CN105184028A - Design method for single-phase full-bridge power frequency inverter filter - Google Patents

Abstract

The invention discloses a design method for a single-phase full-bridge power frequency inverter filter. The design method includes the steps that 1, maximal allowable output voltage drop amount parameters in inverter design indexes are called out; 2, then the parameters are substituted into a filtering parameter formula to be calculated; 3, a single-phase full-bridge power frequency inverter is subjected to simulation run, THD of output voltage in a steady state and a load sudden change running state is captured; 4, the THD obtained in the step 3 is compared with the design index THD; 5, if the THD obtained in the step 3 is smaller than the design index THD, design is completed. Compared with the prior art, inverter load characteristic indexes can be directly achieved, the quantitative relation between filter parameters and inverter load characteristic parameters is clearly described, the experiment shows that load transient characteristic errors achieved by filtering parameters obtained through the method are smaller than 5%, and application and popularization value is achieved.

Description

A kind of single-phase full bridge power frequency inverter filtering device method for designing

Technical field

The present invention relates to a kind of circuit design method, particularly relate to a kind of single-phase full bridge power frequency inverter filtering device method for designing.

Background technology

Wave filter is the requisite device of power frequency inverter, and it and square wave inverter circuit form inverter, realizes filtering radio-frequency component and retains the object of low-frequency component, finally realizing low-frequency ac source.And the design of wave filter often Method of Spreading Design based on filtering theory.Existing digital filter design techniques cannot determine the quantitative relation of filter parameter and whole inverter load transient characteristic, because prior art is based on filtering theory, instead of based on inverter circuit load transient characteristic, therefore, need a kind of new method for designing to be born.

Summary of the invention

Object of the present invention is just to provide a kind of single-phase full bridge power frequency inverter filtering device method for designing to solve the problem.

The present invention is achieved through the following technical solutions above-mentioned purpose:

The present invention includes following steps:

(1) the maximum permission output voltage magnitude parameter in inverter design index is recalled;

(2) bring the parameter in step (1) into filtering parameter formula to calculate;

(3) simulation run single-phase full bridge power frequency inverter, catches the THD of output voltage in stable state and load changing running status;

(4) comparison step (3) gained THD and design objective THD;

(5) in step (4), the former is less than the latter, and design completes.

Particularly, described in described step (1), design objective transient state regulating time meets t _s=t _sim, t _simfor the maximum optimum load time, that is: t _sim=max{t _si=f (Δ i _o) | Δ i _o> 0}.

Filtering parameter formula in described step (2) is:

$L=\frac{U_{om}(E-U_{om})}{2P}{\left(1+\sqrt{\frac{2E}{E+U_{om}}}\right)}^{-1}{t}_s---\left(1\right)$

$C=\frac{U_{om}\left({\mathrm{\γU}}_{om}\±\sqrt{{\left({\mathrm{\γU}}_{om}\right)}^2-{(2{\mathrm{PR}}_C/U_{om})}^2}\right)}{2{\mathrm{PR}}_C^2}\·{\left(1+\sqrt{\frac{2E}{E+U_{om}}}\right)}^{-1}{t}_s---\left(2\right)$

Beneficial effect of the present invention is:

The present invention is a kind of single-phase full bridge power frequency inverter filtering device method for designing, compared with prior art, the present invention directly can realize inverter load characteristic index, and the clear quantitative relation describing filter parameter and inverter load characteristic parameter, experiment shows that the load transient characteristic error that the method gained filtering parameter realizes is less than 5%, has the value applied.

Accompanying drawing explanation

Fig. 1 is that sliding formwork of the present invention controls single-phase full bridge power frequency inverter experiment schematic diagram.

Embodiment

Below in conjunction with accompanying drawing, the invention will be further described:

As shown in Figure 1: the present invention includes following steps:

(1) the maximum permission output voltage magnitude parameter in inverter design index is recalled;

(2) bring the parameter in step (1) into filtering parameter formula to calculate;

(3) simulation run single-phase full bridge power frequency inverter, catches the THD of output voltage in stable state and load changing running status;

(4) comparison step (3) gained THD and design objective THD;

(5) in step (4), the former is less than the latter, and filter design completes.

Particularly, described in described step (1), design objective transient state regulating time meets t _s=t _sim, t _simfor the maximum optimum load time, that is: t _sim=max{t _si=f (Δ i _o) | Δ i _o> 0}.

