A kind of linear amplifier and great power pulse power source thereof
(1) technical field
The present invention relates to a kind of linear amplifier that adopts power device IGBT to use as linear unit, and the great power pulse power source that uses above-mentioned linear amplifier, power electronics and power technique fields belonged to.
(2) background technology
Adopt that power device does that the switching device parallel connection realizes big electric current, tracking error is little, duty ratio is low, when the output current pulse is controlled power supply, exist modulated process to cause operating lag, and output need add low-pass filtering, in control, increase limit like this, in closed-loop control, be not easy to guarantee system stability.
If adopt linear unit field effect transistor or transistor to realize, linear unit withstand voltage all lower is difficult to guarantee system requirements.
(3) summary of the invention
The present invention is in order to solve the deficiency of above technology, a kind of linear amplifier that adopts power device IGBT to use as linear unit is provided, entire circuit has constituted controllable linear current source, because this amplifier is a linear amplifier, has good tracking performance, have the constant-current source characteristic, therefore when realizing big electric current, need not add equalizing reactor and just be easy to realize in parallel.
Another object of the present invention is to provide a kind of great power pulse power source that uses above-mentioned linear amplifier, because the power supply of linear amplifier is variable, power consumption at linear amplifier is big, and adopting power supply is the variable loss that reduces power device, improves the efficient of system.
The present invention realizes by following measure:
Linear amplifier of the present invention is made up of two operational amplifier A 1 and A2, a power device IGBT and a noninductive resistance R1; Two operational amplifiers are connected into the emitter follower that is in series and are connected with collector electrode output, the Current Negative Three-Point Capacitance amplifier that power device IGBT is connected into, the end of noninductive resistance R1 is connected the other end ground connection of noninductive resistance R1 with the backward end of emitter follower A2 and the emitter-base bandgap grading of power device IGBT respectively.
Great power pulse power source of the present invention is made up of a master current source I, two current source I1 and I2, two controllable voltage V1 and V2, three capacitor C, C1 and C2 and K switch, diode D, inductance L, noninductive current-limiting resistance R2; Described master current source I is the described linear amplifier of claim 1, and described current source I1 and I2 are constant-current source, and described inductance L is load; The end that the input termination controllable voltage V1 of current source I1, output connect capacitor C 1 and K switch over the ground; The other end of K switch connects the negative pole of load L, diode D respectively and connects capacitor C over the ground; The other end of load L is in series with noninductive current-limiting resistance R2, master current source I; The positive pole of diode D joins with the output of current source I2 and an end of capacitor C 2 respectively, the other end ground connection of capacitor C 2, the input termination controllable voltage V2 of current source I2.
Linear amplifier of the present invention, circuit part are designed to form linear amplifier by two-stage calculation amplifier collector electrode output, the Current Negative Three-Point Capacitance amplifier that is connected into power device IGBT that be in series.Because emitter follower has the input impedance height and output impedance is low, circuit has also been realized low-voltage except that inter-stage has good isolation characteristic, the function of big electric current.The collector electrode that power device IGBT is connected into is exported, the Current Negative Three-Point Capacitance form, has improved the stability of power device.Because the power supply of linear amplifier is not constant, but allow itself and output voltage amplitude adapt, reduce the pressure drop on the power device as far as possible, linear amplifier has current source characteristic, and therefore a plurality of amplifiers need not add the effect that current-limiting reactor also can be good at realizing tracking performance and the output of big electric current when in parallel.
The input signal of current linear amplifier is from control voltage Vi, and emitter follower and collector electrode are exported because current linear amplifier has adopted, the form of Current Negative Three-Point Capacitance, has satisfied the needs of output current, has improved the stability of electric current output.
The linear amplifier that adopts power device IGBT to use as linear unit, entire circuit has constituted controllable linear current source, because this amplifier is a linear amplifier, has good tracking performance, has the constant-current source characteristic, therefore when realizing big electric current, need not add equalizing reactor and just be easy to realize in parallel.
Great power pulse power source is owing to adopted the electric power system of current linear amplifier and linear current source, under the control of input current and two constant-current sources of output current, the variation of the output current energy tracing preset signal controlling voltage Vi of power supply has improved the stability and the precision of source current output.Because the power supply of linear amplifier is variable, and is big at the power consumption of linear amplifier, adopting power supply is the variable loss that reduces power device, improves the efficient of system.
(4) description of drawings
Fig. 1 is the schematic diagram of linear amplifier of the present invention
Among the figure: A1, A2 are operational amplifier; IGBT is a power device; R1 is a noninductive resistance; Vi is control voltage; V0 is a main power source.
Fig. 2 is the schematic diagram of great power pulse power source of the present invention
Among the figure: V1, V2 are controllable voltage; I1, I2 are current source; I is a master current source; C, C1, C2 are electric capacity; K is a switch; L is an inductance; R2 is noninductive current-limiting resistance; D is a diode.
(5) embodiment
Below in conjunction with the drawings and specific embodiments the present invention is made specific description.
Shown in the accompanying drawing 1, be to utilize power device IGBT to realize the method circuit theory diagrams of great power pulse power source as linear unit, be to be connected into by two operational amplifier A 1 and A2 that the emitter follower that is in series is connected with collector electrode output, the Current Negative Three-Point Capacitance amplifier that an IGBT is connected into, the end of noninductive resistance R1 is connected with the backward end of emitter follower A2 and the emitter-base bandgap grading of IGBT respectively, the other end ground connection of noninductive resistance R1 is formed linear amplifier.
Accompanying drawing 2, be current linear amplifier electric power system (great power pulse power source) schematic diagram, form by two controllable voltages of V1, V2, two current sources of I1, I2, three capacitor C, C1, C2 and K switch, diode D, inductance L (load), noninductive current-limiting resistance R2, master current source I.Described master current source I is the linear amplifier of Fig. 1, and the main power source V0 of linear amplifier is connected with noninductive current-limiting resistance R2.Wherein I1, I2 are constant-current source, are used for charging to C1, C2.
The charge and discharge number of times of capacitor C 1, C depends on the open frequency of K switch.When switch disconnects, current source I1 is under the effect of controllable voltage V1, characteristic with constant-current source is charged to capacitor C 1, and when K switch was closed, the electric current of current source I1 and capacitor C 1 provided electric current to capacitor C charging and inductance L (load), noninductive current-limiting resistance R2, master current source I.In working order, when K switch disconnected, capacitor C was to inductance L (load), noninductive current-limiting resistance R2, master current source I discharge.When the voltage of inductance L (load) was lower than the knot pressure drop of diode D, at this moment the electric current of capacitor C 2 discharged to inductance L (load), resistance R, master current source I by diode D.When the voltage at I two ends, main flow source was higher than the knot pressure drop of diode D, capacitor C 2 stopped discharge.Therefore, under the effect of two controllable voltage V1, V2 and two constant-current source I1, I2, master current source I adjusts load current, makes the electric current by load remain constant-current characteristics.