CN110768538A - Vehicle-mounted auxiliary power supply DC-DC converter and control method thereof - Google Patents

Vehicle-mounted auxiliary power supply DC-DC converter and control method thereof Download PDF

Info

Publication number
CN110768538A
CN110768538A CN201911165054.2A CN201911165054A CN110768538A CN 110768538 A CN110768538 A CN 110768538A CN 201911165054 A CN201911165054 A CN 201911165054A CN 110768538 A CN110768538 A CN 110768538A
Authority
CN
China
Prior art keywords
converter
switch tube
power switch
pulse generator
pwm pulse
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
CN201911165054.2A
Other languages
Chinese (zh)
Inventor
罗文广
蓝红莉
马明
唐俊超
王涛
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.)
Guangxi University of Science and Technology
Original Assignee
Guangxi University of Science and Technology
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 Guangxi University of Science and Technology filed Critical Guangxi University of Science and Technology
Priority to CN201911165054.2A priority Critical patent/CN110768538A/en
Publication of CN110768538A publication Critical patent/CN110768538A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS 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
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion 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
    • H02M3/325—Conversion 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
    • H02M3/335—Conversion 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
    • H02M3/33507—Conversion 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 with automatic control of the output voltage or current, e.g. flyback converters
    • H02M3/33523—Conversion 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 with automatic control of the output voltage or current, e.g. flyback converters with galvanic isolation between input and output of both the power stage and the feedback loop
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS 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
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion 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
    • H02M3/325—Conversion 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
    • H02M3/335—Conversion 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
    • H02M3/33569—Conversion 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
    • H02M3/33576—Conversion 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
    • H02M3/33592—Conversion 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

Abstract

The invention aims to provide a vehicle-mounted auxiliary power supply DC-DC converter, which comprises an input capacitor C1, a Buck converter, a Boost converter, an output capacitor C2 and an LLC resonant converter, wherein the input capacitor C1 is connected with the Buck converter; the Buck converter and the Boost converter are respectively composed of two branches, the two branches of the Buck converter and the two branches of the Boost converter are correspondingly connected in series one by one to form two groups of Buck-Boost branch structures connected in parallel; the Buck-Boost branch structure is connected with an input capacitor C1 in parallel and then is connected with an automobile power battery, and the Buck-Boost branch structure is connected with an output capacitor C2 in parallel and then is connected with the input end of the LLC resonant converter. The invention also provides an integrated digital control method of the vehicle-mounted auxiliary power supply DC-DC converter. The converter overcomes the defects of the prior art and has the characteristics of wide input voltage range, low conduction loss, lower cost and the like.

