CN102751876A - Isolation type new energy power supply equipment based on three-port power converter - Google Patents

Abstract

The invention discloses an isolated new energy power supply device based on a three-port power converter, which consists of a new energy battery, an energy storage, a reverse resistance diode, two coupled inductors, four main switch tubes, and two clamp The switch tube, two clamping capacitors, two rectifier diodes and two filter capacitors are connected to each other; the present invention adopts an interleaved parallel structure and controls the phase of the main switch tube to achieve low ripple of the input current, so that it is easy to realize new energy The maximum power point tracking control of the battery; at the same time, the present invention adopts the active clamping structure to realize the soft switching of the main switching tube, thereby reducing the loss and improving the efficiency; in addition, the present invention adopts two coupled inductances on the load side The series structure can achieve higher boosting capacity; when the new energy battery is working, it can supply power to the load side and the battery at the same time; when the new energy battery is not working, the battery can still supply power to the load side.

Description

An isolated new energy power supply device based on a three-port power converter

technical field

The invention belongs to the technical field of new energy power conversion, and in particular relates to an isolated new energy power supply device based on a three-port power converter.

Background technique

In the new energy power supply system, since the electric energy generated by new energy is DC with low voltage, and in many application scenarios (such as grid-connected power generation system), DC with high voltage is required, so the new energy power supply system has power conversion The converter converts the low-voltage direct current into a suitable high-voltage direct current; in addition, the power converter is also responsible for the energy management and control among the new energy, the battery and the load.

The output voltage gain of the conventional step-up (Boost) interleaved parallel DC-DC converter is small, and the voltage stress of the power switch tube is relatively large. The recovery current is large, and the reverse recovery loss is large. In recent years, some soft switching circuits have been studied successively, and the soft switching of the power switch tube is realized by adding active power switches and passive inductors, capacitors and other devices or by adding diodes and passive inductors, capacitors and other devices.

In the actual new energy power supply system, in order to realize the continuity of energy in grid-connected or independent systems, it is necessary to add batteries to realize a dispatchable system. To this end, multiple power converter devices or multi-stage devices are required, thereby increasing the complexity and cost of system control. Therefore, the traditional new energy power supply system is shown in Figure 1. This system requires two sets of power converters to realize the power conversion of new energy-battery, new energy-load and battery-load; and a large number of power conversion devices are expensive, low efficiency.

As shown in Figure 2, a new energy power supply system based on a three-port power converter can well solve the problem of many traditional power conversion devices; a typical structure is shown in Figure 3, the advantage of this circuit structure is that the switches used There are fewer tubes, but the disadvantages are also obvious. The main disadvantages are as follows:

(1) Because it is a single magnetic core structure, the transmission power is limited, and this topology cannot be used in occasions with high power;

(2) Since the essence of the circuit is a half-bridge structure, there is a limited boosting capacity of the secondary side, which limits the application of this topology in high boosting occasions. For example, the input source is a photovoltaic cell or a fuel cell, and the output load is grid-connected. or standalone inverters;

(3) Due to the large current ripple on the primary side, it will encounter great difficulties in the control of this topology when it is necessary to control the optimal operating point of the input source, such as a fuel cell or a photovoltaic panel.

Contents of the invention

In view of the above-mentioned technical defects existing in the prior art, the present invention provides an isolated new energy power supply device based on a three-port power converter, which can realize soft switching of the switching tube, low primary current ripple, and high power conversion efficiency .

An isolated new energy power supply device based on a three-port power converter, including: a new energy battery, an energy storage, a reverse resistance diode, two coupled inductors, four main switch tubes, two clamp switch tubes, Two clamp capacitors, two rectifier diodes, and two filter capacitors; where:

