Disclosure of Invention
The invention provides a superposition type converter based on coupling inductance and a control method thereof, aiming at the problems of large current stress and high voltage stress of the existing boost converter.
The invention provides a superposition type converter based on coupling inductance, which comprises a power supply, an input module, a coupling inductance module and an output module;
the coupling inductance module comprises a first coupling inductance and a second coupling inductance, the first coupling inductance comprises a first primary winding and a first secondary winding, and the second coupling inductance comprises a second primary winding and a second secondary winding; the first end of the first primary winding is connected with the positive pole of the power supply; the first end of the second primary winding is connected with the positive pole of the power supply; the first secondary winding and the second secondary winding are respectively connected with the output module;
the input module comprises a first capacitor, a second capacitor, a first diode, a first switch tube, a second switch tube and a third inductor; the anode of the first diode is connected with the second end of the first primary winding and the second end of the second capacitor, the cathode of the first diode is connected with the first end of the first capacitor, and the second end of the first capacitor is connected with the cathode of the power supply; the first end of the third inductor is connected with the negative electrode of the first diode, and the second end of the third inductor is connected with the first end of the first switching tube and the first end of the second capacitor; the first end of the second switching tube is connected with the second end of the second primary winding; the second end of the first switch tube and the second end of the second switch tube are respectively connected with the negative pole of the power supply.
Optionally, the circuit further includes a clamping module, where the clamping module includes a third capacitor, a fourth capacitor, a second diode, a third diode, a fourth diode, and a fifth diode;
the second end of the third capacitor is connected with the second end of the second primary winding, the first end of the third capacitor is connected with the cathode of the second diode and the anode of the fourth diode, the anode of the second diode is connected with the first end of the first switching tube, and the anode of the second diode and the cathode of the fourth diode are connected with the output module;
the first end of the fourth capacitor is connected with the first end of the second switch tube, the second end of the fourth capacitor is connected with the anode of the third diode and the cathode of the fifth diode, the cathode of the third diode is connected with the second end of the second switch tube, and the anode of the fifth diode is connected with the output module.
Optionally, the output module includes a fifth capacitor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a sixth diode, a seventh diode, and an output load;
the first end of the fifth capacitor is connected with the second end of the eighth capacitor, and the first end of the eighth capacitor is connected with the first end of the output load; the second end of the fifth capacitor is connected with the first end of the sixth capacitor, and the second end of the sixth capacitor is connected with the second end of the output load;
the anode of the sixth diode is connected with the first end of the fifth capacitor, the cathode of the sixth diode is connected with the anode of the seventh diode, and the cathode of the seventh diode is connected with the first end of the eighth capacitor;
the first secondary winding, the second secondary winding and the seventh capacitor are connected in series and then connected to two ends of the sixth diode in parallel;
the negative electrode of the fourth diode is connected with the first end of the fifth capacitor, the positive electrode of the second diode is connected with the first end of the sixth capacitor, and the positive electrode of the fifth diode is connected with the second end of the sixth capacitor.
Optionally, a first end of the first secondary winding is connected to an anode of the sixth diode, a second end of the first secondary winding is connected to a first end of the second secondary winding, a second end of the second secondary winding is connected to a second end of the seventh capacitor, and a first end of the seventh capacitor is connected to a cathode of the sixth diode.
Optionally, the first end of the first primary winding and the first end of the first secondary winding are homonymous ends; the first end of the second primary winding and the first end of the second secondary winding are homonymous terminals with each other.
Optionally, the first coupling inductor includes a first leakage inductor and a first excitation inductor; the second coupling inductor comprises a second leakage inductor and a second excitation inductor;
the turn ratio of the first coupling inductor is equal to that of the second coupling inductor, and the coupling coefficient of the first coupling inductor is equal to that of the second coupling inductor; the first leakage inductance is equal to the second leakage inductance, and the first excitation inductance is equal to the second excitation inductance.
Optionally, the first switch tube is a field effect tube, the first end of the first switch tube is a drain electrode of the field effect tube, the second end of the first switch tube is a source electrode of the field effect tube, and the third end of the first switch tube is a gate electrode of the field effect tube;
the second switch tube is a field effect tube, the first end of the second switch tube is a drain electrode of the field effect tube, the second end of the second switch tube is a source electrode of the field effect tube, and the third end of the second switch tube is a grid electrode of the field effect tube.
In a second aspect of the present invention, the superposition type converter based on coupled inductors according to the first aspect provides a control method, including the following steps:
generating a first control signal and a second control signal, wherein the frequency of the first control signal is the same as that of the second control signal, the phase difference between the first control signal and the second control signal is 180 degrees, and the duty ratio of the first control signal and the duty ratio of the second control signal are respectively greater than 0.5;
transmitting the first control signal to a third end of the first switch tube, and controlling the on-off of the first switch tube; and the second control signal is transmitted to the third end of the second switch tube and controls the second switch tube to be switched on and off.