Description

Vehicle-mounted auxiliary power supply DC-DC converter and control method thereof
Technical Field
The invention relates to the field of new energy automobile power supply auxiliary equipment, in particular to a vehicle-mounted auxiliary power supply DC-DC converter and a control method thereof.
Background
The traditional fuel oil automobile consumes a large amount of energy, and also brings a series of problems of environmental pollution, greenhouse effect and the like, the energy shortage and the environmental pollution become the most prominent problems in the world at present, and the development of new energy automobiles becomes inevitable. In the power system scheme of the new energy automobile, a power battery (high-voltage battery) serving as a main energy source generally supplies power to a motor to provide power for the running of the automobile; the low-voltage auxiliary battery supplies power for vehicle-mounted auxiliary equipment such as an automobile air conditioner, a sound entertainment system, a front and back wiper motor, a front and back washing motor, a headlamp, a fog lamp and the like. As for the used low-voltage auxiliary battery, the traditional fuel oil automobile mostly adopts a lead-acid storage battery, and the low-voltage auxiliary battery of the new energy automobile can select a lithium ion battery with more excellent performance. Generally, the low-voltage auxiliary battery has limited stored energy and cannot supply power for a long time, and the current new energy automobile adopts the following solutions: the power battery charges the low-voltage auxiliary battery through the auxiliary power supply DC-DC converter and can temporarily supply power for the vehicle-mounted auxiliary equipment. Although lithium ion batteries have excellent performance in various aspects, the requirements on the charging mode are strict, the charging mode is generally a constant-current and constant-voltage charging mode, and the service life and the capacity of the batteries are changed depending on various factors such as cycle times, charging modes and the like. Therefore, the auxiliary power supply DC-DC converter is required to accurately control the voltage and current during the charging process, so as to ensure the constant current-constant voltage charging process of the lithium ion battery. On the other hand, the output voltage of the power battery is used as the input of the auxiliary power supply DC-DC converter, but the voltage fluctuation range is large, and is generally 200V-450V, so the auxiliary power supply DC-DC converter has to meet the requirement of wide input voltage range. In addition, the auxiliary power DC-DC converter is generally required to have high conversion efficiency, low voltage and current ripple, and low voltage and current stress of the power switch tube.
Most of the existing vehicle-mounted auxiliary power supply DC-DC converters have a plurality of defects: the input voltage range is not wide enough; zero voltage conduction of the power switch tube is not easy to realize; the conduction loss is large, and the conversion efficiency is low; the power switch tube bears higher thermal stress and electrical stress; the required capacity is large; overall higher cost, etc.
Disclosure of Invention
The invention aims to provide a vehicle-mounted auxiliary power supply DC-DC converter which overcomes the defects of the prior art and has the characteristics of wide input voltage range, low conduction loss, lower cost and the like.
The technical scheme of the invention is as follows:
a vehicle-mounted auxiliary power supply DC-DC converter comprises an input capacitor C1, a Buck converter, a Boost converter, an output capacitor C2 and an LLC resonant converter;
the Buck converter and the Boost converter are respectively composed of two branches, the two branches of the Buck converter and the two branches of the Boost converter are correspondingly connected in series one by one to form two groups of Buck-Boost branch structures connected in parallel;
the Buck-Boost branch structure is connected with an input capacitor C1 in parallel and then is connected with an automobile power battery, and the Buck-Boost branch structure is connected with an output capacitor C2 in parallel and then is connected with the input end of the LLC resonant converter.
Preferably, the Buck converter comprises a power switch tube D1, a power switch tube D2, a diode D1, a diode D2, an inductor L1 and an inductor L2; the collectors of the power switch tube D1 and the power switch tube D2 are both connected with the anode of the input capacitor C1 and are connected with the anode of the automobile power battery as a terminal S1; the emitter of the power switch tube D1 and the cathode of the diode D1 are both connected with one end of the inductor L1; the emitter of the power switch tube D2 and the cathode of the diode D2 are both connected with one end of the inductor L2; and the anode of the diode d1 and the anode of the diode d2 are both connected with the cathode of the input capacitor C1 and are connected with the cathode of the automobile power battery as a terminal S2.
Preferably, the Boost converter comprises a power switch tube D3, a power switch tube D4, a diode D3, a diode D4, an inductor L1 and an inductor L2; the collector of the power switch tube D3 and the anode of the diode D3 are both connected with the other end of the inductor L1; the collector of the power switch tube D4 and the anode of the diode D4 are both connected with the other end of the inductor L2; the emitter of the power switch tube D3 and the emitter of the power switch tube D4 are both connected with a terminal S2, the cathodes of the diode D3 and the diode D4 are both connected with the anode of an output capacitor C2, the cathode of the output capacitor C2 is connected with a terminal S2, and an inductor L1, an inductor L2 and a Buck converter are shared.
