CN107612030A - A Current Quasi-Critical Continuous + Soft Switching Photovoltaic Converter Control Device Based on Power Prediction - Google Patents

Abstract

The present invention discloses a kind of quasi- critical continuous mode of electric current based on power prediction, the photovoltaic converter control device of device Sofe Switch, includes main circuit, signal deteching circuit and DSP digitial controllers.Wherein main circuit includes inverter and converted with rectifier two stage power, and variable inductance joins with high frequency transformer primary edge series；Signal deteching circuit includes two voltage sensors and two current sensors；DSP digitial controllers include MPPT maximum power point tracking module, photovoltaic cell voltage regulator, power prediction adjuster, signal modulator, absolute value block and variable inductance current regulator.Wherein power governor quickly obtains circuit modulation ratio according to detection parameters, adds the dynamic characteristic of converter；Variable inductance current regulator ensure that variable inductance electric current runs on quasi- critical conduction mode, and device can be made all to realize lossless switch.The implementation of the present invention can make photovoltaic converter realize quick dynamic characteristic and higher conversion efficiency.

Description

A Current Quasi-Critical Continuous + Soft Switching Photovoltaic Converter Control Based on Power Prediction system

technical field

The invention relates to a photovoltaic converter control device based on a power prediction method, with quasi-critical continuous current and soft switching of devices, and belongs to the technical field of control of power electronic converters.

Background technique

Photovoltaic power generation is an important form of renewable energy power generation, which has positive and far-reaching significance for alleviating the current severe pollution situation. Whether the power generated by photovoltaic cells can be directly used by electrical equipment, it needs to be processed by a power converter to obtain a stable form of power supply, and then sent to electrical equipment or the grid. For low-power photovoltaic converters, designers are more inclined to design the inductor current in the converter to work in discontinuous mode (DCM) or critical continuous mode (BCM), but the current stress of the device is greater in DCM , and BCM needs frequency conversion control to realize, these become the important reasons that restrict the large-scale promotion of low-power photovoltaic converters. In addition, although the inductor current works in the BCM or DCM state, the zero current switching (ZCS) of the switching device can be realized, but the terminal voltage of half of the switching devices in the bridge circuit is still the input voltage before they are turned on, so the parasitic capacitance The stored energy is consumed in vain when the device is turned on, so it is still difficult to achieve a high efficiency of the converter working in DCM or BCM.

When the traditional photovoltaic converter works, it must ensure the maximum output power of the photovoltaic cell. Usually, the output voltage of the photovoltaic cell is controlled as the outer loop, and the inductor current is used as the inner loop. It takes a certain amount of time for the output signal of the voltage loop to be regulated by the current inner loop and then to the signal output to modulate the driving signal, which makes the dynamic performance of the converter slower.

Therefore, it is very necessary to find a topology suitable for photovoltaic converters and corresponding control devices to ensure that the photovoltaic power generation system has high-efficiency, reliability and fast dynamic response characteristics, and this solution was born from this.

Contents of the invention

Purpose of the invention: Aiming at the deficiencies in the power conversion technology and control technology of the existing low-power photovoltaic power generation system, the present invention uses a variable inductance in the photovoltaic converter to replace the commonly used inductance with fixed inductance, so that the device can operate at a constant frequency Just realize quasi-critical operation mode (BCM); Under BCM state, the device that realizes zero-current switching (ZCS) still has certain loss when opening, and the present invention detects variable inductance current in every half switch cycle, and carries out Closed-loop control enables all devices in the converter to realize lossless switching; in view of the slow dynamic characteristics of existing photovoltaic converters, the power predictive control method can greatly improve the dynamic characteristics of the converter.

Technical solution: A photovoltaic converter based on power prediction current quasi-critical continuous + device soft switching and its control device, including a main circuit, a signal detection circuit and a DSP digital controller.

