CN110071650A - Eight Switch Three Winding Power Electronic Transformer - Google Patents

Abstract

The invention discloses an eight-switch three-winding power electronic transformer which comprises two primary windings, one secondary winding and eight one-way switches, wherein each one-way switch is a power device, the eight one-way switches are divided into a group of switch groups in pairs, the conduction directions of the two one-way switches in each group of switch groups are opposite, the two primary windings are respectively connected with the positive electrode and the negative electrode of a direct-current voltage source at an input side through four groups of switch groups, and the two primary windings are switched to be in an excitation state by the four groups of switch groups. Compared with the prior art, the invention reduces equivalent transformer leakage inductance and improves the efficiency of transformer energy transmission by alternately exciting the primary windings and the two windings, and the current stress of a power device cannot be increased due to the reduction of the excitation inductance.

Description

Eight Switch Three Winding Power Electronic Transformer

technical field

The invention relates to the field of transformers, in particular to an eight-switch three-winding power electronic transformer.

Background technique

Transformers usually use primary and secondary double windings for energy transfer, and convert direct current into high-frequency alternating current through the full-bridge inverter circuit on the primary side. However, due to the limitation of the manufacturing process, the leakage inductance of the transformer will reduce the energy transmission efficiency. Consider improving the transformer circuit topology, magnetic core, winding structure, etc., to reduce the loss caused by leakage inductance, so as to improve the energy transmission efficiency of the transformer.

SUMMARY OF THE INVENTION The purpose of the present invention is to provide an eight-switch three-winding power electronic transformer, so as to solve the problem of reducing the transmission efficiency caused by the large leakage inductance of the transformer in the prior art.

In order to achieve the above object, the technical scheme adopted in the present invention is:

The eight-switch three-winding power electronic transformer includes two independent primary windings and one secondary winding, and is characterized in that it also includes eight one-way switches, each one-way switch is a power device, and the eight one-way switches are two The two are divided into one group and are divided into four groups of switch groups. The two one-way switches in each group of switch groups have opposite conduction directions. At the same time, the negative pole of the input side DC voltage source is connected through the second group of switches, the other ends of the two primary windings are connected to the positive pole of the input side DC voltage source through the third group of switches, and the input side DC voltage source is connected through the fourth group of switches. Negative pole, the two-way primary windings are switched to be in the excitation state by four groups of switch groups.

The eight-switch three-winding power electronic transformer is characterized in that: among the eight one-way switches, the emitter of the first one-way switch and the collector of the second one-way switch are commonly connected to the input side DC voltage The positive pole of the source, the collector of the first one-way switch is connected to one end of the primary winding of the second way, and the emitter of the second one-way switch is connected to one end of the primary winding of the first way. The one-way switch constitutes the first group of switches;

The emitter of the third one-way switch is connected with the collector of the fourth one-way switch and then connected to the negative pole of the DC voltage source on the input side. The collector of the third one-way switch is connected to one end of the primary winding of the second channel. The emitters of the four one-way switches are connected to one end of the first primary winding, and the third one-way switch and the fourth one-way switch form a second group of switches;

The emitter of the fifth one-way switch and the collector of the sixth one-way switch are connected to the positive pole of the input side DC voltage source, and the collector of the fifth one-way switch is connected to the other end of the first primary winding, The emitter of the sixth one-way switch is connected to the other end of the second primary winding, and the fifth one-way switch and the sixth one-way switch form a third group of switches;

The emitter of the seventh one-way switch and the collector of the eighth one-way switch are connected to the negative pole of the input side DC voltage source, and the collector of the seventh one-way switch is connected to the other end of the first primary winding, The emitter of the eighth one-way switch is connected to the other end of the second primary winding, and the seventh one-way switch and the eighth one-way switch constitute a fourth group of switches.

The eight-switch three-winding power electronic transformer is characterized in that: when the first group of switch groups and the fourth group of switch groups are turned on, the forward voltage of the DC voltage source on the input side passes through the second switch group in the first group of switch groups. The one-way switch and the seventh one-way switch in the fourth group of switches are applied to the first primary winding, thereby realizing the excitation state of the first primary winding. At this time, the reverse voltage of the DC voltage source on the input side The eighth one-way switch in the fourth group of switches and the first one-way switch in the first group of switches are applied to the second primary winding to reduce the current flowing through the second primary winding .

The eight-switch three-winding power electronic transformer is characterized in that: when the second group of switch groups and the third group of switch groups are turned on, the voltage of the DC voltage source on the input side passes through the sixth one-way in the third group of switch groups. The switch and the third one-way switch in the second switch group are applied to the second primary winding, thereby realizing the excitation state of the second primary winding. At this time, the reverse voltage of the DC voltage source on the input side passes through the first winding. The fourth one-way switch in the second switch group and the fifth one-way switch in the third switch group are applied to the first primary winding to reduce the current flowing through the first primary winding.

The invention includes eight one-way switches, two transformer primary windings and one transformer secondary winding, wherein the eight one-way switches are power devices in the circuit. The present invention has two groups of working states, namely, the excitation state of the first primary winding and the excitation state of the second primary winding. When in the excitation state of the first primary winding, the corresponding four one-way switches are turned on, the DC voltage source on the input side is applied to both ends of the first primary winding, and the current flowing through the first primary winding increases, The current flowing through the second primary winding decreases. In the excitation state of the second primary winding, the corresponding other four one-way switches are turned on, the DC voltage source on the input side is applied to both ends of the second primary winding, and the current flowing through the second primary winding increases , the current flowing through the first primary winding decreases. In this way, the high-frequency inversion of the DC voltage on the input side and the energy transmission from the primary side to the secondary side of the transformer are realized.

The invention controls the high-frequency changes of the voltages at both ends of the two primary windings through the two groups of switch states of the eight one-way switches, so as to realize the transfer of energy from the primary to the secondary, and the two primary windings do not operate in parallel. The reduction of the excitation inductance will not lead to an increase in the current stress of the power devices in the circuit, but the primary leakage inductance will have a parallel effect, reducing the leakage inductance, which can reduce the loss caused by the leakage inductance and improve the energy transmission efficiency of the transformer. .

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

1. The parallel effect of the leakage inductance of the transformer is realized by alternating excitation of the two windings on the primary side, reducing the equivalent leakage inductance of the transformer and improving the efficiency of the energy transmission of the transformer.

2. The two primary windings will not cause the parallel operation of the excitation inductance, so the current stress of the power device will not be increased due to the reduction of the excitation inductance.

Description of drawings

Fig. 1 is the circuit diagram of the transformer of the present invention.

FIG. 2 is a circuit diagram of the present invention when the primary winding of the first path is in the excitation state.

FIG. 3 is a circuit diagram of the present invention when the primary winding of the second path is in the excitation state.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

As shown in Figure 1, the eight-switch three-winding power electronic transformer includes two independent primary windings L ₁ , L ₂ and one secondary winding L ₃ , and also includes eight one-way switches S ₁₁ , S ₁₂ , S ₂₁ , S ₂₂ , S ₃₁ , S ₃₂ , S ₄₁ , S ₄₂ , each one-way switch is a power device, and the eight one-way switches are divided into two groups, divided into four groups of switch groups, each group of switch groups The conduction directions of the two one-way switches are opposite, and one end of each of the two primary windings L ₁ and L ₂ is connected to the positive pole of the input-side DC voltage source U _DC through the first group of switches, and at the same time, it is connected to the input-side DC through the second group of switches. The negative pole of the voltage source U _DC , the other ends of the two primary windings L ₁ and L ₂ are respectively connected to the positive pole of the input side DC voltage source U _DC through the third group of switches, and at the same time are connected to the input side DC voltage source U _DC through the fourth group of switches. For the negative pole, the two primary windings are switched to be in the excitation state by four groups of switch groups, and the secondary winding L3 outputs a high _- frequency DC voltage U _O .

Among the eight one-way switches, the emitter of the first one-way switch _S11 and the collector of the second one-way switch _S12 are connected to the positive pole of the input side DC voltage source U _DC , and the first one-way switch The collector of _S11 is connected to one end of the _second primary winding L2, and the _emitter of the second one-way switch _S12 is connected to _one end of the first primary winding L1. One-way switches S ₁₂ constitute the first switch group;

The emitter of the third one-way switch _S21 and the collector of the fourth one-way switch _S22 are connected to the negative electrode of the input side DC voltage source U _DC , and the collector of the third one-way switch _S21 is connected to the third one-way switch S21. One end of the _two -way primary winding L2, the emitter of the fourth one-way switch _S22 is connected to _one end of the first-way primary winding L1, which is composed of the third one-way switch _S21 and the fourth one-way switch _S22 The second group of switches;

The emitter of the fifth one-way switch _S31 and the collector of the sixth one-way switch _S32 are connected to the positive pole of the input side DC voltage source U _DC , and the collector of the fifth one-way switch _S31 is connected to the first The other end of one primary winding L1, the emitter of the sixth _one -way switch _S32 is connected to the other end of the _second primary winding L2, by the fifth one-way switch _S31 and the sixth one-way switch S ₃₂ constitute the third switch group;

The emitter of the seventh one-way switch _S41 and the collector of the eighth one-way switch _S42 are connected to the negative electrode of the input side DC voltage source U _DC , and the collector of the seventh one-way switch _S41 is connected to the first The other end of one primary winding L1, the emitter of the eighth _one -way switch _S42 is connected to the other end of the _second primary winding L2, by the seventh one-way switch _S41 and the eighth one-way switch S ₄₂ constitute the fourth switch group.

As shown in FIG. 2 , when the first group of switches and the fourth group of switches are turned on, the forward voltage of the DC voltage source U _DC on the input side passes through the second one-way switch S ₁₂ , the second one in the first group of switches The seventh one-way switch S ₄₁ in the four switch groups is applied to the first primary winding L ₁ , thereby realizing the excitation state of the first primary winding L ₁ . At this time, the input side DC voltage source U _DC The reverse voltage is applied to the second primary winding L ₂ through the eighth one-way switch S ₄₂ in the fourth switch group and the first one-way switch S ₁₁ in the first switch group, so that the reverse voltage flows through the first one-way switch S 11 in the first switch group. _The current of the secondary winding L2 decreases.

When in the excitation state of the first primary winding, the corresponding four switches S ₁₁ , S ₁₂ , S ₄₁ and S ₄₂ are turned on, and the DC voltage source U _DC on the input side is applied to both ends of the primary winding L ₁ , The voltage at both ends of L ₁ is positive and negative at the bottom. The direction of the current flowing through the first primary winding L ₁ is from top to bottom, and the magnitude increases. The current flowing through the second primary winding L ₂ is from bottom to top, and the magnitude decreases. Small.

As shown in FIG. 3 , when the second group of switch groups and the third group of switch groups are turned on, the voltage of the DC voltage source U _DC on the input side passes through the sixth one-way switch S ₃₂ in the third group of switch groups, the second group of The third one-way switch S ₂₁ in the switch group is applied to the second primary winding L ₂ , thereby realizing the excitation state of the second primary winding L ₂ . At this time, the reverse direction of the input side DC voltage source U _DC The voltage is applied to the primary winding L ₁ of the first channel through the fourth one-way switch S ₂₂ in the second switch group and the fifth one-way switch S ₃₁ in the third switch group, so that the voltage flows through the first channel _The current in the primary winding L1 decreases.

When in the excitation state of the secondary winding on the primary side, the corresponding other four switches S ₂₁ , S ₂₂ , S ₃₁ , and S ₃₂ are turned on, and the DC voltage source U _DC on the input side is applied to the two terminals of the secondary winding L ₂ on the primary side. terminal, the voltage at _both ends of L2 is negative and positive at the bottom, the current flowing through the _second primary winding L2 increases from bottom to top, and the direction of the current flowing through the _first primary winding L1 is from top to bottom, size reduction.

The excitation state of the first primary winding and the excitation state of the second primary winding alternately reciprocate to achieve high-frequency inversion of the DC voltage on the input side and energy transmission from the primary side of the transformer to the secondary side.

Claims (4)

1. eight switch three winding electric power electric transformers, including the independent primary side winding of two-way and vice-side winding all the way, feature It is: further includes eight single-way switch, each single-way switch is power device, and eight single-way switch are divided into one group two-by-two, altogether Be divided into four groups of switching groups, two single-way switch conducting directions in every group of switching group on the contrary, two-way primary side winding respectively one end passes through First group of switching group connection input side DC voltage source anode passes through second group of switching group connection input side DC voltage source simultaneously Cathode, respectively the other end is positive by third group switching group connection input side DC voltage source for two-way primary side winding, passes through simultaneously 4th group of switching group connects input side DC voltage source cathode, makes the switching of two-way primary side winding in excitation shape by four groups of switching groups State.

2. eight switches three winding electric power electric transformer according to claim 1, it is characterised in that: eight single-way switch In, the emitter of first single-way switch and the collector of second single-way switch are connected to input side DC voltage source after connecing altogether Anode, the collector of first single-way switch connect second tunnel primary side winding one end, the emitter connection of second single-way switch First via primary side winding one end constitutes first group of switching group by first single-way switch and second single-way switch；

The collector of the emitter of third single-way switch and the 4th single-way switch is connected to input side DC voltage after connecing altogether Source cathode, the collector of third single-way switch connect second tunnel primary side winding one end, and the emitter of the 4th single-way switch connects First via primary side winding one end is connect, second group of switching group is constituted by third single-way switch and the 4th single-way switch；

The emitter of 5th single-way switch and the collector of the 6th single-way switch are connected to input side DC voltage after connecing altogether The collector of source anode, the 5th single-way switch connects the first via primary side winding other end, the emitter of the 6th single-way switch The second tunnel primary side winding other end is connected, third group switching group is constituted by the 5th single-way switch and the 6th single-way switch；

The emitter of 7th single-way switch and the collector of the 8th single-way switch are connected to input side DC voltage after connecing altogether The collector of source cathode, the 7th single-way switch connects the first via primary side winding other end, the emitter of the 8th single-way switch The second tunnel primary side winding other end is connected, the 4th group of switching group is constituted by the 7th single-way switch and the 8th single-way switch.

3. eight switches three winding electric power electric transformer according to claim 2, it is characterised in that: first group of switching group and When the 4th group of switching group conducting, the forward voltage of input side DC voltage source is unidirectionally opened by second in first group of switching group The 7th single-way switch in pass, the 4th group of switching group is applied to first via primary side winding, is achieved in first via primary side Winding excited state, the backward voltage of input side DC voltage source is unidirectionally opened by the 8th in the 4th group of switching group at this time First single-way switch in pass, first group of switching group is applied to the second tunnel primary side winding, makes to flow through the second tunnel primary side winding Electric current reduces.

4. eight switches three winding electric power electric transformer according to claim 2, it is characterised in that: second group of switching group and When third group switching group is connected, the voltage of input side DC voltage source by the 6th single-way switch in third group switching group, Third single-way switch in second group of switching group is applied to the second tunnel primary side winding, is achieved in the second tunnel primary side winding Excited state, the backward voltage of input side DC voltage source passes through the 4th single-way switch in second group of switching group, the at this time The 5th single-way switch in three groups of switching groups is applied to first via primary side winding, subtracts the electric current for flowing through first via primary side winding It is small.