Preferably, the LLC resonant converter includes power switch tube D5, power switch tube D6, resonant inductor L3, transformer T1, resonant capacitor C3, MOSFET tube M1, MOSFET tube M2, filter capacitor C4; the collector of the power switch tube D5 is connected with the anode of a capacitor C2, and the emitter of the power switch tube D5 and the collector of the power switch tube D6 are both connected with one end of a resonant inductor L3; an emitter of the power switch tube D6 and one end of the resonant capacitor C3 are both connected with a terminal S2, and a primary-side dotted end of the transformer T1 is connected with the other end of the resonant inductor L3; the non-dotted terminal of the primary side of the transformer T1 is connected with the other end of the resonant capacitor C3; the dotted terminal of the secondary side of the transformer T1 is connected with the source electrode of the MOSFET tube M1; the drain electrode of the MOSFET tube M1 and the drain electrode of the MOSFET tube M2 are both connected with the anode of the filter capacitor C4 and serve as a terminal O1; the secondary side intermediate tap f1 of the transformer T1 is connected to the negative terminal of the filter capacitor C4 as the terminal O2; the transformation ratio of the primary side of the transformer T1 to the two secondary sides separated by the secondary side middle tap f1 is n:1: 1;
the terminal S1 is connected with the positive end of the power battery, and the terminal S2 is connected with the negative end of the power battery; the terminal O1 is used as the positive output end of the vehicle-mounted auxiliary power supply DC-DC converter; and the terminal O2 is connected with the negative electrode output end of the vehicle-mounted auxiliary power supply DC-DC converter.
Preferably, the power switch device further comprises a controller, a PWM pulse generator I, a PWM pulse generator II, a PWM pulse generator III, a PWM pulse generator IV, a PWM pulse generator V and an inverter, wherein pulse output ends of the PWM pulse generator I, the PWM pulse generator II, the PWM pulse generator III, the PWM pulse generator IV, the PWM pulse generator V and the inverter are respectively connected with a gate g1 of the power switch tube D1, a gate g2 of the power switch tube D2, a gate g3 of the power switch tube D3, a gate g4 of the power switch tube, a gate g5 of the power switch tube D6 and a gate g6 of the power switch tube D6; the input ends of the PWM pulse generator I, the PWM pulse generator II, the PWM pulse generator III, the PWM pulse generator IV and the PWM pulse generator V are connected with the controller and receive control signals sent by the controller; and the input end of the inverter is connected with the pulse output end of the PWM pulse generator V.
The invention also provides a control method of the vehicle-mounted auxiliary power supply DC-DC converter, which utilizes the vehicle-mounted auxiliary power supply DC-DC converter and comprises the following steps:
A. the method comprises the following steps of collecting the following analog quantity parameters of the vehicle-mounted auxiliary power supply DC-DC converter through a sensor: voltage V of power batteryinCurrent I through inductor L1L1Current I through inductor L2L2LLC resonant converter input voltage V1Output current I of vehicle-mounted auxiliary power supply DC-DC converterOOutput voltage V of vehicle-mounted auxiliary power supply DC-DC converterO(ii) a B, converting the analog quantity parameters through an A/D converter to obtain corresponding digital quantity parameters serving as input quantities of the step B;
B. SOC estimation and charging determination: to VO、IOPerforming SOC estimation to obtain the charge state of a vehicle-mounted auxiliary battery, performing auxiliary battery charging judgment on the charge state of the vehicle-mounted auxiliary battery, and outputting '0' as the input of the step C when the judgment result is that the vehicle-mounted auxiliary power supply DC-DC converter does not charge the auxiliary battery or supplies power to the auxiliary electrical equipment of the automobile in a constant voltage mode; when the judgment result is that the vehicle-mounted auxiliary power supply DC-DC converter charges the auxiliary battery, outputting '1' to a constant voltage and constant current charging judgment unit, and the constant voltage and constant current charging judgment unit judges VO、IOC, judging, and outputting '0' as the input of the step C when the judgment result is in the constant voltage charging stage; when the judgment result is in the constant current charging stage, outputting '1' as the input of the step C;
C. and (3) outer loop control: preset with reference output voltage VOrefReference output current IOref(ii) a Will VOAnd VOrefSubtracting to obtain a voltage deviation value VΔIs shown byOAnd IOrefSubtracting to obtain a voltage deviation value IΔAnd C, judging according to the input of the step C: when the input of step C is "1", then for IΔConstant current given correction is carried out to obtain V1Reference voltage V of1ref(ii) a When the input of step C is "0", when V is pairedΔConstant voltage given correction is carried out to obtain V1Reference voltage V of1ref(ii) a Will V1refInputting step D;
D. middle ring control: preset with a voltage controller to control V1And V1refSubtracting to obtain a voltage deviation value V'ΔV is'ΔInputting a voltage controller to output a reference current ILref(ii) a Will ILrefInputting step E;
E. inner ring control: presetting a current controller I and a current controller II, and connecting IL1And ILrefSubtracting to obtain current deviation value LΔ1Is shown byL2And ILrefSubtracting to obtain current deviation value LΔ2Is prepared by mixing LΔ1The output of the input current controller I obtains a control duty ratio Zc1Is prepared by mixing LΔ2The output of the input current controller II obtains a control duty ratio Zc2Is a reaction of Zc1、Zc2Inputting step F;
F. duty ratio calculation:
the pulse duty ratios output by the PWM pulse generator I, the PWM pulse generator II, the PWM pulse generator III, the PWM pulse generator IV, the PWM pulse generator V and the inverter are respectively Z1、Z2、Z3、Z4、Z5、Z6；
Through V1ref、VinCalculating an initial duty cycle Z0：
Figure BDA0002287216960000041
When Z is0<1- Δ:
Z1＝Zc1；Z2＝Zc2；Z3＝Z4＝0；Z5＝Z6＝0.5；
when Z is0>1+ Δ:
Z1＝Z2＝1；Z3＝Zc1-1；Z4＝Zc2-1；Z5＝Z6＝0.5；
when 1-delta<Z0<1+ Δ:
Figure BDA0002287216960000042
where Δ is a small positive number defined;