The main circuit of the photovoltaic converter is characterized in that it includes a photovoltaic cell, an input-side filter capacitor C _PV , a high-frequency inverter, a variable inductor, a high-frequency transformer, a rectifier, a DC bus filter capacitor C _DC and a load. The positive terminal of the photovoltaic cell is connected to the positive terminal of the filter capacitor _CPV on the input side and the first terminal of the high-frequency inverter, and the negative terminal of the photovoltaic cell is connected to the negative terminal of the filter capacitor _CPV on the input side and the terminal of the high-frequency inverter The second terminal is connected; the third terminal of the high-frequency inverter is connected to the terminal with the same name of the primary winding W1 of the high-frequency transformer; the two ends of the main winding of the variable inductor are its first terminal and the second terminal respectively, and the variable voltage The first terminal of the inductance main winding is connected to the fourth terminal of the high-frequency inverter, the second terminal of the variable inductance main winding is connected to the end with the same name of the primary winding W1 of the high-frequency transformer; the same name of the secondary winding W2 of the high-frequency transformer Terminal connected to the first terminal of the rectifier, the opposite end of the secondary winding W2 of the high-frequency transformer is connected to the second terminal of the rectifier; the third terminal of the rectifier is connected to the positive terminal of the DC bus filter capacitor C _DC and the first terminal of the load , the fourth terminal of the rectifier is connected to the negative terminal of the DC bus filter capacitor C _DC and the second terminal of the load; the two ends of the auxiliary winding of the variable inductor are respectively its third terminal and the fourth terminal, and it is connected to the voltage Control the output of the current source.

The signal detection circuit is characterized by comprising a first voltage sensor, a second voltage sensor, a first current sensor, and a second current sensor. Wherein the input end of the first voltage sensor is connected to the positive and negative terminals of the photovoltaic cell, the input end of the second voltage sensor is connected to the positive and negative ends of the DC bus filter capacitor C _DC ; the input end of the first current sensor is connected to The photovoltaic cells are connected in series, and the input end of the second current sensor is connected in series with the main winding of the variable inductance.

The DSP digital controller is characterized in that: it includes a maximum power point tracking module, a first subtractor, a variable inductance current regulator, an absolute value module, a second subtractor, a photovoltaic cell voltage regulator, a power prediction regulator and a signal Modulator. Wherein the two input terminals of the maximum power point tracking module are respectively connected to the output terminal of the first voltage sensor and the output terminal of the first current sensor; the positive input terminal and the negative input terminal of the second subtractor are respectively connected to the output of the maximum power point tracking module terminal and the output terminal of the first voltage sensor, the output terminal of the second subtractor is connected to the input terminal of the photovoltaic cell voltage regulator; the first input terminal, the second input terminal and the third input terminal of the power predictive regulator are respectively connected to the first The output terminal of the second voltage sensor, the output terminal of the photovoltaic pool voltage regulator and the output terminal of the first voltage sensor; the input terminal of the signal conditioner is connected to the output terminal of the power prediction regulator, and the output terminal signal of the signal conditioner is used as a high frequency The driving signal of the switching device in the inverter; the input terminal of the absolute value module is connected to the output terminal of the second current sensor, and the positive input terminal and the negative input terminal of the first subtractor are respectively connected to a constant signal _IL generated by the DSP digital chip * and the output of the absolute value module; the input of the variable-inductance current regulator is connected to the output of the first subtractor, and the output of the variable-inductance current regulator is connected to the input of the voltage-controlled current source.

The output signal of the photovoltaic cell voltage regulator is used as the output power reference value P* of the converter, and the power prediction regulator directly obtains the required converter duty cycle from the detection parameters, which saves the adjustment time of the regulator in the traditional method and speeds up The dynamic response of the converter is improved; the variable inductance current regulator ensures that the variable inductance current operates in a quasi-critical continuous state, so that all devices in the converter operate in a soft switching state, which greatly improves the efficiency of the photovoltaic converter.

Beneficial effects: In the present invention, the scheme of variable inductance + inductance current value control within half a cycle can realize the operation of the device in a quasi-critical continuous state. On the one hand, the current stress of the device is ensured to be small, and on the other hand, all devices are realized All are non-destructive switches; in addition, the power predictive control technology adopted in the present invention ensures that the photovoltaic converter has faster dynamic characteristics. To sum up, the implementation of the present invention can make the low-power photovoltaic power generation system have high efficiency and high performance index.

