CN109347332A - The driving circuit and converters of converters bridge architecture - Google Patents

The driving circuit and converters of converters bridge architecture Download PDF

Info

Publication number
CN109347332A
CN109347332A CN201811483797.XA CN201811483797A CN109347332A CN 109347332 A CN109347332 A CN 109347332A CN 201811483797 A CN201811483797 A CN 201811483797A CN 109347332 A CN109347332 A CN 109347332A
Authority
CN
China
Prior art keywords
driving circuit
driving
diode
power tube
circuit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN201811483797.XA
Other languages
Chinese (zh)
Inventor
刘钧
冯颖盈
姚顺
刘骥
付东进
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shenzhen Vmax Power Co Ltd
Original Assignee
Shenzhen Vmax Power Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Shenzhen Vmax Power Co Ltd filed Critical Shenzhen Vmax Power Co Ltd
Priority to CN201811483797.XA priority Critical patent/CN109347332A/en
Publication of CN109347332A publication Critical patent/CN109347332A/en
Pending legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00Conversion of dc power input into dc power output
    • H02M3/22Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33569Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
    • H02M3/33576Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer
    • H02M3/33592Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00Details of apparatus for conversion
    • H02M1/32Means for protecting converters other than automatic disconnection

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)

Abstract

The present invention provides the driving circuits and converters of a kind of converters bridge architecture.The driving circuit includes the first driving circuit for driving the first power tube, with for driving the second driving circuit of the second power tube, PWM signal generator is coupled by isolation element with the first driving circuit and the second driving circuit, the source electrode of first power tube is connect with the drain electrode of the second power tube, the driving circuit of converters bridge architecture further includes that the gate pole residual voltage for generating the first power tube is released to safe voltage the first leadage circuit below, and the gate pole residual voltage for generating the second power tube is released to safe voltage the second leadage circuit below.A possibility that present invention generates the driving stage that negative level is superimposed upon shutdown pipe by using Zener, diode etc. in conjunction with driving transformer, reduces gate voltage spike level, reduces false triggering, increases the reliability of driving circuit.