G. and (3) output control: the pulse duty ratios respectively output by the PWM pulse generator I, the PWM pulse generator II, the PWM pulse generator III, the PWM pulse generator IV, the PWM pulse generator V and the inverter are Z1、Z2、Z3、Z4、Z5、Z6The pulse signals are respectively output to a gate g1 of a power switch tube D1, a gate g2 of a power switch tube D2, a gate g3 of a power switch tube D3, a gate g4 of the power switch tube, a gate g5 of the power switch tube and a gate g6 of the power switch tube D6, so that the control of the power switch tube D1-the power switch tube D6 is realized; in the pulse signals, the pulse signals of the PWM pulse generator II are subjected to 180-degree phase shift relative to the pulse signals of the PWM pulse generator I; the pulse signals of the PWM pulse generator IV are subjected to 180-degree phase shift relative to the pulse signals of the PWM pulse generator III;
H. and repeating the step A to the step G to complete the closed-loop control of the DC-DC converter of the vehicle-mounted auxiliary power supply.
Preferably, Z isc1、Zc2In the range of 0-2.
The Buck-Boost-LLC converter system with a unique structural layout is adopted, and compared with a similar system with the same power capacity, the Buck-Boost-LLC converter system realizes high-precision large-range voltage regulation; according to the scheme of the invention, an inductor with smaller inductance can be adopted, and Buck transformation and Boost transformation share inductors L1 and L2 and capacitors C1 and C2; the Buck converter and the Boost converter adopt a two-phase staggered parallel topological structure to form two parallel branches, current balance is easy to realize between the parallel branches, and the parallel branches have lower inductive current ripples, so that switching loss is reduced; each power switching tube can realize Zero Voltage Switching (ZVS) in the full input voltage and full load range, so that the loss of the power switching tube is further reduced; in addition, the new control method can be integrated for all different operation modes, such as Buck, Boost, Buck-Boost, and five modes of Continuous Conduction Mode (CCM) at high-power load and Discontinuous Conduction Mode (DCM) at low-power load, without switching between respective independent control strategies like the traditional mode, and the situation that the dynamic response of the converter is deteriorated or even deteriorated due to switching does not exist; in addition, constant current-constant voltage charging of the auxiliary battery is realized, and the service life of the auxiliary battery is prolonged.
Drawings
Fig. 1 is a schematic circuit diagram of an integrated vehicle-mounted auxiliary power DC-DC converter provided in embodiment 1 of the present invention;
fig. 2 is a schematic circuit diagram of an integrated vehicle-mounted auxiliary power supply DC-DC converter provided in embodiment 1 of the present invention;
fig. 3 is a schematic flowchart of a control method of an on-vehicle auxiliary power DC-DC converter according to embodiment 1 of the present invention;
FIG. 4 is a schematic circuit diagram of a conventional single-stage vehicle-mounted auxiliary power source DC-DC converter provided in comparative example 1;
fig. 5 is a schematic circuit diagram of a conventional cascaded on-board auxiliary power DC-DC converter provided in comparative example 2.
Detailed Description
The present invention will be described in detail with reference to the accompanying drawings and examples.
Example 1
As shown in fig. 1-2, the vehicle-mounted auxiliary power DC-DC converter provided by this embodiment includes an input capacitor C1, a Buck converter, a Boost converter, an output capacitor C2, and an LLC resonant converter;
the Buck converter and the Boost converter are respectively composed of two branches, the two branches of the Buck converter and the two branches of the Boost converter are correspondingly connected in series one by one to form two groups of Buck-Boost branch structures connected in parallel;
the Buck-Boost branch structure is connected with an input capacitor C1 in parallel and then is connected with an automobile power battery, and the Buck-Boost branch structure is connected with an output capacitor C2 in parallel and then is connected with the input end of the LLC resonant converter;
the Buck converter comprises a power switch tube D1, a power switch tube D2, a diode D1, a diode D2, an inductor L1 and an inductor L2; the collectors of the power switch tube D1 and the power switch tube D2 are both connected with the anode of the input capacitor C1 and are connected with the anode of the automobile power battery as a terminal S1; the emitter of the power switch tube D1 and the cathode of the diode D1 are both connected with one end of the inductor L1; the emitter of the power switch tube D2 and the cathode of the diode D2 are both connected with one end of the inductor L2; the anode of the diode d1 and the anode of the diode d2 are both connected with the cathode of the input capacitor C1 and are connected with the cathode of the automobile power battery as a terminal S2;
the Boost converter comprises a power switch tube D3, a power switch tube D4, a diode D3, a diode D4, an inductor L1 and an inductor L2; the collector of the power switch tube D3 and the anode of the diode D3 are both connected with the other end of the inductor L1; the collector of the power switch tube D4 and the anode of the diode D4 are both connected with the other end of the inductor L2; an emitter of the power switch tube D3 and an emitter of the power switch tube D4 are both connected with a terminal S2, cathodes of the diode D3 and the diode D4 are both connected with an anode of an output capacitor C2, a cathode of the output capacitor C2 is connected with a terminal S2, wherein an inductor L1 and an inductor L2 are shared with the Buck converter;
the LLC resonant converter comprises a power switch tube D5, a power switch tube D6, a resonant inductor L3, a transformer T1, a resonant capacitor C3, a MOSFET tube M1, a MOSFET tube M2 and a filter capacitor C4; the collector of the power switch tube D5 is connected with the anode of a capacitor C2, and the emitter of the power switch tube D5 and the collector of the power switch tube D6 are both connected with one end of a resonant inductor L3; an emitter of the power switch tube D6 and one end of the resonant capacitor C3 are both connected with a terminal S2, and a primary-side dotted end of the transformer T1 is connected with the other end of the resonant inductor L3; the non-dotted terminal of the primary side of the transformer T1 is connected with the other end of the resonant capacitor C3; the dotted terminal of the secondary side of the transformer T1 is connected with the source electrode of the MOSFET tube M1; the drain electrode of the MOSFET tube M1 and the drain electrode of the MOSFET tube M2 are both connected with the anode of the filter capacitor C4 and serve as a terminal O1; the secondary side intermediate tap f1 of the transformer T1 is connected to the negative terminal of the filter capacitor C4 as the terminal O2; the transformation ratio of the primary side of the transformer T1 to the two secondary sides separated by the secondary side middle tap f1 is n:1: 1;