Description of drawings

Fig. 1 is a block diagram of an embodiment of the present invention;

Fig. 2 is the bridge topology main circuit corresponding to the embodiment of the present invention;

Fig. 3 is a schematic diagram of main waveforms of a switching cycle according to an embodiment of the present invention;

Fig. 4 is a working principle diagram of mode 1 of the embodiment of the present invention;

Fig. 5 is a working principle diagram of mode 2 of the embodiment of the present invention;

Fig. 6 is a working principle diagram of mode 3 of the embodiment of the present invention;

Fig. 7 is a working principle diagram of mode 4 of the embodiment of the present invention;

Fig. 8 is a working principle diagram of mode 5 of the embodiment of the present invention;

Fig. 9 is a working principle diagram of mode 6 of the embodiment of the present invention;

10 is a schematic diagram of a variable inductance and a voltage-controlled current source according to an embodiment of the present invention;

Fig. 11 is a graph showing the variation of the inductance value of the variable inductance with the control current according to the embodiment of the present invention;

Fig. 12 is a schematic diagram of a variable inductor current detection point according to an embodiment of the present invention;

Symbol names in the figure: U _PV — output voltage of photovoltaic cells; I _PV — output current of photovoltaic cells; C _PV — filter capacitance of photovoltaic cells; L _r — variable inductance; i _L — variable inductor current ; T——High frequency transformer; n——Transformation ratio of high frequency transformer; W1——Primary winding of high frequency transformer; W2——Secondary winding of high frequency transformer; C _DC ——Equivalent filter capacitance of DC bus; U _DC ——DC bus voltage; I _L * ——reference value of variable inductor current at sampling time; I _{Lf ——feedback} value of variable inductor current at sampling time; I _Le ——variable inductor current negative feedback Error value; U _con —— variable inductor control voltage value; U _PVf —— photovoltaic cell output voltage feedback value; I _PVf —— photovoltaic cell output current feedback value; U _PV * —— photovoltaic cell output voltage reference value; U _PVe - negative feedback error value of photovoltaic cell output voltage; P* - converter output power reference value; U _DCf - DC bus voltage feedback value; _D - converter duty cycle; Driving signal; S1-S4——the first switching tube to the fourth switching tube; D1-D2——the first diode to the second diode; i _in ——the input side current of the converter; u _AB—— AC side voltage of high-frequency inverter; u _CD —— AC side voltage of doubler rectifier; C ₁ -C ₂ ——filtered voltage of doubler rectifier; i _rec1 -i _rec2 —— first diode current to second second tube current; i _DC ——DC bus output current; W _r1 -W _{r2 ——the} first auxiliary winding and the second auxiliary winding of the variable inductor; W _r ——the main winding of the variable inductor; U _con — —Variable inductor control voltage; I _{con ——Variable} inductor control current; U ₁ -U ₂ ——Variable inductor first control chip and second control chip; R ₁ -R ₃ ——Variable voltage Sense the first control resistor to the third control resistor; V1—variable inductance control triode; I _con —variable inductance control current.

detailed description

Below in conjunction with specific embodiment, further illustrate the present invention, should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention, after having read the present invention, those skilled in the art will understand various equivalent forms of the present invention All modifications fall within the scope defined by the appended claims of the present application.

As shown in Figure 1, the photovoltaic converter and its control device based on the current quasi-critical continuous + device soft switching based on power prediction include a main circuit, a signal detection circuit and a DSP digital controller. The following will describe its interconnection and components in detail.

The main circuit of the photovoltaic converter includes a photovoltaic cell, an input-side filter capacitor C _PV , a high-frequency inverter, a variable inductor, a high-frequency transformer, a rectifier, a DC bus filter capacitor C _DC and a load. The positive terminal of the photovoltaic cell is connected to the positive terminal of the filter capacitor _CPV on the input side and the first terminal of the high-frequency inverter, and the negative terminal of the photovoltaic cell is connected to the negative terminal of the filter capacitor _CPV on the input side and the terminal of the high-frequency inverter The second terminal is connected; the third terminal of the high-frequency inverter is connected to the terminal with the same name of the primary winding W1 of the high-frequency transformer; the two ends of the main winding of the variable inductor are its first terminal and the second terminal respectively, and the variable voltage The first terminal of the inductance main winding is connected to the fourth terminal of the high-frequency inverter, the second terminal of the variable inductance main winding is connected to the end with the same name of the primary winding W1 of the high-frequency transformer; the same name of the secondary winding W2 of the high-frequency transformer Terminal connected to the first terminal of the rectifier, the opposite end of the secondary winding W2 of the high-frequency transformer is connected to the second terminal of the rectifier; the third terminal of the rectifier is connected to the positive terminal of the DC bus filter capacitor C _DC and the first terminal of the load , the fourth terminal of the rectifier is connected to the negative terminal of the DC bus filter capacitor C _DC and the second terminal of the load; the two ends of the auxiliary winding of the variable inductor are respectively its third terminal and the fourth terminal, and it is connected to the voltage Control the output of the current source.

