CN115139854A - Energy conversion device and control method thereof - Google Patents

Energy conversion device and control method thereof Download PDF

Info

Publication number
CN115139854A
CN115139854A CN202110352503.5A CN202110352503A CN115139854A CN 115139854 A CN115139854 A CN 115139854A CN 202110352503 A CN202110352503 A CN 202110352503A CN 115139854 A CN115139854 A CN 115139854A
Authority
CN
China
Prior art keywords
battery pack
current
battery
bridge arm
arm converter
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
CN202110352503.5A
Other languages
Chinese (zh)
Inventor
凌和平
黄伟
谢飞跃
郭昌昌
金雪虎
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.)
BYD Co Ltd
Original Assignee
BYD 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 BYD Co Ltd filed Critical BYD Co Ltd
Priority to CN202110352503.5A priority Critical patent/CN115139854A/en
Publication of CN115139854A publication Critical patent/CN115139854A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L53/00—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • B60L58/24—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries for controlling the temperature of batteries
    • B60L58/27—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries for controlling the temperature of batteries by heating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/40—Drive Train control parameters
    • B60L2240/54—Drive Train control parameters related to batteries
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/40—Drive Train control parameters
    • B60L2240/54—Drive Train control parameters related to batteries
    • B60L2240/545—Temperature
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

The technical scheme of the application provides an energy conversion device and a control method thereof, wherein the energy conversion device comprises a bridge arm converter, a first battery pack, a motor, a second battery pack and a controller, the controller is used for acquiring battery parameters of the first battery pack and battery parameters of the second battery pack, and controlling the bridge arm converter according to the battery parameters to enable the first battery pack, the bridge arm converter, a motor winding and the second battery pack to form different current loops so as to heat and/or charge the first battery pack or heat and/or charge the second battery pack. Compared with the prior art, the bridge arm converter and the motor in the vehicle are reused and are respectively connected with the first battery pack and the second battery pack, the duty ratio of the bridge arm converter is determined and controlled by acquiring the battery parameters of the first battery pack and the second battery pack, heating and/or starting between the first battery pack and the second battery pack are realized, and starting of the battery is realized.

Description

Energy conversion device and control method thereof
Technical Field
The present disclosure relates to vehicle technologies, and particularly to an energy conversion device and a control method thereof.
Background
With the wide use of new energy, the battery pack can be used as a power source in various fields. The battery pack is used as a power source in different environments, and the performance of the battery pack is also affected. For example, the performance of the battery pack in a low temperature environment is greatly reduced as compared with that at normal temperature. For example, the discharge capacity of the battery pack at the zero point temperature may decrease as the temperature decreases. At-30 ℃, the discharge capacity of the battery pack is substantially 0, which results in the battery pack being unusable, and thus, the vehicle being unable to start. In order to enable the use of the battery pack in a low temperature environment, it is necessary to preheat the battery pack before the use of the battery pack.
Disclosure of Invention
The application aims to provide an energy conversion device and a control method thereof, which can heat a battery by controlling a bridge arm converter so as to start the battery.
The present application is achieved in a first aspect thereof by providing an energy conversion apparatus, characterized by comprising:
the bridge arm converter comprises bridge arms, a first bus end and a second bus end, wherein the first ends of the bridge arms of each bridge arm of the bridge arm converter are connected together to form the first bus end, and the second ends of the bridge arms of each bridge arm of the bridge arm converter are connected together to form the second bus end;
a first battery pack, a first polarity end of which is connected with the first bus bar end, and a second polarity end of which is connected with the second bus bar end;
a second battery pack;
a first end of a motor winding of the motor is connected with the bridge arm converter, a second end of the motor winding is connected with a neutral point in common and is connected with a first polarity end of a second battery pack, and a second polarity end of the second battery pack is connected with a second bus end of the bridge arm converter;
the controller is used for acquiring battery parameters of the first battery pack and battery parameters of the second battery pack, controlling the bridge arm converter according to the battery parameters of the first battery pack and the battery parameters of the second battery pack, and enabling the first battery pack, the bridge arm converter, the motor winding and the second battery pack to form different current loops so as to heat and/or charge the first battery pack or heat and/or charge the second battery pack.
