CN104638948A - Controllable HFAC /DC (High Frequency Alternating Current/Direct Current) converter based on LCL-T resonant network - Google Patents

Abstract

The invention discloses a controllable HFAC /DC (High Frequency Alternating Current/Direct Current) converter based on an LCL-T resonant network. The controllable HFAC/DC converter comprises an LCL-T resonant network X, a voltage control unit Y and a rectifying bridge circuit Z which are connected in sequence, wherein the voltage control unit Y comprises a first switch tube S1, a second switch tube S2, a first diode VDs1 and a second diode VDs2; the first switch tube S1 and the second switch tube S2 are connected in series reversely; the drain electrode of the first switch tube S1 is connected with the anode of the first diode VDs1; the source electrode of the first switch tube S1 is connected with the cathode of the first diode VDs1; the drain electrode of the second switch tube S2 is connected with the cathode of the first diode VDs1; the source electrode of the first switch tube S1 is connected with the anode of the first diode VDs1. The controllable HFAC/DC converter has the advantages of simple principle, easiness in implementation and the like.

Description

Based on the controlled HFAC/DC converter of LCL-T resonant network

Technical field

The present invention relates to a kind of high-frequency ac distribution (HFAC PDS) technology, particularly a kind of controlled HFAC/DC converter based on LCL-T resonant network.

Background technology

High-frequency ac distribution (HFAC PDS) mode is compared with DC distribution (DC PDS) mode, there is voltage transitions convenience and power density advantages of higher, both can be applicable to small-power, the computer of short-distance transmission and communication equipment, can be applicable to again mid power, the electric automobile of long range propagation and micro-capacitance sensor field.HFAC/DC converter is responsible for effect high-frequency alternating current electricity being converted to direct current supply load.At present, often itself is not containing controlled means for conventional resonant cavity enhanced photodetector, and resonance rectifier is often responsive to input voltage fluctuation, be difficult to realize output voltage constant, or the realization of control program need calculate the zero crossing of resonance current, rather complicated, add the difficulty of application.The present invention is intended to the deficiency overcome in prior art, proposes a kind of controlled HFAC/DC converter based on LCL-T resonant network.

Summary of the invention

The object of the invention is to overcome the shortcoming of prior art and deficiency, a kind of controlled HFAC/DC converter based on LCL-T resonant network is provided, this controlled HFAC/DC converter is applicable to high-frequency ac field of power distribution, is applied particularly to and high-frequency alternating current potential source is converted to controlled VD.

Object of the present invention is achieved through the following technical solutions: a kind of controlled HFAC/DC converter based on LCL-T resonant network, comprising: the LCL-T resonant network X, voltage control unit Y and the rectifier circuit Z that connect successively; Described voltage control unit Y comprises the first switching tube S ₁with second switch pipe S ₂, the first diode VD _s1with the second diode VD _s2; Described first switching tube S ₁with second switch pipe S ₂differential concatenation, described first switching tube S ₁drain electrode and the first diode VD _s1positive pole connect; First switching tube S ₁source electrode and the first diode VD _s1negative electrode connect; Second switch pipe S ₂drain electrode and the first diode VD _s1negative electrode connect; First switching tube S ₁source electrode and the first diode VD _s1positive pole connect; First switching tube S ₁with second switch pipe S ₂shutoff angle be controlling angled a; Input is utilized to have the comparator of alternating-current voltage source and direct voltage to draw described first switching tube S ₁with second switch pipe S ₂break-make control signal, and by control first switching tube S ₁with second switch pipe S ₂break-make control the power output of described controlled HFAC/DC converter; For the adjustment realizing output voltage provides a kind of effective approach, and input power factor is high, and input current abnormality rate is low; Described first switching tube S ₁with second switch pipe S ₂drive singal compare generation by high-frequency input voltage source and adjustable dc voltage, its control circuit is simple, is easy to realize.

Described rectifier circuit Z is by the change regulation output voltage of pilot angle, and to compensate the impact that input voltage fluctuation causes, provide effective approach for realizing the constant of output voltage, the excursion of described pilot angle is 90 ° ~ 180 °.

The input current of described controlled HFAC/DC converter and input voltage same-phase.

Described LCL-T resonant network comprises the first inductance L ₁, the second inductance L ₂with resonant capacitance Cs.

