Isolated MPPT (maximum power point tracking) voltage reduction power conversion unit for stacked light and stacked storage of base station

Abstract

The utility model discloses an isolation type MPPT step-down power conversion unit for stacked light and stacked storage of a base station, which comprises a power part and a control part electrically connected with the power part, and is characterized in that the power part comprises a boost module, an LLC resonance module, a transformer isolation module, a synchronous rectification output module and an output anti-reversion and pre-charging module, a rectifier bridge BR of the boosting module is electrically connected with the input end of a circuit, the boosting module is used for inputting bus voltage which is used for preventing reverse connection and boosting input voltage to be required by the LLC resonance module, the LLC resonance module is electrically connected with the boosting module, and the LLC resonance module is used for generating resonance to improve conversion efficiency. The transformer isolation module is electrically connected with the LLC resonance module, the transformer isolation module is used for realizing conversion from high voltage to low voltage and electrical isolation, the synchronous rectification output module is electrically connected with the transformer isolation module, and the synchronous rectification output module is used for performing synchronous rectification. The output anti-reverse and pre-charging module is electrically connected with the synchronous rectification output module, and the output anti-reverse and pre-charging module is used for output anti-reverse connection and large current impact prevention. The beneficial effects of the utility model are that the input end is provided with the rectifier bridge, AC input can be supported, normal operation can be realized when DC input is connected reversely, the anti-reverse connection function is realized, the complexity of current installation is reduced, the boost circuit is adopted for input, and the voltage is boosted to a certain value so as to be compatible with the requirement of a wide voltage input range; according to the LLC converter, the defect that the input voltage range of the optimal resonant working point of the LLC is narrow is overcome, the voltage is converted into a low voltage value through the transformation ratio of the transformer after boosting, and the conversion efficiency of the converter is improved while the safety level is reached by adopting an LLC soft switching and synchronous rectification technology; the arranged transformer isolation module can realize isolation, so that the circuit is safer; and a pre-charging loop is added at the output side, thereby preventing impact of large current on the module during hot plugging, and prolonging the service life.

Description

Technical Field

[0001] The utility model relates to the field of circuit technology, and in particular to an isolated MPPT step-down power conversion unit for a base station with stacked optics and storage. Background Art

[0002] The power conversion modules with maximum power point tracking (MPPT) used in existing photovoltaic energy storage base stations basically adopt non-isolated DC-DC conversion circuits (BUCK, BUCK-BOOST, etc.). Under this structure, the input and output are non-isolated. As the voltage of the photovoltaic string increases, the input high voltage and the output low voltage are not isolated, which has the following defects: (1) The personal safety factor of maintenance and installation personnel is reduced; (2) If a direct fault occurs on the high-voltage side, if the system is not equipped with additional protection devices, the high voltage will be directly injected into the equipment and batteries on the low-voltage side, which will directly damage the equipment and batteries; (3) The input side does not support positive and negative connection. If connected in reverse, it will not work properly, which increases the complexity of on-site installation; (4) When the base station is connected and powered on, a large current will cause an impact on the circuit.

[0003] Therefore, the existing technology has defects and needs to be improved. Utility Model Content

[0004] The purpose of the utility model is to overcome the deficiencies of the prior art and provide an isolated MPPT step-down power conversion unit for a base station stacked photovoltaic and storage system.

[0005] The technical solution of the present invention is as follows: The present invention provides an isolated MPPT step-down power conversion unit for a base station with stacked photovoltaic and storage, comprising: a power part and a control part electrically connected to the power part, the power part comprising: a boost module, an LLC resonant module, a transformer isolation module, a synchronous rectifier output module, an output reverse protection and pre-charge module, the rectifier bridge BR of the boost module is electrically connected to the input end of the circuit, the boost module is used for input reverse protection and to increase the input voltage to the bus voltage required by the LLC resonant module, the LLC resonant module is electrically connected to the boost module, the LLC The C resonance module is used to generate resonance to improve conversion efficiency. The transformer isolation module is electrically connected to the LLC resonance module. The transformer isolation module is used to achieve high-voltage to low-voltage conversion and electrical isolation. The synchronous rectification output module is electrically connected to the transformer isolation module. The synchronous rectification output module is used to perform synchronous rectification. The output anti-reverse and pre-charge module is electrically connected to the synchronous rectification output module. The output anti-reverse and pre-charge module is used to output reverse connection protection and prevent large current shocks. The control part includes: a main control module, and an LLC controller, a communication and dry contact module electrically connected to the main control module. The main control module is used for data processing and controlling the operation of the power part and the control part of the conversion unit. The LLC controller is used to control the LLC resonance module and the synchronous rectification output module. The communication and dry contact module is used to achieve external communication.