The application provides an energy conversion device and a control method thereof, wherein the energy conversion device comprises a bridge arm converter, a first battery pack, a motor, a second battery pack and a controller, the controller is used for acquiring battery parameters of the first battery pack and battery parameters of the second battery pack, and controlling the bridge arm converter according to the battery parameters of the first battery pack and the battery parameters of the second battery pack to enable the first battery pack, the bridge arm converter, a motor winding and the second battery pack to form different current loops so as to heat and/or charge the first battery pack or heat and/or charge the second battery pack. Compared with the prior art, the bridge arm converter and the motor in the vehicle are reused and are respectively connected with the first battery pack and the second battery pack, the duty ratio of the bridge arm converter is determined and controlled by obtaining the battery parameters of the first battery pack and the second battery pack, heating and/or starting between the first battery pack and the second battery pack are achieved, and starting of the battery is achieved.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required to be used in the embodiments or the prior art description will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings may be obtained according to these drawings without inventive labor.
Fig. 1 is a circuit diagram of an energy conversion device according to an embodiment of the present application;
fig. 2 is another circuit diagram of an energy conversion device according to an embodiment of the present disclosure;
fig. 3 is a flowchart of a control method of an energy conversion device according to a second embodiment of the present application;
fig. 4 is a detailed flowchart of step S102 in a control method of an energy conversion apparatus according to a second embodiment of the present application;
fig. 5 is a schematic view of a current-time variation curve in a control method of an energy conversion device according to a second embodiment of the present application;
fig. 6 is another specific flowchart of step S102 in a control method of an energy conversion apparatus according to a second embodiment of the present application;
fig. 7 is another specific flowchart of step S102 in a control method of an energy conversion apparatus according to a second embodiment of the present application;
FIG. 8 is a schematic diagram of an energy conversion device according to a second embodiment of the present application another specific flowchart of step S102 in the control method of (1);
fig. 9 is another specific flowchart of step S102 in a control method of an energy conversion apparatus according to a second embodiment of the present application;
fig. 10 is a circuit diagram of an energy conversion device according to a second embodiment of the present application;
fig. 11 is a schematic diagram of voltage difference and current waveforms in a control method of an energy conversion apparatus according to a second embodiment of the present application;
fig. 12 is a schematic structural diagram of an energy conversion device according to a second embodiment of the present application;
fig. 13 is a current flow diagram of an energy conversion device according to a second embodiment of the present application;
fig. 14 is another current flow diagram of an energy conversion device provided in the second embodiment of the present application;
fig. 15 is another current flow diagram of an energy conversion device according to the second embodiment of the present application;
fig. 16 is another current flow diagram of an energy conversion device according to the second embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
In order to explain the technical means of the present application, the following description will be given by way of specific examples.
An embodiment of the present application provides an energy conversion apparatus, as shown in fig. 1, the energy conversion apparatus includes:
the bridge arm converter 101 is characterized in that first ends of all paths of bridge arms of the bridge arm converter 101 are connected together to form a first bus end, and second ends of all paths of bridge arms of the bridge arm converter 101 are connected together to form a second bus end;
a first battery pack 103, a first polarity end of the first battery pack 103 is connected with the first bus bar end, and a second polarity end of the first battery pack 103 is connected with the second bus bar end;
a second battery pack 104;
a first end of a motor winding of the motor 102 is connected with the bridge arm converter 101, a second end of the motor winding is connected with a neutral point and is connected with a first polarity end of the second battery pack 104, and a second polarity end of the second battery pack 104 is connected with a second bus end of the bridge arm converter 101;
and the controller is used for acquiring the battery parameters of the first battery pack 103 and the battery parameters of the second battery pack 104, controlling the bridge arm converter according to the battery parameters of the first battery pack 103 and the battery parameters of the second battery pack 104, and enabling the first battery pack 103, the bridge arm converter 101, the motor winding and the second battery pack 104 to form different current loops so as to heat and/or charge the first battery pack 103 or heat and/or charge the second battery pack 104.
The energy conversion device can further comprise a first capacitor C1 and a second capacitor C2, wherein the first end of the first capacitor C1 is connected with the first bus end, and the second end of the first capacitor C1 is connected with the second bus end; a first end of the second capacitor C2 is connected to the first polarity end of the second battery pack 104, and a second end of the second capacitor C2 is connected to the second polarity end of the second battery pack 104.
