CN106199167A - A kind of method of indirect detection inverter DC voltage - Google Patents

Abstract

A kind of method that the invention discloses indirect detection inverter DC voltage, during inverter power supply, constantly gathers virtual value U of inverter output voltage by power board₀₁, when adjusting modulation than m, the real time record modulation numerical value than m, by formula U_dc=K*U₀₁* m is calculated the DC voltage U of inverter_dc, wherein, K is conversion coefficient.The present invention can utilize power board constantly to gather virtual value U of inverter output voltage in inverter control system₀₁And real time record modulation compare m; carry out indirect detection DC voltage, thus eliminate DC voltage testing circuit link, reduce the cost of panel circuit; directly eliminate because electric circumstance is the most severe; variations in temperature etc., cause the interference of DC voltage sampled signal, enhance the protective capability of accumulator; can be widely applied to the product based on inversion function, such as the occasion such as UPS, photovoltaic DC-to-AC converter.

Description

A kind of method of indirect detection inverter DC voltage

Technical field

The invention belongs to electroporation field, relate to a kind of DC voltage detection method, specifically a kind of indirect detection is inverse The method of variable power source DC voltage.

Background technology

Inverter is that direct current energy (accumulator etc.) is transformed into alternating current (generally 220v50HZ sine or square wave).Logical Saying of custom, inverter is a kind of device that unidirectional current (DC) is converted into alternating current (AC).It is by inverter bridge, control logic and filter Wave circuit forms.

Inversion system is typically made up of inversion main frame, distribution system, charger and accumulator etc., the panel of inversion main frame By gathering emergent output voltage, electric current, set of cells, machine open/close signal message, and core is used to control interior kernel analysis information, The output carrying out inversion main frame again controls.

In inversion system power supply process, continue the electric energy of battery consumption.There is overdischarge in accumulator, is to cause accumulator Capacity declines main reason that is too fast and that shorten service life.Battery discharging is relatively big to internal resistance during final voltage, electrolyte Concentration is the thinnest, and particularly pole plate micropore and polar board surface is nearly at neutrality；During battery overdischarge because of internal resistance relatively greatly, have Heating tendency, expanding occurs in volume.When discharge current is bigger, can substantially generate heat, heating deformation, now lead sulfate even occur Concentration the biggest, it will crystallization formed larger particles, i.e. form irreversible sulfation.These crystalline solid poorly conductives, body Long-pending big, the micropore of pole plate can be blocked, hinder infiltration and the exchange of electrolyte, and internal resistance be will be further increased, time length just hinders Stopped the reversible transformation of electric energy and chemical energy, cause charging recovery capability very poor, accumulator is severely damaged, even without Method is repaired.So, in inversion power supply process, to constantly carry out the voltage detecting of accumulator, when finding storage battery under-voltage, and Time stop inverter output, protect accumulator.

The each functional unit of panel of inverter main frame, as it is shown in figure 1, during inverter power supply, power board Constantly gather the numerical value of inverter output voltage, electric current, and according to inverter output voltage, current sample numerical value, be analyzed fortune Calculate, by adjusting modulation degree m, then calculate the pulsewidth of modulating wave, adjust the time opened Yu end of power device, reach to control The stable purpose of inverter output voltage, it is ensured that emergency service meets the needs of load.

Meanwhile, constantly detect accumulator DC pressure by direct current sample circuit, when power board detects accumulator When DC voltage is less than protection voltage, stopping is exported by inverter, to reach to protect the purpose of accumulator.In order to reduce sampling Interference, general accumulator DC pressure sample circuit be designed as electrical isolation sample circuit, have use as shown in Figure 2 with Hall Sensor, as the sample circuit of isolating device, also has the sampling using light Rhizoma Nelumbinis G1, G2 as isolating device used as shown in Figure 3 Circuit.

Above sample circuit has two shortcomings:

1, accumulator DC pressure testing circuit, adds complexity and the cost of panel circuit.

2, the electric circumstance within electric power host is more severe, and variations in temperature etc. easily causes accumulator DC Pressure sampled signal interference, causes sampled signal distortion.

Summary of the invention

The present invention is directed to the deficiencies in the prior art, it is provided that a kind of method of indirect detection inverter DC voltage, take Disappear DC voltage testing circuit link, it is to avoid uses distorted signals, reduces the cost of panel circuit simultaneously.

The purpose of the present invention can be achieved through the following technical solutions:

A kind of method of indirect detection inverter DC voltage, comprises the following steps:

Step S1: during inverter power supply, constantly gathers the effective of inverter output voltage by power board Value U₀₁。

Step S2；During inverter power supply, when adjusting modulation than m, the real time record modulation numerical value than m；

Step S3, by formula U_dc=K*U₀₁* m is calculated the DC voltage U of inverter_dc, wherein, K is conversion system Number.

