CN211741472U - Portable direct current high voltage generator circuit - Google Patents
Portable direct current high voltage generator circuit Download PDFInfo
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- CN211741472U CN211741472U CN202020055614.0U CN202020055614U CN211741472U CN 211741472 U CN211741472 U CN 211741472U CN 202020055614 U CN202020055614 U CN 202020055614U CN 211741472 U CN211741472 U CN 211741472U
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Abstract
The utility model discloses a portable direct current high voltage generator circuit, which comprises a power frequency rectification circuit, a full-bridge voltage regulating circuit, a full-bridge inverter circuit, a high-frequency pulse transformer and a voltage doubling rectification circuit which are connected in sequence; aiming at the problem that the voltage-multiplying rectification circuit of the current direct-current high-voltage generator has more stages and causes larger voltage loss, the circuit structure is improved at the direct-current-direct-current converter circuit part, and a full-bridge circuit is used for voltage regulation and frequency conversion, so that the maximum value of the rectified voltage is output, and the effect of reducing the stages of voltage-multiplying rectification is achieved. In addition, aiming at the defects of large volume, heavy weight and the like of the traditional direct current high voltage generator, partial adjustment is carried out on the capacitance value of the voltage-doubling rectifying part, and the aims of saving cost and reducing circuit volume are achieved by reducing certain capacitance values which have little influence on output characteristics, so that the generator is more miniaturized and economical.
Description
Technical Field
The utility model belongs to the technical field of high voltage generator designs, concretely relates to portable direct current high voltage generator circuit.
Background
The dc high voltage generator is one of the main testing devices in the high voltage testing apparatus, and has a wide application in the high voltage testing, such as the dc withstand voltage test for lightning rod, power cable, power capacitor, motor stator winding, etc. with the development of the dc high voltage transmission project, more and more power devices need to perform various dc high voltage tests to ensure safety and reliability.
The conventional high voltage generator is generally installed in a laboratory or an outdoor test field, the whole set of equipment is heavy, and when the field test is carried out on electrical equipment of a power system, the current required by the high voltage generator is generally not large, usually in the order of milliamperes, but the generator is expected to be small and light so as to be convenient to transport and carry. The small portable direct-current high-voltage generator is developed, at present, a main power circuit part of the small direct-current high-voltage generator mainly adopts a switching power supply technology, the direct-current high-voltage generator is developed by adopting the switching power supply technology, the frequency of the device is set to be high, the size of the power supply device can be greatly reduced, and the direct-current withstand voltage test of outdoor power equipment becomes possible. However, the capacitance value of the capacitor is generally in direct proportion to the volume, and the capacitance value of the voltage-doubling rectifying circuit part of the conventional direct-current high-voltage generator is small, and the voltage withstanding value is very high, so that the volume of the voltage-doubling rectifying cylinder is large.
SUMMERY OF THE UTILITY MODEL
The aforesaid to prior art is not enough, the utility model provides a portable direct current high voltage generator circuit has solved the great and voltage doubler rectifier circuit progression of the volume of current high voltage generator circuit and more and the great problem of voltage loss that arouses.
In order to achieve the purpose of the invention, the utility model adopts the technical scheme that: a portable direct-current high-voltage generator circuit comprises a power frequency rectifying circuit, a full-bridge voltage regulating circuit, a full-bridge inverter circuit, a high-frequency pulse transformer and a voltage doubling rectifying circuit which are connected in sequence;
the full-bridge voltage regulating circuit comprises a field effect transistor S1 and a field effect transistor S2;
the drain electrode of the field effect transistor S1 and the source electrode of the field effect transistor S2 are used as the input end of the full-bridge voltage regulating circuit and are connected with the output end of the power frequency rectifying circuit;
the drain electrode of the field effect tube S1 is also connected with the drain electrode of the field effect tube S3, the source electrode of the field effect tube S2 is also connected with the source electrode of the super-effect tube S4, the source electrode of the field effect tube S1 and the drain electrode of the field effect tube S2 are both connected with one end of a primary winding of a transformer T1, and the source electrode of the field effect tube S3 and the drain electrode of the field effect tube S4 are both connected with the other end of the primary winding of the transformer T1;
one end of a secondary winding of the transformer T1 is respectively connected with the anode of a diode VD1 and the cathode of a diode VD2, the cathode of the diode VD1 is respectively connected with one end of an inductor L1 and the cathode of a diode VD3, the other end of the inductor L1 is respectively connected with the anode of a capacitor C1 and one end of a resistor R1, the anode of a diode VD2 is respectively connected with the anode of the diode VD4, the cathode of the capacitor C1 and the other end of the resistor R1, and the other end of the secondary winding of the transformer T1 is respectively connected with the anode of the diode VD3 and the cathode of the diode VD 4;
the output end of the resistor R1 serving as a full-bridge voltage regulating circuit is connected with the input end of the full-bridge inverter circuit, and the two ends of the resistor R1 output 0-300V direct-current voltage.