the terminal S1 is connected with the positive end of the power battery, and the terminal S2 is connected with the negative end of the power battery; the terminal O1 is used as the positive output end of the vehicle-mounted auxiliary power supply DC-DC converter; the terminal O2 and the negative electrode output end of the vehicle-mounted auxiliary power supply DC-DC converter;
the power switch tube power supply further comprises a controller, a PWM pulse generator I, a PWM pulse generator II, a PWM pulse generator III, a PWM pulse generator IV, a PWM pulse generator V and a phase inverter, wherein pulse output ends of the PWM pulse generator I, the PWM pulse generator II, the PWM pulse generator III, the PWM pulse generator IV, the PWM pulse generator V and the phase inverter are respectively connected with a gate g1 of the power switch tube D1, a gate g2 of the power switch tube D2, a gate g3 of the power switch tube D3, a gate g4 of the power switch tube, a gate g5 of the power switch tube and a gate g6 of the power switch tube D6; the input ends of the PWM pulse generator I, the PWM pulse generator II, the PWM pulse generator III, the PWM pulse generator IV and the PWM pulse generator V are connected with the controller and receive control signals sent by the controller; and the input end of the inverter is connected with the pulse output end of the PWM pulse generator V.
As shown in fig. 3, the control method of the on-vehicle auxiliary power supply DC-DC converter of the embodiment includes the following steps:
A. the following analog quantities of the on-board auxiliary power supply DC-DC converter by the sensorCollecting parameters: voltage V of power batteryinCurrent I through inductor L1L1Current I through inductor L2L2LLC resonant converter input voltage V1Output current I of vehicle-mounted auxiliary power supply DC-DC converterOOutput voltage V of vehicle-mounted auxiliary power supply DC-DC converterO(ii) a B, converting the analog quantity parameters through an A/D converter to obtain corresponding digital quantity parameters serving as input quantities of the step B;
B. SOC estimation and charging determination: to VO、IOPerforming SOC estimation to obtain the charge state of a vehicle-mounted auxiliary battery, performing auxiliary battery charging judgment on the charge state of the vehicle-mounted auxiliary battery, and outputting '0' as the input of the step C when the judgment result is that the vehicle-mounted auxiliary power supply DC-DC converter does not charge the auxiliary battery or supplies power to the auxiliary electrical equipment of the automobile in a constant voltage mode; when the judgment result is that the vehicle-mounted auxiliary power supply DC-DC converter charges the auxiliary battery, outputting '1' to a constant voltage and constant current charging judgment unit, and the constant voltage and constant current charging judgment unit judges VO、IOC, judging, and outputting '0' as the input of the step C when the judgment result is in the constant voltage charging stage; when the judgment result is in the constant current charging stage, outputting '1' as the input of the step C;
C. and (3) outer loop control: preset with reference output voltage VOrefReference output current IOref(ii) a Will VOAnd VOrefSubtracting to obtain a voltage deviation value VΔIs shown byOAnd IOrefSubtracting to obtain a voltage deviation value IΔAnd C, judging according to the input of the step C: when the input of step C is "1", then for IΔConstant current given correction is carried out to obtain V1Reference voltage V of1ref(ii) a When the input of step C is "0", when V is pairedΔConstant voltage given correction is carried out to obtain V1Reference voltage V of1ref(ii) a Will V1refInputting step D;
D. middle ring control: preset with a voltage controller to control V1And V1refSubtracting to obtain a voltage deviation value VΔ', will VΔ' input voltage controller, output to obtain reference voltageStream ILref(ii) a Will ILrefInputting step E;
E. inner ring control: presetting a current controller I and a current controller II, and connecting IL1And ILrefSubtracting to obtain current deviation value LΔ1Is shown byL2And ILrefSubtracting to obtain current deviation value LΔ2Is prepared by mixing LΔ1The output of the input current controller I obtains a control duty ratio Zc1Is prepared by mixing LΔ2The output of the input current controller II obtains a control duty ratio Zc2Is a reaction of Zc1、Zc2Inputting step F;
F. duty ratio calculation:
the pulse duty ratios output by the PWM pulse generator I, the PWM pulse generator II, the PWM pulse generator III, the PWM pulse generator IV, the PWM pulse generator V and the inverter are respectively Z1、Z2、Z3、Z4、Z5、Z6；
Through V1ref、VinCalculating an initial duty cycle Z0：
Figure BDA0002287216960000071
When Z is0<1-delta, in a voltage reduction mode, namely a Buck mode;
Z1＝Zc1；Z2＝Zc2；Z3＝Z4＝0；Z5＝Z6＝0.5；
when Z is0>When the voltage is 1+ delta, the voltage is in a Boost mode, namely the Boost mode;
Z1＝Z2＝1；Z3＝Zc1-1；Z4＝Zc2-1；Z5＝Z6＝0.5；
when 1-delta<Z0<1+ Δ; in a voltage stabilizing mode, namely a Buck-Boost mode;
Figure BDA0002287216960000081
where Δ is a small positive number defined;
G. and (3) output control: the pulse duty ratios respectively output by the PWM pulse generator I, the PWM pulse generator II, the PWM pulse generator III, the PWM pulse generator IV, the PWM pulse generator V and the inverter are Z1、Z2、Z3、Z4、Z5、Z6The pulse signals are respectively output to a gate g1 of a power switch tube D1, a gate g2 of a power switch tube D2, a gate g3 of a power switch tube D3, a gate g4 of the power switch tube, a gate g5 of the power switch tube and a gate g6 of the power switch tube D6, so that the control of the power switch tube D1-the power switch tube D6 is realized; in the pulse signals, the pulse signals of the PWM pulse generator II are subjected to 180-degree phase shift relative to the pulse signals of the PWM pulse generator I; the pulse signals of the PWM pulse generator IV are subjected to 180-degree phase shift relative to the pulse signals of the PWM pulse generator III;