Optionally, the period of the first control signal and the period of the second control signal satisfy that the superposition type converter based on the coupling inductance operates in the following six operating modes:
a first modality: the first switch tube is conducted under the action of the first leakage inductance with zero current, and the second switch tube is conducted; the first diode, the second diode, the third diode, the fourth diode, the fifth diode and the sixth diode are cut off in the reverse direction, and the seventh diode is turned on in the forward direction; the power supply charges the first excitation inductor and the second excitation inductor, and the energy of the second excitation inductor is transmitted to the eighth capacitor through the second secondary winding and the seventh diode;
and a second working mode: the first switch tube is conducted, the second switch tube is conducted, the first diode, the second diode, the third diode, the fourth diode, the fifth diode, the sixth diode and the seventh diode are cut off in the reverse direction, and the power supply charges the first excitation inductor, the second excitation inductor, the first leakage inductor and the second leakage inductor;
the third working mode is as follows: the first switch tube is conducted, the second switch tube is turned off, the third diode, the fourth diode and the sixth diode are conducted in the forward direction, the fourth capacitor is charged by the second leakage inductor, and the voltage stress of the second switch tube is clamped on the voltage of the fourth capacitor; partial energy of the second excitation inductor and partial energy of the third capacitor charge the fifth capacitor through the fourth diode, and residual energy of the second excitation inductor and residual energy of the third capacitor charge the sixth diode and the seventh capacitor through the second secondary winding;
the fourth working mode: the first switch tube is conducted, and the second switch tube is conducted under the action of the second leakage inductance at zero current; the first diode, the second diode, the third diode, the fourth diode, the fifth diode, the sixth diode and the seventh diode are cut off in the reverse direction; the power supply charges the first excitation inductor and the second excitation inductor;
a fifth working mode: the first switch tube is turned off, the second switch tube is turned on, the first diode is turned on, and the second diode, the third diode, the fourth diode, the fifth diode, the sixth diode and the seventh diode are reversely cut off; the power supply charges the first excitation inductor, the second excitation inductor, the first leakage inductor and the second leakage inductor;
a sixth working mode: the first switch tube is turned off, the second switch tube is turned on, the first diode, the second diode, the fifth diode and the seventh diode are turned on in the forward direction, and the third diode, the fourth diode and the sixth diode are turned off in the reverse direction; the energy of the first leakage inductor is transmitted to the first capacitor, and the voltage stress of the first switch tube is clamped on the voltage of the third capacitor; partial energy of the first excitation inductor and partial energy of the second capacitor are transmitted to the sixth capacitor through the first diode, and residual energy of the first excitation inductor, residual energy of the second capacitor and energy of the seventh capacitor are transmitted to the eighth capacitor.
Has the beneficial effects that: the boost converter and the quasi-Z source module are input and connected in parallel by adopting a staggered parallel structure, and the first switch tube and the second switch tube are staggered and connected in parallel, so that the current stress and the voltage stress of the switch tubes can be effectively reduced, the voltage resistance value selection requirement of a capacitor can be reduced, a high-performance device can be replaced, and the power density and the efficiency of a system can be improved; the ports of the boost converter and the quasi-Z source module are output in series, namely, the output ends are superposed, so that the overlapping is stable, the input current ripple can be greatly reduced, and the power grade of the converter is improved.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
Detailed Description
Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. The following description refers to the accompanying drawings in which the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary examples do not represent all implementations consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the invention, as detailed in the appended claims.
Example 1
The embodiment provides a superposition type converter based on a coupling inductor, which comprises a power source Vin, an input module, a coupling inductor module, a clamping module and an output module;
the coupling inductance module comprises a first coupling inductance and a second coupling inductance, wherein the first coupling inductance comprises a first primary winding Np1 and a first secondary winding Ns1, and the second coupling inductance comprises a second primary winding Np2 and a second secondary winding Ns2; a first end of the first primary winding Np1 is connected with the positive pole of the power Vin; a first end of the second primary winding Np2 is connected with the positive pole of the power Vin; the first secondary winding Ns1 and the second secondary winding Ns2 are respectively connected with the output module;
the input module comprises a first capacitor C1, a second capacitor C2, a first diode D1, a first switch tube S1, a second switch tube S2 and a third inductor L3; the anode of the first diode D1 is connected to the second end of the first primary winding Np1 and the second end of the second capacitor C2, the cathode of the first diode D1 is connected to the first end of the first capacitor C1, and the second end of the first capacitor C1 is connected to the cathode of the power source Vin; a first end of a third inductor L3 is connected with a negative electrode of the first diode D1, and a second end of the third inductor L3 is connected with a first end of the first switching tube S1 and a first end of the second capacitor C2; a first end of the second switching tube S2 is connected to a second end of the second primary winding Np 2; the second end of the first switch tube S1 and the second end of the second switch tube S2 are respectively connected to the negative electrode of the power source Vin.