[0006] Specifically:

[0007] The boost module further includes: an inductor L1, a diode D1, an IGBT transistor Q1, a capacitor C1 and an input current detection element HAL;

[0008] The LLC resonant module includes: MOS transistor Q2, MOS transistor Q3, MOS transistor Q4, MOS transistor Q5, resonant inductor Lr, excitation inductor of transformer T1, resonant capacitor Cr, and mutual inductor T2;

[0009] The transformer isolation module includes: a transformer T1;

[0010] The synchronous rectification output module includes MOS transistors Q6, Q7, Q8, Q9, capacitor C1, and output current detection element LR;

[0011] The output anti-reverse and pre-charge module includes: MOS tube Q10, MOS tube Q11, resistor R1, and diode D2;

[0012] The capacitor C1 and the capacitor C2 are both polar capacitors, the IGBT transistor is an N-channel, and the MOS transistors Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, Q10, and Q11 are all N-channel MOS transistors;

[0013] The positive output end of the rectifier bridge BR is electrically connected to one end of the inductor L1, and the other end of the inductor L1 is electrically connected to the positive electrode of the diode D1 and the collector of the IGBT transistor Q1. The gate of the IGBT transistor Q1 is electrically connected to the main control module. The input current detection element HAL is provided between the rectifier bridge BR and the inductor L1 for detecting the input current. The negative electrode of the diode D1 is electrically connected to the positive electrode of the capacitor C1, the drain of the MOS tube Q2, and the drain of the MOS tube Q3. The source of the MOS tube Q2 is electrically connected to the drain of the MOS tube Q4 and one end of the resonant inductor Lr. The source of the MOS transistor Q3 is electrically connected to the drain of the MOS transistor Q5 and one end of the resonant capacitor Lr. The gates of the MOS transistor Q2, Q3, Q4 and Q5 are all electrically connected to the LLC controller. The negative electrode of the output end of the rectifier bridge BR is electrically connected to the emitter of the IGBT transistor Q1, the negative electrode of the capacitor C1, the source of the MOS transistor Q4 and the source of the MOS transistor Q5. The mutual inductor T2 is provided between the MOS transistor Q4 and the resonant capacitor Cr for collecting the resonant cavity current. The other end of the resonant inductor Lr is electrically connected to the variable The positive electrode of the primary side of the transformer T1 is electrically connected, the other end of the resonant capacitor Cr is electrically connected to the negative electrode of the primary side of the transformer T1, the positive electrode of the secondary side of the transformer T1 is electrically connected to the source electrode of the MOS transistor Q6 and the drain electrode of the MOS transistor Q8, the negative electrode of the secondary side of the transformer T1 is electrically connected to the source electrode of the MOS transistor Q7 and the drain electrode of the MOS transistor Q9, the gate electrodes of the MOS transistors Q6, Q7, Q8 and Q9 are all electrically connected to the LLC controller, the sources of the MOS transistors Q8 and Q9 are all electrically connected to the negative output terminal of the circuit, and the The output current detection element LR is provided between the MOS transistor Q9 and the negative output terminal of the circuit for detecting the output current. The drain of the MOS transistor Q6, the drain of the MOS transistor Q7, and the drain of the MOS transistor Q10 are all electrically connected to one end of the resistor R1. The source of the MOS transistor Q10 is electrically connected to the source of the MOS transistor Q11. The other end of the resistor R1 is electrically connected to the negative electrode of the diode D2. The anode of the diode D2 and the drain of the MOS transistor Q11 are both electrically connected to the positive output terminal of the circuit. The gate of the MOS transistor Q10 and the gate of the MOS transistor Q11 are both electrically connected to the main control module.

[0014] By adopting the above scheme, the beneficial effects of the utility model are: a rectifier bridge is set at the input end to support AC input, and it can work normally when the DC input is connected reversely, realizing the anti-reverse connection function, reducing the complexity of the current installation, and the input adopts a boost circuit to increase the voltage to a certain value to be compatible with the requirements of a wide voltage input range, overcoming the defect of the LLC's narrow input voltage range of the optimal resonant working point, and after the voltage is boosted, the voltage is converted to a low voltage value through the transformer ratio, and the LLC soft switch and synchronous rectification technology are adopted to achieve the safety level while improving the conversion efficiency of the converter; the transformer isolation module set can achieve isolation, making the circuit safer; a pre-charging circuit is added on the output side to prevent the impact of large current on the module during hot plugging, thereby extending the service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a structural block diagram of an embodiment of the present utility model.

[0016] Figure 2 This is a circuit diagram of the power part of an embodiment of the present invention. DETAILED DESCRIPTION

[0017] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] Please refer to Figure 1 and Figure 2In this embodiment, the utility model provides an isolated MPPT step-down power conversion unit for a base station with stacked photovoltaic and storage, comprising: a power part and a control part electrically connected to the power part; the power part comprises: a boost module, an LLC resonant module, a transformer isolation module, a synchronous rectifier output module, an output reverse protection and pre-charge module; the rectifier bridge BR of the boost module is electrically connected to the input end of the circuit; the boost module is used for input reverse protection and for increasing the input voltage to the bus voltage required by the LLC resonant module; the LLC resonant module is electrically connected to the boost module; the LLC resonant module is used for generating resonance to improve conversion efficiency; the transformer isolation module is electrically connected to the LLC resonant module; The transformer isolation module is used to achieve high-voltage to low-voltage conversion and electrical isolation, the synchronous rectification output module is electrically connected to the transformer isolation module, the synchronous rectification output module is used to perform synchronous rectification, the output anti-reverse and pre-charge module is electrically connected to the synchronous rectification output module, the output anti-reverse and pre-charge module is used to output reverse connection protection and prevent large current shocks, the control part includes: a main control module, and an LLC controller, a communication and dry contact module electrically connected to the main control module, the main control module is used for data processing and controlling the operation of various parts of the conversion unit, the LLC controller is used to control the LLC resonance module and the synchronous rectification output module, and the communication and dry contact module is used to achieve external communication.

[0019] Specifically:

[0020] The boost module further includes: an inductor L1, a diode D1, an IGBT transistor Q1, a capacitor C1 and an input current detection element HAL.

[0021] The LLC resonant module includes: MOS transistor Q2, MOS transistor Q3, MOS transistor Q4, MOS transistor Q5, resonant inductor Lr, excitation inductor of transformer T1, resonant capacitor Cr, and mutual inductor T2;

[0022] The transformer isolation module includes: a transformer T1.

[0023] The synchronous rectification output module includes a MOS transistor Q6, a MOS transistor Q7, a MOS transistor Q8, a MOS transistor Q9, a capacitor C1, and an output current detection element LR.

[0024] The output anti-reverse and pre-charge module includes: MOS transistor Q10, MOS transistor Q11, resistor R1, and diode D2.

[0025] The capacitor C1 and the capacitor C2 are both polarized capacitors, the IGBT transistor is an N-channel transistor, and the MOS transistors Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, Q10, and Q11 are all N-channel MOS transistors.

[0026] The positive output end of the rectifier bridge BR is electrically connected to one end of the inductor L1, and the other end of the inductor L1 is electrically connected to the positive electrode of the diode D1 and the collector of the IGBT transistor Q1. The gate of the IGBT transistor Q1 is electrically connected to the main control module through an isolation driver. The input current detection element HAL is provided between the rectifier bridge BR and the inductor L1 for detecting the input current. The negative electrode of the diode D1 is electrically connected to the positive electrode of the capacitor C1, the drain of the MOS transistor Q2, and the drain of the MOS transistor Q3. The source of the MOS transistor Q2 is electrically connected to the drain of the MOS transistor Q4 and one end of the resonant inductor Lr. The source of the MOS transistor Q3 is electrically connected to the drain of the MOS transistor Q5 and one end of the resonant capacitor Lr. The gates of the MOS transistor Q2, Q3, Q4 and Q5 are all electrically connected to the LLC controller through a driver. The negative electrode of the output end of the rectifier bridge BR is electrically connected to the emitter of the IGBT transistor Q1, the negative electrode of the capacitor C1, the source of the MOS transistor Q4 and the source of the MOS transistor Q5. The mutual inductor T2 is provided between the MOS transistor Q4 and the resonant capacitor Cr for collecting the resonant cavity current. The other end of the resonant inductor Lr is electrically connected to the LLC controller. The positive electrode of the primary side of the transformer T1 is electrically connected, the other end of the resonant capacitor Cr is electrically connected to the negative electrode of the primary side of the transformer T1, the positive electrode of the secondary side of the transformer T1 is electrically connected to the source of the MOS transistor Q6 and the drain of the MOS transistor Q8, the negative electrode of the secondary side of the transformer T1 is electrically connected to the source of the MOS transistor Q7 and the drain of the MOS transistor Q9, the gate of the MOS transistor Q6, the gate of the MOS transistor Q7, the gate of the MOS transistor Q8, and the gate of the MOS transistor Q9 are all electrically connected to the LLC controller through the isolation driver, and the source of the MOS transistor Q8 and the MOS transistor Q9 are both electrically connected to the negative output terminal of the circuit. The output current detection element LR is provided between the MOS transistor Q9 and the negative output terminal of the circuit for detecting the output current. The drain of the MOS transistor Q6, the drain of the MOS transistor Q7, and the drain of the MOS transistor Q10 are all electrically connected to one end of the resistor R1. The source of the MOS transistor Q10 is electrically connected to the source of the MOS transistor Q11. The other end of the resistor R1 is electrically connected to the negative electrode of the diode D2. The anode of the diode D2 and the drain of the MOS transistor Q11 are both electrically connected to the positive output terminal of the circuit. The gate of the MOS transistor Q10 and the gate of the MOS transistor Q11 are both electrically connected to the main control module.

[0027] Please continue to refer to Figure 1 and Figure 2When the circuit of this solution is operating, the circuit's input terminals IN+ and IN- are connected to the input terminals of the rectifier bridge BR. The main control module controls the IGBT transistors via PWM signals, raising the input voltage to the bus voltage required by the LLC (capacitor C1 voltage). The LLC controller samples the capacitor C1 voltage, the input voltage, and the input current through the input current detector HAL to achieve precise control and protection. The LLC controller can control the high-frequency switching of MOS transistors Q2, Q3, Q4, and Q5, causing the resonant inductor Lr, the resonant capacitor Cr, and the excitation inductance of the transformer T1 to resonate. This achieves zero-voltage turn-on of the MOS transistors Q2, Q3, Q4, and Q5 and zero-current turn-off of the subsequent rectifier, thereby improving converter efficiency. The LLC controller also uses the voltages of capacitors C1 and C2, and samples the resonant cavity current through the transformer T2 to achieve precise control and protection. When the base station needs to be hot-swapped, the external power line charges the capacitor C2 through the resistor R1 and diode D2. The MOS transistors Q10 and Q11 are turned on only when the voltage of C2 reaches a certain value (the error between the voltage of C2 and the voltage of the external battery, power supply, etc. on the output side reaches a set value), thereby preventing large current shocks and arcing at the external terminals. Furthermore, the MOS transistors Q10 and Q11 are also used for output reverse protection. When it is detected that the output side battery is connected reversely, the MOS transistors Q10 and Q11 are also turned off, thereby preventing damage to the converter due to reverse voltage.

[0028] To sum up, the beneficial effects of this solution are: a rectifier bridge is set at the input end to support AC input, and it can work normally when the DC input is reversed, realizing the anti-reverse connection function and reducing the complexity of the current installation. The input adopts a boost circuit to increase the voltage to a certain value to be compatible with the requirements of a wide voltage input range, overcoming the defect of the LLC's resonant optimal operating point input voltage range being narrow. After the voltage is boosted, the voltage is converted to a low voltage value through the transformer ratio, and the LLC soft switching and synchronous rectification technology are adopted to achieve the safety level while improving the conversion efficiency of the converter; the transformer isolation module set can achieve isolation, making the circuit safer; a pre-charging circuit is added on the output side to prevent the impact of large current on the module during hot plugging, thereby extending the service life.