H. repeating the step A-G to complete the closed-loop control of the DC-DC converter of the vehicle-mounted auxiliary power supply;
wherein Z isc1、Zc2In the range of 0-2;
the control flow is realized by programming a microprocessor system, wherein the constant current given correction, the constant voltage given correction, the voltage controller, the current controller I and the current controller II can be realized by adopting a conventional PI control algorithm or other appropriate control algorithms.
Comparative example 1
In order to further explain the present invention, a conventional single-stage vehicle-mounted auxiliary power DC-DC converter described in the prior art is provided, and as shown in fig. 4, the conventional single-stage vehicle-mounted auxiliary power DC-DC converter is a full-bridge phase-shift LLC converter, and includes power switching tubes D9, D10, D11, D12, a resonant inductor L4, a transformer T2, a resonant capacitor C4, diodes D5, D6, and a filter capacitor C5. The converter has a simple topological structure, uses fewer components, can utilize resonance between a leakage inductance of a transformer and a parasitic capacitor of a power switch tube, can realize ZVS by all the power switch tubes without any auxiliary circuit, and clamps the voltage stress to the input voltage, so that the converter is widely applied to occasions with medium and small power. It also suffers from the following two major disadvantages: (1) the requirement of wide input voltage range cannot be completely met, if the input voltage range is to be increased, the transformer excitation inductance of the converter needs to be designed to be small enough, but the resonant current is increased, the conduction loss and the hysteresis loss are increased, and the efficiency of the converter is reduced. (2) With the reduction of the load, the ZVS range of the converter hysteresis bridge arm power switching tube is narrowed, and the efficiency of the converter is reduced. Although the ZVS range of the switching tube of the lagging bridge arm can be expanded by increasing the leakage inductance of the transformer of the converter, the duty ratio of the trigger pulse is easy to lose, and the conduction loss of the primary side is increased; or the ZVS range is enlarged by reducing the excitation inductance of the transformer, but the effective value stress and the conduction loss of the current on the primary side are increased, and in addition, the output inductance is also larger.
Comparative example 2
In order to overcome the main problems presented in comparative example 1, a cascaded converter, i.e. a preceding DC/DC converter plus an LLC resonant converter, may be used. The output voltage of the front-stage DC-DC converter is stable, so that the LLC resonant converter has fixed input voltage, the model selection and the component parameter design are easy, and the efficiency of the whole converter system is improved. Fig. 5 shows a conventional cascaded vehicle-mounted auxiliary power DC-DC converter recorded in the prior art, which includes a Buck-Boost converter and a half-bridge LLC resonant converter. The Buck-Boost converter is formed by connecting power switching tubes D13, D14, D15, D16, an inductor L5 and a capacitor C7; compared with the comparative example 1, because a preceding-stage DC-DC converter (Buck-Boost converter) has the functions of voltage reduction and voltage Boost and outputs relatively stable voltage, the voltage stress borne by a power switching tube of the LLC resonant converter is reduced, so that the half-bridge LLC resonant converter can adopt the half-bridge form and reduce the number of the power switching tubes, and the power switching tubes M1 and M2 are used for replacing rectifier diodes D7 and D8 in the embodiment 1 of the invention, thereby being more beneficial to the low-voltage and high-current working state of the output side of the converter and being capable of working in a synchronous rectification state to reduce the conduction loss of the converter.
The main differences between the system of comparative example 2 shown in fig. 5 and the system of example 1 of the present invention are: the pre-stage Buck-Boost converter in the embodiment 1 of the invention adopts a two-phase staggered parallel topology structure, the voltage grade and power capacity requirements of the power switch tube of each parallel branch are low, the current balance is easy to realize, and the pre-stage Buck-Boost converter has lower inductive current ripples, thereby reducing the switching loss; the power switch tube can have higher switching frequency, so that the whole converter system has higher power density; the input current is shared by two inductors which are connected in parallel in a staggered mode, and the energy stored by the inductors is only half of that stored by the inductors in comparative example 2, so that the size of the inductors can be effectively reduced; zero Voltage Switching (ZVS) of each power switching tube is easy to realize in the full input voltage and full load range, the loss of the power switching tube is further reduced, and the efficiency and the reliability of the converter are improved.
Compared with the comparative example 2, the embodiment 1 of the invention adopts a unique integrated digital control method, can be integrated and used for all different operation modes (such as Buck, Boost, Buck-Boost, a Continuous Conduction Mode (CCM) under high-power load and a Discontinuous Conduction Mode (DCM) under low-power load), does not need to switch between respective independent control strategies like the traditional mode, and does not have the situation that the dynamic response of the converter is deteriorated or even deteriorated due to switching; in addition, constant current-constant voltage charging of the auxiliary battery is realized, and the service life of the auxiliary battery is prolonged; and the current balance of the two parallel branches is further realized in the aspect of a control strategy, and the inductive current ripple is smaller.
In summary, the scheme of the embodiment 1 of the present application has significant advancement compared with the prior art scheme.