Further, the power frequency rectifying circuit is a single-phase uncontrollable rectifying circuit;
the single-phase uncontrollable rectifying circuit comprises a diode VD5 and a diode VD 6;
the anode of the diode VD5 is connected with the cathode of the diode VD6, the cathode of the diode VD5 is respectively connected with the cathode of the diode VD7, the anode of the capacitor C2 and one end of the resistor R2, the anode of the diode VD6 is respectively connected with the anode of the diode VD8, the cathode of the capacitor C2 and the other end of the resistor R2, and the anode of the diode VD7 is connected with the cathode of the diode VD 8;
the anode of the diode VD5 and the anode of the diode VD7 are used as input ends of a power frequency rectifying circuit and are connected with a 220V alternating current power supply;
two ends of the resistor R2 are used as the output end of the power frequency rectifying circuit and connected with the input end of the full-bridge voltage regulating circuit, and two ends of the resistor R2 output 300V direct-current voltage;
one end of the resistor R2 is used as a positive voltage input end of the full-bridge voltage regulating circuit, and the other end of the resistor R2 is used as a negative voltage input end of the full-bridge voltage regulating circuit.
Further, the full-bridge inverter circuit is an SPWM inverter circuit;
the SPWM inverter circuit inverts the 0-300V direct-current voltage output by the full-bridge voltage regulating circuit into 0-300V alternating-current voltage.
Further, the voltage-doubling rectifying circuit comprises a diode VD 9;
the anode of the diode VD9 is connected to the anode of the capacitor C5, the cathode of the capacitor C7 and one end of the resistor R3, the anode of the diode VD9 is connected to the anode of the diode VD10, the cathode of the capacitor C3 and the anode of the capacitor C4, the cathode of the capacitor C5 is connected to the cathode of the diode VD10, the anode of the diode VD11 and the anode of the capacitor C6, the cathode of the capacitor C6 is connected to one end of the resistor R4, the anode of the capacitor C7 is connected to the other end of the resistor R4 and one end of the resistor R5, the other end of the resistor R3 is connected to the other end of the resistor R5, the cathode of the diode VD11 is connected to the anode of the diode VD12 and the cathode of the capacitor C4, and the cathode of the diode VD12 is connected to one end of the resistor R4;
the anode of the diode VD9 and the anode of the capacitor C3 are used as input ends of a voltage-doubling rectifying circuit and are connected with a secondary winding of the high-frequency pulse transformer;
the cathode of the diode VD12 is used as the output end of the voltage doubling rectifying circuit to output 120kV voltage.
Further, in the full-bridge voltage regulating circuit, the fet S1, the fet S2, the fet S3 and the fet S4 are all power fets with the model number of IFRP 460;
the diode VD1, the diode VD2, the diode VD3 and the diode VD4 are all fast recovery rectifier diodes with the model number of FR607 and the element parameter of 1000V/6A;
the capacitor C1 is a 1000 muF/450V aluminum electrolytic capacitor.
The inductor is a patch inductor with L1 being 1.5 muH.
Further, in the power frequency rectifying circuit, the diode VD5, the diode VD6, the diode VD7 and the diode VD8 are all fast recovery rectifying diodes with the model number FR607 and the element parameter of 1000V/6A;
the capacitor C2 is a 1000 muF/450V aluminum electrolytic capacitor.
Further, the transformation ratio of the high-frequency pulse transformer is 1: 100.
In the voltage-doubling rectifying circuit, the capacitor C3, the capacitor C4, the capacitor C5 and the capacitor C6 are all CH82 type high-voltage sealed composite dielectric capacitors, C3 ═ C4 ═ 10 μ F, C5 ═ C6 ═ 1 μ F, and the voltage withstanding value of the capacitor C3 is equal to
The withstand voltage values of the capacitor C4, the capacitor C5 and the capacitor C6 are all
U4 is the output voltage of the secondary winding of the pulse boosting transformer;
the diode VD9, the diode VD10, the diode VD11 and the diode VD12 are all high-voltage rectifier silicon stacks 2CL100kV-200 mA;
the resistor R4 is a filter resistor with a value of 1 omega, and the capacitor C7 is a filter capacitor with a value of 8 multiplied by 10-6μF；
The resistor R5 is a high-voltage protection resistor, and the value of the resistor R5 is 0.9M omega;
the resistor R3 is a load resistor, the maximum output current of the resistor R3 is 2mA, and the value of the maximum output current is 60M omega.
The utility model has the advantages that: in the direct current voltage regulation part, a structure of a full bridge circuit is used, and compared with most of the existing direct current-direct current converter circuits, the direct current voltage regulation circuit applied to the direct current high-voltage generator has the advantages that:
(1) the full-bridge circuit is provided with an isolation transformer, and the transformer is excited bidirectionally, so that high power is easily achieved.
(2) The full-bridge circuit is twice higher than the maximum output voltage of the half-bridge circuit, so that the voltage-multiplying series required by the voltage-multiplying rectifying circuit of the last stage is twice less than that of the half-bridge circuit, the cost can be greatly reduced, and the problem of overlarge voltage loss caused by too many series can be solved.
(3) The capacitance values of the voltage-multiplying rectifying part are subjected to multiple simulation tests, so that the values of the capacitors in the voltage-multiplying circuit can be different, and the purposes of saving cost and reducing the circuit volume can be achieved by reducing certain values of the capacitors which have little influence on the output characteristics.
Drawings
Fig. 1 is the circuit structure diagram of the portable dc high voltage generator provided by the present invention.
Fig. 2 is the utility model provides a power frequency rectification circuit schematic diagram.
Fig. 3 is the schematic diagram of the full-bridge voltage regulating circuit provided by the utility model.
Fig. 4 is a schematic diagram of the voltage-doubling rectifying circuit provided by the present invention.
Fig. 5 is a waveform diagram of the output voltage and current of the dc high voltage generator provided by the present invention.
Detailed Description
The following description of the embodiments of the present invention is provided to facilitate the understanding of the present invention by those skilled in the art, but it should be understood that the present invention is not limited to the scope of the embodiments, and various changes will be apparent to those skilled in the art as long as they are within the spirit and scope of the present invention as defined and defined by the appended claims, and all inventions contemplated by the present invention are protected.
Example 1:
as shown in fig. 1, a portable dc high-voltage generator circuit includes a power frequency rectification circuit, a full-bridge voltage regulation circuit, a full-bridge inverter circuit, a high-frequency pulse transformer and a voltage-doubling rectification circuit, which are connected in sequence; the circuit structure forms a high-voltage direct current generator with the voltage grade of 120KV, wherein an input 220V alternating current voltage is rectified into a 300V direct current voltage by a power frequency rectification circuit, the 300V direct current voltage is continuously adjustable at 0-300V by a full-bridge voltage regulating circuit, the frequency is changed, the full-bridge inverter circuit inverts 0-300V, a high-frequency pulse transformer initially increases the voltage with the amplitude of 300V output by a front-stage circuit to 30000V, and then the voltage is increased to 120KV by a voltage doubling rectification circuit.
In the embodiment, the portable direct-current high-voltage generator aims at the problem that the voltage loss is caused by more stages of voltage-multiplying rectification circuits of the conventional direct-current high-voltage generator, the circuit structure is improved in the direct-current-direct-current converter circuit part, and a full-bridge circuit is used for voltage regulation and frequency conversion, so that the output voltage with the maximum rectification value is output, and the effect of reducing the stages of voltage-multiplying rectification is achieved. In addition, aiming at the defects of large volume, heavy weight and the like of the traditional direct current high voltage generator, the capacitance value of the voltage doubling rectifying part is partially adjusted, the aims of saving cost and reducing the circuit volume are achieved by reducing certain capacitance values which have little influence on the output characteristics, the generator is more miniaturized and economical, the circuit elements in the generator are subjected to detailed model selection, simulation is completed, and the finally obtained high-voltage direct current voltage ripple value, ripple factor and the like meet the requirements of the direct current high voltage generator in the power industry standard of the people's republic of China, so that the feasibility of the design is proved.
Example 2:
as shown in fig. 2, the power frequency rectification circuit in the above embodiment 1 is a simple single-phase uncontrollable rectification circuit with capacitor filtering, which is composed of a diode and a capacitor; specifically, the single-phase uncontrollable rectifying circuit comprises a diode VD5 and a diode VD 6;
the anode of the diode VD5 is connected with the cathode of the diode VD6, the cathode of the diode VD5 is respectively connected with the cathode of the diode VD7, the anode of the capacitor C2 and one end of the resistor R2, the anode of the diode VD6 is respectively connected with the anode of the diode VD8, the cathode of the capacitor C2 and the other end of the resistor R2, and the anode of the diode VD7 is connected with the cathode of the diode VD 8;
the anode of the diode VD5 and the anode of the diode VD7 are used as input ends of a power frequency rectifying circuit and are connected with a 220 alternating current power supply;
two ends of the resistor R2 are used as the output end of the power frequency rectifying circuit and connected with the input end of the full-bridge voltage regulating circuit, and two ends of the resistor R2 output 300V direct-current voltage;
one end of the resistor R2 is used as the positive voltage input end of the full-bridge voltage regulating circuit, and the other end of the resistor R2 is used as the negative voltage input end of the full-bridge voltage regulating circuit.