Beneficial effects of the present invention: the present invention can utilize power board constantly to adopt in inverter control system Virtual value U of collection inverter output voltage₀₁, and real time record modulation ratio m, carry out indirect detection DC voltage, thus eliminate DC voltage testing circuit link, reduces the cost of panel circuit, directly eliminates because electric circumstance is more severe, variations in temperature Deng, cause the interference of DC voltage sampled signal, enhance the protective capability of accumulator, can be widely applied to inversion function be The product on basis, such as the occasion such as UPS, photovoltaic DC-to-AC converter.

Accompanying drawing explanation

With specific embodiment, the present invention is described in further detail below in conjunction with the accompanying drawings.

Fig. 1 is inverter host control panel each functional unit schematic diagram.

Fig. 2 is the accumulator DC pressure sample circuit figure using Hall element as isolating device.

Fig. 3 is the accumulator DC pressure sample circuit figure using light Rhizoma Nelumbinis G1, G2 as isolating device.

Fig. 4 is the flow chart of the present invention.

Fig. 5 is SPWM waveform schematic diagram.

Detailed description of the invention

Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clear, complete Describe, it is clear that described embodiment is only a part of embodiment of the present invention rather than whole embodiments wholely.Based on Embodiment in the present invention, those of ordinary skill in the art obtained under not making creative work premise all other Embodiment, broadly falls into the scope of protection of the invention.

As shown in Figure 4, a kind of method that the invention provides indirect detection inverter DC voltage, including following step Rapid:

Step S1: during inverter power supply, constantly gathers the effective of inverter output voltage by power board Value U₀₁。

Step S2；During inverter power supply, when adjusting modulation than m, the real time record modulation numerical value than m.

Step S3, by formula U_dc=K*U₀₁* m is calculated the DC voltage U of inverter_dc, wherein, K is conversion system Number.

The principle of inversion is to control the opening and turning off of power device, and DC converting becomes equivalent with sine wave a series of The rectangular pulse waveform (SPWM waveform) that constant amplitude is the most wide, is then passed through filtering and boosting, becomes the exchange of only fundametal compoment Electric energy.

SPWM waveform schematic diagram is as it is shown in figure 5, wherein: U_cIt is carrier signal, U_cmIt is carrier amplitude, u_mIt is modulated signal, U_m It is modulated signal maximum amplitude, U₀It is SPWM output voltage, U_dcIt is DC voltage, u₀₁It it is the fundametal compoment of output voltage.

Modulated signal is represented by:

u_m=U_msinωt

Wherein: ω um angular frequency

Um um amplitude.

Modulation than m is:

$m=\frac{U_{01m}}{U_{dc}}$

Wherein: U_01mIt it is the maximum of the fundametal compoment of output voltage.

In the control of inverter output voltage, the general virtual value gathering inverter output voltage, i.e. output voltage Fundametal compoment virtual value U₀₁, above formula can become:

$m=\frac{\sqrt{2}{U}_{01}}{U_{dc}}$

The control principle of inverter output voltage: inverter control system gathers the output voltage of inverter, current values, It is analyzed computing, adjusts and modulate ratio m, then calculate the pulsewidth of modulating wave, adjust the time opened Yu end of power device, reach To the purpose controlling inverter output voltage.

Owing to modulation is than fundametal compoment virtual value U of m and output voltage₀₁It is to control the known quantity during calculating, so, DC voltage can calculate according to formula below:

U_dc=K*U₀₁*m

Wherein: K is conversion coefficient.

The present invention can utilize power board constantly to gather inverter output voltage in inverter control system Virtual value U₀₁, and real time record modulation ratio m, carry out indirect detection DC voltage, thus eliminate DC voltage testing circuit ring Joint, reduces the cost of panel circuit, directly eliminates because electric circumstance is more severe, and variations in temperature etc. causes DC voltage to adopt The interference of sample signal, enhances the protective capability of accumulator, can be widely applied to the product based on inversion function, as UPS, The occasions such as photovoltaic DC-to-AC converter.

In the description of this specification, the description of reference term " embodiment ", " example ", " concrete example " etc. means Specific features, structure, material or feature in conjunction with this embodiment or example description is contained at least one enforcement of the present invention In example or example.In this manual, the schematic representation to above-mentioned term is not necessarily referring to identical embodiment or example. And, the specific features of description, structure, material or feature can be to close in any one or more embodiments or example Suitable mode combines.

Above content is only to present configuration example and explanation, affiliated those skilled in the art couple Described specific embodiment makes various amendment or supplements or use similar mode to substitute, without departing from invention Structure or surmount scope defined in the claims, all should belong to protection scope of the present invention.

Claims (1)

1. the method for an indirect detection inverter DC voltage, it is characterised in that: comprise the following steps:

Step S1: during inverter power supply, constantly gathers virtual value U of inverter output voltage by power board₀₁；

Step S2；During inverter power supply, when adjusting modulation than m, the real time record modulation numerical value than m；

Step S3, by formula U_dc=K*U₀₁* m is calculated the DC voltage U of inverter_dc, wherein, K is conversion coefficient.