Energy feedback type bipolar current pulse generation buck converter topology and control method

Abstract

The application discloses an energy feedback type bipolar current pulse generation Buck converter topology structure, which comprises a lithium battery, a super capacitor C, a first switch tube S1, a second switch tube S2, a third switch tube S3, a first diode D1, a second diode D2, a filter inductor L, an output filter capacitor Co, a thyristor commutation circuit and a resistive-inductive load; the positive electrode of the lithium battery is connected with the collector of the S3, and the negative electrode is connected with the anode of the D1; the emitter of the S3 is connected with the negative electrode of the C and the collector of the S1; the C is connected with the cathode of the D1 and the collector of the S2; the D2 is connected with the emitter of the S1, the emitter of the S2 and the left terminal of the L; the right terminal of the L is connected with the output capacitor Co and the upper terminal of the thyristor commutation circuit; the anode of the D1 is connected with the output capacitor Co and the lower terminal of the thyristor commutation circuit; under the large inductive load, a bipolar pulse current with higher rising rate and higher amplitude is obtained, and the energy is efficiently recycled.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of power electronics, and particularly relates to an energy feedback type bipolar current pulse generation Buck converter and a control method thereof. BACKGROUND

[0002] The inductive load bipolar current pulse generation device is a core component of a magnetic field generating device such as a strong magnetic field generator and a geophysical exploration magnetic field transmitter. In actual application, the frequency and amplitude of the bipolar current pulse need to be adjusted to control the frequency and strength of the magnetic field generated by the magnetic field generating coil. Since the time constant of the large inductive load is large, in order to obtain a magnetic field with higher frequency and strength, the voltage across the inductive load needs to be further increased, and the current change rate during the rising process of the pulse current needs to be increased, so as to generate the required magnetic field. Therefore, the voltage regulation range of the bipolar current pulse generation circuit needs to be wide. Meanwhile, a large amount of energy needs to be absorbed by the corresponding circuit during the falling process of the pulse current.

[0003] The existing bipolar pulse current generation circuit is limited by the topology, and it is difficult to meet the requirements of wide-range voltage regulation and variable output voltage polarity at the same time. Meanwhile, due to the lack of energy recovery during the falling process of the pulse current, the energy utilization rate of the circuit is low. Therefore, how to obtain the current pulse with the required width / height and rising / falling time under a relatively simplified topology, and how to realize efficient energy recovery without adding additional energy dissipation devices are a series of problems that need to be solved at present. SUMMARY

[0004] The technical problem to be solved by the application is to overcome the shortcomings of the prior art, and to provide an energy feedback type bipolar current pulse generation Buck converter and a control method thereof, which solve the problem that it is difficult to obtain a bipolar pulse current with high rising rate and high amplitude under the condition of a large inductive load, and realize efficient energy recovery.

[0005] To solve the above problems, the technical scheme adopted by the application is as follows:

[0006] The energy feedback type bipolar current pulse generation Buck converter topology is characterized by comprising a lithium battery, a super capacitor C, a first switch tube S1, a second switch tube S2, a third switch tube S3, a first diode D1, a second diode D2, a filter inductor L, an output filter capacitor Co, a thyristor commutation circuit and a resistive-inductive load; the positive electrode of the lithium battery is connected with the collector of the third switch tube S3, and the negative electrode of the lithium battery is connected with the anode of the first diode D1; the emitter of the third switch tube is connected with the negative electrode of the super capacitor C and the collector of the first switch tube S1; the super capacitor C is connected with the cathode of the first diode D1 and the collector of the second switch tube S2; the second diode D2 is connected with the emitter of the first switch tube, the emitter of the second switch tube and the left terminal of the filter inductor L; the right terminal of the filter inductor L is connected with the output capacitor Co and the upper terminal of the thyristor commutation circuit; the anode of the first diode D1 is connected with the output capacitor Co and the lower terminal of the thyristor commutation circuit.

[0007] Further, the thyristor commutation circuit is composed of a third thyristor TR3, a fourth thyristor TR4, a fifth thyristor TR5 and a sixth thyristor TR6; wherein the anode of the third thyristor TR3 is connected with the anode of the fourth thyristor TR4; the cathode of the third thyristor TR3 is connected with the upper terminal of the resistive-inductive load and the anode of the fifth thyristor TR5; the anode of the sixth thyristor TR6 is connected with the lower terminal of the resistive-inductive load and the cathode of the fourth thyristor; the cathode of the sixth thyristor is connected with the cathode of the fifth thyristor.

[0008] Further, the energy feedback type bipolar current pulse generation Buck converter topology comprises a forward current pulse generation method and a reverse current pulse generation method.