[0029] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An isolated MPPT step-down power conversion unit for a base station with stacked photovoltaic and storage, characterized in that: include: A power part and a control part electrically connected to the power part, the power part includes: a boost module, an LLC resonant module, a transformer isolation module, a synchronous rectifier output module, an output reverse protection and pre-charge module, the rectifier bridge BR of the boost module is electrically connected to the input end of the circuit, the boost module is used for input reverse protection and raising the input voltage to the bus voltage required by the LLC resonant module, the LLC resonant module is electrically connected to the boost module, the LLC resonant module is used to resonate to improve conversion efficiency, the transformer isolation module is electrically connected to the LLC resonant module, the transformer isolation module is used to achieve high voltage to low voltage conversion and Electrical isolation, the synchronous rectification output module is electrically connected to the transformer isolation module, the synchronous rectification output module is used to perform synchronous rectification, the output anti-reverse and pre-charge module is electrically connected to the synchronous rectification output module, the output anti-reverse and pre-charge module is used to output anti-reverse connection and prevent large current impact, the control part includes: a main control module, and an LLC controller, a communication and dry contact module electrically connected to the main control module, the main control module is used for data processing and controlling the operation of various parts of the conversion unit, the LLC controller is used to control the LLC resonant module and the synchronous rectification output module, and the communication and dry contact module is used to realize communication with the outside.

2. The isolated MPPT step-down power conversion unit for base station stacked photovoltaic and storage according to claim 1 is characterized in that: The boost module further includes: an inductor L1, a diode D1, an IGBT transistor Q1, a capacitor C1 and an input current detection element HAL; The LLC resonant module includes: MOS transistor Q2, MOS transistor Q3, MOS transistor Q4, MOS transistor Q5, resonant inductor Lr, excitation inductor of transformer T1, resonant capacitor Cr, and mutual inductor T2; The transformer isolation module includes: a transformer T1; The synchronous rectification output module includes MOS transistors Q6, Q7, Q8, Q9, capacitor C1, and output current detection element LR; The output anti-reverse and pre-charge module includes: MOS tube Q10, MOS tube Q11, resistor R1, and diode D2; The capacitor C1 and the capacitor C2 are both polar capacitors, the IGBT transistor is an N-channel, and the MOS transistors Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, Q10, and Q11 are all N-channel MOS transistors; The positive output end of the rectifier bridge BR is electrically connected to one end of the inductor L1, and the other end of the inductor L1 is electrically connected to the positive electrode of the diode D1 and the collector of the IGBT transistor Q1. The gate of the IGBT transistor Q1 is electrically connected to the main control module. The input current detection element HAL is provided between the rectifier bridge BR and the inductor L1 for detecting the input current. The negative electrode of the diode D1 is electrically connected to the positive electrode of the capacitor C1, the drain of the MOS tube Q2, and the drain of the MOS tube Q3. The source of the MOS tube Q2 is electrically connected to the drain of the MOS tube Q4 and one end of the resonant inductor Lr. The source of the MOS transistor Q3 is electrically connected to the drain of the MOS transistor Q5 and one end of the resonant capacitor Lr. The gates of the MOS transistor Q2, Q3, Q4 and Q5 are all electrically connected to the LLC controller. The negative electrode of the output end of the rectifier bridge BR is electrically connected to the emitter of the IGBT transistor Q1, the negative electrode of the capacitor C1, the source of the MOS transistor Q4 and the source of the MOS transistor Q5. The mutual inductor T2 is provided between the MOS transistor Q4 and the resonant capacitor Cr for collecting the resonant cavity current. The other end of the resonant inductor Lr is electrically connected to the variable The positive electrode of the primary side of the transformer T1 is electrically connected, the other end of the resonant capacitor Cr is electrically connected to the negative electrode of the primary side of the transformer T1, the positive electrode of the secondary side of the transformer T1 is electrically connected to the source electrode of the MOS transistor Q6 and the drain electrode of the MOS transistor Q8, the negative electrode of the secondary side of the transformer T1 is electrically connected to the source electrode of the MOS transistor Q7 and the drain electrode of the MOS transistor Q9, the gate electrodes of the MOS transistors Q6, Q7, Q8 and Q9 are all electrically connected to the LLC controller, the sources of the MOS transistors Q8 and Q9 are all electrically connected to the negative output terminal of the circuit, and the The output current detection element LR is provided between the MOS transistor Q9 and the negative output terminal of the circuit for detecting the output current. The drain of the MOS transistor Q6, the drain of the MOS transistor Q7, and the drain of the MOS transistor Q10 are all electrically connected to one end of the resistor R1. The source of the MOS transistor Q10 is electrically connected to the source of the MOS transistor Q11. The other end of the resistor R1 is electrically connected to the negative electrode of the diode D2. The anode of the diode D2 and the drain of the MOS transistor Q11 are both electrically connected to the positive output terminal of the circuit. The gate of the MOS transistor Q10 and the gate of the MOS transistor Q11 are both electrically connected to the main control module.

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