CN204559456U - A kind of PWM controls reactor - Google Patents

Abstract

A PWM control reactor, including a voltage source, a resistor R and an inductance L1 connected in parallel to each other in series, and a capacitor C connected to both ends of the voltage source, composed of insulated gate bipolar transistors IGBT1, IGBT2 and IGBT2 connected in reverse series The IGBT3 and IGBT4 are connected in series, the output terminals 1 of the first IBGT driving circuit and the second IBGT driving circuit are connected to IGBT1 and IGBT2 respectively, and the output terminals 2 of the third IBGT driving circuit and the fourth IBGT driving circuit are respectively connected to IGBT3 and IGBT4 . The utility model adopts the above scheme, the structural design is reasonable, the inductance parameters are adjusted by PWM control technology, the adjustment speed is fast, the adjustment range is large, the adjustment efficiency is greatly improved, and the effect of the reactor in actual operation is guaranteed; at the same time, its control strategy is simple. , strong controllability, simplifies the equipment structure, and reduces the equipment cost; the harmonic content is low in the process of inductance adjustment, which ensures the stability of the equipment.

Description

A PWM control reactor

technical field

The utility model relates to a PWM control reactor. the

Background technique

At present, most of the reactors are magnetically saturated reactors, and the speed of adjusting the inductance parameters is usually slow, and the general adjustment time is about 1s. In practical applications, the inductance parameters often need to be adjusted in real time according to the parameter changes of the system. The arc suppressing coil for small current grounding faults is automatically put into the device, and the inductance current needs to be put in in time according to the real-time detection situation, so the reactor with low efficiency adjustment is not effective; To increase the tuning range, it is necessary to use taps to select the tuning range, which leads to a very complicated equipment structure and greatly increases the equipment cost. The adjustment speed is reduced; in addition, the magnetic saturation reactor adjusts the inductance parameter by adjusting the conduction angle of the thyristor, so there is a problem of generating harmonics.

Utility model content

In order to make up for the deficiencies of the prior art, the utility model provides a PWM control reactor, which has a reasonable structural design, uses PWM control technology to adjust the inductance parameters, has a fast adjustment speed, a large adjustment range, greatly improves the adjustment efficiency, and ensures The effect of the reactor in actual operation is improved; at the same time, its control strategy is simple, the controllability is strong, the equipment structure is simplified, and the equipment cost is reduced; the harmonic content is low in the process of inductance adjustment, which ensures the stability of the equipment and solves the problem of Problems existing in the prior art.

The technical scheme that the utility model adopts for solving the problems of the technologies described above is:

A PWM control reactor, including a voltage source, a resistor R and an inductance L1 connected in parallel to each other in series, and a capacitor C connected to both ends of the voltage source, composed of insulated gate bipolar transistors IGBT1, IGBT2 in reverse series and reverse series The IGBT3 and IGBT4 are connected in series, the output terminals 1 of the first IBGT driving circuit and the second IBGT driving circuit are connected to IGBT1 and IGBT2 respectively, and the output terminals 2 of the third IBGT driving circuit and the fourth IBGT driving circuit are respectively connected to IGBT3 and IGBT4 The PWM control circuit is respectively connected with the first IBGT drive circuit, the second IBGT drive circuit, the third IBGT drive circuit and the fourth IBGT drive circuit, and a synchronous circuit is connected with the PWM control circuit and the main circuit respectively.

The first IBGT driver circuit, the second IBGT driver circuit, the third IBGT driver circuit and the fourth IBGT driver circuit all include a driver chip U4, the driver chip U4 is an IR21084 chip, and the No. 6 pin of the driver chip U4 is The output terminal 1 is connected to the gate of IGBT1 or IGT2, and the No. 7 pin is the output terminal 2, which is connected to the gate of IGBT3 or IGBT4; it also includes a photoelectric coupling chip U3, and the photoelectric coupling chip U3 is a 6N137 chip. The No. 2 pin of the coupling chip U3 is connected to the PWM control circuit through a resistor R1, its No. 6 pin is connected to the No. 2 pin and the No. 3 pin of the driver chip U4, and is respectively connected to the power supply Vcc through a resistor R2, A capacitor C2 is grounded, and a capacitor C1 is provided between the No. 8 pin and the No. 5 pin.

The utility model adopts the above scheme, the structure design is reasonable, the inductance parameters are adjusted by PWM control technology, the adjustment speed is fast, the adjustment range is large, the adjustment efficiency is greatly improved, and the effect of the reactor in actual operation is guaranteed; at the same time, its control strategy is simple , strong controllability, simplifies the equipment structure, and reduces the equipment cost; the harmonic content is low in the process of inductance adjustment, which ensures the stability of the equipment.

Description of drawings

Fig. 1 is the structural representation of the utility model.

Fig. 2 is a circuit diagram of the IBGT driving circuit of the present invention.

Fig. 3 is a schematic diagram of PWM1 and PWM2 waveforms of the present invention.

Detailed ways

In order to clearly illustrate the technical characteristics of the program, the utility model is described in detail below in conjunction with the accompanying drawings through specific embodiments.

As shown in Figure 1-3, a PWM control reactor includes a voltage source, a resistor R and an inductor L1 connected in parallel to each other in series and a capacitor C connected to both ends of the voltage source. Transistors IGBT1, IGBT2 are connected in series with IGBT3 and IGBT4 in reverse series, the output terminals 1 of the first IBGT driving circuit and the second IBGT driving circuit are respectively connected to IGBT1 and IGBT2, and the output of the third IBGT driving circuit and the fourth IBGT driving circuit Terminal 2 is connected to IGBT3 and IGBT4 respectively, the PWM control circuit is connected to the first IBGT drive circuit, the second IBGT drive circuit, the third IBGT drive circuit and the fourth IBGT drive circuit respectively, and a synchronous circuit is connected to the PWM control circuit and the main circuit respectively connected.

The first IBGT driver circuit, the second IBGT driver circuit, the third IBGT driver circuit and the fourth IBGT driver circuit all include a driver chip U4, the driver chip U4 is an IR21084 chip, and the No. 6 pin of the driver chip U4 is The output terminal 1 is connected to the gate of IGBT1 or IGT2, and the No. 7 pin is the output terminal 2, which is connected to the gate of IGBT3 or IGBT4; it also includes a photoelectric coupling chip U3, and the photoelectric coupling chip U3 is a 6N137 chip. The No. 2 pin of the coupling chip U3 is connected to the PWM control circuit through a resistor R1, its No. 6 pin is connected to the No. 2 pin and the No. 3 pin of the driver chip U4, and is respectively connected to the power supply Vcc through a resistor R2, A capacitor C2 is grounded, and a capacitor C1 is provided between the No. 8 pin and the No. 5 pin.

The 4th pin of the driver chip U4 is grounded through a resistor R3, the 5th pin is grounded, and connected to the power supply Vcc through a capacitor C3, and the 6th pin is connected to the power supply Vcc through a capacitor C4. A capacitor C5 is provided between the pin 13 and the pin 13, and the pin 13 is connected to the power supply Vcc through a diode D1.

By adjusting the resistance value of R3, the output dead time between output terminal 1 and output terminal 2 can be changed, and it is no longer necessary to use software to adjust the dead time; the photoelectric coupling chip U3 is used for electrical isolation, and the control is reliable and isolated The effect is good. Resistor R2 can avoid false conduction caused by spike noise. Capacitor C1 is a 0.1uf capacitor with good high-frequency characteristics, which can absorb the ripple on the power line and reduce the impact on the power supply when the receiving end of the photoelectric isolation chip U3 is switched. . Resistor R2 and capacitor C2 determine the faster response time of the circuit.

During operation, the IGBT1, IGBT2, IGBT3 and IGBT4 work together to realize the sense adjustment, and the PWM control circuit controls the IGBT drive circuit to output PWM waveforms, and the output terminal 1 and output terminal 2 of the IGBT drive circuit output PWM1 and PWM2 waveforms respectively. In the positive half cycle, that is, at time _t1 , PWM1 is at high level, and PWM2 is at low level. At this time, the switch tube of IGBT1 is in the open state, and IGBT2 cannot be turned on due to its own reverse voltage, and at the same time, IGBT3 and IGBT4 are in the off state. At this time, the current returns to the voltage source through the anti-parallel diodes of IGBT1 and IGBT2 and the reactor L2. In the negative half cycle of the system voltage, that is, at time _t2 , PWM1 is at low level and PWM2 is at high level. At this time, IGBT1 is in the off state. conduction, IGBT4 is in the conduction state, and the inductor current forms a freewheeling circuit through the antiparallel diode of IGBT3 and IGBT4. During the entire operation process, IGBT1 and IGBT2 are used as switching devices for whether the main circuit is on or not, while IGBT3 and IGBT4 are used as switching devices for anti-electrical freewheeling circuits.

During operation of a voltage cycle, the following formula can be derived:

t ₁ +t ₂ =t (1)

${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; L</span>}\frac{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}}{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; no</span>}}{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; \&Delta;i</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

If there is no filter element R, C, L1, only in the time t ₁ , there will be current in the main circuit, so it can be obtained from the formulas (1), (2) and (3), in the main circuit in the time t The average current in is:

$\mathrm{<span\; class="notranslate">\; \&rho;</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; \&Delta;t</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; t</span>}}$

$\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; L</span>}}\underset{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; no</span>}}{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

When △t→0

$\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; \&Integral;</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; d</span>}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

From the formula (5), it can be concluded that the adjustment of the duty cycle is the adjustment of ρ, which can be equivalent to adjusting the inductance. Therefore, when the duty cycle of the PWM waveform is adjusted, the adjustment of the equivalent inductance can be completed. adjust.

The PWM control reactor of the utility model is adopted to adjust the inductance parameters by using PWM control technology, the adjustment speed is fast, the adjustment range is large, the adjustment efficiency is greatly improved, and the effect of the reactor in actual operation is guaranteed; at the same time, its control strategy is simple, It has strong controllability, simplifies the equipment structure, and reduces the equipment cost; the harmonic content is low in the process of inductance adjustment, which ensures the stability of the equipment.

The parts of the utility model that are not described in detail are the known techniques of those skilled in the art.

Claims (2)

1. A kind of PWM control reactor, it is characterized in that: comprise a voltage source, the resistance R of mutual parallel connection and inductance L1 are connected in series with a capacitor C after the two ends of voltage source, by the insulated gate bipolar transistor IGBT1 of reverse series connection , IGBT2 and reverse-series IGBT3, IGBT4 are connected in series, the output terminals 1 of the first IBGT driving circuit and the second IBGT driving circuit are connected to IGBT1 and IGBT2 respectively, and the output terminals 2 of the third IBGT driving circuit and the fourth IBGT driving circuit They are respectively connected to IGBT3 and IGBT4, the PWM control circuit is respectively connected to the first IBGT drive circuit, the second IBGT drive circuit, the third IBGT drive circuit and the fourth IBGT drive circuit, and a synchronous circuit is respectively connected to the PWM control circuit and the main circuit. 2. A PWM control reactor according to claim 1, characterized in that: the first IBGT drive circuit, the second IBGT drive circuit, the third IBGT drive circuit and the fourth IBGT drive circuit each include a drive chip U4, the driver chip U4 is an IR21084 chip, the No. 6 pin of the driver chip U4 is the output terminal 1, which is connected to the gate of IGBT1 or IGT2, and the No. 7 pin is the output terminal 2, which is connected to the gate of IGBT3 or IGBT4 ; Also includes an optocoupler chip U3, the optocoupler chip U3 is a 6N137 chip, the No. 2 pin of the optocoupler chip U3 is connected to the PWM control circuit through a resistor R1, and its No. 6 pin is connected to No. 2 of the driver chip U4 The pin is connected to the No. 3 pin, and is respectively connected to the power supply Vcc through a resistor R2, and is set to be grounded through a capacitor C2. A capacitor C1 is provided between the No. 8 pin and the No. 5 pin.