[0009] Further, the forward current pulse generation method comprises the following steps:

[0010] Step 1, turn on the third thyristor TR3 and the sixth thyristor TR6; at this time, the lithium battery and the super capacitor are both put into operation; the first switch tube S1 is turned off, the second switch tube S2 is turned on, and the output voltage is controlled by adjusting the duty cycle of the third switch tube S3 so as to control the smooth rise of the load current; before the end of the current control stage, the first switch tube S1 should be turned on in advance to ensure that the inductor current always exists.

[0011] Step 2, at this time, the lithium battery and the super capacitor are both put into operation; the first switch S1 is turned on, the second switch S2 and the third switch S3 are turned on complementarily, and the output voltage is controlled by adjusting the duty cycle of the second switch S2 and the third switch S3, so as to control the load current to rise smoothly; it should be noted that, in order to ensure that the inductor current always exists, the second switch S2 and the third switch S3 should be turned on complementarily in a period, and the time of the complementary conduction is 2ΔdT.

[0012] Step 3, at this time, the lithium battery is cut off, and the super capacitor is put into operation to absorb the load energy; the third switch S3 is turned off, the second switch S2 and the first switch S1 are turned on complementarily, and the speed of the super capacitor absorbing the load coil energy is controlled by adjusting the duty cycle of the second switch S2 and the first switch S1; the load coil energy is recovered to the super capacitor in this stage.

[0013] Steps 1-3 are executed in cycles, and the topology can generate a forward current pulse with adjustable pulse height, width, rising time and falling time.

[0014] Further, in step 2, the second switch S2 and the third switch S3 are turned on complementarily in a period, and the time of the complementary conduction is 2ΔdT.

[0015] Further, the method for generating a reverse current pulse comprises:

[0016] Step 1, turn on the fourth thyristor S4 and the fifth thyristor S5; at this time, the lithium battery and the super capacitor are both put into operation; the first switch S1 is turned off, the second switch S2 is turned on, and the output voltage is controlled by adjusting the duty cycle of the third switch S3, so as to control the load current to rise smoothly; before the end of the current control stage, the first switch S1 should be turned on in advance to ensure that the inductor current always exists;

[0017] Step 2, at this time, the lithium battery and the super capacitor are both put into operation; the first switch S1 is turned on, the second switch S2 and the third switch S3 are turned on complementarily, and the output voltage is controlled by adjusting the duty cycle of the second switch S2 and the third switch S3, so as to control the load current to rise smoothly; it should be noted that, in order to ensure that the inductor current always exists, the second switch S2 and the third switch S3 should be turned on complementarily in a period, and the time of the complementary conduction is 2ΔdT.

[0018] Step 3, at this time, the lithium battery is cut off, and the super capacitor is put into operation to absorb the load energy; the third switch S3 is turned off, the second switch S2 and the first switch S1 are turned on complementarily, and the speed of the super capacitor absorbing the load coil energy is controlled by adjusting the duty cycle of the second switch S2 and the first switch S1; the load coil energy is recovered to the super capacitor in this stage.

[0019] The steps 1-3 are circularly executed, and the reverse current pulse with adjustable pulse height, width, rising time and falling time can be controlled by the topology.

[0020] The present application has the following advantages and features:

[0021] The present application is a Buck converter topology for generating bipolar current pulse with energy feedback, which solves the problem of difficult to obtain high rising rate and high amplitude bipolar pulse current under large inductance load by using a new Buck converter structure containing lithium battery and super capacitor, and realizes efficient energy recovery. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The topology diagram of the preferred embodiment of the present application is shown in the figure.

[0023] Figure 2 The working principle diagram of the preferred embodiment of the present application (super capacitor is the abbreviation of super capacitor) is shown in the figure.

[0024] Figure 3 The switch tube driving signal diagram of the preferred embodiment of the present application is shown in the figure.

[0025] Figure 4 The working state diagram of different stages of the preferred embodiment of the present application is shown in the figure.

[0026] Figure 5 The inductive load voltage and current waveform of the preferred embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0028] Please refer to Figure 1 The present application relates to a Buck converter topology for generating bipolar current pulse with energy feedback, which includes lithium battery, super capacitor C, first switch tube S1, second switch tube S2, third switch tube S3, first diode D1, second diode D2, filter inductor L, output filter capacitor Co, thyristor commutation circuit and inductive load.