Description

The driving circuit and converters of converters bridge architecture
Technical field
The present invention relates to Technics of Power Electronic Conversion fields, and in particular to a kind of driving electricity of converters bridge architecture Road and converters.
Background technique
In converters, main control unit issues control signal, and control power circuit realizes transformation of electrical energy.Due to master It is weaker to control cell signal driving capability, needs by driving circuit as control circuit and power circuit interface.Modern electric electricity Such as Vehicular charger, high-power communication power supply in sub- converting means, the power of processing is increasing, and bridge architecture is because of its change Power is changed to be widely adopted better than other structures.
Bridge architecture is capable of handling more high-power, drives that there is also false triggering risks to it.When the conducting of upper (lower) pipe, produce Raw voltage change cause under (on) junction capacitance voltage change, form electric current, the electric current and parasitic inductance drive resistance phase interaction With due to voltage spikes can be generated.The due to voltage spikes causes down tube straight-through, causes input source short-circuit, converting means damage.To avoid Straight-through phenomenon occurs, and in addition to requiring control signal to add dead zone, complementary pipe driving signal generally requires superposition negative electricity in low level Pressure avoids false triggering to improve driving anti-interference.
Common bridge drive circuit is broadly divided into two kinds: building circuit drives using separating component;Using dedicated drive Dynamic chip drives.It is driven using driving chip, negative pressure can be generated when power tube shutdown, anti-interference relatively strong, reliable performance, but deposit In disadvantage that is expensive, and needing additional auxiliary supply source power supply.It is relatively simple that separating component builds driving circuit structure, but It only provides driving capability enlarging function, that is, generate high level when opening, when shutdown generates low level, and when shutdown has no negative pressure It is added on power tube gate pole, jamproof performance is weaker, and reliability is weaker.
It is therefore desirable to provide a kind of to have the characteristics that structure is simple, driving of reliable performance, bridge architecture low in cost Circuit makes electronic product with more the market competitiveness, becomes problem anxious to be resolved.
Summary of the invention
The present invention provides the driving circuits and converters of a kind of converters bridge architecture, with solution The problem of false triggering risk certainly exists in the prior art.
To solve the above problems, providing a kind of converters bridge architecture as one aspect of the present invention Driving circuit, including PWM signal generator, isolation element, the first power tube, the second power tube, for driving described first First driving circuit of power tube and the second driving circuit for driving second power tube, the PWM signal generator It is coupled by the isolation element with first driving circuit and the second driving circuit, the source electrode of first power tube and institute State the drain electrode connection of the second power tube, which is characterized in that the driving circuit of the converters bridge architecture further includes Gate pole residual voltage for generating first power tube is released to safe voltage the first leadage circuit below, Yi Jiyong It releases in the gate pole residual voltage for generating second power tube to safe voltage the second leadage circuit below, described first Leadage circuit is electrically connected with first driving circuit, and second leadage circuit is electrically connected with second driving circuit.
Preferably, first driving circuit is identical as second driving circuit, first leadage circuit with it is described Second leadage circuit is identical.
Preferably, the isolation element is isolation drive transformer.
Preferably, first power tube include first open diode, second open diode, driving resistance, gate pole Resistance, the first discharge diode and the second discharge diode, the first end of the first secondary windings of the isolation drive transformer Pass sequentially through described first open diode, second open diode, driving resistance, gate electrode resistance and the first secondary windings the The connection of two ends, the both ends of the gate electrode resistance are connect with the gate pole of first power tube and source electrode correspondingly respectively, institute State one end that second opens diode connect with the emitter of first discharge diode, the other end and it is described first electric discharge three The base stage of pole pipe connects, and the collector of first discharge diode passes through first resistor and the second of first secondary windings End connection, the one end of the driving resistance connecting with the gate electrode resistance and the collector of second discharge diode connect It connects, the base stage of second discharge diode is connect with the collector of first discharge diode, second electric discharge, three poles The emitter of pipe is connect with the second end of first secondary windings.
Preferably, first leadage circuit includes Zener diode and negative pressure clamp diode, and described first opens two The one end of pole pipe connecting with the first end of first secondary windings passes sequentially through the Zener diode, two pole of negative pressure clamper It manages and is connected with the one end of the driving resistance being connect with the gate electrode resistance.
Preferably, the base stage of first discharge diode passes through the second end of second resistance and first secondary windings Connection.
Preferably, the one end of the driving resistance connecting with the gate electrode resistance is put by 3rd resistor with described second The collector of electric triode connects.
The present invention also provides a kind of converters, the drive including above-mentioned converters bridge architecture Dynamic circuit.
The present invention generates the driving stage that negative level is superimposed upon shutdown pipe by using Zener etc. in conjunction with driving transformer, A possibility that reducing false triggering.The present invention builds circuit using discrete component, not only of simple structure and low cost, and And greatly improve the reliability of driving circuit in the prior art.
Detailed description of the invention
Fig. 1 schematically shows bridge drive circuit schematic diagram of the invention;
Fig. 2 schematically shows bridge drive circuit upper tubes of the invention to open schematic diagram;
Fig. 3 schematically shows down tube on bridge drive circuit of the invention and simultaneously turns off schematic diagram;
Fig. 4 schematically shows bridge drive circuit down tubes of the invention to open schematic diagram.
Appended drawing reference in figure: 1, PWM signal generator;2, isolation element;3, the first power tube;4, the second power tube;5, First opens diode;6, second diode is opened;7, resistance is driven;8, gate electrode resistance;9, the first discharge diode;10, Two discharge diodes;11, first resistor;12, Zener diode;13, negative pressure clamp diode;14, second resistance;15, third Resistance.