The signal detection circuit includes a first voltage sensor, a second voltage sensor, a first current sensor, and a second current sensor. Wherein the input end of the first voltage sensor is connected to the positive and negative terminals of the photovoltaic cell, the input end of the second voltage sensor is connected to the positive and negative ends of the DC bus filter capacitor C _DC ; the input end of the first current sensor is connected to The photovoltaic cells are connected in series, and the input end of the second current sensor is connected in series with the main winding of the variable inductance.

The DSP digital controller includes a maximum power point tracking module, a first subtractor, a variable inductance current regulator, an absolute value module, a second subtractor, a photovoltaic cell voltage regulator, a power prediction regulator and a signal modulator. Wherein the two input terminals of the maximum power point tracking module are respectively connected to the output terminal of the first voltage sensor and the output terminal of the first current sensor; the positive input terminal and the negative input terminal of the second subtractor are respectively connected to the output of the maximum power point tracking module terminal and the output terminal of the first voltage sensor, the output terminal of the second subtractor is connected to the input terminal of the photovoltaic cell voltage regulator; the first input terminal, the second input terminal and the third input terminal of the power predictive regulator are respectively connected to the first The output terminal of the second voltage sensor, the output terminal of the photovoltaic pool voltage regulator and the output terminal of the first voltage sensor; the input terminal of the signal conditioner is connected to the output terminal of the power prediction regulator, and the output terminal signal of the signal conditioner is used as a high frequency The driving signal of the switching device in the inverter; the input terminal of the absolute value module is connected to the output terminal of the second current sensor, and the positive input terminal and the negative input terminal of the first subtractor are respectively connected to a constant signal _IL generated by the DSP digital chip * and the output of the absolute value module; the input of the variable-inductance current regulator is connected to the output of the first subtractor, and the output of the variable-inductance current regulator is connected to the input of the voltage-controlled current source.

The photovoltaic converter shown in Figure 1 can be used as the main circuit of the photovoltaic converter of the present invention as long as the energy buffer inductor is connected in series with the transformer, and common half-bridge, full-bridge, forward and flyback converters can be used as The transformer of the flyback converter itself realizes the function of inductance, so its transformer can be designed as a transformer with variable self-inductance value. In order to illustrate in detail, this article takes the bridge converter as an object for description, as shown in Figure 2. Figure 3 is the working waveform of the bridge converter in one switching cycle. In Figure 3, by controlling the values of the variable inductor at the time t ₀ and the time t ₃ respectively -I _L * and +I _L *(I _L * is a value greater than zero and close to zero), it can ensure that all the switching tubes S1-S4 in the bridge converter work in the zero-voltage switching state, and there is no loss in the whole process; while the diodes D1-D2 on the secondary side of the transformer are all Commutation is performed under zero current conditions.

In Figure 3, the duty cycle D of the converter is defined as

In actual work, I _L * is a value close to zero, so the time period t ₀ -t ₁ and t ₃ -t ₄ are very small and can be approximately ignored. The length of the time period t ₁ -t ₂ can be regarded as is DT _s , the maximum value of variable inductor current is

Then the average value of the input side current i _in of the photovoltaic converter is equal to

Then the power value processed by the photovoltaic converter is equal to

From this, the duty cycle of the converter is obtained as

If the duty ratio D is calculated according to a known quantity, the formula (5) needs to be changed into the form of formula (6).

Equation (6) is the power predictive regulator in Figure 1. If there is no error in all signal detection, theoretically only need to calculate the duty cycle D through formula (6), it can ensure that the output power of the converter tracks the reference power value P*, so that the converter has a faster dynamic characteristic.

Corresponding to the working waveform of the converter shown in Figure 3, the working process of the corresponding six switching modes in one switching cycle is briefly described as follows:

Switch mode 1 [corresponding to Figure 4]:

Before time t ₀ , the current of the variable inductor is negative, the switch tubes S1 and S2 are turned on, the rectifier diode D2 on the secondary side of the transformer is turned on, the voltage u _AB = 0, u _CD <0, the stored in the variable inductor Energy is transferred to the DC bus side through diode D2. At time t ₀ , the switch tube S2 is turned off, S4 is turned on, the current of the variable inductor continues to be negative, the voltage u _AB >0, u _CD <0, therefore, the energy stored in the variable inductor passes through the diode on the one hand D2 transmits to the DC bus side, and on the other hand, it also transmits energy to the input side voltage U _PV , so the variable inductor current i _L drops rapidly, and i _L drops to 0 at time t ₁ .

Switch mode 2 [corresponding to Figure 5]:

At _t1 moment, i _L drops to 0, after that, i _L becomes a positive value, diode D2 is cut off, and D1 starts to conduct. Voltage u _AB >0, u _CD >0, since the bridge circuit is still a step-down circuit in essence, the inductor current increases linearly, and the energy stored in the photovoltaic filter capacitor is transmitted to the DC bus and variable inductor at the same time energy.

Switch mode 3 [corresponding to Figure 6]:

At time _t2 , switch S1 is turned off, S3 is turned on, diode D1 remains on, voltage u _AB = 0, u _CD > 0, the energy stored in the inductor is transmitted to the DC bus side, and the energy stored in the variable inductor The energy decreases and the current i _L decreases.

At time _t3 , the switching tube S4 is turned off, and S2 is turned on, and the corresponding working process thereafter is symmetrical to the time period from _t0 to _t3 , which will not be repeated here, and its specific switching mode diagrams are shown in Figure 7 to Figure 9 .

From the working waveforms shown in Figure 3 and the modal diagrams shown in Figures 4 to 9, it can be seen that during the turn-on and turn-off processes of all the switch tubes, the direction of the variable inductor current can always be opposite to the switch tube The effective charging and discharging of the parasitic capacitance of the capacitor ensures that all switching tubes always realize zero-voltage switching, which is of great significance for improving the efficiency of the converter.

Figure 10 shows the core, winding structure and circuit of the voltage-controlled current source of the variable inductance. Among them, the iron core of the variable inductance is composed of a pair of EE-type ferrite cores, and one piece is cut off at the joint of the magnetic core columns in the middle of the two EE-type iron cores to form an air gap of a certain length; in the middle The main winding W _r of the variable inductance is wound on the core leg, and the auxiliary windings W _{r_1} and W _{r_2} are respectively wound on the core legs on both sides, and connected in series. The voltage-controlled current source is composed of two single-supply operational amplifiers U1-U2, voltage divider resistors R1-R2, feedback resistor R3, and current regulator V1. The current source control voltage U _con passes through the voltage divider resistors R1-R2 and follows the device, the voltage obtained at the positive input terminal of op amp U2 is

According to the principle of virtual short and virtual break of the operational amplifier, the voltage on the feedback resistor R3 is equal to U ₂₊ , then

A variable inductor is established for the patent of the present invention, and the variation curve of its main winding inductance L _r with I _con is shown in Fig. 11 . It can be seen that the variable inductance can be changed in the range of 2.8 μH to 8.5 μH by using a small current source loss, that is, the quasi-critical continuous operation mode of the variable inductance current can be realized in a wide power range.

An advantage of the present invention is that all the switching tubes can realize lossless switching. In order to realize this feature, it must be ensured that the current i _L is less than zero when the switching tube S2 is turned off and S4 is turned on (time t _a in FIG. 12 ). Ensure that the current i _L is greater than zero when the switch tube S4 is turned off and S2 is turned on (time t _b in Fig. 12). Therefore, the current value at time t _a and time t _b must be controlled, that is, the discrete sampling time t _a and t The current i _L value at time _b is closed-loop controlled, and the obtained modulation signal is used to control the size of the variable inductance. If the detected value is too small, the value of the variable inductance needs to be increased, and vice versa, and finally the current i _L The absolute value at time t _a and time t _b is equal to I _L *.

In summary, the present invention applies the variable inductance to the low-power photovoltaic converter, which can ensure that the converter works in the current quasi-critical continuous mode, and the switching device works at a constant frequency. On the one hand, the current stress of the switching device is lower , on the other hand, it facilitates the realization of control; by detecting the current value of the variable inductance in every half switching cycle, and fine-tuning the variable inductance value, it is further realized that all switching devices are working in the zero-voltage switching state, improving the The efficiency of the photovoltaic converter is improved; the dynamic response of the converter is significantly improved through power predictive control. Therefore, the invention has the advantages of low device current stress, high conversion efficiency, convenient control and realization, and fast dynamic response.

Claims (5)

1. a kind of its feature of the main circuit of photovoltaic converter of the quasi- critical continuous mode of the electric current based on power prediction+device Sofe Switch exists In：Including photovoltaic cell, input side filter capacitor C_PV, high-frequency inverter, variable inductance, high frequency transformer, rectifier, direct current it is female Line filter capacitor and load.The wherein anode of photovoltaic cell and input side filter capacitor C_PVAnode and high-frequency inverter The first terminal connects, negative terminal and the input side filter capacitor C of photovoltaic cell_PVNegative terminal and high-frequency inverter Second terminal connect Connect；The third terminal of high-frequency inverter is connected with high frequency transformer primary side winding W1 Same Name of Ends；The main winding two of variable inductance End is the forth terminal company of its first terminal and Second terminal, variable inductance main winding the first terminal and high-frequency inverter respectively Connect, variable inductance main winding Second terminal is connected with high frequency transformer primary side winding W1 different name end；High frequency transformer secondary around Group W2 Same Name of Ends is connected to the first terminal of rectifier, and high frequency transformer vice-side winding W2 different name end is connected to rectifier Second terminal；The third terminal of rectifier is connected to dc bus filter capacitor C_DCAnode and load the first terminal, it is whole The forth terminal of stream device is connected to dc bus filter capacitor C_DCNegative terminal and load Second terminal；The auxiliary of variable inductance Winding both ends are its third terminal and forth terminal respectively, are connected to the output end of VCCS.

2. a kind of signal deteching circuit of the photovoltaic converter of the quasi- critical continuous mode of the electric current based on power prediction+device Sofe Switch, It is characterized in that：Including first voltage sensor, second voltage sensor, the first current sensor, the second current sensor.Its The input of middle first voltage sensor is terminated on the positive and negative terminal of photovoltaic cell, and the input of second voltage sensor terminates to Dc bus filter capacitor C_DCPositive and negative both ends on；The input of first current sensor is in series with the photovoltaic cell, the The input of two current sensors is in series with the variable inductance main winding.

3. a kind of DSP digitial controllers of the photovoltaic converter of the quasi- critical continuous mode of the electric current based on power prediction+device Sofe Switch, It is characterized in that：Including MPPT maximum power point tracking module, the first subtracter, variable inductance current regulator, absolute value block, Two subtracters, photovoltaic cell voltage regulator, power prediction adjuster and signal modulator.Wherein MPPT maximum power point tracking mould Two inputs of block connect the output end of first voltage sensor and the output end of the first current sensor respectively；Second subtracts Positive input terminal, the negative input end of musical instruments used in a Buddhist or Taoist mass connect the defeated of the output end of MPPT maximum power point tracking module and first voltage sensor respectively Go out end, the output end of the second subtracter is connected to the input of photovoltaic cell voltage adjuster；The first of power prediction adjuster is defeated Enter terminal, the second input terminal, the 3rd input terminal and connect the output end of second voltage sensor, the regulation of photovoltaic cell voltage respectively The output end of device and the output end of first voltage sensor；The input of signal conditioner is connected to power prediction adjuster Output end, the drive signal of the output end signal of signal conditioner as switching device in high-frequency inverter；Absolute value block Input connects the output end of the second current sensor, and positive input terminal and the negative input end of the first subtracter are connected respectively to DSP A constant signal I caused by digit chip_L* with the output end of absolute value block；The input of variable inductance current regulator connects The output end of the first subtracter is connected to, the output end of variable inductance current regulator is connected to the input of VCCS End.

4. power prediction adjuster as claimed in claim 3, it is characterised in that：The first input end of power prediction adjuster Son, the second input terminal, the signal of the 3rd input terminal are respectively U_DCf、P^*、U_PVf, then the output modulation of power prediction adjuster It is than signal D：Wherein, L_rFor the inductance value of variable inductance, n is the no-load voltage ratio of transformer, T_sFor The switch periods of converter.

5. power output a reference value of the photovoltaic cell voltage regulator output signal as claimed in claim 3 as converter P*, and power prediction adjuster directly obtains required converter dutycycle by detection parameters, eliminates in conventional method and adjusts The regulating time of device is saved, accelerates the dynamic response of converter；Variable inductance current regulator ensure that variable inductance electric current is transported Row is in quasi- critical continuous mode state so that all devices run on lossless Sofe Switch state in converter, substantially increase light Lie prostrate the efficiency of converter.