Claims (7)

1. A vehicle-mounted auxiliary power supply DC-DC converter comprises an input capacitor C1, a Buck converter, a Boost converter, an output capacitor C2 and an LLC resonant converter;
the method is characterized in that:
the Buck converter and the Boost converter are respectively composed of two branches, the two branches of the Buck converter and the two branches of the Boost converter are correspondingly connected in series one by one to form two groups of Buck-Boost branch structures connected in parallel;
the Buck-Boost branch structure is connected with an input capacitor C1 in parallel and then is connected with an automobile power battery, and the Buck-Boost branch structure is connected with an output capacitor C2 in parallel and then is connected with the input end of the LLC resonant converter.
2. The vehicle-mounted auxiliary power supply DC-DC converter according to claim 1, wherein:
the Buck converter comprises a power switch tube D1, a power switch tube D2, a diode D1, a diode D2, an inductor L1 and an inductor L2; the collectors of the power switch tube D1 and the power switch tube D2 are both connected with the anode of the input capacitor C1 and are connected with the anode of the automobile power battery as a terminal S1; the emitter of the power switch tube D1 and the cathode of the diode D1 are both connected with one end of the inductor L1; the emitter of the power switch tube D2 and the cathode of the diode D2 are both connected with one end of the inductor L2; and the anode of the diode d1 and the anode of the diode d2 are both connected with the cathode of the input capacitor C1 and are connected with the cathode of the automobile power battery as a terminal S2.
3. The vehicle-mounted auxiliary power supply DC-DC converter according to claim 2, wherein:
the Boost converter comprises a power switch tube D3, a power switch tube D4, a diode D3, a diode D4, an inductor L1 and an inductor L2; the collector of the power switch tube D3 and the anode of the diode D3 are both connected with the other end of the inductor L1; the collector of the power switch tube D4 and the anode of the diode D4 are both connected with the other end of the inductor L2; the emitter of the power switch tube D3 and the emitter of the power switch tube D4 are both connected with a terminal S2, the cathodes of the diode D3 and the diode D4 are both connected with the anode of an output capacitor C2, and the cathode of an output capacitor C2 is connected with a terminal S2; wherein inductor L1, inductor L2 are common to the Buck converter.
4. The vehicle-mounted auxiliary power supply DC-DC converter according to claim 3, wherein:
the LLC resonant converter comprises a power switch tube D5, a power switch tube D6, a resonant inductor L3, a transformer T1, a resonant capacitor C3, a MOSFET tube M1, a MOSFET tube M2 and a filter capacitor C4; the collector of the power switch tube D5 is connected with the anode of a capacitor C2, and the emitter of the power switch tube D5 and the collector of the power switch tube D6 are both connected with one end of a resonant inductor L3; an emitter of the power switch tube D6 and one end of the resonant capacitor C3 are both connected with a terminal S2, and a primary-side dotted end of the transformer T1 is connected with the other end of the resonant inductor L3; the non-dotted terminal of the primary side of the transformer T1 is connected with the other end of the resonant capacitor C3; the dotted terminal of the secondary side of the transformer T1 is connected with the source electrode of the MOSFET tube M1; the drain electrode of the MOSFET tube M1 and the drain electrode of the MOSFET tube M2 are both connected with the anode of the filter capacitor C4 and serve as a terminal O1; the secondary side intermediate tap f1 of the transformer T1 is connected to the negative terminal of the filter capacitor C4 as the terminal O2; the transformation ratio of the primary side of the transformer T1 to the two secondary sides separated by the secondary side middle tap f1 is n:1: 1;
the terminal S1 is connected with the positive end of the power battery, and the terminal S2 is connected with the negative end of the power battery; the terminal O1 is used as the positive output end of the vehicle-mounted auxiliary power supply DC-DC converter; and the terminal O2 is connected with the negative electrode output end of the vehicle-mounted auxiliary power supply DC-DC converter.
5. The vehicle-mounted auxiliary power supply DC-DC converter according to claim 4, characterized in that:
the power switch tube power supply further comprises a controller, a PWM pulse generator I, a PWM pulse generator II, a PWM pulse generator III, a PWM pulse generator IV, a PWM pulse generator V and a phase inverter, wherein pulse output ends of the PWM pulse generator I, the PWM pulse generator II, the PWM pulse generator III, the PWM pulse generator IV, the PWM pulse generator V and the phase inverter are respectively connected with a gate g1 of the power switch tube D1, a gate g2 of the power switch tube D2, a gate g3 of the power switch tube D3, a gate g4 of the power switch tube, a gate g5 of the power switch tube and a gate g6 of the power switch tube D6; the input ends of the PWM pulse generator I, the PWM pulse generator II, the PWM pulse generator III, the PWM pulse generator IV and the PWM pulse generator V are connected with the controller and receive control signals sent by the controller; and the input end of the inverter is connected with the pulse output end of the PWM pulse generator V.
6. A control method of a vehicle-mounted auxiliary power supply DC-DC converter using the vehicle-mounted auxiliary power supply DC-DC converter according to claim 5, characterized by comprising the steps of:
A. the method comprises the following steps of collecting the following analog quantity parameters of the vehicle-mounted auxiliary power supply DC-DC converter through a sensor: voltage V of power batteryinCurrent I through inductor L1L1Current I through inductor L2L2LLC resonant converter input voltage V1Output current I of vehicle-mounted auxiliary power supply DC-DC converterOOutput voltage V of vehicle-mounted auxiliary power supply DC-DC converterO(ii) a B, converting the analog quantity parameters through an A/D converter to obtain corresponding digital quantity parameters serving as input quantities of the step B;
B. SOC estimation and charging determination: to VO、IOPerforming SOC estimation to obtain the charge state of a vehicle-mounted auxiliary battery, performing auxiliary battery charging judgment on the charge state of the vehicle-mounted auxiliary battery, and outputting '0' as the input of the step C when the judgment result is that the vehicle-mounted auxiliary power supply DC-DC converter does not charge the auxiliary battery or supplies power to the auxiliary electrical equipment of the automobile in a constant voltage mode; when the judgment result is that the vehicle-mounted auxiliary power supply DC-DC converter charges the auxiliary battery, outputting '1' to a constant voltage and constant current charging judgment unit, and the constant voltage and constant current charging judgment unit judges VO、IOC, judging, and outputting '0' as the input of the step C when the judgment result is in the constant voltage charging stage; when the judgment result is in the constant current charging stage, outputting '1' as the input of the step C;
C. and (3) outer loop control: preset with reference output voltage VOrefReference output current IOref(ii) a Will VOAnd VOrefSubtracting to obtain a voltage deviation value VΔIs shown byOAnd IOrefAre subtracted to obtainVoltage deviation value IΔAnd C, judging according to the input of the step C: when the input of step C is "1", then for IΔConstant current given correction is carried out to obtain V1Reference voltage V of1ref(ii) a When the input of step C is "0", when V is pairedΔConstant voltage given correction is carried out to obtain V1Reference voltage V of1ref(ii) a Will V1refInputting step D;
D. middle ring control: preset with a voltage controller to control V1And V1refSubtracting to obtain a voltage deviation value VΔ', will VΔAn input voltage controller for outputting a reference current ILref(ii) a Will ILrefInputting step E;
E. inner ring control: presetting a current controller I and a current controller II, and connecting IL1And ILrefSubtracting to obtain current deviation value LΔ1Is shown byL2And ILrefSubtracting to obtain current deviation value LΔ2Is prepared by mixing LΔ1The output of the input current controller I obtains a control duty ratio Zc1Is prepared by mixing LΔ2The output of the input current controller II obtains a control duty ratio Zc2Is a reaction of Zc1、Zc2Inputting step F;
F. duty ratio calculation:
the pulse duty ratios output by the PWM pulse generator I, the PWM pulse generator II, the PWM pulse generator III, the PWM pulse generator IV, the PWM pulse generator V and the inverter are respectively Z1、Z2、Z3、Z4、Z5、Z6；
Through V1ref、VinCalculating an initial duty cycle Z0：
Figure FDA0002287216950000031
When Z is0<1- Δ:
Z1＝Zc1；Z2＝Zc2；Z3＝Z4＝0；Z5＝Z6＝0.5；
when Z is0>1+ Δ:
Z1＝Z2＝1；Z3＝Zc1-1；Z4＝Zc2-1；Z5＝Z6＝0.5；
when 1-delta<Z0<1+ Δ:
Figure FDA0002287216950000032
Z5＝Z6＝0.5；
where Δ is a small positive number defined;
G. and (3) output control: the pulse duty ratios respectively output by the PWM pulse generator I, the PWM pulse generator II, the PWM pulse generator III, the PWM pulse generator IV, the PWM pulse generator V and the inverter are Z1、Z2、Z3、Z4、Z5、Z6The pulse signals are respectively output to a gate g1 of a power switch tube D1, a gate g2 of a power switch tube D2, a gate g3 of a power switch tube D3, a gate g4 of the power switch tube, a gate g5 of the power switch tube and a gate g6 of the power switch tube D6, so that the control of the power switch tube D1-the power switch tube D6 is realized; in the pulse signals, the pulse signals of the PWM pulse generator II are subjected to 180-degree phase shift relative to the pulse signals of the PWM pulse generator I; the pulse signals of the PWM pulse generator IV are subjected to 180-degree phase shift relative to the pulse signals of the PWM pulse generator III;
H. and repeating the step A to the step G to complete the closed-loop control of the DC-DC converter of the vehicle-mounted auxiliary power supply.
7. The control method of the on-vehicle auxiliary power supply DC-DC converter according to claim 6, characterized in that: z isc1、Zc2In the range of 0-2.
CN201911165054.2A 2019-11-25 2019-11-25 Vehicle-mounted auxiliary power supply DC-DC converter and control method thereof Pending CN110768538A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201911165054.2A CN110768538A (en) 2019-11-25 2019-11-25 Vehicle-mounted auxiliary power supply DC-DC converter and control method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201911165054.2A CN110768538A (en) 2019-11-25 2019-11-25 Vehicle-mounted auxiliary power supply DC-DC converter and control method thereof