Specific embodiment
The embodiment of the present invention is described in detail below in conjunction with attached drawing, but the present invention can be defined by the claims Implement with the multitude of different ways of covering.
The object of the present invention is to provide a kind of reliable performances, bridge drive circuit of simple structure and low cost, that is, use Separating component, which is built to be capable of providing, generates high level when opening, and negative pressure is generated when shutdown to enhance the driving of anti-interference ability Circuit.
One aspect of the present invention provides a kind of driving circuit of converters bridge architecture, including PWM letter Number generator 1, isolation element 2, the first power tube 3, the second power tube 4, for driving the first of first power tube 3 to drive Circuit and the second driving circuit for driving second power tube 4, the PWM signal generator 1 are first by the isolation Part 2 is coupled with first driving circuit and the second driving circuit, the source electrode of first power tube 3 and second power tube 4 drain electrode connection, which is characterized in that the driving circuit of the converters bridge architecture further includes for by described the The gate pole residual voltage that one power tube 3 generates is released to safe voltage the first leadage circuit below and for by described the The gate pole residual voltage that two power tubes 4 generate is released to safe voltage the second leadage circuit below, first leadage circuit It is electrically connected with first driving circuit, second leadage circuit is electrically connected with second driving circuit.
Preferably, first driving circuit is identical as second driving circuit, first leadage circuit with it is described Second leadage circuit is identical.
Preferably, the isolation element 2 is isolation drive transformer.
Preferably, first power tube 3 include first open diode 5, second open diode 6, driving resistance 7, Gate electrode resistance 8, the first discharge diode 9 and the second discharge diode 10, the first secondary windings of the isolation drive transformer First end pass sequentially through described first open diode 5, second open diode 6, driving resistance 7, gate electrode resistance 8 and first The second end of secondary windings connects, the both ends of the gate electrode resistance 8 respectively with the gate pole of first power tube 3 and source electrode one by one Correspondingly connected, described second one end for opening diode 6 connect with the emitter of first discharge diode 9, the other end It is connect with the base stage of first discharge diode 9, the collector of first discharge diode 9 passes through first resistor 11 and institute State the second end connection of the first secondary windings, one end connecting with the gate electrode resistance 8 and described second of the driving resistance 7 The collector of discharge diode 10 connects, the collection of the base stage of second discharge diode 10 and first discharge diode 9 Electrode connection, the emitter of second discharge diode 10 are connect with the second end of first secondary windings.
Preferably, first leadage circuit includes Zener diode 12 and negative pressure clamp diode 13, and described first opens The one end of logical diode 5 connecting with the first end of first secondary windings passes sequentially through the Zener diode 12, negative pressure Clamp diode 13 is connected with the one end of the driving resistance 7 connecting with the gate electrode resistance 8.
Preferably, the base stage of first discharge diode 9 pass through second resistance 14 and first secondary windings the The connection of two ends.
Preferably, the one end of the driving resistance 7 connect with the gate electrode resistance 8 passes through 3rd resistor 15 and described the The collector of two discharge diodes 10 connects.
The present invention also provides a kind of converters, for example, phase-shifted full-bridge converter, LLC converter and half-bridge Converter etc., the driving circuit including above-mentioned converters bridge architecture.
In the following, being carried out to working process and principle of the invention as described below.
Such as Fig. 2, when bridge drive circuit upper tube in the present invention is opened, PWM_H is high level, and PWM_L is low level, Driving signal is reached into power tube driving by isolation element 2, high level is loaded onto the by circuit shown in arrow in Fig. 2 The gate pole of one power tube 3, then the first power tube 3 is connected.Meanwhile negative voltage being loaded onto the gate pole of the second power tube 4, it realizes The negative pressure clamper of second power tube 4 turns off.
Such as Fig. 3, on bridge drive circuit in the present invention when down tube shutdown, PWM_H is low level, and PWM_L is low electricity Flat, no driving signal reaches power tube through isolation element 2 and drives, and circuit shown in dotted lines in Figure 3 forces Q11, Q12 conducting by Q1 Gate pole residual voltage is released to safe voltage hereinafter, same R23, R24, R21, R22, R2g force the first discharge diode 9, the Two discharge diodes 10 conducting, to releasing the gate pole residual voltage of the first power tube 3 and the second power tube 4 to safe voltage Hereinafter, the first power tube 3 and the second power tube 4 are turned off at this time.
As shown in figure 4, PWM_H is low level when bridge drive circuit down tube is opened, PWM_L is high level, by every Driving signal is reached into power tube driving from element 2.High level is loaded onto the second function by the second driving circuit of the second power tube 4 The gate pole of rate pipe 4, the conducting of the second power tube 4.And negative voltage is loaded onto first by the first driving circuit of the first discharge diode 9 The gate pole of power tube 3 realizes the shutdown of 3 negative pressure clamper of the first power tube.Due to the presence of the first leadage circuit, so that the second power When pipe 4 is connected, under the cooperation of upper winding, a upper negative level is generated, the both ends GS of the first power tube 3 are added in, to be formed Stable negative pressure judgement, therefore the first power tube 3 does not turn on, that is, eliminates the risk of false triggering.
The present invention generates the driving stage that negative level is superimposed upon shutdown pipe by using Zener etc. in conjunction with driving transformer, A possibility that reducing false triggering.The present invention builds circuit using discrete component, not only of simple structure and low cost, and And greatly improve the reliability of driving circuit in the prior art.
The foregoing is only a preferred embodiment of the present invention, is not intended to restrict the invention, for the skill of this field For art personnel, the invention may be variously modified and varied.All within the spirits and principles of the present invention, made any to repair Change, equivalent replacement, improvement etc., should all be included in the protection scope of the present invention.

