2}\·\frac{m(1-m)}{\sqrt{{R_L}^2+{L_L}^2}}\·{\cos }^2\left(\frac{\mathrm{\α}}{2}\right)$

By above formula, found out by can reach the control to power stream to the control of phase shifting angle, can formulate power-voltage double-loop control strategy block diagram of direct current DC-DC sectionalizer as shown in the figure.DC bus 2 is during to DC bus 1 transferring energy, and the control signal of locking VT1, VT2, VT3, VT4, applies driving signal to VT5, VT6, VT7, VT8, and principle is identical.

When DC bus breaks down, the power conversion on direct current DC-DC sectionalizer both sides is ACTIVE CONTROL, can by 8 converter control pulse signals of locking, realize switching function, fast detecting and isolated fault bus.

The advantage of this utility model is: the control of direct current DC-DC sectionalizer is simple, at aspects such as DC micro-electric net electrical isolation, power flow control electric pressure buses different from contact, has embodied significant superiority; During fault, the fault bus of the micro-electrical network of isolated DC, reduces power failure range fast, improves system reliability.

Accompanying drawing explanation

Fig. 1 is direct current DC-DC sectionalizer topological diagram of the present utility model, and Fig. 2 is driving voltage and output voltage waveforms, and Fig. 3 is power-voltage double-loop control strategy block diagram of direct current DC-DC sectionalizer.

Embodiment

Direct current DC-DC sectionalizer connects two DC buss (6,7), adopts two full-bridge topologies, carries out AC coupled, as shown in Figure 1 by high frequency transformer (3).The former limit of direct current DC-DC sectionalizer and secondary respectively have four IGBT, each IGBT RC buffer circuit in parallel, be arranged in former limit and the secondary of high-frequency isolation transformer, have two conversion stages, guarantee to draw maximum transmission power point in bidirectional power flow commutation course.

When system is normally moved, direct current DC-DC sectionalizer adopts full control phase shifting control strategy, and its turn-on and turn-off are controlled by master signal, realizes the adjusting of control to exchanging power between different electric pressure buses, active and passive busbar voltage.The DC bus (6) of take is example to DC bus (7) transferring energy, respectively the VT1 of H bridge, VT3 and VT2, VT4 being applied to pulsewidth is 50%, the driving signal of phase phasic difference α, the control signal of the VT5 of locking simultaneously, VT6, VT7, VT8, obtains driving voltage and output voltage waveforms as shown in Figure 2.By can reach the control to power stream to the control of phase shifting angle, can formulate power-voltage double-loop control strategy block diagram of direct current DC-DC sectionalizer as shown in the figure.DC bus (7) is during to DC bus (6) transferring energy, and the control signal of locking VT1, VT2, VT3, VT4, applies driving signal to VT5, VT6, VT7, VT8, and principle is identical.

When DC bus breaks down, the power conversion on direct current DC-DC sectionalizer both sides is ACTIVE CONTROL, can by 8 converter control pulse signals of locking, realize switching function, fast detecting and isolated fault bus.

Claims (2)

1. the direct current DC-DC sectionalizer based on shift power current control, is characterized in that: full-bridge converter (1,2), high frequency transformer (3), resonant capacitance (4,5), consist of; The upper and lower side of four brachium pontis of each full-bridge converter (1,2) is connected respectively to together, is connected with both sides DC bus (6,7), and upper end bus is positive electrode bus, and lower end bus is negative pole bus; DC capacitor is connected between two ends positive electrode bus and negative pole bus according to electric capacity polarity;

The output of full-bridge converter (1,2) is connected with secondary with the former limit of high frequency transformer (3) through resonant capacitance (5,6) respectively.

2. direct current DC-DC sectionalizer according to claim 1, it is characterized in that: described each full-bridge converter (1,2), by 4 branch roads containing IGBT device, form, each IGBT device of route and backward diode, RC buffer circuit compose in parallel;

Each brachium pontis of full-bridge converter is in series up and down by 2 above-mentioned branch roads, and the tie point of two IGBT devices is brachium pontis output.