CN202679079U - An energy storage device equalizing charge device applicable to a transformer with a random transformation ratio - Google Patents

Abstract

The utility model provides an energy storage device equalizing charge device applicable to a transformer with a random transformation ratio and belongs to a single voltage equalizing device of an energy storage device group in series. The equalizing charge device comprising a DC/DC converter (1), a DC/AC inverter (2), and n voltage equalizing branches (3) is capable of acquiring energy from the energy storage device group in series and transferring the energy to single energy storage devices with lower terminal voltages in the energy storage device group in series in order to achieve equalized terminal voltages of single energy storage devices in the energy storage device group in series. The equalizing charge device is characterized in that the device is compatible with the transformer with a random transformation ratio, that accuracy requirement of the transformer is low, that the device can be applied to the single energy storage device with random amount of energy storage devices in series after the transformation ratio of the transformer is designed, and that the device has strong flexibility and strong versatility. In addition, low loss is achieved by the low number of required transformers and diodes and all switching tubes equipped with soft switching capability.

Description

A voltage equalizing charging device for energy storage equipment suitable for transformers with any variable ratio

technical field

The utility model proposes a voltage equalizing charging device for energy storage equipment suitable for transformers with arbitrary variable ratios, which belongs to a device for voltage equalizing charging of single energy storage devices connected in series. the

Background technique

Since the voltage of a single energy storage device is generally relatively small, when the single energy storage device is used alone, it often cannot meet the load's requirements for voltage value, power, and discharge time. In practical applications, in order to meet the needs of capacity and voltage value, high-power energy storage systems generally need to be composed of multiple single energy storage devices connected in series and in parallel. During the charging process, due to the discreteness of the parameters among the individual energy storage devices, the voltage rise rate of each individual energy storage device will be different, resulting in an unbalanced voltage of the individual energy storage If the energy storage equipment is overcharged, if things go on like this, it will seriously affect the service life and reliability of the energy storage equipment group. Therefore, voltage equalization measures should be taken for the series energy storage equipment group when charging. the

In recent years, many researchers have conducted in-depth research on the single voltage equalization method of the series energy storage equipment group. At present, the commonly used voltage equalization methods can be divided into two categories: one is the method of energy transfer, such as DC/DC conversion The device method, the flying capacitor method; the other is the method of energy consumption, such as the switch resistance method, the parallel resistance method and the Zener tube method. Although the cost of the energy-consuming voltage equalizing circuit is low and the structure is simple, the energy is wasted and the heat is serious. The energy transfer type voltage equalization circuit consumes less energy in the process of voltage equalization, and has gradually become a research hotspot. A representative energy transfer type voltage equalization scheme-transformer voltage equalization method is introduced below. the

Fig. 1 shows a voltage equalization device for charge compensation of single energy storage devices connected in series as described in the People's Republic of China Patent Application Publication No. CN101369741A. The energy storage device group generates a DC voltage, which is inverted by an inverter (31), and the inverted AC voltage is transmitted to a rectifier through a transformer, and the rectifier rectifies the AC voltage into a DC voltage and converts the AC current into DC current, thereby charging the single energy storage device with the lowest terminal voltage. The voltage equalization device first charges the single energy storage device with the lowest terminal voltage until its terminal voltage rises to the terminal voltage of the single energy storage device with the second lowest terminal voltage, and then the voltage equalization device charges the two single energy storage devices The equipment is charged at the same time until the terminal voltage of the two rises to the terminal voltage of the single energy storage device with the third lowest terminal voltage, and then the voltage equalization device charges the three single energy storage devices at the same time, and so on until all the single energy storage devices The terminal voltages of the energy storage devices are equal and reach one-nth of the terminal voltage of the energy storage device group, and the terminal voltage balance of the individual energy storage devices is realized, and n is a natural number. the

The above-mentioned transformer-based voltage equalization device has shortcomings. The transformer design requires high precision of the transformation ratio, and the device cannot be applied to any number of single energy storage devices in series after the transformation ratio of the transformer is designed, and the flexibility is low. , The versatility is not strong, and the working voltage of the two voltage-dividing capacitors is also unbalanced, and the number of transformers and diodes increases with the number of energy storage devices in series. Assuming that there are n energy storage devices, then you need n transformers and 4n diodes, the number of transformers and diodes is large. the