The bridge arm converter 101 comprises M bridge arms, first ends of each bridge arm in the M bridge arms are connected in common to form a first bus end of the bridge arm converter 101, second ends of each bridge arm in the M bridge arms are connected in common to form a second bus end of the bridge arm converter 101, each bridge arm comprises two power switch units which are connected in series, the power switch units can be of transistor type, IGBT type, MOS type and the like, a middle point of each bridge arm is formed between the two power switch units, the motor 102 comprises M-phase windings, the first ends of each phase of winding in the M-phase windings are respectively connected with the middle point of each bridge arm in the M bridge arms in a one-to-one correspondence mode, the second ends of each phase of winding in the M-phase windings are connected in common to form a neutral point, and the neutral point is connected with the second capacitor C2.
For example, when M =3, the leg converter 101 includes three legs, a first end of each of the three legs being connected together to form a first junction of the leg converter 101, and a second end of each of the three legs being connected together to form a second junction of the leg converter 101; the bridge arm converter 101 comprises a first power switch unit, a second power switch unit, a third power switch unit, a fourth power switch unit, a fifth power switch and a sixth power switch, wherein the first power switch unit and the fourth power switch unit are connected in series to form a first bridge arm, the second power switch unit and the fifth switch unit are connected in series to form a second bridge arm, the third power switch unit and the sixth switch unit are connected in series to form a third bridge arm, one ends of the first power switch unit, the third power switch unit and the fifth power switch unit are connected in common to form a first junction end of the bridge arm converter 101, and one ends of the second power switch unit, the fourth power switch unit and the sixth power switch unit are connected in common to form a second junction end of the bridge arm converter 101.
The motor winding comprises M-phase windings, the first end of each phase winding in the M-phase windings is the first end of the motor winding, the first ends of each phase winding in the M-phase windings are connected with the middle point of each bridge arm in the M bridge arms in a one-to-one correspondence mode, and the second ends of each phase winding in the M-phase windings are connected together to form a neutral point.
For example, corresponding to the bridge arm converter 101, when the bridge arm converter 101 includes three bridge arms, the motor winding includes three-phase windings, a first end of each phase winding in the three-phase windings is connected to a midpoint of each bridge arm in the three bridge arms in a one-to-one correspondence, and second ends of each phase winding in the three-phase windings are connected together to form a neutral point. And a first phase winding of the three-phase winding is connected with the midpoint of the first bridge arm, a second phase winding of the three-phase winding is connected with the midpoint of the second bridge arm, and a third phase winding of the three-phase winding is connected with the midpoint of the third bridge arm.
The controller (not shown) may include a vehicle controller, a control circuit of the bridge arm converter 101, and a BMS battery manager circuit, which are connected by a CAN line. The controller may be a controller of the first battery pack in communication with a controller of the second battery pack, may be a controller of the second battery pack in communication with a controller of the first battery pack, or may be a controller of the first battery pack and a controller of the second battery pack.
The controller is used for acquiring battery parameters of the first battery pack 103 and battery parameters of the second battery pack 104, controlling the bridge arm converter according to the battery parameters of the first battery pack 103 and the battery parameters of the second battery pack 104, and enabling the first battery pack 103, the bridge arm converter 101, the motor winding and the second battery pack 104 to form different current loops so as to heat and/or charge the first battery pack 103 or heat and/or charge the second battery pack 104.
The selection of the battery parameters of the first battery pack 10 and the second battery pack 104 is determined by a working scene, the battery parameters of the first battery pack 103 can be temperature, maximum discharge current and maximum charge power, the battery parameters of the second battery pack can be temperature, maximum discharge current and maximum charge power, and when the temperature of the first battery pack 103 is lower than a preset temperature and the temperature of the second battery pack 104 is a normal temperature, or when the temperature of the second battery pack is lower than a preset temperature and the temperature of the first battery pack 103 is a normal temperature, the controller controls the bridge arm converter to enable the first battery pack 103, the bridge arm converter 101, the motor winding and the second battery pack 104 to form different current loops, so that the first battery pack or the second battery pack is heated and/or charged.