The clamping module comprises a third capacitor C3, a fourth capacitor C4, a second diode D2, a third diode D3, a fourth diode D4 and a fifth diode D5;
a second end of the third capacitor C3 is connected with a second end of the second primary winding Np2, a first end of the third capacitor C3 is connected with a cathode of the second diode D2 and an anode of the fourth diode D4, an anode of the second diode D2 is connected with a first end of the first switching tube S1, and an anode of the second diode D2 and a cathode of the fourth diode D4 are connected with the output module;
the first end of the fourth capacitor C4 is connected with the first end of the second switch tube S2, the second end of the fourth capacitor C4 is connected with the anode of the third diode D3 and the cathode of the fifth diode D5, the cathode of the third diode D3 is connected with the second end of the second switch tube S2, and the anode of the fifth diode D5 is connected with the output module.
The output module comprises a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, an eighth capacitor C8, a sixth diode D6, a seventh diode D7 and an output load R;
a first end of the fifth capacitor C5 is connected with a second end of the eighth capacitor C8, and a first end of the eighth capacitor C8 is connected with a first end of the output load R; a second end of the fifth capacitor C5 is connected with a first end of the sixth capacitor C6, and a second end of the sixth capacitor C6 is connected with a second end of the output load R;
the anode of the sixth diode D6 is connected to the first end of the fifth capacitor C5, the cathode of the sixth diode D6 is connected to the anode of the seventh diode D7, and the cathode of the seventh diode D7 is connected to the first end of the eighth capacitor C8;
the first secondary winding Ns1, the second secondary winding Ns2 and the seventh capacitor C7 are connected in series and then connected to two ends of a sixth diode D6 in parallel;
the cathode of the fourth diode D4 is connected to the first end of the fifth capacitor C5, the anode of the second diode D2 is connected to the first end of the sixth capacitor C6, and the anode of the fifth diode D5 is connected to the second end of the sixth capacitor C6.
A first end of the first secondary winding Ns1 is connected to an anode of the sixth diode D6, a second end of the first secondary winding Ns1 is connected to a first end of the second secondary winding Ns2, a second end of the second secondary winding Ns2 is connected to a second end of the seventh capacitor C7, and a first end of the seventh capacitor C7 is connected to a cathode of the sixth diode D6.
The first end of the first primary winding Np1 and the first end of the first secondary winding Ns1 are homonymous ends; the first end of the second primary winding Np2 and the first end of the second secondary winding Ns2 are homonymous terminals.
The first coupling inductor comprises a first leakage inductor Lk1 and a first excitation inductor Lm1; the second coupling inductor comprises a second leakage inductor Lk2 and a second excitation inductor Lm2;
the turn ratio of the first coupling inductor is equal to that of the second coupling inductor, and the coupling coefficient of the first coupling inductor is equal to that of the second coupling inductor; the first leakage inductance Lk1 is equal to the second leakage inductance Lk2, and the first magnetizing inductance Lm1 is equal to the second magnetizing inductance Lm 2.
The first switch tube S1 is a field effect tube, the first end of the first switch tube S1 is a drain electrode of the field effect tube, the second end of the first switch tube S1 is a source electrode of the field effect tube, and the third end of the first switch tube S1 is a grid electrode of the field effect tube;
the second switch tube S2 is a field effect tube, a first end of the second switch tube S2 is a drain electrode of the field effect tube, a second end of the second switch tube S2 is a source electrode of the field effect tube, and a third end of the second switch tube S2 is a gate electrode of the field effect tube.
The superposition type converter based on the coupling inductor provided by the embodiment works in the following six working modes:
a first modality: the first switching tube S1 is conducted under the action of the first leakage inductance Lk1 at zero current, and the second switching tube S2 is conducted; the first diode D1, the second diode D2, the third diode D3, the fourth diode D4, the fifth diode D5 and the sixth diode D6 are turned off in the reverse direction, and the seventh diode D7 is turned on in the forward direction; the power source Vin charges the first magnetizing inductance Lm1 and the second magnetizing inductance Lm2, and the energy of the second magnetizing inductance Lm2 is transmitted to the eighth capacitor C8 through the second secondary winding Ns2 and the seventh diode D7;
and a second working mode: the first switch tube S1 is conducted, the second switch tube S2 is conducted, the first diode D1, the second diode D2, the third diode D3, the fourth diode D4, the fifth diode D5, the sixth diode D6 and the seventh diode D7 are reversely cut off, and the power supply Vin charges the first excitation inductor Lm1, the second excitation inductor Lm2, the first leakage inductor Lk1 and the second leakage inductor Lk 2;
a third working mode: the first switch tube S1 is conducted, the second switch tube S2 is turned off, the third diode D3, the fourth diode D4 and the sixth diode D6 are conducted in the forward direction, the fourth capacitor C4 is charged by the second leakage inductor Lk2, and the voltage stress of the second switch tube S2 is clamped on the voltage of the fourth capacitor C4; part of energy of the second magnetizing inductance Lm2 and part of energy of the third capacitor C3 charge the fifth capacitor C5 through the fourth diode D4, and the remaining energy of the second magnetizing inductance Lm2 and the remaining energy of the third capacitor C3 charge the sixth diode D6 and the seventh capacitor C7 through the second secondary winding Ns2;
the fourth working mode: the first switching tube S1 is conducted, and the second switching tube S2 is conducted under the action of the second leakage inductance Lk2 at zero current; the first diode D1, the second diode D2, the third diode D3, the fourth diode D4, the fifth diode D5, the sixth diode D6 and the seventh diode D7 are reversely turned off; a power supply Vin charges a first excitation inductor Lm1 and a second excitation inductor Lm2;
a fifth working mode: the first switch tube S1 is turned off, the second switch tube S2 is turned on, the first diode D1 is turned on, and the second diode D2, the third diode D3, the fourth diode D4, the fifth diode D5, the sixth diode D6 and the seventh diode D7 are reversely cut off; the power source Vin charges a first excitation inductor Lm1, a second excitation inductor Lm2, a first leakage inductor Lk1 and a second leakage inductor Lk 2;
a sixth working mode: the first switch tube S1 is turned off, the second switch tube S2 is turned on, the first diode D1, the second diode D2, the fifth diode D5 and the seventh diode D7 are turned on in the forward direction, and the third diode D3, the fourth diode D4 and the sixth diode D6 are turned off in the reverse direction; the energy of the first leakage inductor Lk1 is transmitted to the first capacitor C1, and the voltage stress of the first switch tube S1 is clamped on the voltage of the third capacitor C3; part of energy of the first magnetizing inductance Lm1 and part of energy of the second capacitor C2 are transferred to the sixth capacitor C6 through the first diode D1, and the remaining energy of the first magnetizing inductance Lm1, the remaining energy of the second capacitor C2, and the energy of the seventh capacitor C7 are transferred to the eighth capacitor C8.
Example 2
As shown in fig. 1, an overlay type variator based on a coupling inductor according to an embodiment of the disclosure includes a power source Vin, an input module, a coupling inductor module, an output module, and a clamping module.
The input module comprises a first capacitor C1, a second capacitor C2, a first diode D1, a first switch tube S1, a second switch tube S2 and a third inductor L3; the anode of the first diode D1 is connected with the second end of the second capacitor C2, the cathode of the first diode D1 is connected with the first end of the first capacitor C1, and the second end of the first capacitor C1 is connected with the cathode of the power source Vin; a first end of the third inductor L3 is connected to a negative electrode of the first diode D1, and a second end of the third inductor L3 is connected to a first end of the first switching tube S1; a first end of the second switching tube S2 is connected to a second end of the second primary winding Np 2; the second end of the first switch tube S1 and the second end of the second switch tube S2 are respectively connected to the negative electrode of the power source Vin. The coupling inductance module comprises a first coupling inductance and a second coupling inductance, wherein the first coupling inductance comprises a first primary winding Np1 and a first secondary winding Ns1, and the second coupling inductance comprises a second primary winding Np2 and a second secondary winding Ns2; a first end of the first primary winding Np1 is connected with the positive electrode of the power Vin, and a second end of the first primary winding Np1 is connected with the positive electrode of the first diode D1; a first end of the second primary winding Np2 is connected with the positive pole of the power Vin; the first secondary winding Ns1 and the second secondary winding Ns2 are connected to the output module, respectively.
The first end of the first primary winding Np1 and the first end of the first secondary winding Ns1 are dotted terminals; the first end of the second primary winding Np2 and the first end of the second secondary winding Ns2 are homonymous terminals.
The first coupling inductor comprises a first leakage inductor Lk1 and a first excitation inductor Lm1; the second coupling inductor comprises a second leakage inductor Lk2 and a second excitation inductor Lm2; the first end of the first primary winding Np1 is connected with the positive pole of a power Vin through a first leakage inductance Lk1, and a first excitation inductance Lm1 is connected in parallel with the two ends of the first primary winding Np 1; a first end of the second primary winding Np2 is connected with the positive electrode of the power Vin through a second leakage inductance Lk2, and a second excitation inductance Lm2 is connected in parallel with two ends of the second primary winding Np 2; the turn ratio of the first coupling inductor is equal to that of the second coupling inductor, and the coupling coefficient of the first coupling inductor is equal to that of the second coupling inductor; the first leakage inductance Lk1 is equal to the second leakage inductance Lk2, and the first magnetizing inductance Lm1 is equal to the second magnetizing inductance Lm 2.
The clamping module comprises a third capacitor C3, a fourth capacitor C4, a second diode D2, a third diode D3, a fourth diode D4 and a fifth diode D5; a second end of the third capacitor C3 is connected with a second end of the second primary winding Np2, a first end of the third capacitor C3 is connected with a cathode of the second diode D2 and an anode of the fourth diode D4, an anode of the second diode D2 is connected with a first end of the first switching tube S1, and an anode of the second diode D2 and a cathode of the fourth diode D4 are connected with the output module; the first end of the fourth capacitor C4 is connected with the first end of the second switch tube S2, the second end of the fourth capacitor C4 is connected with the anode of the third diode D3 and the cathode of the fifth diode D5, the cathode of the third diode D3 is connected with the second end of the second switch tube S2, and the anode of the fifth diode D5 is connected with the output module.
The output module comprises a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, an eighth capacitor C8, a sixth diode D6, a seventh diode D7 and an output load R. A first end of the fifth capacitor C5 is connected with a second end of the eighth capacitor C8, and a first end of the eighth capacitor C8 is connected with a first end of the output load R; a second end of the fifth capacitor C5 is connected with a first end of the sixth capacitor C6, and a second end of the sixth capacitor C6 is connected with a second end of the output load R; the anode of the sixth diode D6 is connected to the first end of the fifth capacitor C5, the cathode of the sixth diode D6 is connected to the anode of the seventh diode D7, and the cathode of the seventh diode D7 is connected to the first end of the eighth capacitor C8. The cathode of the fourth diode D4 is connected to the first end of the fifth capacitor C5, the anode of the second diode D2 is connected to the first end of the sixth capacitor C6, and the anode of the fifth diode D5 is connected to the second end of the sixth capacitor C6.
The first secondary winding Ns1, the second secondary winding Ns2 and the seventh capacitor C7 are connected in series and then connected to two ends of a sixth diode D6 in parallel; specifically, the cathode of the fourth diode D4 is connected to the first end of the fifth capacitor C5, the anode of the second diode D2 is connected to the first end of the sixth capacitor C6, and the anode of the fifth diode D5 is connected to the second end of the sixth capacitor C6.
In this embodiment, the first switch tube S1 is a field effect tube, a first end of the first switch tube S1 is a drain of the field effect tube, a second end of the first switch tube S1 is a source of the field effect tube, and a third end of the first switch tube S1 is a gate of the field effect tube; the second switch tube S2 is a field effect tube, a first end of the second switch tube S2 is a drain electrode of the field effect tube, a second end of the second switch tube S2 is a source electrode of the field effect tube, and a third end of the second switch tube S2 is a gate electrode of the field effect tube.
The superposition type converter based on the coupling inductor provided by the embodiment has six working modes in one working period, which is specifically as follows.
A first modality: the first switching tube S1 is conducted under the action of the first leakage inductance Lk1 at zero current, and the second switching tube S2 is conducted; the first diode D1, the second diode D2, the third diode D3, the fourth diode D4, the fifth diode D5 and the sixth diode D6 are turned off in the reverse direction, and the seventh diode D7 is turned on in the forward direction; the power source Vin charges the first magnetizing inductance Lm1 and the second magnetizing inductance Lm2, and the energy of the second magnetizing inductance Lm2 is transmitted to the eighth capacitor C8 through the second secondary winding Ns2 and the seventh diode D7; the current flow path of the first mode is shown in fig. 2.
And a second working mode: the first switch tube S1 is conducted, the second switch tube S2 is conducted, the first diode D1, the second diode D2, the third diode D3, the fourth diode D4, the fifth diode D5, the sixth diode D6 and the seventh diode D7 are cut off in the reverse direction, and the power source Vin charges the first excitation inductor Lm1, the second excitation inductor Lm2, the first leakage inductor Lk1 and the second leakage inductor Lk 2; the current flow path of the second mode is shown in fig. 3.
The third working mode is as follows: the first switch tube S1 is conducted, the second switch tube S2 is turned off, the third diode D3, the fourth diode D4 and the sixth diode D6 are conducted in the forward direction, the fourth capacitor C4 is charged by the second leakage inductor Lk2, and the voltage stress of the second switch tube S2 is clamped on the voltage of the fourth capacitor C4; part of energy of the second magnetizing inductance Lm2 and part of energy of the third capacitor C3 charge the fifth capacitor C5 through the fourth diode D4, and the remaining energy of the second magnetizing inductance Lm2 and the remaining energy of the third capacitor C3 charge the sixth diode D6 and the seventh capacitor C7 through the second secondary winding Ns2; the current flow path of the third mode is shown in fig. 4.
The fourth working mode: the first switch tube S1 is conducted, and the second switch tube S2 is conducted under the action of the second leakage inductance Lk2 in a zero current mode; the first diode D1, the second diode D2, the third diode D3, the fourth diode D4, the fifth diode D5, the sixth diode D6 and the seventh diode D7 are turned off; a power supply Vin charges a first excitation inductor Lm1 and a second excitation inductor Lm2; the current flow path of the fourth mode is shown in fig. 5.
A fifth working mode: the first switch tube S1 is turned off, the second switch tube S2 is turned on, the first diode D1 is turned on, and the second diode D2, the third diode D3, the fourth diode D4, the fifth diode D5, the sixth diode D6 and the seventh diode D7 are reversely cut off; the power source Vin charges a first excitation inductor Lm1, a second excitation inductor Lm2, a first leakage inductor Lk1 and a second leakage inductor Lk 2; the current flow path of the fifth mode is shown in fig. 6.
A sixth working mode: the first switch tube S1 is turned off, the second switch tube S2 is turned on, the first diode D1, the second diode D2, the fifth diode D5 and the seventh diode D7 are turned on in the forward direction, and the third diode D3, the fourth diode D4 and the sixth diode D6 are turned off in the reverse direction; the energy of the first leakage inductor Lk1 is transmitted to the first capacitor C1, and the voltage stress of the first switch tube S1 is clamped on the voltage of the third capacitor C3; part of energy of the first excitation inductor Lm1 and part of energy of the second capacitor C2 are transmitted to the sixth capacitor C6 through the first diode D1, and the remaining energy of the first excitation inductor Lm1, the remaining energy of the second capacitor C2 and the energy of the seventh capacitor C7 are transmitted to the eighth capacitor C8 through the first secondary winding Ns1, the second secondary winding Ns2 and the seventh diode D7, so as to charge the eighth capacitor C8; the current flow path in the sixth mode is shown in fig. 7.
In the superimposed converter based on the coupled inductor provided in this embodiment, in one duty cycle, theoretical waveforms of the diodes D2, D3, D4, D5, D6, D7 and the switching tubes S1, S2 are as shown in fig. 8, where,V gs1 is the gate-source voltage of the first switch tube S1,V gs2 is the gate-source voltage of the second switching tube S2,i Lm1 being the current of the first magnetizing inductance Lm1,i Lm2 being the current of the second magnetizing inductance Lm2,i in an input current of a power source Vin;i Lk1 is the current of the first leakage inductance Lk1,i Lk2 is the current of the second leakage inductance Lk2,i ds1 is the drain-source current of the first switch tube S1,i ds2 is the drain-source current of the second switch tube S2,i D2 is the current of the second diode D2,i D3 is the current of the third diode D3,i D4 is the current of the fourth diode D4,i D5 is the current of the fifth diode D5,i D6 is the current of the sixth diode D6,i D7 the current of the seventh diode D7 is Ts, the duty cycle of the first switching tube S1, and D is the duty cycle of the first switching tube S1. In the figure, during one working cycle,t 0 tot 1 The time period corresponds to a first modality,t 1 tot 2 The time period corresponds to the second modality,t 2 to is thatt 3 The time period corresponds to a third modality,t 3 to is thatt 4 The time period corresponds to a fourth modality,t 4 to is thatt 5 The time period corresponds to a fifth modality,t 5 tot 0 ´The time period corresponds to a sixth modality,t 0 ´to is thatt 2 ´Belonging to the next working cycle。
The superposed converter based on the coupled inductor provided in this embodiment has a high voltage gain, and the gain calculation method is as follows.
Since the first leakage inductance Lk1 and the second leakage inductance Lk2 have little influence on the steady-state performance, the influence of the first leakage inductance Lk1 and the second leakage inductance Lk2 is ignored for simplifying the analysis. Since the power source Vin charges the first magnetizing inductance Lm1 and the second magnetizing inductance Lm2, respectively, the voltages of the first magnetizing inductance Lm1 and the second magnetizing inductance Lm2 are as follows:
in the formula (I), the compound is shown in the specification,V Lm1 is the voltage of the first magnetizing inductance Lm1,V in is the voltage of the power supply Vin,V C1 is the voltage across the first capacitor C1;V Lm2 is the voltage of the first magnetizing inductance Lm 1.
According to the "volt-second balance" law, the voltage of the clamp capacitor can be expressed as follows:
the clamping capacitance comprises a third capacitance C3 and a fourth capacitance C4, wherein,V C3 is the voltage across the third capacitor C3,V C4 is the voltage across the fourth capacitor C4, d is the duty cycle of the first switching tube S1,V in is the voltage of the power source Vin.
According to the third mode of the loop column writing KVL equation, the voltage relationship between the two ends of the fifth capacitor C5 and the seventh capacitor C7 is as follows:
in the formula (I), the compound is shown in the specification,V C5 is the voltage across the fifth capacitor C5,V C6 is the voltage across the sixth capacitor C6,V in is the voltage of the power supply Vin,V Lm1 is the voltage of the first magnetizing inductance Lm1,V C3 is the voltage across the third capacitor C3, d is the duty cycle of the first switching tube S1,V C7 is the voltage across the seventh capacitor C7,V Lm2 is the voltage of the second magnetizing inductance Lm2, and n is the turns ratio of the first coupling inductance.
Similarly, according to the current loop column of the fifth mode, the KVL equation is written, and the voltage relationship between the two ends of the eighth capacitor C8 is as follows:
in the formula (I), the compound is shown in the specification,V C8 is the voltage across the eighth capacitor C8, n is the turns ratio of the first coupling inductor,V Lm1 is the voltage of the first magnetizing inductance Lm1,V Lm2 is the voltage of the second magnetizing inductance Lm2,V C7 is the voltage across the seventh capacitor C7, d is the duty cycle of the first switching tube S1,V in is the voltage of the power source Vin.
According to the output circuit of the circuit, the output voltage of the circuit is provided by the output capacitor, and the output capacitor comprises a fifth capacitor C5, a sixth capacitor C6 and an eighth capacitor C8. Thus, the output voltage of the converter is represented as:
in the formula (I), the compound is shown in the specification,V o to output a voltage, i.e. the voltage across the output load R,V C5 is the voltage across the fifth capacitor C5,V C6 is the voltage across the sixth capacitor C6,V C8 is the voltage across the eighth capacitor C8, n is the turns ratio of the first coupling inductor, d is the duty cycle of the first switching tube S1,V in is the voltage of the power source Vin.
Therefore, the voltage gain of the superimposed converter based on the coupled inductor provided by this embodiment is expressed as:
wherein G is a voltage gain, n is a turn ratio of the first coupling inductor, and d is a duty ratio of the first switching tube S1.
According to the superposed converter based on the coupling inductor, the ports of the boost converter and the quasi-Z source module are connected in parallel for input and in series for output, and the clamping module is arranged, so that the superposed converter still has clamping and boosting functions, and the structural characteristics of parallel input and series output can reduce the volumes of a magnetic element and a capacitor, reduce the voltage withstanding value selection requirement of the capacitor, be replaced into a high-performance device and improve the power density and efficiency of a system. The boost converter at the input end is connected with the port of the quasi-Z source module in parallel, the first switch tube S1 and the second switch tube S2 are connected in parallel in a staggered mode, the current stress and the voltage stress of the first switch tube S1 and the second switch tube S2 are small, the power grade of the converter can be improved, the work of the diodes D2, D3, D4, D5, D6 and D7 is staggered, and the voltage stress of the diodes D2, D3, D4, D5, D6 and D7 can be effectively reduced; the output port boost converter and the quasi-Z source module are connected in series, namely the output ends are overlapped, overlapping is stable, and current ripple and output voltage ripple of the output ends are reduced.
The output side is connected in series with the seventh capacitor C7 through the first secondary winding Ns1, the second secondary winding Ns2 to form a voltage doubling unit, so that the output gain can be improved, and the superposition type converter can obtain an ideal gain under a proper duty ratio.
The clamping module can absorb the energy of the first leakage inductor Lk1 and the second leakage inductor Lk2, reduce the voltage stress of the first switching tube S1 and the second switching tube S2, and clamp the voltage of the first switching tube S1 and the second switching tube S2 at a lower capacitor voltage.
Example 3
The embodiment provides a control method of a superposition type converter based on coupling inductance, which comprises the following steps:
generating a first control signal and a second control signal, wherein the frequency of the first control signal is the same as that of the second control signal, the phase difference between the first control signal and the second control signal is 180 degrees, and the duty ratio of the first control signal and the duty ratio of the second control signal are respectively greater than 0.5;
transmitting the first control signal to a third end of the first switch tube S1, and controlling the on-off of the first switch tube S1; the second control signal is transmitted to the third end of the second switch tube S2, and the second switch tube S2 is controlled to be switched on and off.