The anode of the new energy battery is connected to the anode of the reverse resistance diode, the cathode of the reverse resistance diode is connected to the drain of the first main switching tube and the drain of the second main switching tube, and the source of the first main switching tube is connected to the third main switching tube. The drain of the switch tube, the source of the first clamp switch tube are connected to the non-identical end of the primary coil of the first coupling inductor, the source of the second main switch tube is connected to the drain of the fourth main switch tube, and the second clamp The source of the position switch is connected to the non-identical end of the primary coil of the second coupled inductor, the source of the third main switch is connected to the source of the fourth main switch and the negative pole of the energy storage, and the first clamp switch The drain of the second clamping switch tube is connected to one end of the first clamping capacitor, the drain of the second clamping switch tube is connected to one end of the second clamping capacitor, the negative pole of the new energy battery is connected to the other end of the first clamping capacitor, the second clamping capacitor The other end of the bit capacitor, the terminal with the same name of the primary coil of the first coupled inductor, the terminal with the same name of the primary coil of the second coupled inductor are connected to the positive pole of the energy storage;

The non-identical end of the secondary coil of the first coupled inductor is connected to the non-identical end of the secondary coil of the second coupled inductor, and the identical end of the secondary coil of the second coupled inductor is connected to the anode of the first rectifier diode and the cathode of the second rectifier diode , the terminal with the same name of the secondary coil of the first coupling inductor is connected to one terminal of the first filter capacitor and one terminal of the second filter capacitor, the cathode of the first rectifier diode is connected to the other end of the first filter capacitor and constitutes a positive output terminal, and the second The anode of the rectifier diode is connected to the other end of the second filter capacitor to form a negative output end;

Both the grid of the main switching tube and the grid of the clamping switching tube receive control signals provided by external equipment.

Both the main switch tube and the clamp switch tube are NMOS tubes.

A new energy battery is a device that directly converts renewable energy (such as nuclear energy, solar energy, wind energy, biomass energy, geothermal energy, etc.) into electrical energy. Preferably, the new energy battery is a photovoltaic cell; The energy battery is not restricted by the environment and is easy to use.

An energy storage is a device (such as a storage battery, a supercapacitor, etc.) for storing electrical energy. Preferably, the energy storage is a storage battery; it has high energy storage density, is cheap, and has universal applicability.

Working principle of the present invention is:

When the new energy battery can work, the first main switch tube and the second main switch tube work, the clamp switch tube does not work, the electric energy output by the new energy battery supplies power to the load, and the leakage in the first coupling inductor and the second coupling inductor The energy in the induction can charge the battery, and can limit the voltage stress of the switch tube; when the new energy battery is not working, the battery turns on the third main switch tube, the fourth main switch tube, the first clamp switch tube, and the second clamp switch tube sequentially. The clamp switch tube supplies power to the load, the third main switch tube and the first clamp switch tube form a soft switch circuit, and the fourth main switch tube and the second clamp switch tube form a soft switch circuit.

The invention adopts the interleaved parallel structure, which can improve the power transmission capacity of the equipment very well, and its power transmission capacity can be extended to 10KW; due to the interleaved parallel structure, the low ripple of the input current can be realized by controlling the phase of the main switching tube , so that it is easy to realize the maximum power point tracking control of the new energy battery; at the same time, the present invention adopts the active clamp structure to realize the soft switching of the main switching tube, thereby reducing the loss and improving the efficiency; in addition, the present invention adopts the load Two coupled inductive series structures on the side can achieve higher boosting capacity; when the new energy battery is working, it can supply power to the load side and the battery at the same time; when the new energy battery is not working, the battery can still supply power to the load. side power supply.

Description of drawings

Figure 1 is a schematic structural diagram of a new energy power supply system based on multiple power converters.

Fig. 2 is a schematic structural diagram of a new energy power supply system based on a three-port power converter.

FIG. 3 is a schematic diagram of a circuit structure of a traditional new energy power supply system based on a three-port power converter.

Fig. 4 is a schematic diagram of the circuit structure of the new energy power supply system of the present invention.

Fig. 5 is a schematic diagram of the circuit principle of the power conversion working state 1 when the photovoltaic cell supplies power in the present invention.

Fig. 6 is a schematic diagram of the circuit principle of the power conversion working state 2 when the photovoltaic cell supplies power in the present invention.

Fig. 7 is a schematic diagram of the circuit principle of the power conversion working state 3 when the photovoltaic cell is powered by the present invention.

Fig. 8 is a schematic diagram of the circuit principle of the power conversion working state 4 when the photovoltaic cell is powered by the present invention.

Fig. 9 is a schematic diagram of the circuit principle of the power conversion working state 5 when the photovoltaic cell is powered by the present invention.