When the controller controls the bridge arm converter to heat the first battery pack or the second battery pack, the first battery pack, the bridge arm converter, the motor winding and the second battery pack form a first heating circuit, and the motor winding, the bridge arm converter and the second battery pack form a second heating circuit; when the second heating circuit works, the motor winding discharges the second battery pack through the bridge arm converter; due to the fact that the internal resistance exists in the second battery pack, when the first heating circuit and the second heating circuit are controlled to work alternately through the bridge arm converter, the internal resistance of the second battery pack can generate heat due to the fact that current flows into and flows out of the second battery pack, and the temperature of the second battery pack is increased. In the same way, the first battery pack can be heated, the second battery pack, the motor winding and the bridge arm converter form a third heating circuit, the second battery pack, the motor winding, the bridge arm converter and the first battery pack form a fourth heating circuit, and the second battery pack discharges the motor winding through the bridge arm converter when the third heating circuit works; when the fourth heating circuit works, the second battery pack and the motor winding discharge the first battery pack through the bridge arm converter; due to the internal resistance in the first battery pack, when the discharging process and the charging process are performed, the current flowing into and out of the first battery pack generates heat from the internal resistance of the first battery pack, thereby increasing the temperature of the first battery pack. Alternatively, the heating circuit may be a charging circuit, and when the charging circuit is operated by the bridge arm converter, the first battery pack is charged to the second battery pack, or the second battery pack is charged to the first battery pack. Or, the heating circuit may also be a charging heating circuit, and when the charging heating circuit is operated by the bridge arm converter, the first battery pack is enabled to simultaneously charge and heat the second battery pack, or the second battery pack is enabled to charge and heat the first battery pack.
The first battery pack can be used on a first vehicle, the second battery pack can be used on a second vehicle, and when the second vehicle cannot be started due to the fact that the ambient temperature is too low, the first battery pack can be used for heating and charging the second battery pack through the energy conversion device, and the second battery pack is started.
As an embodiment, the energy conversion device further comprises an inductor, as shown in fig. 2, connected between the neutral point of the motor winding and the positive pole of the second battery pack.
The energy conversion device is additionally provided with the inductor, so that filtering and energy storage are performed, the charge and discharge efficiency is improved, and the buffer effect is achieved.
An embodiment of the present application provides a control method based on an energy conversion device, and as shown in fig. 3, the control method of the energy conversion device includes:
and S101, acquiring the battery parameters of the first battery pack and the battery parameters of the second battery pack.
For step S101, when the first battery pack and the second battery pack are controlled to be in different states, acquiring a battery parameter of the first battery pack and a battery parameter of the second battery pack that are different, for example, acquiring a maximum discharge current of the first battery pack and acquiring a temperature and a maximum discharge current of the second battery pack when the second battery pack is heated; when the second battery pack is heated and charged, acquiring the maximum discharge current and the maximum charging power of the first battery pack, and acquiring the temperature, the maximum discharge current and the maximum charging power of the second battery pack; when the first battery pack is heated, acquiring the maximum discharge current of the second battery pack, and acquiring the temperature and the maximum discharge current of the first battery pack; when the first battery pack is heated and charged, the maximum discharging current and the maximum charging power of the second battery pack are obtained, and the temperature, the maximum discharging current and the maximum charging power of the first battery pack are obtained.
And S102, controlling the bridge arm converter according to the battery parameters of the first battery pack and the battery parameters of the second battery pack, so that the first battery pack, the bridge arm converter, the motor winding and the second battery pack form different current loops, and heating and/or charging the first battery pack or heating and/or charging the second battery pack is realized.
As for step S102, as an implementation, an application scenario of this implementation is that the temperature is extremely low, and only the second battery pack is heated, at this time, acquiring the battery parameters of the first battery pack and the battery parameters of the second battery pack includes:
the maximum discharge current of the first battery pack is acquired, and the temperature and the maximum discharge current of the second battery pack are acquired.
The controller may obtain a maximum discharge current of the first battery pack, and obtain a temperature and a maximum discharge current of the second battery pack by communicating with a power manager of the first battery pack and a power manager of the second battery pack.
In this embodiment, as shown in fig. 4, step S102 includes:
and S121, when the temperature of the second battery pack is lower than a first preset temperature value, acquiring a target current amplitude of a target current waveform of the current loop according to the maximum charging and discharging current of the first battery pack and the maximum charging and discharging current of the second battery pack.
The first preset temperature value is a lower temperature value, for example, 40 ℃ below zero, the temperature of the second battery pack is lower at the moment, the second battery pack needs to be heated, and the first battery pack is used for discharging the second battery pack through the heating circuit to heat the second battery pack.
In step S121, obtaining a target current amplitude of a target current waveform of the current loop according to the maximum charging and discharging current of the first battery pack and the maximum charging and discharging current of the second battery pack includes:
and obtaining a smaller current value in the maximum charging and discharging current of the first battery pack and the maximum charging and discharging current of the second battery pack, and performing doubling operation on the smaller current value to obtain a target current amplitude of a target current waveform of the current loop.
And S122, acquiring a target duty ratio according to the target current amplitude and the target current waveform function.
Wherein the target current waveform function is y = ((a × sin (2 × pi × f × t) + B) × R + Ub)/Ua; a is a target current amplitude of a current waveform, f is a current frequency, B is a target current average value, R is the sum of internal resistances of the first battery pack and the second battery pack, ua is a voltage of the first battery pack, ub is a voltage of the second battery pack, and y is a target duty ratio.
Under the conditions provided by this embodiment, a may be obtained from step S121 in the target current waveform function, the current frequency f is a fixed frequency, for example, 800Hz, and the target current average value B is 0, and the target duty ratio y may be obtained by being substituted into the target current waveform function, where the target current waveform is the phase a shown in fig. 5.
And S123, controlling the bridge arm converter according to the target duty ratio to enable the first battery pack, the bridge arm converter, the motor winding and the second battery pack to form different current loops so as to heat the second battery pack.
The control of the bridge arm converter according to the target duty ratio to charge and discharge the first battery pack and the second battery pack means that the bridge arm converter is controlled according to the target duty ratio to enable a first heating circuit formed by the bridge arm converter, a motor winding and the second battery pack and a second heating circuit formed by the bridge arm converter and the second battery pack to work alternately, and the second battery pack has current flowing in and flowing out to enable internal resistance of the second battery pack to generate heat, so that the temperature of the second battery pack is increased.
The technical effects of this embodiment are: when one of the first battery pack and the second battery pack is detected to be under an extremely low temperature condition and cannot be started, the duty ratio is obtained according to the battery parameters of the first battery pack and the second battery pack, the bridge arm converter is controlled to heat the first battery pack or the second battery pack according to the duty ratio, and the first battery pack or the second battery pack is started.
As an embodiment, for step S102, the application environment of this embodiment is that the second battery pack is heated and charged at a lower temperature, and the obtaining of the battery parameter of the first battery pack and the battery parameter of the second battery pack includes:
and acquiring the maximum discharge current and the maximum charging power of the first battery pack, and acquiring the temperature, the maximum discharge current and the maximum charging power of the second battery pack.
The controller may obtain the maximum discharge current and the maximum charge power of the first battery pack and obtain the temperature, the maximum discharge current, and the maximum charge power of the second battery pack by communicating with the power manager of the first battery pack and the power manager of the second battery pack.
In this embodiment, as shown in fig. 6, step S102 includes:
and S124, when the temperature of the second battery pack is not lower than a first preset temperature value and lower than a second preset temperature value, acquiring a target current average value of a target current waveform of the current loop according to the maximum charging power of the first battery pack and the maximum charging power of the second battery pack, and acquiring a target current amplitude value of the target current waveform of the current loop according to the maximum charging and discharging current of the first battery pack and the maximum charging and discharging current of the second battery pack.
The temperature of the second battery pack is not lower than the first preset temperature value and is lower than the second preset temperature, which means that the second battery pack can be charged with low power at the time of a low battery temperature condition, such as-20 ℃, and meanwhile, the second battery pack still has a heating requirement.
In step S124, obtaining a target current average value of a target current waveform of the current loop according to the maximum charging power of the first battery pack and the maximum charging power of the second battery pack includes:
and obtaining a target current average value according to the smaller maximum charging power in the maximum charging power of the first battery pack and the maximum charging power of the second battery pack.
The maximum charging power of the second battery pack is related to the temperature of the second battery pack, when the temperature of the second battery pack does not reach the lowest temperature meeting the maximum charging power of the second battery pack, the maximum charging power of the second battery pack is increased along with the temperature increase of the second battery pack, and when the maximum charging power of the second battery pack is increased, the target current average value is increased.
In step S124, obtaining a target current amplitude of a target current waveform of the current loop according to the maximum charging and discharging current of the first battery pack and the maximum charging and discharging current of the second battery pack includes:
and obtaining a smaller current value in the maximum charging and discharging current of the first battery pack and the maximum charging and discharging current of the second battery pack, performing difference operation on the smaller current value and the target current average value, and performing doubling operation to obtain a target current amplitude of a target current waveform of the current loop.
And S125, acquiring a target duty ratio according to the target current average value, the target current amplitude and the target current waveform function.
Wherein the target current waveform function is y = ((a × sin (2 × pi × f × t) + B) × R + