High-peak current isolation driving circuit

Abstract

The invention discloses a high-peak current isolation driving circuit, which comprises a transformer T1, a current limiting group, a clamping circuit and an anti-interference resistor Rn + 1, the clamping circuit comprises a voltage-regulator tube V1 and a voltage-regulator tube V2; each secondary winding corresponds to one current-limiting electric group, the 2n + 1 pin of the nth secondary winding is connected with one end of a current-limiting resistor Rn, and the other ends of the current-limiting resistors R1 to Rn are connected together and are connected to a driving output end g; the fourth pin of the first secondary winding is connected with the 2n + 2 pin ends of the other (n-1) secondary windings, and is connected to a driving output e end; the negative end of the voltage-regulator tube V1 is connected with the driving output end g, the negative end of the voltage-regulator tube V2 is connected with the driving output end e, and meanwhile, the positive ends of the voltage-regulator tube V1 and the voltage-regulator tube V2 are connected together; one end of the anti-interference resistor Rn + 1 is connected with the driving output end g, and the other end of the anti-interference resistor Rn + 1 is connected with the driving output end e. The device is small in size, high in reliability and low in cost.

Description

Technical Field

[0001] The invention relates to pulse power technology, in particular to a high peak current isolation drive circuit. Background Art

[0002] Ultra-high voltage pulse modulators are required in radar transmitters, high-energy physics equipment, high-power microwave weapons and other equipment, and the pulse output voltage can reach the order of tens of kilovolts to hundreds of kilovolts. At present, solid-state rigid tube modulators with transformer coupling topology are mostly used. This form of transformer has low primary voltage and large pulse peak current, and requires a large number of modulation components to be connected in parallel to achieve the purpose of use.

[0003] The modulation component uses high-voltage and high-current IGBT as the switch tube. The output pulse current of a single switch tube exceeds 1kA. Therefore, it is necessary to design a high-peak current isolation drive circuit to meet the drive requirements of this high-voltage and high-current IGBT. First, in order to reduce the leading edge of the pulse power loop, the drive circuit must be able to provide a sufficiently large gate drive current to ensure the turn-on speed of the IGBT; secondly, in high-power occasions, the operating environment is more complex and the interference is large, so the drive circuit must have good electrical isolation function and high reliability; thirdly, the modulation components are used in parallel, the number is large, the drive circuit must be simple, the lines are few, and the cost is low.

[0004] At present, the driver of high-voltage and high-current IGBT generally adopts integrated dedicated driver chip, which has integrated over-current and under-voltage protection and soft shutdown functions. However, it is large in size, expensive, and requires external power supply. The circuit is complex and not very versatile. Summary of the invention

[0005] In response to the problems existing in the prior art, the present invention provides a high peak current isolation drive circuit which is small in size, high in reliability and low in cost, serves as a connecting bridge between a control circuit and a power circuit, meets the use requirements of high-power occasions, and reduces the failure damage rate of high-voltage and high-current IGBTs.

[0006] The purpose of the present invention is achieved through the following technical solutions.

[0007] A high peak current isolation driving circuit, comprising:

[0008] A transformer T1, n current limiting resistors, a clamping circuit, and an anti-interference resistor Rn+1; the transformer T1 includes a primary winding and n secondary windings, and the winding directions of all secondary windings are consistent and the number of turns is the same; the transformer T1 is a step-down transformer, and the primary-to-secondary turns ratio is n:1; the clamping circuit includes two voltage regulator tubes V1 and V2; each secondary winding corresponds to a current limiting resistor, the 3rd pin of the first secondary winding is connected to one end of the current limiting resistor R1, the 5th pin of the second secondary winding is connected to one end of the current limiting resistor R2, and so on, the nth secondary winding is connected to the nth secondary winding. The 2n+1 pin is connected to one end of the current limiting resistor Rn, and the other end of the current limiting resistor R1 to Rn is connected together and connected to the drive output g end; the 4th pin of the first secondary winding is connected to the 2n+2 pins of the other (n-1) secondary windings and connected to the drive output e end; the negative end of the voltage regulator tube V1 is connected to the drive output g end, the negative end of the voltage regulator tube V2 is connected to the drive output e end, and the positive ends of the two voltage regulator tubes V1 and V2 are connected together; one end of the anti-interference resistor Rn+1 is connected to the drive output g end, and the other end is connected to the drive output e end, n≥2.

[0009] A transformer is used with one primary and n secondaries. The secondary winding of each transformer has the same number of turns and the same winding direction.

[0010] A step-down transformer is used with a primary to secondary turns ratio of n:1.

[0011] N secondary windings and n current limiting resistors are used, and each secondary corresponds to a current limiting resistor.

[0012] The odd-numbered ends of the secondary winding of the transformer are connected together after passing through a current-limiting resistor, and the even-numbered ends are directly connected in parallel.

[0013] A voltage regulator clamping circuit and an anti-interference resistor are used and connected to the g and e ends of the IGBT.

[0014] Compared with the prior art, the advantages of the present invention are:

[0015] 1. Transformer isolation transmission is adopted, all the circuits are passive devices, no auxiliary power supply is required, and the circuit is simple;

[0016] 2. The transformer step-down driving mode is adopted, with high primary voltage, small current and low secondary output voltage, which can provide a larger driving current and accelerate the IGBT opening front edge;

[0017] 3. The parallel output of multiple secondary windings reduces the loop inductance and can provide larger pulse current and faster pulse front edge;

[0018] 4. The transformer can easily achieve primary and secondary voltage isolation;

[0019] 5. Use one transformer, fewer components, small size and light weight;

[0020] 6. Simple design and manufacturing, convenient debugging and low cost;

[0021] 7. The transformer driving method has high reliability, can achieve a higher switching frequency, and does not have aging failure problems;

[0022] 8. The high peak current drive circuit has a small overall size and can be directly installed with the drive end of the IGBT, eliminating the connection between the two and saving installation space. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a circuit structure diagram of the present invention.

[0024] Figure 2 This is an installation structure diagram of the present invention. DETAILED DESCRIPTION

[0025] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0026] The high peak current isolation drive circuit includes a transformer T1, n (n≥2) current limiting resistors, a clamping circuit, and an anti-interference resistor Rn+1. Transformer T1 includes a primary winding, n (n≥2) secondary windings, and all secondary windings have the same winding direction and the same number of turns. Transformer T1 is a step-down transformer with a primary-to-secondary turns ratio of n (n≥2):1. The clamping circuit includes two voltage regulators V1 and V2. Each secondary winding corresponds to a current limiting resistor. The 3rd pin of the first secondary winding is connected to one end of the current limiting resistor R1, and the 5th pin of the second secondary winding is connected to one end of the current limiting resistor R2. By analogy, the 2n+1th pin of the nth secondary winding is connected to one end of the current limiting resistor Rn, and the current limiting resistors R1 to the other end of Rn are connected together and connected to the drive output g terminal. The 4th pin of the first secondary winding is connected to the 2n+2 pins of the other (n-1) secondary windings and connected to the drive output e terminal. The negative end of the voltage regulator tube V1 is connected to the drive output g end, the negative end of the voltage regulator tube V2 is connected to the drive output e end, and the positive ends of the two voltage regulator tubes V1 and V2 are connected together. One end of the anti-interference resistor Rn+1 is connected to the drive output g end, and the other end is connected to the drive output e end.

[0027] The following is combined with Figure 1 The present invention is further described.

[0028] The invention comprises a transformer T1, n (n≥2) current limiting resistors, a clamping circuit and an anti-interference resistor Rn+1.

[0029] The transformer has a primary winding, which is usually multiple turns, and n secondary windings, n≥2, which are usually multiple turns. All secondary windings have the same winding direction and the same number of turns. Transformer T1 is a step-down transformer, and the primary-secondary turns ratio is n (n≥2):1. The voltage regulator tubes V1 and V2 clamp the output voltage of the drive circuit to the operating voltage required by the IGBT, which is usually 15∽20V. The current limiting resistor Rn is a resistor ranging from several ohms to tens of ohms, and the anti-interference resistor is a resistor of several thousand ohms. The positive and negative pulse power signals output by the pulse trigger circuit are input to the primary winding, and positive and negative pulse waveforms with the same frequency and width are obtained on all secondary windings. After passing through the current limiting and clamping circuits, they are used to drive the IGBT.

[0030] Combination Figure 1 The present invention is a high peak current isolation drive circuit suitable for 1700V / 600A IGBT.

[0031] The high peak current isolation drive circuit includes a transformer, current limiting circuit, clamping circuit, anti-interference resistor, and connector. All of these are installed on a 75×60 printed circuit board. Figure 2 shown.

[0032] The transformer is designed as a primary winding and 6 secondary windings, with 18 primary turns and 3 secondary turns, and adopts a 6:1 step-down drive mode. The primary and secondary isolation is achieved by insulated wires and insulating films wrapped between the primary and secondary wires, and the insulation withstand voltage is ≥3000V. Each odd-numbered end of the secondary winding is connected to a current limiting resistor, with a total of 6 resistors, and the resistance of R1-6 is 10Ω. The other ends of R1-6 are connected in parallel and directly connected to the gate g of the IGBT through the pad hole of the printed circuit board with screws. The coupled ends of each secondary winding are connected in parallel and connected to the emitter e of the IGBT through the pad hole of the printed circuit board with screws. The two 20V voltage regulators V1 and V2 are connected in series to form a clamping circuit, so that the IGBT can obtain a suitable driving voltage. R7 is an anti-interference resistor, RJ14-5.1kΩ, and is connected between the gate and emitter of the IGBT to prevent parasitic interference and oscillation and avoid misleading IBGT conduction. Connector XS1 is connected to the primary of the transformer to facilitate installation and removal.

[0033] Working principle of high peak current isolation drive circuit: After receiving the timing signal and enable signal from the system, the external pulse trigger circuit starts to work and outputs positive and negative trigger pulses. The frequency and positive width of the pulse waveform are the same as the frequency width of the timing signal. The product of the width and amplitude of the negative pulse is basically equal to the product of the width and amplitude of the positive pulse to prevent transformer saturation. After transformer isolation and voltage reduction, positive and negative pulse waveforms with the same frequency and pulse width of about 25V are obtained. After being clamped by the current limiting resistor, voltage regulator tubes V1 and V2, the required drive waveform is provided for the IGBT.

[0034] The maximum output pulse width of the high peak current isolation drive circuit is determined by the size of the transformer core and the number of primary and secondary turns, and can be flexibly adjusted according to the required technical indicators. The output pulse front edge can reach dozens of ns, which greatly improves the IGBT turn-on speed, the trigger waveform is stable, not easily disturbed, and can work reliably for a long time in high-power and strong interference situations.

Claims

1. A high peak current isolation drive circuit, characterized in that include: A transformer T1, n current limiting resistors, a clamping circuit, and an anti-interference resistor Rn+1; The transformer T1 includes a primary winding and n secondary windings, all of which have the same winding direction and the same number of turns; the transformer T1 is a step-down transformer, and the primary-to-secondary turns ratio is n:1; the clamping circuit includes two voltage regulators V1 and V2; each secondary winding corresponds to a current limiting resistor, the 3rd pin of the first secondary winding is connected to one end of the current limiting resistor R1, the 5th pin of the second secondary winding is connected to one end of the current limiting resistor R2, and so on, the 2n+1th pin of the nth secondary winding is connected to one end of the current limiting resistor Rn , the other end of the current limiting resistor R1 to Rn is connected together and connected to the drive output g end; the 4th pin of the first secondary winding is connected to the 2n+2 pins of the other (n-1) secondary windings, and connected to the drive output e end; the negative end of the voltage regulator tube V1 is connected to the drive output g end, the negative end of the voltage regulator tube V2 is connected to the drive output e end, and the positive ends of the two voltage regulator tubes V1 and V2 are connected together; one end of the anti-interference resistor Rn+1 is connected to the drive output g end, and the other end is connected to the drive output e end, n≥2.

2. The high peak current isolation driving circuit according to claim 1, characterized in that: A transformer is used with one primary and n secondaries. The secondary winding of each transformer has the same number of turns and the same winding direction.

3. The high peak current isolation driving circuit according to claim 1, characterized in that: A step-down transformer is used with a primary to secondary turns ratio of n:

1.

4. The high peak current isolation driving circuit according to claim 1, characterized in that: N secondary windings and n current limiting resistors are used, and each secondary corresponds to a current limiting resistor.

5. The high peak current isolation driving circuit according to claim 1, characterized in that: The odd-numbered ends of the secondary winding of the transformer are connected together after passing through a current-limiting resistor, and the even-numbered ends are directly connected in parallel.

6. The high peak current isolation driving circuit according to claim 1, characterized in that: A voltage regulator clamping circuit and an anti-interference resistor are used and connected to the g and e ends of the IGBT.

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