The parameter selection of the rectifier bridge in the power frequency rectification circuit is mainly based on the reverse withstand voltage value V of the diodeBRAnd a maximum rectified current IFConsidering 20% fluctuation of the mains supply, the reverse voltage withstanding value V of the diodeBRShould be greater than 1.2Umax＝1.2×310＝372V；
According to input power PinOn-state current I of diode is estimated as 600WF：
Considering enough safety margin, finally selecting a fast recovery rectifier diode with the model number of FR607 at 1000V/6A;
the selection of the capacitance of the filter capacitor C1 in fig. 2 can be calculated as follows:
wherein the power W provided by C in each cycleinIs composed of
A is the number of phases of the AC input, singlyTaking 1 and F as frequency; vlin(min)220V, the pulsating value V of the rectified and filtered direct current voltagepp＝Vlin(min)X (20% to 25%) (single-phase input), the capacitance C of the required capacitance can be calculated by the above formula to be 580 μ F, and the capacitance can be increased to 1000 μ F (generally, the larger the filter performance is, the better). Finally, 1000 muF/450V aluminum electrolytic capacitor is selected.
Example 3:
as shown in fig. 3, the full-bridge voltage regulating circuit in embodiment 1 realizes frequency conversion and voltage regulation; specifically, the full-bridge voltage regulating circuit comprises a field effect transistor S1 and a field effect transistor S2;
the drain electrode of the field effect transistor S1 and the source electrode of the field effect transistor S2 are used as the input end of the full-bridge voltage regulating circuit and are connected with the output end of the power frequency rectifying circuit;
the drain electrode of the field effect tube S1 is also connected with the drain electrode of the field effect tube S3, the source electrode of the field effect tube S2 is also connected with the source electrode of the super-effect tube S4, the source electrode of the field effect tube S1 and the drain electrode of the field effect tube S2 are both connected with one end of the primary winding of the transformer T1, and the source electrode of the field effect tube S3 and the drain electrode of the field effect tube S4 are both connected with the other end of the primary winding of the transformer T1;
one end of a secondary winding of the transformer T1 is connected with the anode of the diode VD1 and the cathode of the diode VD2 respectively, the cathode of the diode VD1 is connected with one end of the inductor L1 and the cathode of the diode VD3 respectively, the other end of the inductor L1 is connected with the anode of the capacitor C1 and one end of the resistor R1 respectively, the anode of the diode VD2 is connected with the anode of the diode VD4, the cathode of the capacitor C1 and the other end of the resistor R1 respectively, and the other end of the secondary winding of the transformer T1 is connected with the anode of the diode VD3 and the cathode of the diode VD4 respectively;
the two ends of the resistor R1 are used as the output end of the full-bridge voltage regulating circuit and connected with the input end of the full-bridge inverter circuit, and the two ends of the resistor R1 output 0-300V direct-current voltage.
In this embodiment, the operating frequency of the full-bridge inverter circuit is set to 40kHz, the full-bridge inverter circuit in fig. 3 is substantially a dc-ac-dc circuit of an electrical isolation transformer, and the inverter circuit in the full-bridge inverter circuit is composed of four switching tubes(field effect transistor S1-S4) for receiving the input DC voltage U2Inverting into 300V AC voltage, adding to one side of transformer T1, rectifying by isolation transformer T2 with 1:1 transformation ratio, and outputting DC voltage Ud by an LC filter circuit (composed of C1 and L1). Therefore, the average value of the rectified voltage Ud can be changed by changing the duty ratio of the switching tube so as to achieve the purpose of adjusting the final output voltage, and the output voltage and the input voltage of the full-bridge voltage regulating circuit have the following relations:
wherein, N1 and N2 represent the number of winding turns of the primary side and the secondary side of the transformer T1, respectively;
tonis the proportion of the switch that conducts during a cycle.