[0029] The positive electrode of the lithium battery of the topology is connected with the collector of the third switch tube S3, and the negative electrode of the lithium battery is connected with the anode of the first diode D1; the emitter of the third switch tube is connected with the negative electrode of the super capacitor C and the collector of the first switch tube S1; the super capacitor C is connected with the cathode of the first diode D1 and the collector of the second switch tube S2; the second diode D2 is connected with the emitter of the first switch tube, the emitter of the second switch tube and the left terminal of the filter inductor L. The right terminal of the filter inductor L is connected with the output capacitor Co and the upper terminal of the thyristor commutation circuit. The anode of the first diode D1 is connected with the output capacitor Co and the lower terminal of the thyristor commutation circuit.

[0030] Corresponding to the above, the application provides an energy feedback type bipolar current pulse generation method suitable for the application. The method can control the output of the required bipolar current pulse while maintaining the stability of the super capacitor voltage during operation. Taking the process of generating a forward pulse current as an example, the waveforms of the load current and the load voltage are as shown in Figure 2 The following will combine Figure 2 to analyze the entire working state in detail.

[0031] Step 1, turn on the third thyristor S3 and the sixth thyristor S6. At this time, the lithium battery and the super capacitor are both put into operation, and the working state is as shown in stage 1 of Figure 2 . The first switch tube S1 is turned off, the second switch tube S2 is turned on, and the output voltage is controlled by adjusting the duty cycle of the switch tube S3 to control the smooth rise of the load current. Before the end of stage 1, in order to ensure that the inductor current always exists, the switch tube S1 needs to be turned on in advance before entering the next state. The circuit working state is as shown in (a) (b) of Figure 4 .

[0032] Step 2, at this time, the lithium battery and the super capacitor are both put into operation, and the working state is as shown in stage 2 of Figure 2 . The first switch tube S1 is turned on, and the second switch tube S2 and the third switch tube S3 are complementary turned on. It should be noted that in order to ensure that the inductor current always exists, the switch tubes S2 and S3 should have overlapping conduction time, as shown in Figure 3 . The overlapping conduction time in one period is 2ΔdT. Under this control mode, there are three states in each switch cycle, as shown in Figure 4 . In ts1-ts2, the circuit working state is as shown in (c) of Figure 4 ; in ts2-ts3, the circuit working state is as shown in (d) of Figure 4 ; and in ts3-ts4, the circuit working state is as shown in (e) of Figure 4 .

[0033] Step 3, at this time, the lithium battery is cut off, and the super capacitor is put into operation to absorb the load energy, and the working state is as shown in Figure 2 Phase 3. The second switch S2 and the third switch S3 are turned off, the first switch S1 is turned on, and the super capacitor is reversely connected to the output end. The load coil energy is recovered to the super capacitor in this phase. The working state of the circuit is as shown in Figure 4 (f).

[0034] Steps 1-3 are executed in cycles, and the topology can be controlled to generate a forward current pulse with adjustable pulse height, width, pulse rise and fall time.

[0035] If step 1 is modified to turn on the fourth thyristor S4 and the fifth thyristor S5, and steps 1-3 are executed in cycles, the topology can be controlled to generate a reverse current pulse with adjustable pulse height, width, pulse rise and fall time.

[0036] Figure 5 The present application proposes an energy feedback type bipolar current pulse generation Buck converter to generate the simulation waveform of the voltage and current across the inductive load. Under the foregoing basic control method, the bipolar current pulse with the required pulse width / height, pulse rise / fall time is generated.

[0037] The present application proposes an energy feedback type bipolar current pulse generation Buck converter. The energy feedback type bipolar current pulse generation Buck converter in the present application solves the problem of difficulty in obtaining a bipolar pulse current with high rise rate and high amplitude under a large inductive load and simultaneously realizes efficient energy recovery through a novel Buck converter structure containing a lithium battery and a super capacitor. In the pulse current rise phase, the super capacitor can provide a large power for the inductive load; in the pulse current plateau phase, the lithium battery Buck converter can continuously provide stable energy for the inductive load; and in the pulse current fall phase, the super capacitor can recover the energy released by the inductive load.

[0038] The basic principles, main features and advantages of the present application are shown and described above. It should be understood by those skilled in the art that the present application is not limited by the above embodiments, and the above embodiments and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application.

Claims

1. An energy feedback type bipolar current pulse generation buck converter topology, characterized by :Including lithium battery, super capacitor C, first switch tube S1, second switch tube S2, third switch tube S3, first diode D1, second diode D2, filter inductor L, output filter capacitor Co, thyristor commutation circuit and blocking inductive load; the positive pole of the lithium battery of the topology structure is connected with the collector of the third switch tube S3, the negative pole of the lithium battery is connected with the anode of the first diode D1; the emitter of the third switch tube is connected with the negative pole of the super capacitor C and the collector of the first switch tube S1; the super capacitor C is connected with the cathode of the first diode D1 and the collector of the second switch tube S2; the anode of the second diode D2 is connected with the emitter of the first switch tube; the cathode of the second diode D2 is connected with the emitter of the second switch tube; the left terminal of the filter inductor L is connected on the line connected between the second diode D2 and the second switch tube S2; the right terminal of the filter inductor L is connected with the output capacitor Co and the upper terminal of the thyristor commutation circuit; the anode of the first diode D1 is connected with the output capacitor Co and the lower terminal of the thyristor commutation circuit. The thyristor commutation circuit is composed of a third thyristor TR3, a fourth thyristor TR4, a fifth thyristor TR5 and a sixth thyristor TR6; wherein the anode of the third thyristor TR3 is connected with the anode of the fourth thyristor TR4; the cathode of the third thyristor TR3 is connected with the upper terminal of the blocking inductive load and the anode of the fifth thyristor TR5; the anode of the sixth thyristor TR6 is connected with the lower terminal of the blocking inductive load and the cathode of the fourth thyristor; the cathode of the sixth thyristor is connected with the cathode of the fifth thyristor.

2. The energy feedback type bipolar current pulse generation buck converter topology of claim 1, wherein Including the method for generating forward current pulse and the method for generating reverse current pulse of the Buck converter topology structure for generating bipolar current pulse with energy feedback as claimed in claims 1-2.

3. An energy feedback type bipolar current pulse generation control method characterized by The method for generating forward current pulse comprises the following steps:

4. The energy feedback type of bipolar current pulse generation control method according to claim 3, characterized by, Step 1, turn on the third thyristor TR3 and the sixth thyristor TR6; at this time, the lithium battery and the super capacitor are both put into operation; the first switch tube S1 is turned off, the second switch tube S2 is turned on, and the output voltage is controlled by adjusting the duty cycle of the third switch tube S3 so as to control the steady rise of the load current; before the end of the current control stage, the first switch tube S1 should be turned on in advance to ensure that the inductive current always exists; Step 2, at this time, the lithium battery and the super capacitor are both put into operation; the first switch tube S1 is turned on, the second switch tube S2 and the third switch tube S3 are complementary turned on, and the output voltage is controlled by adjusting the duty cycle of the second switch tube S2 and the third switch tube S3 so as to control the steady rise of the load current; it should be noted that, in order to ensure that the inductive current always exists, the second switch tube S2 and the third switch tube S3 should have overlapping conduction time in a cycle, ​ Step 3, at this time, the lithium battery is cut off, and the super capacitor is put into operation to absorb the load energy; the third switch S3 is turned off, and the second switch S2 and the first switch S1 are complementary on; the duty cycle of the second switch S2 and the first switch S1 is adjusted to control the speed of the super capacitor absorbing the load coil energy; the load coil energy is recovered to the super capacitor in this stage; Steps 1-3 are executed in cycles, and the topology can generate forward current pulses with adjustable pulse height, width, pulse rise and fall time.

5. The energy feedback type of bipolar current pulse generation control method according to claim 4, characterized by In step 2, the second switch S2 and the third switch S3 are complementary on in a cycle.

6. The energy feedback type bipolar current pulse generation control method according to claim 3, characterized by, The method for generating reverse current pulses comprises: Step 1, turn on the fourth thyristor S4 and the fifth thyristor S5; at this time, the lithium battery and the super capacitor are put into operation; the first switch S1 is turned off, the second switch S2 is turned on, and the duty cycle of the third switch S3 is adjusted to control the output voltage and thus control the smooth rise of the load current; before the current control stage ends, the first switch S1 should be turned on in advance to ensure that the inductor current always exists; Step 2, at this time, the lithium battery and the super capacitor are put into operation; the first switch S1 is turned on, and the second switch S2 and the third switch S3 are complementary on; the duty cycle of the second switch S2 and the third switch S3 is adjusted to control the output voltage and thus control the smooth rise of the load current; it should be noted that, in order to ensure that the inductor current always exists, the second switch S2 and the third switch S3 should be complementary on; Step 3, at this time, the lithium battery is cut off, and the super capacitor is put into operation to absorb the load energy; the third switch S3 is turned off, and the second switch S2 and the first switch S1 are complementary on; the duty cycle of the second switch S2 and the first switch S1 is adjusted to control the speed of the super capacitor absorbing the load coil energy; the load coil energy is recovered to the super capacitor in this stage; Steps 1-3 are executed in cycles, and the topology can generate reverse current pulses with adjustable pulse height, width, pulse rise and fall time.

7. The energy feedback type of bipolar current pulse generation control method according to claim 6, characterized by In step 2, the second switch S2 and the third switch S3 are complementary on in a cycle.

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