Filtering parameter formula in described step (2) is:

$L=\frac{U_{om}(E-U_{om})}{2P}{\left(1+\sqrt{\frac{2E}{E+U_{om}}}\right)}^{-1}{t}_s---\left(1\right)$

$C=\frac{U_{om}\left({\mathrm{\γU}}_{om}\±\sqrt{{\left({\mathrm{\γU}}_{om}\right)}^2-{(2{\mathrm{PR}}_C/U_{om})}^2}\right)}{2{\mathrm{PR}}_C^2}\·{\left(1+\sqrt{\frac{2E}{E+U_{om}}}\right)}^{-1}{t}_s---\left(2\right)$

Wave filter according to this method design directly can realize inverter load characteristic index, and the clear quantitative relation describing filter parameter and inverter load characteristic parameter, experiment shows that the load transient characteristic error that the method gained filtering parameter realizes is less than 5% (when output voltage magnitude (overshoot) is lower than 5%).

Experimental data is as follows:

The optimum loading characteristic formula of table 1 and numerical simulation contrast

Wherein, ${\mathrm{\δ}}_i=\left|\frac{{\mathrm{\Δu}}_{oc}^{undershoot}-{\mathrm{\Δu}}_{os}^{undershoot}}{{\mathrm{\Δu}}_{os}^{undershoot}}\right|\·100,{\mathrm{\ξ}}_i=\left|\frac{t_{sic}-t_{sis}}{t_{sis}}\right|\·100.$

As shown in Table 1, when load current step load the output voltage caused fall rate be less than 5% time, the deviation ratio of output voltage magnitude is lower than 10% (9.665%), optimum load time deviation ratio lower than 10% (6.05%), optimal load characteristic formulae discovery result and simulation result substantially identical.As Δ i _oduring>=36A, output voltage magnitude is higher than 5% of crest voltage, and relatively large deviation appears in optimum loading characteristic formula.Otherwise, if the maximum magnitude of constraint output voltage, then can determine the load capability of inverter; If maximum load occur in zero load and fully loaded between, just can determine the power of inverter.

Table 2 optimum off-load characteristic formula and numerical simulation contrast

Wherein, ${\mathrm{\δ}}_d=\left|\frac{{\mathrm{\Δu}}_{oc}^{overshoot}-{\mathrm{\Δu}}_{os}^{overshoot}}{{\mathrm{\Δu}}_{os}^{overshoot}}\right|\·100,{\mathrm{\ξ}}_d=\left|\frac{t_{sdc}-t_{sds}}{t_{sds}}\right|\·100$

As shown in Table 2, the result of calculation of optimum off-load characteristic formula is almost consistent with the simulation experiment result, and deviation causes primarily of the factor such as proximate analysis, simulation accuracy.The data of summary analysis 1 and 2 are known, and transient state process is shorter, and optimum transient response formulae discovery result is more accurate; In table 2, optimum off-load transient response numerical value is always less than table 1, requires that the inverter performance one of design meets off-load requirement surely according to loading.

With major design index for condition, in conjunction with optimum loading characteristic design single-phase full bridge power frequency inverter filtering parameter C and L.Major design index is: (1) input voltage is E, output voltage amplitude Uom, frequency 50Hz; (2) inverter power P (W); (3) load regulation γ; (4) transient state regulating time t _s; (5) total harmonic distortion factor THD≤5%.

More than show and describe ultimate principle of the present invention and principal character and advantage of the present invention.The technician of the industry should understand; the present invention is not restricted to the described embodiments; what describe in above-described embodiment and instructions just illustrates principle of the present invention; without departing from the spirit and scope of the present invention; the present invention also has various changes and modifications, and these changes and improvements all fall in the claimed scope of the invention.Application claims protection domain is defined by appending claims and equivalent thereof.

Claims (3)

1. a single-phase full bridge power frequency inverter filtering device method for designing, is characterized in that, comprise the following steps:

(1) the maximum permission output voltage magnitude parameter in inverter design index is recalled;

(2) bring the parameter in step (1) into filtering parameter formula to calculate;

(3) simulation run single-phase full bridge power frequency inverter, catches the THD of output voltage in stable state and load changing running status;

(4) comparison step (3) gained THD and design objective THD;

(5) in step (4), the former is less than the latter, and design completes.

2. single-phase full bridge power frequency inverter filtering device method for designing according to claim 1, is characterized in that: described in described step (1), design objective transient state regulating time meets t _s=t _sim, t _simfor the optimum load time of maximum load, that is: t _sim=max{t _si=f (Δ i _o) | Δ i _o> 0}.

3. single-phase full bridge power frequency inverter filtering device method for designing according to claim 1, is characterized in that: the filtering parameter formula in described step (2) is:

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