CN201300269Y

CN201300269Y - Electric spark pulse power supply

Info

Publication number: CN201300269Y
Application number: CNU2008202179209U
Authority: CN
Inventors: 仲兴荣; 胡丹峰; 刘家胜
Original assignee: Suzhou University
Current assignee: Suzhou University
Priority date: 2008-11-14
Filing date: 2008-11-14
Publication date: 2009-09-02
Anticipated expiration: 2018-11-14

Abstract

The utility model discloses an electric spark pulse power supply, which comprises a DC power supply circuit, a switch circuit, a power amplifying circuit and a pulse generating circuit, the pulse generating circuit is connected with the control terminal of the switching circuit through the power amplifying circuit, and is characterized in that: It includes a current-limiting transformer, the output end of the current-limiting transformer is connected to the input end of the DC power supply circuit, and the output end of the DC power supply circuit is directly connected to the machining electrode through a switch circuit to form a discharge machining circuit. The utility model generates a DC power supply through a current-limiting transformer, and the DC power supply is directly connected with a switch circuit, thereby improving the utilization rate of electric energy, processing quality and stability.

Description

A kind of spark pulse power

Technical field

The utility model relates to a kind of machining tool parts, is specifically related to a kind of spark pulse power that is used for machining tool.

Background technology

The pulse power is the critical component of electric spark machine tool.The effect of the pulse power that spark machined is used is the unidirectional pulse electric current that the industrial frequency AC current conversion is become certain frequency, comes ablation metal to supply with the discharging gap energy needed.The pulse power has very big influence to technical-economic indexes such as the stability of the production efficiency of spark machined, surface quality, process and tool electrode loss.

What spark machined generally adopted at present is resistance current limliting independent pulse generator, and this independent pulse generator mainly is made up of Industrial Frequency Transformer, current-limiting resistance, impulse generator, power amplification circuit, on-off circuit etc.Rectifying and wave-filtering becomes the DC voltage about 80～100V after adopting Industrial Frequency Transformer with 380V voltage transformation, adds to amplify that the rear drive power transistor is opened between by certain pulsewidth arteries and veins and disconnection makes on the discharging gap GAP and adds pulse voltage by the pulse of impulse generator through electric current man-hour.Can flow through pulse current i when the gap is breakdown, realize spark machined.There is following problem in this system: 1. the Industrial Frequency Transformer volume in the system is big, and efficient is low; 2. discharge in the major loop owing to limit electric current, prevent that overcurrent from burning out transistor on the one hand, can require to set the size of processing electric current on the other hand according to technological parameter with resistance R.But just because of the existence of this resistance, make that system to consume many electric energy that because the electric current that flows through when major loop is when being i, general discharge time, to keep voltage be about 20V in the crack, the energy that consumption is used to process at discharging gap is: P _GAP=20i (W) and consume at ohmically energy is: P _R=(U-20) i (W) is because U=is (so 80～100V) P _R=(60～80V) i (W), gross energy P=(80～100V) i (W) that consume, this shows that the energy that really is used to process only accounts for 20～25% of wastage in bulk or weight energy, and all the other energy of 75～80% are consumed in vain and become Joule heat and slattern on current-limiting resistance R, blow away this part heat but also will add one group of fan that cools off usefulness by force for this reason, increase by tens energy again to last hectowatt.

From the above, there is bigger deficiency in the pulse power that uses at present, and energy utilization rate is lower, and job stability is low, is not suitable for promoting the use of.

Summary of the invention

The utility model purpose provides a kind of spark pulse power, and the improvement by to structure has improved efficiency of energy utilization.

For achieving the above object, the technical solution adopted in the utility model is: a kind of spark pulse power, comprise DC power supply circuit, on-off circuit, power amplification circuit and pulse generating circuit, described pulse generating circuit is connected with the control end of on-off circuit through power amplification circuit, also comprise a current-limiting transformer, the output of current-limiting transformer is connected to the input of described DC power supply circuit, and the output of described DC power supply circuit directly connects and composes discharge processing loop through on-off circuit and machined electrode.

In the technique scheme, the output current of described current-limiting transformer is 10～30A, and power output is 1～3KW.

Above, DC power supply circuit alternating current that current-limiting transformer is provided is exported after by rectification and filtering.L, the N end of the alternating current input current-limiting transformer T1 of 220V, the alternating current of output 70V is through obtaining the DC voltage of 100V behind full-wave rectification B1 and filter capacitor C1, the C2.The dc source that this DC voltage is used as spark machined.Because self current-limiting protection function of current-limiting transformer, even under the situation of load short circuits, output current is limited under certain electric current.Simultaneously, current-limiting transformer has output voltage to be changed with the size of load current, and when load current increased, output voltage can diminish.Under the situation of load short circuits, the vanishing of current-limiting transformer output voltage meets the specific (special) requirements of spark machined to power supply.And previously used Industrial Frequency Transformer is output as a constant alternating voltage, and under the situation of load short circuits, if there is not current-limiting resistance, then transformer can damage.Simultaneously, current-limiting transformer has also played the effect of regulating machining voltage.So, can not use current-limiting resistance behind the use current-limiting transformer, thereby improve the efficient of power supply.

During work, it at first is the pulse signal that impulse generator produces high-frequency parameterization, carry out power amplification by power pushing circuit, thereby the break-make of control HF switch pipe, what the other end of HF switch pipe connected is dc source, and this direct current produces the electrical discharge pulse power source of high frequency through the break-make of switching tube.

Because the technique scheme utilization, the advantage that the utility model compared with prior art has is:

1, because the utility model replaces original Industrial Frequency Transformer by using current-limiting transformer, and removed current-limiting resistance, made dc source directly be connected, greatly improved the utilization rate of electric energy, improved crudy and stability with on-off circuit.

2, the utility model is simple in structure, and cheap for manufacturing cost, and is easy to operate, is fit to promote the use of.

Description of drawings

Accompanying drawing 1 is the circuit structure diagram of the utility model embodiment one;

Accompanying drawing 2 is the circuit structure diagram of dc source among the utility model embodiment one;

Accompanying drawing 3 is a pulse generating circuit structure chart among the utility model embodiment one;

Accompanying drawing 4 is a power amplification circuit structure chart among the utility model embodiment one;

Accompanying drawing 5 is an on-off circuit structure chart among the utility model embodiment one.

Wherein: 1, pulse generating circuit; 2, power amplification circuit; 3, on-off circuit; 4, DC power supply circuit; 5, current-limiting transformer; 6, machined electrode.

The specific embodiment

Below in conjunction with drawings and Examples the utility model is further described:

Embodiment one: shown in accompanying drawing 1 and accompanying drawing 2, a kind of spark pulse power, comprise a pulse generating circuit 1, described pulse generating circuit is connected with on-off circuit 3 through power amplification circuit 2, also comprise a direct current power circuit 4, the input of described DC power supply circuit 4 is connected with the output of current-limiting transformer 5, and the output of described DC power supply circuit 4 directly connects and composes discharge processing loop through on-off circuit 3 and machined electrode 6.Described current-limiting transformer output current is 10～30A, and power output is 1～3KW.

As shown in Figure 3, pulse generating circuit is made up of shake U2 and filter capacitor C3, C4, C5 etc. of extensive logic circuit chip EPM7032 (U1), toggle switch S1, exclusion RP1, clock.The 5V power supply enters the power input VCC of U1 after by capacitor C 3, C4, C5 filtering.The clock of 1MHz shakes and produces the clock signal of the clock signal of 1MHz frequency as U1, is the synchronizing signal of U1 work.1,2,3,4 retainings of toggle switch S1 are used as the pulsewidth time that is provided with, and 5,6,7,8 retainings are used for being provided with the time between arteries and veins.When toggle switch was in ON, the value that U1 reads in was 1, and when toggle switch was in OFF, the value that U1 reads in was 0.1,2,3,4 retainings of S1 can be used as 16 retaining pulsewidth times were set, and are respectively 10us, 20us, 30us, 40us, 50us, 60us, 70us, 80us, 90us, 100us, 110us, 120us, 130us, 140us, 150us, 160us.Wherein, the value of reading in is 0000 o'clock, and pulsewidth is 10us, and the value of reading in is 1111 o'clock, and pulsewidth is 160us.In like manner, 4,5,6,7 retainings of S1 can be used as the time between 16 retaining arteries and veins that is provided with, and are respectively 10us, 20us, 30us, 40us, 50us, 60us, 70us, 80us, 90us, 100us, 110us, 120us, 130us, 140us, 150us, 160us.The PW0 of the value input U1 of 1,2,3,4 retainings of S1, PW1, PW2, PW3, the PP0 of the value input U1 of 5,6,7,8 retainings of S1, PP1, PP2, PP3.U1 is according to the power requirement of the pulse power, and the 6 road identical pulse signals that S1 is provided with are pressed in output, is used for driving amplifying the gauge tap device.The generation of pulse be between the pulsewidth that is provided with according to S1 with VHDL language and arteries and veins the time produce, from the pin Pulse1 of U1, Pulse2, Pulse3, Pulse4, Pulse5, Pulse6 output.

In the present embodiment, the device for power switching of on-off circuit uses MOSFET pipe IRFP250.When the drive circuit of design MOSFET pipe, paired pulses drives signal certain requirement.Pulse drive signal must have certain current driving ability and very fast switching speed.Therefore, the pulse signal from the output of U1 pin can not must carry out certain amplification to the pulse signal of U1 pin output and could drive powerful MOSFET pipe directly as the driving signal of MOSFET pipe.Its drive circuit as shown in Figure 4.Drive circuit uses a slice to have 7 tunnel on all four Darlington pipe driving chip ULN2004A (Q1).Resistance R 1 is in the inside of Q1, and R2 draws driving resistance on being.Import 1 to 6 pin of Q1 respectively from the driving pulse Pulse1 of U1 output to Pulse6,16 to 11 pin of Q1 are connected to the driving signal DrivePulse1 of driving power 12V generation MOSFET pipe to DrivePulse6 by resistance R 2 to R7.This circuit charges by the input capacitance of 2 pairs of MOSFET pipes of resistance R, carries out repid discharge by Darlington transistor.Thereby carry out the MOSFET pipe quick conducting and by, reduce the conducting of MOSFET pipe and by power consumption.

Because this pulse power operating current reaches 20A, therefore use the MOSFET pipe design on-off circuit of 6 parallel connections, as shown in Figure 5.The MOSFET pipe Q2 of 6 parallel connections, Q3, Q3, Q4, Q5, Q6 gate drive signal are respectively pulse signal DrivePulse1, DrivePulse2, DrivePulse3, DrivePulse4, DrivePulse5 and the DrivePulse6 through amplifying among Fig. 4.MOSFET manages Q2, Q3, and Q3, Q4, Q5, the source S ground connection of Q6, drain D connects together and receives electrode, and workpiece is received the positive pole of the dc source that is obtained by Fig. 2.MOSFET pipe Q2 among Fig. 5, Q3, Q3, Q4, Q5, the grid of Q6 and the voltage-stabiliser tube D1 between the source electrode, D2, D3, D4, D5, D6 are in order to protect the MOSFET pipe breakdown with the grid source electrode that prevents it.Fast recovery diode D7 is in order to provide continuous current circuit under the situation of turn-offing at the MOSFET pipe, in order to reduce too high voltage change ratio, to avoid the MOSFET pipe to be damaged.

Claims

1. spark pulse power, comprise DC power supply circuit (4), on-off circuit (3), power amplification circuit (2) and pulse generating circuit (1), described pulse generating circuit (1) is connected through the control end of power amplification circuit (2) with on-off circuit (3), it is characterized in that: also comprise a current-limiting transformer (5), the output of current-limiting transformer (5) is connected to the input of described DC power supply circuit (4), and the output of described DC power supply circuit (4) directly connects and composes discharge processing loop through on-off circuit (3) and machined electrode (6).

2. a kind of spark pulse power according to claim 1 is characterized in that: the output current of described current-limiting transformer (5) is 10～30A, and power output is 1～3KW.