Fig. 10 is a schematic diagram of the circuit principle of the power conversion working state 6 when the photovoltaic cell supplies power according to the present invention.

Fig. 11 is a schematic diagram of the circuit principle of the power conversion working state 7 when the photovoltaic cell is powered by the present invention.

Fig. 12 is a schematic diagram of the circuit principle of the power conversion working state 8 when the photovoltaic battery supplies power of the present invention.

Fig. 13 is a schematic diagram of the circuit principle of the power conversion working state 1 when the battery supplies power of the present invention.

Fig. 14 is a schematic diagram of the circuit principle of the power conversion working state 2 when the battery supplies power of the present invention.

Fig. 15 is a schematic diagram of the circuit principle of the power conversion working state 3 when the battery supplies power of the present invention.

Fig. 16 is a schematic diagram of the circuit principle of the power conversion working state 4 when the battery supplies power of the present invention.

Fig. 17 is a schematic diagram of the circuit principle of the power conversion working state 5 when the battery supplies power of the present invention.

Fig. 18 is a schematic diagram of the circuit principle of the power conversion working state 6 when the battery supplies power of the present invention.

Fig. 19 is a schematic diagram of the circuit principle of the power conversion working state 7 when the battery supplies power of the present invention.

Fig. 20 is a schematic diagram of the circuit principle of the power conversion working state 8 when the battery supplies power of the present invention.

Detailed ways

In order to describe the present invention more specifically, the technical solutions and working principles of the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 4, an isolated new energy power supply device based on a three-port power converter includes: a photovoltaic cell F, a storage battery E, a reverse resistance diode D, two coupled inductors L ₁ ~ L ₂ , four One main switch tube S ₁ ～S ₄ , two clamp switch tubes Q ₁ ～Q ₂ , two clamp capacitors C ₁ ～C ₂ , two rectifier diodes Z ₁ ～Z ₂ and two filter capacitors Co ₁ ～ Co ₂ ; where:

The anode of the photovoltaic cell F is connected to the anode of the reverse resistance diode D, and the cathode of the reverse resistance diode D is connected to the drain of the first main switch _S1 and the drain of the second main switch _S2 , and the first main switch S The source of ₁ is connected to the drain of the third main switch _S3 , the source of the first clamping switch _Q1 and the non-identical end of the primary coil of the first coupling inductor _L1 , and the second main switch _S2 The source of the fourth main switching tube _S4 , the source of the second clamping switching tube _Q2 and the non-identical terminal of the primary side coil of the second coupling inductor _L2 are connected, and the third main switching tube _S3 The source is connected to the source of the fourth main switching tube _S4 and the negative pole of the storage battery E, the drain of the first clamping switching tube _Q1 is connected to one end of the first clamping capacitor _C1 , and the second clamping switching tube Q1 The drain of ₂ is connected to one end of the second clamping capacitor _C2 , the negative electrode of the photovoltaic cell F is connected to the other end of the first clamping capacitor _C1 , the other end of the second clamping capacitor _C2 , and the first coupling inductance _L1 The same-named end of the primary side coil, the same-named end of the second coupled inductance _L2 primary side coil are connected to the positive pole of the storage battery E;

The non-identical end of the secondary coil of the first coupled inductor _L1 is connected to the non-identical end of the secondary coil of the second coupled inductor _L2 , and the identical end of the secondary coil of the second coupled inductor _L2 is connected to the anode of the first rectifier diode _Z1 It is connected to the cathode of the second rectifier diode _Z2 , the same-named end of the secondary coil of the first coupling inductor _L1 is connected to one end of the first filter capacitor _Co1 and one end of the second filter capacitor _Co2 , and the end of the first rectifier diode _Z1 The cathode is connected to the other end of the first filter capacitor Co ₁ and connected to one end of the resistive load R, and the anode of the second rectifier diode Z ₂ is connected to the other end of the second filter capacitor Co ₂ and connected to the other end of the resistive load R;

The gates of the main switch tubes S ₁ -S ₄ and the gates of the clamp switch tubes Q ₁ -Q ₂ all receive control signals provided by external devices; in this embodiment, the main switch tubes S ₁ -S ₄ and the clamp switches Tubes Q ₁ -Q ₂ are all NMOS tubes.

This implementation mode is divided into the following two working states:

(1) Photovoltaic cell F is working normally (sunshine during the day), the energy of the output circuit is provided by photovoltaic cell F, and the clamp switches Q ₁ ~ Q ₂ are in the normally closed state and do not participate in the working process; the working status of the circuit includes the following process:

Working state 1 (as shown in Figure 5), the main switch tubes S ₁ and S ₂ are both turned on, and Q ₁ and Q ₂ are turned off. Under the action of the input voltage, the primary side of the coupling inductor stores energy, the excitation current of the primary side increases linearly, and the capacitance Co ₁ and Co ₂ are connected in series to supply power to the load R.

Working state 2 (as shown in Figure 6), S ₁ is turned off, the excitation current of coupled inductor L ₁ charges the parasitic capacitance of S ₁ , the voltage between switch tube S ₁ increases linearly, and the excitation current of the primary side of coupled inductor L ₂ continues to increase linearly, Capacitors Co ₁ and Co ₂ are connected in series to supply power to the load R.

Working state 3 (as shown in Figure 7), the rectifier diode Z ₂ is turned on after the voltage across the parasitic capacitor of S ₁ rises to a certain value, at this time, the coupled inductor L ₁ works in the flyback state, and L ₂ works in the forward state , the energy in the photovoltaic cell F and the coupled inductor begins to transfer to the capacitor Co ₂ , and the capacitors Co ₁ and Co ₂ are connected in series to supply power to the load R.

Working state 4 (as shown in Figure 8), when the voltage across the parasitic capacitor of S ₁ rises to the clamping voltage, S ₃ reverses and conducts the diode, L ₂ continues to store energy and the current increases linearly, and the energy in the coupled inductor L ₁ is transferred to the capacitor _Co2 charges, and also charges the storage battery E at the same time.

In working state 5 (as shown in Figure 9), _S3 is turned on. At this time, _S3 is turned on as a zero-voltage switch, and the current flowing through its anti-parallel diode is quickly transferred to _S3 .

In working state 6 (as shown in Figure 10), S ₃ is turned off, leakage inductance L ₁ resonates with the parasitic capacitance of switching tube S ₁ , part of the energy on the leakage inductance is transferred to load R, and the other part is transferred to L ₂ .

In working state 7 (as shown in Figure ₁₁ ), the voltage drop across the parasitic capacitance of S ₁ is 0, and the resonance process between the parasitic capacitance and leakage inductance L ₁ ends. The voltage of Co ₂ decreases linearly.

In working state 8 (as shown in Figure 12), S ₁ is turned on. At this time, S ₁ is turned on by zero-voltage switching, the rectifier diode continues to conduct continuous current until the current drops to 0, and diode Z ₂ is turned off. At this time, both S ₁ and S ₂ are turned on, the excitation current of the primary side increases linearly, and the capacitors Co ₁ and Co ₂ are connected in series to supply power to the load R.

The working state of the switch tube _S2 in one cycle is the same as that of _S1 .

(2) When the photovoltaic cell F is not working (no light at night or in rainy days), the output circuit energy is provided by the battery E, and the main switch tubes S ₁ and S ₂ are in the normally closed state and do not participate in the working process; the working status of the circuit includes the following process:

Working state 1 (as shown in Figure 13), S ₃ and S ₄ are both turned on, Q ₁ and Q ₂ are turned off, the primary side of the coupling inductor stores energy under the action of the input voltage, the excitation current of the primary side increases linearly, and the capacitors Co ₁ , _Co2 supplies power to the load R in series.

Working state 2 (as shown in Figure 14), S ₃ is turned off, the excitation current of the inductor L ₁ charges the parasitic capacitance of S ₃ , the voltage between the switch tubes increases linearly, the excitation current of the primary side of L ₂ continues to increase linearly, and the capacitances Co ₁ and Co ₂ in series to supply power to the load R.

Working state 3 (as shown in Figure 15), the rectifier diode Z ₁ is turned on after the voltage across the parasitic capacitor S ₃ rises to a certain value, at this time the coupled inductor L ₁ works in the flyback state, and L ₂ works in the forward state , the energy in the storage battery E and the coupled inductor begins to transfer to the capacitor Co ₁ , and the capacitors Co ₁ and Co ₂ are connected in series to supply power to the load R.

Working state 4 (as shown in Figure 16), when the voltage across the parasitic capacitor of S ₃ rises to the clamping voltage, Q ₁ reverses and conducts the diode, L ₂ continues to store energy and the current increases linearly, and the energy in the coupled inductor L ₁ is output to Capacitor Co ₁ is charged.

In working state 5 (as shown in Figure 17), Q ₁ is turned on. At this time, Q ₁ is turned on as a zero-voltage switch, and the current flowing through its anti-parallel diode is quickly transferred to Q ₁ .

Working state 6 (as shown in Figure 18), Q ₁ is turned off, leakage inductance L ₁ resonates with switch tube S ₃ parasitic capacitance Cs3, part of the energy on leakage inductance L ₁ is transferred to load R, and the other part is transferred to battery E.

In working state 7 (as shown in Figure ₁₉ ), the voltage drop across the parasitic capacitance of S ₃ is 0, and the resonance process between the parasitic capacitance and leakage inductance L ₁ ends. The voltage of Co ₁ decreases linearly.

In working state 8 (as shown in Figure 20), S ₃ is turned on. At this time, S ₃ is turned on for zero-voltage switching, and the rectifier diode continues to conduct continuous current until the current drops to 0, and diode Z ₁ is turned off. At this time, both S ₃ and S ₄ are turned on, the excitation current of the primary side increases linearly, and the capacitors Co ₁ and Co ₂ are connected in series to supply power to the load R.

The working state of the switch tube S ₄ in one cycle is the same as that of the switch tube S ₃ .

Claims (4)

1. An isolated new energy power supply device based on a three-port power converter, characterized in that it includes: a new energy battery, an energy storage, a reverse resistance diode, two coupled inductors, four main switch tubes, two A clamp switch tube, two clamp capacitors, two rectifier diodes and two filter capacitors; where: The anode of the new energy battery is connected to the anode of the reverse resistance diode, the cathode of the reverse resistance diode is connected to the drain of the first main switching tube and the drain of the second main switching tube, and the source of the first main switching tube is connected to the third main switching tube. The drain of the switch tube, the source of the first clamp switch tube are connected to the non-identical end of the primary coil of the first coupling inductor, the source of the second main switch tube is connected to the drain of the fourth main switch tube, and the second clamp The source of the position switch is connected to the non-identical end of the primary coil of the second coupled inductor, the source of the third main switch is connected to the source of the fourth main switch and the negative pole of the energy storage, and the first clamp switch The drain of the second clamping switch tube is connected to one end of the first clamping capacitor, the drain of the second clamping switch tube is connected to one end of the second clamping capacitor, the negative pole of the new energy battery is connected to the other end of the first clamping capacitor, the second clamping capacitor The other end of the bit capacitor, the terminal with the same name of the primary coil of the first coupled inductor, the terminal with the same name of the primary coil of the second coupled inductor are connected to the positive pole of the energy storage; The non-identical end of the secondary coil of the first coupled inductor is connected to the non-identical end of the secondary coil of the second coupled inductor, and the identical end of the secondary coil of the second coupled inductor is connected to the anode of the first rectifier diode and the cathode of the second rectifier diode , the terminal with the same name of the secondary coil of the first coupling inductor is connected to one terminal of the first filter capacitor and one terminal of the second filter capacitor, the cathode of the first rectifier diode is connected to the other end of the first filter capacitor and constitutes a positive output terminal, and the second The anode of the rectifier diode is connected to the other end of the second filter capacitor to form a negative output end; Both the grid of the main switching tube and the grid of the clamping switching tube receive control signals provided by external equipment. 2. The isolated new energy power supply device based on a three-port power converter according to claim 1, wherein both the main switch tube and the clamp switch tube are NMOS tubes. 3. The isolated new energy power supply device based on a three-port power converter according to claim 1, wherein the new energy battery is a photovoltaic battery. 4. The isolated new energy power supply device based on a three-port power converter according to claim 1, wherein the energy storage is a storage battery.

Images