Described rectifier circuit Z comprises the 3rd diode VD ₁, the 4th diode VD ₂, the 5th diode VD ₃, the 6th diode VD ₄with filter capacitor C ₀, described 3rd diode VD ₁with the 4th diode VD ₂positive pole be connected, the 5th diode VD ₃with the 6th diode VD ₄negative pole be connected; 3rd diode VD ₁negative pole and the 5th diode VD ₃positive pole be connected; 4th diode VD ₂negative pole and the 6th diode VD ₄positive pole be connected; 4th diode VD ₂negative pole and second switch pipe S ₂source electrode be connected; 3rd diode VD ₁negative pole and the first switching tube S ₁source electrode be connected.

Wherein, the first inductance L ₁with the second inductance L ₂there is resonance inputting under high-frequency ac voltage source frequency in inductance value equivalent inductive and electric capacity; Described voltage control unit Y is by the first switching tube S of two differential concatenations ₁with second switch pipe S ₂composition, described first switching tube S ₁drain electrode and the first diode VD _s1positive pole connect; First switching tube S ₁source electrode and the first diode VD _s1negative electrode connect; Second switch pipe S ₂drain electrode and the second diode VD _s2negative electrode connect; Second switch pipe S ₂source electrode and the second diode VD _s2positive pole connect; Described rectifying bridge unit Z is by the 3rd diode VD ₁, the 4th diode VD ₂, the 5th diode VD ₃, the 6th diode VD ₄with filter capacitor C ₀form; Described converter is by control first switching tube S ₁with second switch pipe S ₂break-make, can controls transfer to the watt level of load; The break-make control signal of described switching tube, compare acquisition by input high-frequency alternating current potential source with adjustable dc voltage, its principle is simple, easy to operate, is easy to realize.

The present invention has following advantage and effect relative to prior art:

(1) the present invention adopts LCL-T resonant network from power end to load end transmitted power, and LCL-T resonant network can realize converting high-frequency alternating current potential source to constant-current source, and current phase and amplitude be not with the impact connecing load after resonant network.

(2) the present invention employs voltage control unit after LCL-T resonant network, can the size of regulation output voltage by the angle of opening changing switching tube, realizing the controllability of output voltage, providing effective way for compensating input voltage fluctuation.

(3) control signal of the switching tube of voltage control unit of the present invention compares acquisition by input high-frequency alternating current potential source with adjustable dc voltage, and principle is simple, is easy to realize.

(4) input voltage of the present invention and the basic same-phase of input current, input power factor is high, and input current abnormality rate is low, and converter has excellent properties.

Accompanying drawing explanation

Fig. 1 is the structural representation of the controlled HFAC/DC converter based on LCL-T resonant network.

Fig. 2 is the drive signal generation circuit schematic diagram of the controlled HFAC/DC converter voltage control unit based on LCL-T resonant network.

Fig. 3 is the controlled HFAC/DC converter Vital Voltage current waveform figure based on LCL-T resonant network.

Fig. 4 is the equivalent circuit diagram based on Substitution Theoren and superposition theorem of the controlled HFAC/DC converter based on LCL-T resonant network.

Embodiment

Below in conjunction with embodiment and accompanying drawing, the present invention is described in further detail, but embodiments of the present invention are not limited thereto.

Embodiment

As shown in Figure 1, be the structural representation of the controlled HFAC/DC converter based on LCL-T resonant network; The described controlled HFAC/DC converter based on LCL-T resonant network is made up of LCL-T resonant network X, voltage control unit Y and rectifying bridge unit Z; LCL-T resonant network X is by the first inductance L ₁, the second inductance L ₂with resonant capacitance Cs, wherein there is resonance inputting under high-frequency ac voltage source frequency in inductance and electric capacity; Voltage control unit Y is by the first switching tube S of two differential concatenations ₁with second switch pipe S ₂composition, described first switching tube S ₁drain electrode and the first diode VD _s1positive pole connect; First switching tube S ₁source electrode and the first diode VD _s1negative electrode connect; Second switch pipe S ₂drain electrode and the second diode VD _s2negative electrode connect; Second switch pipe S ₂source electrode and the second diode VD _s2positive pole connect; Full-controlled rectifier bridge unit Z is by the 3rd diode VD ₁, the 4th diode VD ₂, the 5th diode VD ₃, the 6th diode VD ₄with filter capacitor C ₀form.Alternating-current voltage source becomes current source after LCL-T resonant network, by the angular dimension of the switching tube conducting in control voltage control unit Y, can change filter capacitor C ₀charge volume is how many, can change the value of output voltage.

Below in conjunction with mains voltage current waveform figure shown in the voltage control unit drive signal generation circuit schematic diagram shown in Fig. 2 and Fig. 3, operation principle of the present invention is described.As shown in Figure 2, input voltage source v _shalf-sinusoid is formed after rectification link | v _s|, will | v _s| with DC reference voltage V _refrelatively, voltage control unit first switching tube S is produced ₁with second switch pipe S ₂drive singal U _g, adopt analog circuit to realize, simple and convenient.With input voltage for example, according to the difference of circuit working state, one-period can divide following 6 stages:

Stage I: at t ₁-t ₂in time period, voltage control unit Y turns off, resonance current i _l2by the 4th diode VD ₂with the 5th diode VD ₃to filter capacitor C ₀charging, if ignore the impact of output voltage ripple, output voltage is fixed value U _o,then the voltage at voltage control unit Y two ends is v _o=-U _o.

Stage II: at t ₂-t ₃in time period, voltage control unit Y turns off, i _l2by the 3rd diode VD ₁with the 6th diode VD ₄to filter capacitor C ₀charging, then the voltage at voltage control unit Y two ends is v _o=U _o.

Stage III: at t ₃-t ₄in time period, voltage control unit Y conducting, i _l2flow through Y, then the voltage at voltage control unit Y two ends is v _o=0.

Stage IV: at t ₄-t ₅in time period, voltage control unit Y turns off, i _l2by the 3rd diode VD ₁with the 6th diode VD ₄to filter capacitor C ₀charging, then the voltage at voltage control unit Y two ends is v _o=U _o.

Stage V: at t ₅-t ₆in time period, voltage control unit Y turns off, i _l2by the 4th diode VD ₂with the 5th diode VD ₃to filter capacitor C ₀charging, the voltage at voltage control unit Y two ends is v _o=-U _o.

Stage VI: at t ₆-t ₇in time period, voltage control unit Y conducting, i _l2flow through Y, then the voltage at voltage control unit Y two ends is v _o=0.

V _owaveform be fundamental frequency be ω ₁regular waveform, the equivalent circuit diagram shown in Fig. 4 can be obtained by Substitution Theoren and superposition theorem.To voltage v _ocarry out Fourier analysis can obtain:

$\begin{array}{c}{v}_o=\underset{n=1}{\overset{\∞}{\mathrm{\Σ}}}\frac{4U_o}{\mathrm{n\π}}\·\sin \left(\frac{\mathrm{n\π}}{2}\right)\·\left\{\right[\cos \left(\frac{\mathrm{n\α}}{2}\right)-\cos \left(\mathrm{n\φ}\right)]\·\cos \left(n{\mathrm{\ω}}_{1}t\right)+\sin \left(\mathrm{n\φ}\right)\·\sin \left(n{\mathrm{\ω}}_{1}t\right)\}\\ =\underset{n=1}{\overset{\∞}{\mathrm{\Σ}}}\frac{4U_o}{\mathrm{n\π}}\·\sin \left(\frac{\mathrm{n\π}}{2}\right)\·\sqrt{A_n^2+B_n^2}\·\cos (n{\mathrm{\ω}}_{1}t-{\mathrm{\θ}}_n)\end{array},---\left(1\right)$

Wherein, A _n=cos (n α/2)-cos (n Φ), B _n=sin (n Φ), θ _n=arctan (B _n/ A _n), α is the charging angle in half period, setting i _reffor lagging behind voltage source v _s90 ° of waveforms, then Φ is i _l2zero crossing be ahead of i _refangle.The size of Φ is following zero of a function:

(b) (c) in Fig. 4 is analyzed separately and apply superposition theorem and obtains, input current i _l1for:

$i_{L_1}=\underset{n=1}{\overset{\∞}{\mathrm{\Σ}}}\frac{4U_o}{n(n^3-2n)\mathrm{\π}{X}_1}\·\sin \left(\frac{\mathrm{n\π}}{2}\right)\·\sqrt{A_n^2+B_n^2}\·\sin (n{\mathrm{\ω}}_{1}t-{\mathrm{\θ}}_n),---\left(2\right)$

Balanced can be obtained output voltage by output input power:

$U_o=\frac{2V_s{R}_o\·(\cos \mathrm{\φ}-\cos \frac{\mathrm{\α}}{2})}{\mathrm{\π}{X}_1},---\left(3\right)$

Further analysis can obtain input power factor expression formula and input current abnormality rate expression formula respectively as shown in following formula (4) (5):

$\mathrm{PF}=\frac{\cos \mathrm{\θ}}{\sqrt{1+{\mathrm{THD}}^2}},---\left(4\right)$

Wherein, $\mathrm{\θ}=\mathrm{\π}-\mathrm{\θ}1=\mathrm{\π}-\arctan (B1/A1)=\mathrm{\π}\arctan (B1/A1)=\mathrm{\π}-\arctan \frac{\sin \left(\mathrm{\Φ}\right)}{\cos (\mathrm{\α}/2)-\cos \left(\mathrm{\Φ}\right)},$

$\mathrm{THD}=\frac{\sqrt{\underset{n=2}{\overset{\∞}{\mathrm{\Σ}}}{\{\frac{4U_o}{\sqrt{2}\·n(n^3-2n)\mathrm{\π}{X}_1}\·\sin \left(\frac{\mathrm{n\π}}{2}\right)\·\sqrt{A_n^2+B_n^2}\}}^2}}{-\frac{4U_o}{\sqrt{2}\·\mathrm{\π}{X}_1}\·\sqrt{A_1^2+B_1^2}}\·100\%,---\left(5\right)$

When controlling angled a changes in the scope of 90 ° to 180 °, output voltage can change along with the change of control angle, for compensating the impact that input voltage fluctuation causes, realize the constant of output voltage and effective controlling soil moist is provided, and input power factor is close to 1, input current waveform aberration rate is low.

Above-described embodiment is the present invention's preferably execution mode; but embodiments of the present invention are not restricted to the described embodiments; change, the modification done under other any does not deviate from Spirit Essence of the present invention and principle, substitute, combine, simplify; all should be the substitute mode of equivalence, be included within protection scope of the present invention.

Claims (5)

1. based on a controlled HFAC/DC converter for LCL-T resonant network, it is characterized in that: comprise the LCL-T resonant network (X), voltage control unit (Y) and the rectifier circuit (Z) that connect successively; Described voltage control unit (Y) comprises the first switching tube (S ₁), second switch pipe (S ₂), the first diode (VD _s1) and the second diode (VD _s2);

Described first switching tube (S ₁) and second switch pipe (S ₂) differential concatenation, described first switching tube (S ₁) drain electrode and the first diode (VD _s1) positive pole connect; First switching tube (S ₁) source electrode and the first diode (VD _s1) negative electrode connect; Second switch pipe (S ₂) drain electrode and the first diode (VD _s1) negative electrode connect; First switching tube (S ₁) source electrode and the first diode (VD _s1) positive pole connect; First switching tube (S ₁) and second switch pipe (S ₂) shutoff angle be controlling angled a;

Input is utilized to have the comparator of alternating-current voltage source and direct voltage to draw described first switching tube (S ₁) and second switch pipe (S ₂) break-make control signal, and by control first switching tube (S ₁) and second switch pipe (S ₂) break-make control the power output of described controlled HFAC/DC converter.

2. the controlled HFAC/DC converter based on LCL-T resonant network according to claim 1, is characterized in that, described rectifier circuit (Z) is by the change regulation output voltage of pilot angle, and the excursion of described pilot angle is 90 ° ~ 180 °.

3. the controlled HFAC/DC converter based on LCL-T resonant network according to claim 1, is characterized in that, the input current of described controlled HFAC/DC converter and input voltage same-phase.

4. the controlled HFAC/DC converter based on LCL-T resonant network according to claim 1, it is characterized in that, described LCL-T resonant network (X) comprises the first inductance (L1), the second inductance (L2) and resonant capacitance (Cs).

5. the controlled HFAC/DC converter based on LCL-T resonant network according to claim 1, is characterized in that, described rectifier circuit (Z) comprises the 3rd diode (VD ₁), the 4th diode (VD ₂), the 5th diode (VD ₃), the 6th diode (VD ₄) and filter capacitor (C ₀), described 3rd diode (VD ₁) and the 4th diode (VD ₂) positive pole be connected, the 5th diode (VD ₃) and the 6th diode (VD ₄) negative pole be connected; 3rd diode (VD ₁) negative pole and the 5th diode (VD ₃) positive pole be connected; 4th diode (VD ₂) negative pole and the 6th diode (VD ₄) positive pole be connected; 4th diode (VD ₂) negative pole and second switch pipe (S ₂) source electrode be connected; 3rd diode (VD ₁) negative pole and the first switching tube (S ₁) source electrode be connected.