The period of the first control signal and the period of the second control signal meet the following six working modes of the superposition type converter based on the coupling inductor:
a first modality: the first switching tube S1 is conducted under the action of the first leakage inductance Lk1 at zero current, and the second switching tube S2 is conducted; the first diode D1, the second diode D2, the third diode D3, the fourth diode D4, the fifth diode D5 and the sixth diode D6 are turned off in the reverse direction, and the seventh diode D7 is turned on in the forward direction; the power source Vin charges the first magnetizing inductance Lm1 and the second magnetizing inductance Lm2, and the energy of the second magnetizing inductance Lm2 is transmitted to the eighth capacitor C8 through the second secondary winding Ns2 and the seventh diode D7; the current flow path of the first mode is shown in fig. 2.
The second working mode is as follows: the first switch tube S1 is conducted, the second switch tube S2 is conducted, the first diode D1, the second diode D2, the third diode D3, the fourth diode D4, the fifth diode D5, the sixth diode D6 and the seventh diode D7 are reversely cut off, and the power supply Vin charges the first excitation inductor Lm1, the second excitation inductor Lm2, the first leakage inductor Lk1 and the second leakage inductor Lk 2; the current flow path in the second mode is shown in fig. 3.
The third working mode is as follows: the first switch tube S1 is conducted, the second switch tube S2 is turned off, the third diode D3, the fourth diode D4 and the sixth diode D6 are conducted in the forward direction, the first diode D1, the second diode D2, the fifth diode D5 and the seventh diode D7 are turned off, the second leakage inductor Lk2 charges the fourth capacitor C4, and the voltage stress of the second switch tube S2 is clamped on the voltage of the fourth capacitor C4; part of energy of the second magnetizing inductance Lm2 and part of energy of the third capacitor C3 charge the fifth capacitor C5 through the fourth diode D4, and the remaining energy of the second magnetizing inductance Lm2 and the remaining energy of the third capacitor C3 charge the sixth diode D6 and the seventh capacitor C7 through the second secondary winding Ns2; the current flow path of the third mode is shown in fig. 4.
The fourth working mode: the first switching tube S1 is conducted, and the second switching tube S2 is conducted under the action of the second leakage inductance Lk2 at zero current; the first diode D1, the second diode D2, the third diode D3, the fourth diode D4, the fifth diode D5, the sixth diode D6 and the seventh diode D7 are reversely turned off; a power supply Vin charges a first excitation inductor Lm1 and a second excitation inductor Lm2; the current flow path of the fourth mode is shown in fig. 5.
A fifth working mode: the first switch tube S1 is turned off, the second switch tube S2 is turned on, the first diode D1 is turned on, and the second diode D2, the third diode D3, the fourth diode D4, the fifth diode D5, the sixth diode D6 and the seventh diode D7 are reversely cut off; the power source Vin charges a first excitation inductor Lm1, a second excitation inductor Lm2, a first leakage inductor Lk1 and a second leakage inductor Lk 2; the current flow path of the fifth mode is shown in fig. 6.
A sixth working mode: the first switch tube S1 is turned off, the second switch tube S2 is turned on, the first diode D1, the second diode D2, the fifth diode D5 and the seventh diode D7 are turned on in the forward direction, and the third diode D3, the fourth diode D4 and the sixth diode D6 are turned off in the reverse direction; the energy of the first leakage inductance Lk1 is transmitted to the first capacitor C1, and the voltage stress of the first switch tube S1 is clamped to the voltage of the third capacitor C3; part of the energy of the first magnetizing inductance Lm1 and part of the energy of the second capacitor C2 is transferred to the sixth capacitor C6 through the first diode D1, and the remaining energy of the first magnetizing inductance Lm1, the remaining energy of the second capacitor C2, and the energy of the seventh capacitor C7 are transferred to the eighth capacitor C8. The current flow path in the sixth mode is shown in fig. 7.
It is understood that the same or similar parts in the above embodiments may be mutually referred to, and the same or similar contents in other embodiments may be referred to for the contents which are not described in detail in some embodiments.
It should be noted that, in the description of the present invention, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Further, in the description of the present invention, the meaning of "a plurality" means at least two unless otherwise specified.
Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and alternate implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present invention.
It should be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.
It will be understood by those skilled in the art that all or part of the steps carried out in the method of implementing the above embodiments may be implemented by hardware related to instructions of a program, which may be stored in a computer readable storage medium, and the program, when executed, includes one or a combination of the steps of the method embodiments.
In addition, functional units in the embodiments of the present invention may be integrated into one processing module, or each unit may exist alone physically, or two or more units are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. The integrated module, if implemented in the form of a software functional module and sold or used as a stand-alone product, may also be stored in a computer readable storage medium.
The storage medium mentioned above may be a read-only memory, a magnetic or optical disk, etc.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.