Utility model content

The existing transformer voltage equalization method requires high precision of transformation ratio, and the designed transformer has low flexibility and poor versatility. As more units of energy storage devices are connected in series, the number of transformers and diodes required also increases. The purpose of this utility model is to provide a voltage equalizing charging device for energy storage equipment suitable for transformers with any variable ratio. It is applied to any number of energy storage equipment groups connected in series, and has high flexibility and strong versatility. And the number of required transformers and diodes is significantly reduced. Assuming that there are 2n energy storage devices, then only n transformers and 2n diodes are needed, which is reduced by half. At the same time, all switching tubes can realize soft switching with low loss. By means of the device, voltage equalization charging of any number of single energy storage devices connected in series can be efficiently realized. the

A device suitable for voltage balancing of supercapacitor cells connected in series, comprising a DC/DC converter (1), a DC/AC inverter (2), and n voltage equalizing branches (3). It is characterized by:

The DC/DC converter (1) is a DC converter composed of a main switch (M ₁ ), diodes (D _a5 , D _a6 ), an inductor (L ₀ ), and a capacitor (C ₀ ), and an auxiliary switch tube (M ₂ ), resonant inductance (L _a ), resonant capacitors (C _a1 , C _a2 ), and diodes (D _a1 , D _a2 , D _a3 , D _a4 ) constitute an auxiliary resonant network. One end of the resonant capacitor (C _a1 ) is connected to the negative pole of the diode (D _a2 ) and the collector of the main switch (M ₁ ) is connected to the positive pole of the energy storage device group; one end of the resonant inductance (L _a ) is connected to The cathode of the diode (D _a1 ), the anode of the diode (D _a2 ) are connected to the other end of the resonant capacitor (C _a1 ); the other end of the resonant inductance (L _a ) is connected to one end of the resonant capacitor (C _a2 ); The other end of the resonant capacitor (C _a2 ) is connected to the cathode of the diode (D _a3 ) and the collector of the auxiliary switch (M ₂ ); the anode of the diode (D _a3 ) is connected to the main switch (M ₁ ) The emitter, the emitter of the auxiliary switch tube (M ₂ ), the cathodes of the diodes (D _a4 , D _a5 ), and one end of the inductor (L ₀ ) are connected; the anode of the diode (D _a5 ) is connected to the capacitor (C ₀ ) One end of the inductor (L ₀ ) is connected to the other end of the capacitor (C ₀ ) and the anode of the diode (D _a1 , D _a5 , D _a6 ); the cathode of the diode (D _a6 ) Connect to the negative pole of the energy storage device group.

The DC/AC converter consists of 4 switching tubes (Q ₁ , Q ₂ , Q ₃ , Q ₄ ), 4 diodes (D _b1 , D _b2 , D _b3 , D _b4 ) and 4 capacitors (C _b1 , C _b2 , C _b3 , C _b4 ). The collector of the switching tube (Q ₃ ), the negative pole of the diode (D _b3 ), one end of the capacitor (C _b3 ), the collector of the switching tube (Q ₄ ), the negative pole of the diode (D _b4 ), the capacitor (C _b4 ), one end of the capacitor (C ₀ ), and the anode of the diode (D _a5 ); the emitter of the switch (Q ₃ ), the anode of the diode (D _b3 ), and the other end of the capacitor (C _b3 ) , the collector of the switch tube (Q ₁ ), the cathode of the diode (D _b1 ) and one end of the capacitor (C _b1 ); the emitter of the switch tube (Q ₄ ), the anode of the diode (D _b4 ), the capacitor The other end of (C _b4 ), the collector of the switch tube (Q ₂ ), the cathode of the diode (D _b2 ) and one end of the capacitor (C _b2 ) are connected; the emitter of the switch tube (Q ₁ ), the diode ( The positive pole of D _b1 ), the other end of the capacitor (C _b1 ), the emitter of the switch tube (Q ₂ ), the positive pole of the diode (D _b2 ), the other end of the capacitor (C _b2 ) and the positive pole of the diode (D _a6 ) connect. The series connection point of the emitter of the switch tube (Q ₃ ) and the collector of the switch tube (Q ₁ ) Point A leads to one end of the inductor (L _b ), and the other end of the inductor (L _b ) is connected to each voltage equalizing branch The terminal with the same name of the primary winding (n ₁ ) of the transformer (T _n ), the series connection point of the emitter of the switch tube (Q ₄ ) and the collector of the switch tube (Q ₂ ) is connected to each voltage equalizing branch at point B. The opposite end of the primary winding (n ₁ ) of the transformer (T _n ).

Each of the n voltage equalizing branches is composed of a transformer (T _n ), a diode (D _2n-1 ), a diode (D _2n ), an energy storage device (E _2n-1 ) and a The energy storage device (E _2n ) is composed. The series connection of the energy storage device (E _2n-1 ) and the series connection of the energy storage device (E _2n ) and the parallel connection of the series connection of the diode (D _2n-1 ) and the diode (D _2n ) , the series point of the energy storage device (E _2n-1 ) and the energy storage device (E _2n ) is connected to the terminal with the same name of the secondary winding (n ₂ ) of the transformer (T _n ), the diode (D _2n-1 ) and the diode (D _2n ) in series with the opposite terminal of the secondary winding (n ₂ ) of the transformer (T _n ).

The subscript n in the above symbols is a natural number. the

The above-mentioned energy storage equipment includes supercapacitors and lithium-ion batteries. the

A method applicable to an energy storage equipment voltage equalization charging device with any variable ratio transformer, characterized in that: the terminal voltage of the energy storage equipment group is first transformed by a DC/DC converter, and then reversed by a DC/AC inverter. Transformation, then through the voltage transformation of the transformer, and then through the AC/DC rectification, and finally the energy of the energy storage equipment group can be transferred to the single energy storage equipment with lower voltage after double transformation. the

Adopting a voltage equalizing charging device for energy storage equipment suitable for transformers with any transformation ratio of the utility model has the following beneficial effects: the device is compatible with transformers with any transformation ratio, and has low requirements on the accuracy of the transformer, and the device is designed after the transformation ratio of the transformer is designed. It can be applied to any number of single energy storage devices connected in series, and has high flexibility and strong versatility. And the number of required transformers and diodes is significantly reduced. Assuming that there are 2n energy storage devices, then only n transformers and 2n diodes are needed, which is reduced by half. At the same time, all switching tubes can realize soft switching with low loss. By means of the device, the voltage equalization charging of the single energy storage devices connected in series can be realized efficiently. the

Description of drawings

Fig. 1 is the schematic diagram of the energy transfer type voltage equalization circuit of patent CN101369741A;

Fig. 2 is the principle block diagram of the voltage equalization device of the present utility model;

Fig. 3 is the circuit schematic diagram of an embodiment of the voltage equalization device of the present utility model;

Fig. 4 is the working state diagram of the DC/DC conversion circuit of this voltage equalization device;

FIG. 5 is a working state diagram of the DC/AC inverter circuit of the voltage equalization device. the

Detailed ways

Fig. 2 is a schematic block diagram of a device for equalizing and charging energy storage devices connected in series according to the present invention. The voltage equalizing charging device includes a DC/DC converter (1), a DC/AC inverter (2) and a plurality of voltage equalizing branches (3), and the number of the voltage equalizing branches (3) is energy storage 1/2 of the number of devices. The terminal voltage of the energy storage device group is transformed by the DC/DC converter (1), then the transformed DC voltage is inverted by the DC/AC converter (2), and finally the inverted AC voltage It is transmitted to the AC/DC rectifier (3) through multiple transformers, and the AC/DC rectifier (3) converts the AC voltage into a DC voltage and applies it to a single energy storage device with a lower voltage at each terminal. the

Fig. 3 shows an embodiment of a voltage equalizing charging device for an energy storage device suitable for a transformer with any variable ratio according to the present invention. The device includes: a DC/DC converter (1), a DC converter composed of a main switch (M ₁ ), diodes (D _a5 , D _a6 ), an inductor (L ₀ ), and a capacitor (C ₀ ). Auxiliary resonant network composed of auxiliary switching tube (M ₂ ), resonant inductor (L _a ), resonant capacitor (C _a1 , C _a2 ), diodes (D _a1 , D _a2 , D _a3 , D _a4 ); a DC/AC inverter The inverter consists of 4 switches (Q ₁ , Q ₂ , Q ₃ , Q ₄ ), 4 diodes (D _b1 , D _b2 , D _b3 , D _b4 ) and 4 capacitors (C _b1 , C _b2 , C _b3 , C _b4 ); and each of the n equalizing branches consists of a transformer (T _n ), a diode (D _2n-1 ), a diode (D _2n ), an energy storage device (E _{2n -1} ) and an energy storage device (E _2n ).