Claims (8)

1. a kind of driving circuit of converters bridge architecture, including PWM signal generator (1), isolation element (2), First power tube (3), the second power tube (4), the first driving circuit for driving first power tube (3) and for driving The second driving circuit of second power tube (4) is moved, the PWM signal generator (1) passes through the isolation element (2) and institute State the first driving circuit and the coupling of the second driving circuit, the source electrode of first power tube (3) and second power tube (4) Drain electrode connection, which is characterized in that the driving circuit of the converters bridge architecture further includes being used for described first The gate pole residual voltage that power tube (3) generates is released to safe voltage the first leadage circuit below and for by described the The gate pole residual voltage that two power tubes (4) generate is released to safe voltage the second leadage circuit below, first vent discharge Road is electrically connected with first driving circuit, and second leadage circuit is electrically connected with second driving circuit.
2. the driving circuit of converters bridge architecture according to claim 1, which is characterized in that described first Driving circuit is identical as second driving circuit, and first leadage circuit is identical as second leadage circuit.
3. the driving circuit of converters bridge architecture according to claim 2, which is characterized in that the isolation Element (2) is isolation drive transformer.
4. the driving circuit of converters bridge architecture according to claim 3, which is characterized in that described first Power tube (3) include first open diode (5), second open diode (6), driving resistance (7), gate electrode resistance (8), first Discharge diode (9) and the second discharge diode (10), the first end of the first secondary windings of the isolation drive transformer according to It is secondary by described first open diode (5), second open diode (6), driving resistance (7), gate electrode resistance (8) and for the first time The second end connection of grade winding, the both ends of the gate electrode resistance (8) gate pole and source electrode one with first power tube (3) respectively One is correspondingly connected, described second one end for opening diode (6) connect with the emitter of first discharge diode (9), The other end is connect with the base stage of first discharge diode (9), and the collector of first discharge diode (9) passes through first Resistance (11) is connect with the second end of first secondary windings, and driving resistance (7) connect with the gate electrode resistance (8) One end connect with the collector of second discharge diode (10), the base stage of second discharge diode (10) with it is described The collector of first discharge diode (9) connects, the emitter of second discharge diode (10) and first grade around The second end connection of group.
5. the driving circuit of converters bridge architecture according to claim 4, which is characterized in that described first Leadage circuit includes Zener diode (12) and negative pressure clamp diode (13), described first open diode (5) with it is described First secondary windings first end connection one end pass sequentially through the Zener diode (12), negative pressure clamp diode (13) with One end connection of driving resistance (7) being connect with the gate electrode resistance (8).
6. the driving circuit of converters bridge architecture according to claim 4, which is characterized in that described first The base stage of discharge diode (9) is connect by second resistance (14) with the second end of first secondary windings.
7. the driving circuit of converters bridge architecture according to claim 4, which is characterized in that the driving The one end of resistance (7) connecting with the gate electrode resistance (8) passes through 3rd resistor (15) and second discharge diode (10) Collector connection.
8. a kind of converters, which is characterized in that become including power electronics described in any one of claims 1 to 7 The driving circuit of parallel operation bridge architecture.
CN201811483797.XA 2018-12-06 2018-12-06 The driving circuit and converters of converters bridge architecture Pending CN109347332A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201811483797.XA CN109347332A (en) 2018-12-06 2018-12-06 The driving circuit and converters of converters bridge architecture

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201811483797.XA CN109347332A (en) 2018-12-06 2018-12-06 The driving circuit and converters of converters bridge architecture

Publications (1)

Publication Number Publication Date
CN109347332A true CN109347332A (en) 2019-02-15

Family

ID=65297607

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201811483797.XA Pending CN109347332A (en) 2018-12-06 2018-12-06 The driving circuit and converters of converters bridge architecture

Country Status (1)

Country Link
CN (1) CN109347332A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110572014A (en) * 2019-08-29 2019-12-13 合肥博雷电气有限公司 MOS tube driving circuit with turn-off negative voltage
CN111614236A (en) * 2020-06-15 2020-09-01 南京工程学院 SiC MOSFET gate auxiliary circuit based on bridge circuit

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003348817A (en) * 2002-05-29 2003-12-05 Mitsubishi Electric Corp Gate driving circuit
US20170040994A1 (en) * 2015-03-30 2017-02-09 Halliburton Energy Services, Inc. Simplified gate driver for power transistors
CN207200579U (en) * 2017-09-15 2018-04-06 肇庆市锐高电子有限公司 Full-bridge switching power supply
CN209217954U (en) * 2018-12-06 2019-08-06 深圳威迈斯新能源股份有限公司 The driving circuit and converters of converters bridge architecture

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003348817A (en) * 2002-05-29 2003-12-05 Mitsubishi Electric Corp Gate driving circuit
US20170040994A1 (en) * 2015-03-30 2017-02-09 Halliburton Energy Services, Inc. Simplified gate driver for power transistors
CN207200579U (en) * 2017-09-15 2018-04-06 肇庆市锐高电子有限公司 Full-bridge switching power supply
CN209217954U (en) * 2018-12-06 2019-08-06 深圳威迈斯新能源股份有限公司 The driving circuit and converters of converters bridge architecture

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110572014A (en) * 2019-08-29 2019-12-13 合肥博雷电气有限公司 MOS tube driving circuit with turn-off negative voltage
CN110572014B (en) * 2019-08-29 2021-03-30 合肥博雷电气有限公司 MOS tube driving circuit with turn-off negative voltage
CN111614236A (en) * 2020-06-15 2020-09-01 南京工程学院 SiC MOSFET gate auxiliary circuit based on bridge circuit

Similar Documents

Publication Publication Date Title
CN105337483A (en) Device for preventing current from flowing backwards
CN102946199A (en) Direct current insulation buck converter and matrix voltage detection circuit thereof
CN106786396A (en) One kind amendment ripple inverter intelligent type protective switch of the short circuit circuit
CN101013850B (en) High-frequency constant-current charging power of high-voltage capacitor supplied with accumulator
CN100566111C (en) A kind of six switch five-power level voltage source type inverters and control method thereof
CN105871218A (en) IGBT driving method and device with push-pull type isolation power supply
CN108988619A (en) A kind of IGBT module driving circuit suitable for high-power inverter
CN107834832B (en) A kind of voltage peak absorbing circuit
CN102969918A (en) Three-phase bridge-type inverter system and urgency lower short-circuit protective circuit
CN109347332A (en) The driving circuit and converters of converters bridge architecture
CN105871217B (en) Push-pull type isolation power supply and method for IGBT driving device
CN102263510A (en) Full bridge isolation direct-current (DC) converter capable of discharging to front-end high-voltage bus
CN102082563A (en) IGBT (insulated gate bipolar transistor) driver, signal processing method, motor control system and vehicle
CN206379716U (en) Electric automobile, onboard charger and its current foldback circuit
CN108092237A (en) A kind of full-bridge inverting power switch pipe overcurrent and load over-current protection circuit
CN209217954U (en) The driving circuit and converters of converters bridge architecture
CN109941124A (en) Charging pile and its charging module and charging and voltage stabilizing control method
CN202172363U (en) Full bridge isolated DC converter capable of discharging to front end high voltage bus
CN205945528U (en) IGBT driving device provided with push-pull type isolation power supply
CN204835968U (en) Be applied to intelligent high frequency switching power supply module among electrical power generating system of transformer substation
CN204119028U (en) A kind of twin-stage Boost circuit
CN101212182B (en) Power circuit
CN108233756B (en) A kind of single input is double to be grounded half-bridge inverter and its control method
CN1661384A (en) Device for testing electric pulse strength for insulation
CN207021660U (en) Electrical source input overvoltage protection and output overvoltage protection circuit

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination