CN206349942U

CN206349942U - Prevent the unbalanced circuit arrangement of series connection electrolysis capacitance voltage in inverter

Info

Publication number: CN206349942U
Application number: CN201621379266.2U
Authority: CN
Inventors: 薄涛; 李剑铎
Original assignee: GLOBAL MAINSTREAM DYNAMIC ENERGY TECHNOLOGY Ltd
Current assignee: Hangzhou Xuda New Energy Technology Co ltd
Priority date: 2016-12-15
Filing date: 2016-12-15
Publication date: 2017-07-21
Anticipated expiration: 2026-12-15

Abstract

Prevent the unbalanced circuit arrangement of series connection electrolysis capacitance voltage in inverter, including dc bus (2), switching tube (6), voltage difference judge module (7) and dead band comparator (8)；The connecting valve pipe (6) between dc bus (2) and dc-to-ac inverter (3), simultaneously, voltage difference judge module (7) connects the electrochemical capacitor both sides on dc bus (2) respectively, voltage difference judge module (7) connection dead band comparator (8), dead band comparator (8) connecting valve pipe (6).Extra discharge resistance need not be increased, extra consumers will not generally be increased in circuit, the equilibrium function of bus capacitor is realized using the switching device of inverter in itself, the regulation process in dead band is continuous, electrochemical capacitor voltage is of substantially equal, saves the loss under poised state, improves system effectiveness, reduce system heat generation, it is ensured that solar inverter efficient stable can be run for a long time.

Description

Prevent the unbalanced circuit arrangement of series connection electrolysis capacitance voltage in inverter

Technical field

The utility model is related to the structure improved technology of solar inverter apparatus, especially prevents from going here and there in inverter Join the circuit arrangement of electrochemical capacitor Voltage unbalance.

Background technology

Solar inverter is that a kind of direct current for issuing solar panel is converted into that public electric wire net can be accessed The power electronic equipment of alternating current.Typical solar inverter will include following components:DC-DC converter (DC-DC), DC-AC inverter (DC-AC), system controller (Controller) and accessory power supply (SPS, Supplementary Power Supply).Meanwhile, Cp is connected DC-DC and DC-AC with Cn as dc bus, is front and rear electricity Road provides stable voltage and absorption ripple current.As shown in Figure 1, photovoltaic panel direct current input direct-current-DC converter 1, enters One step connects DC-AC inverter 3, and further exchange output by dc bus 2, meanwhile, DSP master controllers 4 and SPS Accessory power supply 5 while connect DC-DC converter 1 and DC-AC inverter 3, moreover, SPS accessory power supplys 5 connect respectively Connect DSP master controllers 4.

In solar inverter practical work process, DC bus-bar voltage reaches as high as more than 600V, and on the market compared with Common electrochemical capacitor is pressure-resistant can not all to meet this voltage request.In order to meet the requirement of DC bus-bar voltage, electrochemical capacitor It must be used in series.But when alminium electrolytic condenser series connection, also need to ensure the voltage being added on each electric capacity no more than it Maximum permissible voltage.In such a case it is necessary to consider whole busbar voltage by the insulaion resistance of series capacitance to distribute.Due to The insulation impedance otherness of single electric capacity is very big, and voltage distribution difference perhaps can be very big, may result in the electricity on single electric capacity Pressure exceedes permissible value.In order to ensure the voltage on electrochemical capacitor is that in the range of the safe voltage of body, general use is pressed Resistance forces the method pressed, and gives each capacitor equalizing resistance in parallel.The electric current for flowing through resistance Rp and Rn must be remote More than the leakage current of capacitor, the otherwise uncontrollable voltage assigning process of resistance.It is this to force series electrical using equalizing resistance The method for solving capacitor voltage equalizing, can be such that equalizing resistance is chronically under working condition, power consumption is larger, not only influence system integrally to imitate Rate, is also radiating increase difficulty, also brings hidden danger for operation steady in a long-term, equalizing resistance forces isostatic pressing to have shortcomings, and And, particularly more protruded in the situation of high input voltage.

Utility model content

The purpose of this utility model, which is to provide, prevents the unbalanced circuit arrangement of series connection electrolysis capacitance voltage in inverter, with Ensure that solar inverter efficient stable can be run for a long time.

The purpose of this utility model will be realized by following technical measures：Sentence including dc bus, switching tube, voltage difference Disconnected module and dead band comparator；The connecting valve pipe between dc bus and DC-AC inverter, meanwhile, voltage difference judges Module connects the electrochemical capacitor both sides on dc bus, voltage difference judge module connection dead band comparator, dead band comparator respectively Connecting valve pipe.

Especially, dead band comparator connection PWM controller.

Especially, the electrochemical capacitor both sides on dc bus connect sampling resistor respectively, and voltage difference judge module leads to respectively Over-sampling resistance connection electrochemical capacitor both sides.

Especially, the electrochemical capacitor on dc bus is the Cp and Cn of series connection, and switching tube includes bis- groups of the Q1 and Q2 of series connection, Cp and Cn and Q1 and Q2 connects into bridge circuit structure, in Cp and Cn both sides, is connected to voltage difference by sampling resistor respectively Judge module.

Especially, voltage difference judge module exports dead band variation delta t to dead band comparator_dead。

Advantage and effect of the present utility model：Compared to existing solution, it is not necessary to increase extra discharge resistance, typically In the case of will not increase extra consumers in circuit, realize the flat of bus capacitor using the switching device of inverter in itself Weigh function, and the regulation process in dead band is continuous, and electrochemical capacitor voltage is of substantially equal, saves the loss under poised state, improves system System efficiency, reduces system heat generation, it is ensured that solar inverter efficient stable can be run for a long time.

Brief description of the drawings

Fig. 1 is Voltage unbalance structural representation in solution electrochemical capacitor in the prior art.

Fig. 2 is the structural representation of the utility model embodiment 1.

Reference includes：

DC-DC converter 1, dc bus 2, DC-AC inverter 3, DSP master controllers 4, SPS accessory power supplys 5th, switching tube 6, voltage difference judge module 7, dead band comparator 8, PWM controller 9.

Embodiment

The utility model principle is that the loss of switching device substantially has two big kinds：Switching loss and conduction loss, its Middle switching loss and switching frequency f_sw, operating voltage U, operating current I, switching speed t_r、t_fIt is relevant.Formula can be with Approximate Equivalent ForConduction loss and break-over of device impedance R_on, circulating current I_onWith ON time (t_on-t_dead) have Close, formula can using Approximate Equivalent as

Inverter in the process of running in order to above and below preventing switching tube simultaneously turn on caused by dc bus short circuit, Typically all it can increase dead band on the normal duty cycle of switching of switching tube up and down, to avoid leading due to switching tube time delay of action Situation is opened while cause.So corresponding, switching tube switching loss, which becomes, to be turned to： Δf_swFor because dead time changes the on-off times for causing to increase or decrease；Switching tube conduction loss changes For：Δt_deadFor the variable quantity in dead band.Total Dissipation change amount is：As dead band Δ t_deadIncrease, Δ f_swReduce, switching loss is equal with conduction loss It can reduce, so as to have influence on the energy loss of switching device.

In the utility model, the core texture of voltage decision circuitry includes one group of sampling resistor and comparator, when detecting When dc bus Cp voltage is less than Cn, voltage decision circuitry provides the signal of increase Q1 dead times, passes through dead band comparator After being compared with the normal PWM that DSP is provided, control signal controlling switch pipe Q1 losses are reduced so that Cp equivalent parallel resistances become big, Energy loss reduces in Cp, and the voltage that such Cp shares will rise；When the voltage for detecting Cp is more than Cn, voltage judges electricity Road provides the signal of increase Q2 dead times, after being compared by dead band comparator with the normal PWM that DSP is provided, control signal control Switching tube Q2 losses processed are reduced so that Cn equivalent parallel resistances become big, and energy loss reduces in Cn, and the voltage that such Cn shares is just It can rise；When the voltage for detecting Cp is equal with Cn, any action, maintenance voltage equilibrium state are not done in control signal control.

The utility model includes：Dc bus 2, switching tube 6, voltage difference judge module 7 and dead band comparator 8.

The utility model is described in further detail with reference to the accompanying drawings and examples.

Embodiment 1：As shown in Figure 1, the connecting valve pipe 6 between dc bus 2 and DC-AC inverter 3, together When, voltage difference judge module 7 connects the electrochemical capacitor both sides on dc bus 2, the connection dead band ratio of voltage difference judge module 7 respectively Compared with device 8, the connecting valve pipe 6 of dead band comparator 8.

In foregoing, the connection PWM controller 9 of dead band comparator 8.

In foregoing, the electrochemical capacitor both sides on dc bus 2 connect sampling resistor respectively, and voltage difference judge module 7 is distinguished Electrochemical capacitor both sides are connected by sampling resistor.

In foregoing, the electrochemical capacitor on dc bus 2 is the Cp and Cn of series connection, and switching tube 6 includes the Q1 and Q2 bis- of series connection Group, Cp and Cn and Q1 and Q2 connect into bridge circuit structure, in Cp and Cn both sides, are connected to voltage by sampling resistor respectively Poor judge module 7.

In foregoing, voltage difference judge module 7 exports dead band variation delta t to dead band comparator 8_dead。

In the utility model, using the three-phase DC-AC inverter bridges being connected on dc-link capacitance in itself come complete to string Join the voltage adjustment of electric capacity, it is not necessary to increase discharge resistance and the voltage of series capacitance is adjusted.

In the utility model, compared to existing solution, it is not necessary to increase extra discharge resistance, generally will not Increase extra consumers in circuit, the equilibrium function of bus capacitor is realized using the switching device of inverter in itself, extremely The regulation process in area is continuous, and electrochemical capacitor voltage is of substantially equal, saves the loss under poised state, improves system effectiveness, drop Low system heat generation, it is ensured that solar inverter efficient stable can be run for a long time.

Claims

1. prevent the unbalanced circuit arrangement of series connection electrolysis capacitance voltage in inverter, including dc bus (2), switching tube (6), Voltage difference judge module (7) and dead band comparator (8)；Characterized in that, in dc bus (2) and DC-AC inverter (3) Between connecting valve pipe (6), meanwhile, voltage difference judge module (7) connects the electrochemical capacitor both sides on dc bus (2) respectively, Voltage difference judge module (7) connection dead band comparator (8), dead band comparator (8) connecting valve pipe (6).

2. preventing the unbalanced circuit arrangement of series connection electrolysis capacitance voltage in inverter as claimed in claim 1, its feature exists In dead band comparator (8) connection PWM controller (9).

3. preventing the unbalanced circuit arrangement of series connection electrolysis capacitance voltage in inverter as claimed in claim 1, its feature exists In the electrochemical capacitor both sides on dc bus (2) connect sampling resistor respectively, and voltage difference judge module (7) passes through sampling respectively Resistance connection electrochemical capacitor both sides.

4. preventing the unbalanced circuit arrangement of series connection electrolysis capacitance voltage in inverter as claimed in claim 1, its feature exists In the electrochemical capacitor on dc bus (2) is the Cp and Cn of series connection, and switching tube (6) includes bis- groups of the Q1 and Q2 of series connection, and electrolysis is electric Hold Cp and electrochemical capacitor Cn and switching tube Q1 and switching tube Q2 and connect into bridge circuit structure, in electrochemical capacitor Cp and electrochemical capacitor Cn both sides, are connected to voltage difference judge module (7) by sampling resistor respectively.

5. preventing the unbalanced circuit arrangement of series connection electrolysis capacitance voltage in inverter as claimed in claim 1, its feature exists In voltage difference judge module (7) exports dead band variation delta t to dead band comparator (8)_dead。