One end of the resonant capacitor (C _a1 ) is connected to the negative pole of the diode (D _a2 ) and the collector of the main switch (M ₁ ) is connected to the positive pole of the energy storage device group; one end of the resonant inductance (L _a ) is connected to The cathode of the diode (D _a1 ), the anode of the diode (D _a2 ) are connected to the other end of the resonant capacitor (C _a1 ); the other end of the resonant inductance (L _a ) is connected to one end of the resonant capacitor (C _a2 ); The other end of the resonant capacitor (C _a2 ) is connected to the cathode of the diode (D _a3 ) and the collector of the auxiliary switch (M ₂ ); the anode of the diode (D _a3 ) is connected to the main switch (M ₁ ) The emitter, the emitter of the auxiliary switch tube (M ₂ ), the cathodes of the diodes (D _a4 , D _a5 ), and one end of the inductor (L ₀ ) are connected; the anode of the diode (D _a5 ) is connected to the capacitor (C ₀ ) One end of the inductor (L ₀ ) is connected to the other end of the capacitor (C ₀ ) and the anode of the diode (D _a1 , D _a5 , D _a6 ); the cathode of the diode (D _a6 ) Connect to the negative pole of the energy storage device group.

The collector of the switching tube (Q ₃ ), the negative pole of the diode (D _b3 ), one end of the capacitor (C _b3 ), the collector of the switching tube (Q ₄ ), the negative pole of the diode (D _b4 ), the capacitor (C _b4 ), one end of the capacitor (C ₀ ), and the anode of the diode (D _a5 ); the emitter of the switch (Q ₃ ), the anode of the diode (D _b3 ), and the other end of the capacitor (C _b3 ) , the collector of the switch tube (Q ₁ ), the cathode of the diode (D _b1 ) and one end of the capacitor (C _b1 ); the emitter of the switch tube (Q ₄ ), the anode of the diode (D _b4 ), the capacitor The other end of (C _b4 ), the collector of the switch tube (Q ₂ ), the cathode of the diode (D _b2 ) and one end of the capacitor (C _b2 ) are connected; the emitter of the switch tube (Q ₁ ), the diode ( The positive pole of D _b1 ), the other end of the capacitor (C _b1 ), the emitter of the switch tube (Q ₂ ), the positive pole of the diode (D _b2 ), the other end of the capacitor (C _b2 ) and the positive pole of the diode (D _a6 ) connect. The series connection point of the emitter of the switch tube (Q ₃ ) and the collector of the switch tube (Q ₁ ) Point A leads to one end of the inductor (L _b ), and the other end of the inductor (L _b ) is connected to each voltage equalizing branch The terminal with the same name of the primary winding (n ₁ ) of the transformer (T _n ), the series connection point of the emitter of the switch tube (Q ₄ ) and the collector of the switch tube (Q ₂ ) is connected to each voltage equalizing branch at point B. The opposite end of the primary winding (n ₁ ) of the transformer (T _n ).

The series connection of the energy storage device (E _2n-1 ) and the series connection of the energy storage device (E _2n ) and the parallel connection of the series connection of the diode (D _2n-1 ) and the diode (D _2n ) , the series point of the energy storage device (E _2n-1 ) and the energy storage device (E _2n ) is connected to the terminal with the same name of the secondary winding (n ₂ ) of the transformer (T _n ), the diode (D _2n-1 ) and the diode (D _2n ) in series with the opposite terminal of the secondary winding (n ₂ ) of the transformer (T _n ).

The subscript n in the above symbols is a natural number. the

In order for ordinary technical personnel to fully understand the working process of the utility model, it will be further explained in conjunction with Fig. 3 below. Here, the analysis is simplified. We assume that all the components in the circuit are ideal, assuming that the terminal voltage of the energy storage device group is U _in , and the storage The average voltage of the energy storage device group is U _V , the voltage of each individual energy storage device is U _En (n is a natural number), the output voltage of the DC/DC converter is U ₀ , and the primary side voltage of the transformers of all equalizing branches and the secondary side voltage are U _AB and U _CD respectively, the transformation ratio of the transformer is K, the current flowing through the inductance L _b is i _P , and the duty cycle of the switching tube M ₁ is D, where U ₀ =U _AB , U _AB =KU _CD , $u_0=\frac{\stackrel{\‾}{\mathrm{D.}}}{\mathrm{D.}-1}{u}_{\mathrm{in}},$ then there is $u_{\mathrm{cd}}=\frac{I}{K}\frac{\stackrel{\‾}{\mathrm{D.}}}{\mathrm{D.}-1}{u}_{\mathrm{in}}.$

可灵活地使变压器副边输出电压的大小稍高于蓄能设备组的端电压n分之一，n为自然数。  In this embodiment, an appropriate voltage-balancing branch transformer transformation ratio K should be selected first, and then the duty ratio D of the main switch (M ₁ ) in the converter should be properly adjusted, according to the formula

The output voltage of the secondary side of the transformer can be flexibly made slightly higher than one-nth of the terminal voltage of the energy storage device group, where n is a natural number.

The DC/DC converter first transforms the terminal voltage U _in of the energy storage device group into U ₀ , and the DC/AC converter inverts the voltage U ₀ output by the DC/DC converter into an AC voltage U _AB , and then transforms the voltage through the transformer is U _{CD ,} since the transformers are connected in parallel and the transformation _ratio is K _, so the secondary side voltage U _CD of each transformer is equal in size. The rectifier diode D 2n _{- 1 corresponding to the single energy storage device E 2n-1} with the lowest terminal voltage and lower than the average voltage U _V in _2n-1 conducts first, and the other rectifier diodes do not conduct, rectifying the AC voltage into DC Voltage, and convert AC current into DC current, thereby charging the single energy storage device E _2n-1 with the lowest terminal voltage among E ₁ , E ₃ ,..., E _2n- 1 and lower than the average voltage U _V . At the same time, the conduction of the rectifier diode clamps the positive half cycle of the secondary voltage U _CD transformed by all equalizing branches to a lower value, so that no current or only a very small current flows into other single energy storage devices.

Similarly, when the AC voltage U _CD is in the negative half duty cycle, at this time E ₂ , E ₄ , ..., E _2n , the single energy storage device E _2n with the lowest terminal voltage and lower than the average voltage U _V corresponds to The rectifier diode D _2n conducts first, and the other rectifier diodes do not conduct, rectifies the AC voltage into a DC voltage, and converts the AC current into a DC current, thereby supplying the lowest terminal voltage to E ₂ , E ₄ ,..., E _2n And charge the single energy storage device E _2n lower than the average voltage U _V. At the same time, the conduction of the rectifier diode clamps the positive half cycle of the secondary voltage U _CD transformed by all equalizing branches to a lower value, so that no current or only a very small current flows into other single energy storage devices. By analogy, it can finally be obtained that the terminal voltages of all single energy storage devices are equal.

Fig. 4 shows a working mode diagram of a DC/DC conversion circuit (1) of a voltage equalizing charging device for an energy storage device suitable for a transformer with any variable ratio according to the present invention. Referring to Figure 4, the working mode of the DC/DC conversion circuit of the voltage equalizing charging device shown in Figure 3 is analyzed. There are 6 working modes as follows:

Mode 1 (t ₀ ): Before t ₀ , as shown in Fig. 5 : the main switch M ₁ is turned on, the auxiliary switch M ₂ is turned off, and the auxiliary network does not work.

Mode 2 (t ₀ -t ₁ ): At t ₀ , the auxiliary switch tube M ₂ conducts with zero current, L _a resonates with C _a1 and C _a2 , the inductor current increases sinusoidally from zero, and the main switch tube M ₁ The current of the current decreases sinusoidally until i _La reaches the maximum value, and the current of the main switching tube M ₁ drops to zero. At this time, the main switching tube M ₁ is turned off, realizing the zero-current shutdown of the main switching tube M ₁ . The current of the main switching tube M ₁ drops to zero, and at this time, the main switching tube M ₁ is turned off, realizing the zero-current shutdown of the main switching tube M ₁ .

Mode 3 (t ₁ -t ₂ ): at t ₁ , the main switching tube M ₁ is turned off, the voltage U _M1 at both ends of the main switching tube rises, and the voltages of the resonant capacitors C _a1 and C _a2 also gradually rise. When U _Cr1 = U _in , D _a1 is turned on, the resonant branch is transferred from M ₂ , L _a , C _a1 and C _a2 to L _a , C _a2 , M ₂ , D0 and D _a1 circuit, the energy stored in the resonant inductor Transferring to the capacitor C _a2 , the current of the resonant inductor L _a gradually decreases, and the current of the freewheeling diode D _a4 gradually increases, and it is connected with zero current. When the resonant inductor current i _La is zero, the voltage across the capacitor C _a2 reaches the maximum value, D _a1 is cut off, and the resonant branch stops resonating. In the circuit, C _a1 is not only used as a resonant capacitor, but also forms a resonant network conversion circuit with D _a1 , and the transfer of the resonant branch composed of C _a1 and D _a1 is to ensure that the energy of the resonant inductance L _a continues to transfer to the capacitor C _a2 to realize the auxiliary switching tube. The key to current shutdown.

Mode 4 (t ₂ -t ₃ ): at t ₂ , i _La = 0, and the current of the auxiliary switch tube M ₂ connected in series with it is also zero, and the auxiliary switch is turned off during the period from t ₂ to before the main power is turned on. The switching tube _M2 can realize zero-current shutdown of the auxiliary tube. After the auxiliary tube is turned off, the auxiliary network stops working, and the circuit operates in the conventional PWM mode in which the inductor L ₀ is in the freewheeling state, which is the freewheeling stage of the inductor L ₀ .

Mode 5 (t ₃ -t ₄ ): At t ₃ , the main switch M ₁ is turned on. On the one hand, the circuit charges the _inductance L ₀ and supplies power to the load. On the other hand, it is the energy reset process of the resonant element. C _a1 and C _a2 resonate, and the voltage U _Cr1 across the capacitor C _a1 decreases gradually.

Mode 6 (t ₄ -t ₅ ) At t ₄ , when U _Cr1 = 0, D _a2 is turned on, and L _a and C _a2 continue to resonate until the resonant inductance L _a current I _La = 0, D _a3 and D in the resonance When _a2 is cut off, the circuit stops resonating, and the energy of the resonant inductance is fully transferred to the capacitor. The voltage of C _a2 is kept at -U _{Cr max} , and the voltage of C _a1 is kept at zero, preparing for the zero-current shutdown of the main switch in the next switching cycle. After t ₅ , the auxiliary network does not work, and the circuit returns to the conventional PWM operation mode, repeating the work of the last switching cycle. Therefore, the main switching tube M ₁ and the auxiliary switching tube M ₂ belong to zero-current turn-on and zero-current switching-off, realizing soft switching of the switching tubes M ₁ and M ₂ .

Fig. 5 is a working mode diagram of an inverter circuit (2) of a voltage equalizing charging device for an energy storage device suitable for a transformer with any variable ratio according to the utility model. Assuming that the transformation ratio of the transformer is K=N ₁ /N ₂ , Q ₁ and Q ₄ are turned on before time t ₀ , U _AB ＝U ₀ , the output voltage ratio U _K ＝U ₀ N ₂ /N ₁ , the resonant inductor current i _P =i _Lb N ₂ /N ₁ , U _C1 =U _C3 =0, U _C2 =U _C4 =U ₀ . Referring to Figure 5, the working mode of the inverter circuit of the voltage equalization device shown in Figure 3 is analyzed. There are five working modes as follows:

Mode 1 (t ₀ ): at t ₀ , the switching tubes Q ₁ and Q ₄ are turned on, U _AB is positive, the current i _Lb rises from zero, and the transformer secondary voltage U _CD of the equalizing branch is positive, so E ₁ , E ₃ ,..., E _2n-1 The rectifier diode D _2n -1 of the voltage equalizing branch corresponding to one or more single energy storage devices E _2n-1 whose mid-terminal voltage is lower than the transformer secondary voltage Turned on, the transformer primary current flows through the switch tube Q ₄ , capacitor C ₀ , switch tube Q ₁ and leakage inductance L _b , and the transformer secondary current flows through the rectifier diode D _2n-1 and the single energy storage device E _2n-1 , so as to charge one or more single energy storage devices E _2n-1 whose middle-end voltage of E ₁ , E ₃ , ..., E _2n-1 is lower than the voltage of the secondary side of the transformer.

Mode 2 (t ₀ -t ₁ ): At t ₀ , Q ₁ is turned off, i _Q1 starts to drop, capacitor C _b1 starts to charge from 0, U _Cb1 gradually rises, and Q ₁ is softly turned off. At this stage, L _b and the equivalent inductance of the primary side of the transformer release the stored energy through Q ₄ and D _b3 , because the equivalent inductance of the primary side K ² L is relatively large, so that the primary current i _P drops very slowly and basically remains unchanged. Transformer primary side voltage U _AB gradually decreases with the charging of U _Cb1 and the discharge of U _Cb3 , until t ₁ is U _AB = 0, and the output U ₀ also changes to 0 at the same time.

Mode 3 (t ₁ -t ₂ ): At t ₁ , because C _b3 is discharged and i _P > 0, D _b3 is turned on, i _P freewheels through Lr-Q ₄ -D _b3 , and i _P drops. In t ₁ -t _2, because D _b3 is turned on, U _Cb3 =0, so Q ₃ can be turned on in zero voltage state.

Mode 4 (t ₂ -t ₃ ): At t ₂ , Q ₄ will be turned off, and C _b4 connected in parallel with it will take a certain time to charge, so Q ₄ can be turned off in a zero-voltage state. With the charging of C _b4 , U _Cb4 rises, the potential of point B rises, U _AB gradually increases from 0 in the opposite direction, and U _AB enters the negative half cycle. The charging current of C _b4 is still the freewheeling current of the equivalent inductance and L _b . On the one hand, this current charges C _b4 through C _b4 -D _b3 -L _b , and at the same time feeds back the energy storage through C ₂ -C ₀ -D _b3 power supply.

Mode 5 (t ₃ -t ₄ -t ₅ ): At t ₃ , when C _b2 is discharged, D _b2 is turned on, and U _Cb2 is 0, so Q ₂ can be turned on at zero voltage state, so i _P passes through D _b2 and D _b3 continues to flow, and the current drops rapidly. At t ₄ , i _P reaches 0, because Q ₂ and Q ₃ start to conduct, i _P increases negatively, and L _b reversely stores energy. During t ₄ -t ₅ U _AB ＝-U ₀ , U _d ＝U ₀ N ₂ /N ₁ , the transformer primary side voltage U _AB of the voltage equalizing branch is negative, so E ₂ , E ₄ ,..., The rectifier diode D _2n of the voltage equalizing branch corresponding to one or more single energy storage devices E _2n whose _terminal voltage is lower than the absolute value of the secondary side voltage of the transformer is turned on, and the original current of the transformer passes through the switch tube Q ₃ , Capacitor C ₀ , switch tube Q ₂ and leakage inductance L _b flow, the transformer secondary current flows through rectifier diode D _2n and single energy storage device E _2n , thereby to E ₂ , E ₄ ,..., E _2n One or more single energy storage devices E _2n whose terminal voltage is lower than the absolute value of the secondary side voltage of the transformer are charged.

The commutation situation after t ₅ is similar to the above analysis process, and the t ₆ -t ₁₁ stage can be deduced in the same way. Therefore, the switch tubes Q ₁ , Q ₂ , Q ₃ , and Q ₄ belong to zero-voltage turn-on and zero-voltage turn-off, and soft switching of the switch tubes Q ₁ , Q ₂ , Q ₃ , and Q ₄ is realized.

Claims (2)

1. an energy storage system that is applicable to any no-load voltage ratio transformer is all pressed charging device, comprises a DC/DC converter (1), a DC/AC inverter (2), the individual branch road (3) of all pressing of n; It is characterized in that, described DC/DC converter (1) is by main open pipe (M ₁), diode (D _A5, D _A6), inductance (L ₀), electric capacity (C ₀) DC converter that forms, by auxiliary switch (M ₂), resonant inductance (L _a), resonant capacitance (C _A1, C _A2), diode (D _A1, D _A2, D _A3, D _A4) auxiliary resonant net that forms, described resonant capacitance (C _A1) an end and diode (D _A2) negative pole and main switch (M ₁) collector electrode be connected described resonant inductance (L with the positive pole of energy storage system group _a) an end and diode (D _A1) negative pole, diode (D _A2) positive pole and resonant capacitance (C _A1) the other end link to each other described resonant inductance (L _a) the other end and resonant capacitance (C _A2) an end be connected described resonant capacitance (C _A2) the other end and diode (D _A3) negative pole, auxiliary switch (M ₂) collector electrode be connected described diode (D _A3) positive pole and main switch (M ₁) emitter, auxiliary switch (M ₂) emitter, diode (D _A4, D _A5) negative pole, inductance (L ₀) an end be connected described diode (D _A5) positive pole and electric capacity (C ₀) an end be connected described inductance (L ₀) the other end and electric capacity (C ₀) the other end, diode (D _A1, D _A5, D _A6) positive pole be connected described diode (D _A6) negative pole be connected with the negative pole of energy storage system group; Described DC/AC inverter (2) is by 4 switching tube (Q ₁, Q ₂, Q ₃, Q ₄), 4 diode (D _B1, D _B2, D _B3, D _B4) and 4 electric capacity (C _B1, C _B2, C _B3, C _B4) form described switching tube (Q ₃) collector electrode, diode (D _B3) negative pole, electric capacity (C _B3) an end, switching tube (Q ₄) collector electrode, diode (D _B4) negative pole, electric capacity (C _B4) an end, electric capacity (C ₀) an end, diode (D _A5) positive pole be connected described switching tube (Q ₃) emitter, diode (D _B3) positive pole, electric capacity (C _B3) the other end, switching tube (Q ₁) collector electrode, diode (D _B1) negative pole and electric capacity (C _B1) an end be connected described switching tube (Q ₄) emitter, diode (D _B4) positive pole, electric capacity (C _B4) the other end, switching tube (Q ₂) collector electrode, diode (D _B2) negative pole and electric capacity (C _B2) an end be connected described switching tube (Q ₁) emitter, diode (D _B1) positive pole, electric capacity (C _B1) the other end, switching tube (Q ₂) emitter, diode (D _B2) positive pole, electric capacity (C _B2) the other end and diode (D _A6) positive pole be connected switching tube (Q ₃) emitter and switching tube (Q ₁) some A point lead-in wire that is connected in series of collector electrode connect an inductance (L _b) an end, inductance (L _b) the other end connect the transformer (T that each all presses branch road _n) former limit winding (n ₁) Same Name of Ends, switching tube (Q ₄) emitter and switching tube (Q ₂) some B point lead-in wire that is connected in series of collector electrode connect each and all press the transformer (T of branch road _n) former limit winding (n ₁) the different name end; Described n all press branch road each all press transformer (T of route _n), a diode (D _2n-1), a diode (D _2n), an energy storage system (E _2n-1) and an energy storage system (E _2n) form described energy storage system (E _2n-1) and energy storage system (E _2n) series arm and diode (D after being connected in series _2n-1) and diode (D _2n) series arm after the being connected in series composition that is in parallel, energy storage system (E _2n-1) and energy storage system (E _2n) series connection point and transformer (T _n) secondary winding (n ₂) Same Name of Ends link to each other diode (D _2n-1) and diode (D _2n) series connection point and transformer (T _n) secondary winding (n ₂) the different name end link to each other; N in the above-mentioned symbol is natural number.

2. a kind of energy storage system that is applicable to any no-load voltage ratio transformer according to claim 1 is all pressed charging device, it is characterized in that energy storage system comprises super capacitor and lithium-ions battery.

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