Publications (1)

Publication Number Publication Date
CN110768538A true CN110768538A (en) 2020-02-07

Family

ID=69339340

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201911165054.2A Pending CN110768538A (en) 2019-11-25 2019-11-25 Vehicle-mounted auxiliary power supply DC-DC converter and control method thereof

Country Status (1)

Country Link
CN (1) CN110768538A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113037086A (en) * 2021-03-11 2021-06-25 浙江艾罗网络能源技术股份有限公司 Photovoltaic energy storage inverter suitable for photovoltaic power limitation

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113037086A (en) * 2021-03-11 2021-06-25 浙江艾罗网络能源技术股份有限公司 Photovoltaic energy storage inverter suitable for photovoltaic power limitation

Similar Documents

Publication Publication Date Title
Park et al. Design and control of a bidirectional resonant dc–dc converter for automotive engine/battery hybrid power generators
US11323038B2 (en) Single phase single stage bi-directional level 1 electric vehicle battery charger
CN107968471B (en) LCLC resonance circuit, wide-range constant-power output direct-current charger and control method
CN113135109B (en) Topological structure of high-power charging device of electric automobile
CN107222100A (en) A kind of integrated Buck Boost and LLC circuits single-stage LED drive circuit
Gumera et al. Design and implementation of a high efficiency cost effective EV charger using LLC resonant converter
CN210807100U (en) Power transmission circuit
CN111342664A (en) Integrated DC-DC converter and control method thereof
CN112968603B (en) Wide-transformation-ratio transformerless buck-boost converter
Sharma et al. An Onboard Bidirectional Charger for Light Electric Vehicles Using Interleaved ZETA Converter
Amiri et al. A CCM bridgeless single-stage soft-switching AC-DC converter for EV charging application
CN110768538A (en) Vehicle-mounted auxiliary power supply DC-DC converter and control method thereof
Asa et al. PLL control technique of LLC resonant converter for EVs battery charger
Kushwaha et al. A unity power factor converter with isolation for electric vehicle battery charger
Wang et al. High-efficiency high-power bridgeless integrated AC-DC converter for on-board vehicle battery charger
CN210693773U (en) Vehicle-mounted auxiliary power supply DC-DC converter
CN107623444A (en) A kind of design method of vehicle-mounted DC/DC accessory power supplys
CN115001284A (en) Isolated single-stage bidirectional multipurpose topological circuit and control strategy thereof
Salehifar et al. Analysis and comparison of conventional two-stage converter and single stage bridgeless ac-dc converter for off-road battery charger application
Sharma et al. A Bidirectional Electric Vehicle Charger for Wide Output Voltage Range Application
Sreehari et al. Two stage EV charger based on bridgeless PFC converter for e-Rickshaw
Karakaş et al. Full Bridge DC-DC Converter Based Battery Charger with PFC CUK Converter Having Hysteresis Control
RB et al. On-Board EV Charging with VIENNA Rectifier and LLC Resonant Converter
Shukla et al. A Modified Non-bridged Cuk Converter based Electric Vehicle Charger with Reduced Components Count
Rawabi Design and Development of Bridge-less PFC Converter based EV charger

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