CN2886911Y - Variable-frequency speed regulator with harmonic suppression - Google Patents

Abstract

The utility model relates to a variable-frequency controller for restraining the generation of harmonic wave, comprising a rectification circuit (1), a filter circuit (2), an inversion circuit (3), and also including an AC reactor (9) serially connected with an input of power by, a half-controlled silicon rectifier model (7) parallel connected with the rectification circuit (1), a charging resistor (4) between the rectification circuit (1) and the half-controlled silicon rectifier model (7), a first resistance (R1) and a second resistance (R2) respectively connected with a first capacity (C1) and a second capacity (C2) of the filter circuit (2) by joining-up in parallel, a brake circuit (5) connected with the filter circuit (2) by joining-up in parallel, a DC reactor (10) between the filter circuit (2) and the brake circuit (5), an inversion absorption capacity (6) connected with the inversion circuit (3) by joining-up in parallel, and two Hall electronic elements (8) respectively positioned on the A line and C line by series connection. The variable-frequency controller can efficiently control harmonic wave, besides reduce the power output deviation ratio to +- 5%.

Description

Can suppress to produce the variable-frequency governor of harmonic wave

Technical field

The utility model relates to a kind of variable-frequency governor, relates in particular to a kind of variable-frequency governor that can suppress to produce harmonic wave.

Background technology

In industrial circles such as metallurgy, chemical industry, building, mine, use motor device widely.In recent years, because the needs of speed governing and energy-conservation aspect select for use the occasion of variable-frequency governor just more and more.

Fig. 1 is general variable-frequency governor main circuit operation principle: it is made up of rectification circuit 1, filter circuit 2, inverter circuit 3.Rectification circuit is to be made of uncontrollable rectifier diode module, and the direct voltage of rectification output is delivered to the inversion module IGBT of inverter circuit behind the capacitor filtering of filter circuit.Because diode rectifier circuit does not have switching function, the size of rectifier bridge output voltage depends on the amplitude of supply voltage.The net side power factor of diode rectifier should approach 1, but in fact because the intermediate dc loop adopts large capacitor to make filter, the input current of rectifier is the charging capacitor of capacitor, be comparatively precipitous impulse wave, its harmonic content is bigger, though its phasor power factor approaches 1, total power factor is less than 1.And the internal impedance of power supply can play cushioning effect, and the big more then input current harmonics of internal driving value content is more little.Relatively large when power supply capacity, source impedance hour will make harmonic content become big relatively.

For the frequency converter of bipolarity modulation, its output voltage waveforms expansion is:

$u_0\left(t\right)=\frac{{2E}_d}{\mathrm{n\π}}\underset{n=1}{\overset{\∞}{\mathrm{\Σ}}}[1+2\underset{i=1}{\overset{n/2}{\mathrm{\Σ}}}{(-1)}^i\cos \left({\mathrm{n\α}}_i\right)]\sin \left(\mathrm{n\ωt}\right)---\left(1\right)$

In the formula: the frequency n of n-harmonic wave=1,3,5

a _i-switching angle, i=1,2,3 ... N/2;

Ed-frequency converter dc voltage;

The N-carrier wave ratio.

By (1) formula as seen, the amplitude of every harmonic wave is

$u_n\left(t\right)=\frac{{2E}_d}{\mathrm{n\π}}\underset{n=1}{\overset{\∞}{\mathrm{\Σ}}}[1+2\underset{i=1}{\overset{n/2}{\mathrm{\Σ}}}{(-1)}^i\cos \left(n{\mathrm{\α}}_i\right)]---\left(2\right)$

Make n=1, the fundamental voltage amplitude that then draws frequency converter output voltage is:

$u_n\left(t\right)=\frac{{2E}_d}{\mathrm{\π}}\underset{n=1}{\overset{\∞}{\mathrm{\Σ}}}[1+2\underset{i=1}{\overset{n/2}{\mathrm{\Σ}}}{(-1)}^i\cos \left(n{\mathrm{\α}}_i\right)]---\left(3\right)$

From (1), (2), (3) formula as can be seen, contain other harmonic waves except that first-harmonic in the output voltage of universal frequency converter really.Bigger to the motor load influence usually than low-order harmonic, cause torque pulsation, and higher harmonic wave increases the leakage current of frequency converter output cable, makes the motor undercapacity, so the high low-order harmonic of frequency converter output must suppress.In order to address this problem, released a variety of methods that can suppress output harmonic wave on the market, as: two transformers increase the power-supply device internal impedance, adopt the RC filter circuit at power input, at the input mains side special filter is installed, at the input mains side Y-Δ, Δ-Δ combination being installed come filtering, regulate carrier wave ratio of frequency converter or the like by CPU.These methods, the investment costliness that has, what have is wayward, and last effect also all is not ideal.

Summary of the invention

The utility model technical issues that need to address have provided a kind of variable-frequency governor that can suppress to produce harmonic wave, are intended to solve above-mentioned defective.

In order to solve the problems of the technologies described above, the utility model is achieved through the following technical solutions:

The utility model comprises: rectification circuit, filter circuit, inverter circuit; Also comprise: an AC reactor that is connected in series with the input of power supply, one with rectification circuit and the half silicon controlled rectifier module that connects, charging resistor between rectification circuit and half silicon controlled rectifier module, two respectively with filter circuit in first electric capacity and second electric capacity and first resistance that connects and second resistance, one with filter circuit and the braking circuit that connects, direct current reactor between filter circuit and braking circuit, one absorbs electric capacity, two Hall components and parts that are serially connected in respectively on A and the C phase line with inverter circuit and the inversion that connects.

Compared with prior art, the beneficial effects of the utility model are: can effectively suppress harmonic wave, also make in addition power supply output bias rate drop to ± 5%.

Description of drawings

Fig. 1 is the main circuit schematic diagram of general variable-frequency governor;

Fig. 2 is a main circuit schematic diagram of the present utility model;

Fig. 3 is the utility model control system theory diagram;

Fig. 4 is that the electric current and voltage of input and output compares oscillogram;

Embodiment

Below in conjunction with accompanying drawing and embodiment the utility model is described in further detail:

As seen from Figure 2: the utility model comprises: rectification circuit 1, filter circuit 2, inverter circuit 3; Also comprise: an AC reactor 9 that is connected in series with the input of power supply, one with rectification circuit 1 and the half silicon controlled rectifier module 7 that connects, charging resistor 4 between rectification circuit 1 and half silicon controlled rectifier module 7, two respectively with filter circuit 2 in first capacitor C 1 and second capacitor C 2 and first resistance R 1 that connects and second resistance R 2, one with filter circuit 2 and the braking circuit 5 that connects, direct current reactor 10 between filter circuit 2 and braking circuit 5, one absorbs 6, two of electric capacity with inverter circuit 3 and the inversion that connects and is serially connected in Hall components and parts 8 on A and the C phase line respectively;

Described AC reactor 9 is made up of three first inductance L r1, the second inductance L r2, the 3rd inductance L r3, is serially connected in the input of power supply respectively;

Described half silicon controlled rectifier module 7 is by three and half silicon controlled rectifier modules and connect and form; Described the first half silicon controlled rectifier modules are made up of first controllable silicon VS1 and first diode VS2 polyphone; Described the second half silicon controlled rectifier modules are made up of second controllable silicon VS3 and second diode VS4 polyphone; Described the 3 half silicon controlled rectifier module is made up of the 3rd controllable silicon VS5 and the 3rd diode VS6 polyphone;

Described braking circuit 5 is contacted and is formed with an one pole type field effect transistor V7 (have input impedance is very high, noise is low, dynamic range is big, power consumption is little, cost is low and be easy to characteristics such as integrated) again by an external brake resistance Rb (its resistance, watt level need calculate selections according to the watt level of frequency converter) is in parallel with one the 4th diode D7.

Hall integrated circuit is a kind of magneto sensor that utilizes Hall effect work, because it is by Hall element and have electronic circuit to constitute one, so the title Hall integrated circuit.Element with Hall effect is called Hall element.After Hall effect refers to and adds orthogonal Control current I and magnetic field B to element, just can produce not only perpendicular to magnetic direction but also perpendicular to the induced voltage of the sense of current.When not having Control current or during not perpendicular to the magnetic field of the sense of current, just no-output voltage.We can say that Hall element has the ability that magnetic signal is converted to the signal of telecommunication.

As seen from Figure 3: the AC reactor of input serial connection at power supply increases the source impedance value, and the humorous content of electric current of input is reduced relatively.Afterwards, to filter capacitor C1, C2 in filter circuit charging, be the anti-excessive damage device of charging current, be connected in series a charging resistor at the anode of DC side and reduced charging current by rectification module.When the filter capacitor in the filter circuit is charged, in order to guarantee the balance of positive and negative both end voltage, at two filter capacitor two ends each and connect a power, first resistance R 1 and second resistance R 2 that resistance is the same.After C1, C2 charging finished, it provided working power for processor controls, and at this moment, processor can allow half silicon controlled rectifier module triggering and conducting according to outside input instruction, replaces the work of uncontrollable rectification module and charging resistor, realizes importing controlled.Afterwards, further eliminate the not intact direct current noise signal of filtering through direct current reactor again, provide direct-current working volts for the IGBT inverter module again, control the speed-sensitive switch of IGBT inversion module by the DSP microprocessor, make it be reverse into a controlled AC signal and export motor to, and the IGBT inversion module is when speed-sensitive switch, can produce a spike voltage voltage again, in order to eliminate the spike voltage signal, at the positive and negative two ends of each IGBT inversion module and connect an inversion that can absorb the spike voltage signal and absorb electric capacity.That the voltage and current signal that exports motor to when inversion takes place is under-voltage, when overvoltage, overcurrent; the last Hall components and parts that are serially connected in A, C two phase lines can detect immediately; and deliver to the DSP microprocessor and compare analyzing and processing, send corresponding error report and hard stop.When motor is being shut down or during braking; energy feeds back to DC side through inverter; voltage on the DC side filter capacitor is raise; when this value surpasses set point; triode in the braking circuit of this moment is owing to be subjected to the DSP microprocessor monitors; can apply base signal to triode automatically and make it conducting, the resistance in the braking circuit is in parallel with electric capacity, and the regenerated energy that then is stored in the electric capacity falls through this resistance consumption.

As seen from Figure 4: effect of the present utility model is quite obvious.

Claims (2)

1. the variable-frequency governor that can suppress to produce harmonic wave comprises: rectification circuit (1), filter circuit (2), inverter circuit (3); It is characterized in that also comprising: an AC reactor that is connected in series with the input of power supply (9), one with rectification circuit (1) and the half silicon controlled rectifier module (7) that connects, charging resistor (4) between rectification circuit (1) and half silicon controlled rectifier module (7), two respectively with filter circuit (2) in first electric capacity (C1) and second electric capacity (C2) and first resistance (R1) that connects and second resistance (R2), one with filter circuit (2) and the braking circuit (5) that connects, direct current reactor (10) between filter circuit (2) and braking circuit (5), one absorbs electric capacity (6), two Hall components and parts (8) that are serially connected in respectively on A and the C phase line with inverter circuit (3) and the inversion that connects.

2. the variable-frequency governor that can suppress to produce harmonic wave according to claim 1, it is characterized in that: described AC reactor (9) is made up of three first inductance (Lr1), second inductance (Lr2), the 3rd inductance (Lr3), is serially connected in the input of power supply respectively;

Described half silicon controlled rectifier module (7) is by three and half silicon controlled rectifier modules and connect and form; Described the first half silicon controlled rectifier modules are made up of first controllable silicon (VS1) and first diode (VS2) polyphone; Described the second half silicon controlled rectifier modules are made up of second controllable silicon (VS3) and second diode (VS4) polyphone; Described the 3 half silicon controlled rectifier module is made up of the 3rd controllable silicon (VS5) and the 3rd diode (VS6) polyphone;

Described braking circuit (5) is formed with an one pole type field effect transistor (V7) polyphone by an external brake resistance (Rb) is in parallel with one the 4th diode (D7) again.

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