It can be seen that, under the condition of equivalent input voltage, the full-bridge voltage regulating circuit is higher than the output voltage of the half-bridge circuit
The voltage is doubled, and after the primary voltage boosting is carried out by the high-frequency pulse transformer, the number of voltage-doubling rectifying nodes required is reduced by one time. In order to avoid that the upper and lower switches in the half bridge at the same side are momentarily simultaneously conducted in the process of current conversion to damage the switches, the respective duty ratio of each switch cannot exceed 50% (controllable), and the switch tubes 2 and 3 delay the conduction time td＝1/40000/2＝1.25×10-5To obtain the maximum value U of the theoretical output of the full-bridge circuito＝2×0.5×300＝300V。
In the embodiment, when the full-bridge voltage regulating circuit performs parameter selection, the drain breakdown voltage U is generally considered in the selection of the field effect transistor (namely, the power switch tube MOSFET)DSDrain rated current IDAnd an on-resistance RDSThe three most important parameters.
(1) Selecting a pressure resistance:
in half-bridge and full-bridge topologies, the voltage born by the switch tube is input direct current voltage UiConsidering the turn-off period of the switching tube caused by leakage inductance in the circuitThe peak-to-peak prick (should be limited within 20% of a steady-state value) and the fluctuation influence of +/-10% of a power grid, and the voltage borne by a switching tube is 1.2 multiplied by 1.1-1.32UiWhen the switch tube is actually used, the standard can be reduced to 80% of the rated voltage of the switch tube in consideration of economy and convenience of model selection, and the voltage of the switch tube is 1.32Ui＝0.8UDS,UDS＝1.65×220＝513V。
(2) Rated current determination:
when the input power frequency voltage is rectified and filtered to obtain an input voltage of 300V, the amplitude of the pulse current is
There should be a margin in consideration of the effect of the reverse recovery time of the diode and the current spike, rush current, etc. generated by the turn-on and turn-off of the switch due to the load, so ICMTaking the following general:
for the design, the maximum output power is calculated according to 500W, and in the case of the maximum output power, the duty ratio of the switching tube is calculated according to 80 percent, then
Comprehensively considering parameters of voltage resistance and rated current, finally selecting a power field effect transistor IRFP460, wherein the specific parameters are as follows: u shapeDS＝500V，ID＝20A，RDS<0.27Ω。
The selection of the rectifier diodes (VD 1-VD 4) and the filter capacitor (C1) in the embodiment is the same as that of the power frequency rectification, and FR607 fast recovery diodes and 1000 muF/450V aluminum electrolytic capacitors are adopted.
Calculation of filter inductance L1 in this embodiment: in the full-bridge circuit, the inductor and the capacitor form a low-pass filter consisting of
Wherein f isrTo cut-off frequency, fr＝(1/10)fFrequency of operationWhen 40000/10-4000 HZ and C-1000 uf, L1-1.58 × 10-6H, finally selecting the patch inductor with the thickness of 1.5 muH.
Example 4:
the full-bridge inverter circuit in the embodiment 1 is an SPWM inverter circuit, the SPWM inverter circuit inverts a dc voltage of 0 to 300V output from the full-bridge voltage regulator circuit into a dc voltage of 0 to 300V, and sends the dc voltage to the high-frequency pulse transformer for preliminary boosting, and the actual frequency is 20kHz, because the frequency used for the whole device (especially the transformer) is portable (theoretically, the larger the frequency is, the smaller the device volume is); however, too high a frequency causes a drastic increase in the losses due to the distributed capacitance of the transformer and must therefore be limited to a reasonable range, 20kHz being the audible limit of the human ear, below which very strong noise is heard. The frequency of the inverter part and the transformer part is finally set to 20 kHz.
If the transformer is adopted to directly boost and then the direct current high voltage is output in a rectifier bridge rectification mode, the following problems can be caused:
1. the output performance is affected by the large leakage inductance and distributed capacitance caused by the transformer with large transformation ratio, and the insulation of the transformer is more difficult;
2. the design of a rectifier bridge with high withstand voltage requires a high withstand voltage value. Therefore, the existing direct-current high-voltage power supply adopts a two-stage boosting mode of a transformer and a voltage-multiplying circuit, and the output voltage can be boosted to be very high by adjusting the size of a capacitor and the voltage-multiplying stage number. From the above, after full-bridge inversion, an ac peak value of 300V is set, and in order to satisfy the output voltage of 120KV class in consideration of the fact that the voltage boosting is performed by matching with a voltage doubling rectifier circuit, the transformation ratio of the high-frequency pulse transformer is finally selected to be 1:100, that is, the maximum secondary voltage value should be 300 × 100 — 30000V, and the voltage doubling rectifier circuit is two-stage voltage doubling, generates 4 times of dc voltage, and the theoretical final voltage will reach 120 KV.
Example 5:
as shown in fig. 4, the voltage-doubler rectifier circuit in the above embodiment 1 is a two-stage series voltage-doubler rectifier circuit; specifically, the voltage-doubler rectification circuit includes a diode VD 9;
the anode of the diode VD9 is connected to the anode of the capacitor C5, the cathode of the capacitor C7 and one end of the resistor R3, the anode of the diode VD9 is connected to the anode of the diode VD10, the cathode of the capacitor C3 and the anode of the capacitor C4, the cathode of the capacitor C5 is connected to the cathode of the diode VD10, the anode of the diode VD11 and the anode of the capacitor C6, the cathode of the capacitor C6 is connected to one end of the resistor R4, the anode of the capacitor C7 is connected to the other end of the resistor R4 and one end of the resistor R5, the other end of the resistor R3 is connected to the other end of the resistor R5, the cathode of the diode VD11 is connected to the anode of the diode VD12 and the cathode of the capacitor C4, and the cathode of the diode VD12 is connected to one end of the resistor R4;
the anode of the diode VD9 and the anode of the capacitor C3 are used as input ends of a voltage-doubling rectifying circuit and are connected with two secondary windings of the high-frequency pulse transformer;
the cathode of the diode VD12 is used as the output end of the voltage doubling rectifying circuit to output 120kV voltage.
The basic principle of the voltage-doubling rectifying circuit in the embodiment is as follows: when the input voltage is negative half wave, VD9 is conducted, C3 is charged to Um, when the input voltage is positive half wave, VD10 is conducted, the voltage of the transformer T2 is superposed with the voltage on the capacitor C3, C5 is discharged through VD9, the voltage on C5 can be raised to 2Um, the point A obtains stable potential +2Um, the voltage is added to C4 through VD11, therefore, C4 is charged to +2Um, the capacitor C6 is charged to +4Um through VD12, and the point B obtains stable potential +4 Um.
A first-stage RC filter circuit (composed of a resistor R3 and a capacitor C7) is connected to the output point B, the RC filter circuit is generally used in the situation that load current is small, the resistor R plays a role in limiting current in the circuit, and the capacitor C plays a role in smoothing filtering. Finally, a protection resistor R5 and a load resistor R3 (generally dozens of megaohms) are connected to obtain the final 120KV high-voltage direct current waveform.
The element parameter determination process in this embodiment is:
according to a voltage ripple coefficient calculation formula:
the output ripple coefficient S of the direct current high voltage generator is less than 1%, so that the calculation formula for calculating the values of the voltage-multiplying capacitors (C3-C6) is as follows:
thereby obtaining a voltage-multiplying capacitance value of 15 muF;
regarding the selection of the capacitance value of the voltage-doubling circuit, since the volume of the conventional voltage-doubling rectifier is relatively large, especially in the case that the capacitance value of the capacitor is small and the withstand voltage value is quite high, the volume of the capacitor is inevitably made large, and the withstand voltage value of the capacitor cannot be reduced. If the size is to be reduced, the capacitance value which has little influence on the output voltage characteristic can be reduced to achieve the purposes of saving the cost and reducing the circuit size. And if each capacitor can have different influences on the voltage doubling circuit, multiple simulation test tests are carried out on the design, and the conclusion that each capacitor can not have the same influence on the output voltage is obtained. If the capacitance with small influence on output is smaller, and the capacitance with large influence on output is larger, the cost can be saved on the premise of ensuring that the output is not greatly influenced, and the circuit volume is reduced. The internal resistance of the voltage doubling circuit is mainly caused by the capacitive reactance of C3/C4, and the higher the level number is, the larger the internal resistance is. In the design, the capacitors C3 and C4 have large influence on the output amplitude and the ripple value, that is, the overall characteristics of the output waveform are not influenced by setting the capacitors C5 and C6 to be small, but the effects of reducing the volume and the cost can be achieved. According to the analysis, the model on the market is considered, and the CH82 type high-voltage sealed composite dielectric capacitor is finally selected, wherein the rated voltage is 100 kV; nominal capacitance range: 0.01-10 muF, high voltage resistance, high insulation resistance and other electrical properties, and C3-C4-10 muF and C5-C6-1 muF are selected.
According to the principle of the voltage doubling circuit, except that the capacitor C3 has a withstand voltage of
Besides, the withstand voltages of other capacitors are all
In the voltage-doubling rectifying circuit, the diode bears when it is cut off
The highest required withstand voltage of the diode and the capacitor is 84.8kV as well as the capacitor.
The maximum value of the current passing through the diode is the maximum value of the secondary current of the transformer, and the secondary current of the pulse boosting transformer is 1/n times of the primary current, namely
And finally selecting the high-voltage silicon rectifier stack 2CL100kV-200mA by considering a certain margin.
The RC filter circuit: according to RC filter formula
Taking R as 1 omega, the calculated value of the capacitance filter C7 is C7 as 8 multiplied by 10-6μF；
The high-voltage protection resistor R5 in this embodiment is 0.9M Ω.
And finally, a load resistor R3 is connected behind the RC filter circuit, the maximum output current is 2mA, and the pure resistive load can be calculated to be 60M omega under the condition that the maximum output voltage is 120 kV.
Example 6:
as shown in fig. 5, the voltage and current waveforms outputted by the circuit of the dc high voltage generator of the present invention are shown under the above circuit structure and the selection of the parameters of the components; as can be seen from fig. 5, the hvth generator composed of the above parts can perfectly output the maximum voltage of 120KV, at this time the maximum current is 2mA, the calculated rated power is 240W, which all meet the theoretical requirements of design. The ripple voltage value is approximately equal to 1000V, and the ripple factor
Compliance with the relevant standard DL/T848 "ripple factor of high voltage dc generator should be below 1%";
the utility model has the advantages that: in the direct current voltage regulation part, a structure of a full bridge circuit is used, and compared with most of the existing direct current-direct current converter circuits, the direct current voltage regulation circuit applied to the direct current high-voltage generator has the advantages that:
(1) the full-bridge circuit is provided with an isolation transformer, and the transformer is excited bidirectionally, so that high power is easily achieved.
(2) The full-bridge circuit is twice higher than the maximum output voltage of the half-bridge circuit, so that the voltage-multiplying series required by the voltage-multiplying rectifying circuit of the last stage is twice less than that of the half-bridge circuit, the cost can be greatly reduced, and the problem of overlarge voltage loss caused by too many series can be solved.
(3) The capacitance values of the voltage-multiplying rectifying part are subjected to multiple simulation tests, so that the values of the capacitors in the voltage-multiplying circuit can be different, and the purposes of saving cost and reducing the circuit volume can be achieved by reducing certain values of the capacitors which have little influence on the output characteristics.
Claims (8)
1. A portable direct-current high-voltage generator circuit is characterized by comprising a power frequency rectifying circuit, a full-bridge voltage regulating circuit, a full-bridge inverter circuit, a high-frequency pulse transformer and a voltage doubling rectifying circuit which are sequentially connected;
the full-bridge voltage regulating circuit comprises a field effect transistor S1 and a field effect transistor S2;
the drain electrode of the field effect transistor S1 and the source electrode of the field effect transistor S2 are used as the input end of the full-bridge voltage regulating circuit and are connected with the output end of the power frequency rectifying circuit;
the drain electrode of the field effect tube S1 is also connected with the drain electrode of the field effect tube S3, the source electrode of the field effect tube S2 is also connected with the source electrode of the super-effect tube S4, the source electrode of the field effect tube S1 and the drain electrode of the field effect tube S2 are both connected with one end of a primary winding of a transformer T1, and the source electrode of the field effect tube S3 and the drain electrode of the field effect tube S4 are both connected with the other end of the primary winding of the transformer T1;
one end of a secondary winding of the transformer T1 is respectively connected with the anode of a diode VD1 and the cathode of a diode VD2, the cathode of the diode VD1 is respectively connected with one end of an inductor L1 and the cathode of a diode VD3, the other end of the inductor L1 is respectively connected with the anode of a capacitor C1 and one end of a resistor R1, the anode of a diode VD2 is respectively connected with the anode of the diode VD4, the cathode of the capacitor C1 and the other end of the resistor R1, and the other end of the secondary winding of the transformer T1 is respectively connected with the anode of the diode VD3 and the cathode of the diode VD 4;
the output end of the resistor R1 serving as a full-bridge voltage regulating circuit is connected with the input end of the full-bridge inverter circuit, and the two ends of the resistor R1 output 0-300V direct-current voltage.
2. The portable direct current high voltage generator circuit according to claim 1, wherein the power frequency rectification circuit is a single-phase uncontrollable rectification circuit;
the single-phase uncontrollable rectifying circuit comprises a diode VD5 and a diode VD 6;
the anode of the diode VD5 is connected with the cathode of the diode VD6, the cathode of the diode VD5 is respectively connected with the cathode of the diode VD7, the anode of the capacitor C2 and one end of the resistor R2, the anode of the diode VD6 is respectively connected with the anode of the diode VD8, the cathode of the capacitor C2 and the other end of the resistor R2, and the anode of the diode VD7 is connected with the cathode of the diode VD 8;
the anode of the diode VD5 and the anode of the diode VD7 are used as input ends of a power frequency rectifying circuit and are connected with a 220V alternating current power supply;
two ends of the resistor R2 are used as the output end of the power frequency rectifying circuit and connected with the input end of the full-bridge voltage regulating circuit, and two ends of the resistor R2 output 300V direct-current voltage;
one end of the resistor R2 is used as a positive voltage input end of the full-bridge voltage regulating circuit, and the other end of the resistor R2 is used as a negative voltage input end of the full-bridge voltage regulating circuit.
3. The portable direct current high voltage generator circuit according to claim 1, wherein the full bridge inverter circuit is an SPWM inverter circuit;
the SPWM inverter circuit inverts the 0-300V direct-current voltage output by the full-bridge voltage regulating circuit into 0-300V alternating-current voltage.
4. The portable direct current high voltage generator circuit according to claim 3, wherein the voltage doubling rectifying circuit comprises a diode VD 9;
the anode of the diode VD9 is connected to the anode of the capacitor C5, the cathode of the capacitor C7 and one end of the resistor R3, the anode of the diode VD9 is connected to the anode of the diode VD10, the cathode of the capacitor C3 and the anode of the capacitor C4, the cathode of the capacitor C5 is connected to the cathode of the diode VD10, the anode of the diode VD11 and the anode of the capacitor C6, the cathode of the capacitor C6 is connected to one end of the resistor R4, the anode of the capacitor C7 is connected to the other end of the resistor R4 and one end of the resistor R5, the other end of the resistor R3 is connected to the other end of the resistor R5, the cathode of the diode VD11 is connected to the anode of the diode VD12 and the cathode of the capacitor C4, and the cathode of the diode VD12 is connected to one end of the resistor R4;
the anode of the diode VD9 and the anode of the capacitor C3 are used as input ends of a voltage-doubling rectifying circuit and are connected with a secondary winding of the high-frequency pulse transformer;
the cathode of the diode VD12 is used as the output end of the voltage doubling rectifying circuit to output 120kV voltage.
5. The portable direct current high voltage generator circuit according to claim 1, wherein in the full bridge regulator circuit, the fet S1, fet S2, fet S3 and fet S4 are all power fets of type IFRP 460;
the diode VD1, the diode VD2, the diode VD3 and the diode VD4 are all fast recovery rectifier diodes with the model number of FR607 and the element parameter of 1000V/6A;
the capacitor C1 is a 1000 muF/450V aluminum electrolytic capacitor;
the inductor is a patch inductor with L1 being 1.5 muH.
6. The portable direct-current high-voltage generator circuit as claimed in claim 2, wherein in the power frequency rectification circuit, the diode VD5, the diode VD6, the diode VD7 and the diode VD8 are all fast recovery rectifier diodes with the model number FR607 and the element parameter of 1000V/6A;
the capacitor C2 is a 1000 muF/450V aluminum electrolytic capacitor.
7. The portable direct current high voltage generator circuit according to claim 1, wherein the high frequency pulse transformer has a transformation ratio of 1: 100.
8. The portable direct-current high-voltage generator circuit as claimed in claim 4, wherein in the voltage-doubling rectifying circuit, the capacitor C3, the capacitor C4, the capacitor C5 and the capacitor C6 are all CH82 type high-voltage sealed composite dielectric capacitors, and C3 ═ C4 ═ 10 μ F, C5 ═ C6 ═ 1 μ F, and the withstand voltage value of the capacitor C3 is equal to
The withstand voltage values of the capacitor C4, the capacitor C5 and the capacitor C6 are all
U4 is the output voltage of the secondary winding of the pulse boosting transformer;
the diode VD9, the diode VD10, the diode VD11 and the diode VD12 are all high-voltage rectifier silicon stacks 2CL100kV-200 mA;
the resistor R4 is a filter resistor with the value of 1 omega, the capacitor C7 is a filter capacitor,it takes on a value of 8 x 10-6μF；
The resistor R5 is a high-voltage protection resistor, and the value of the resistor R5 is 0.9M omega;
the resistor R3 is a load resistor, the maximum output current of the resistor R3 is 2mA, and the value of the maximum output current is 60M omega.
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| CN202020055614.0U CN211741472U (en) | 2020-01-10 | 2020-01-10 | Portable direct current high voltage generator circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114062743A (en) * | 2021-11-11 | 2022-02-18 | 青岛鼎信通讯股份有限公司 | Full-bridge switch characteristic current generating device applied to power industry |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114062743A (en) * | 2021-11-11 | 2022-02-18 | 青岛鼎信通讯股份有限公司 | Full-bridge switch characteristic current generating device applied to power industry |
| CN114062743B (en) * | 2021-11-11 | 2023-08-15 | 青岛鼎信通讯股份有限公司 | Full-bridge switch characteristic current generating device applied to power industry |
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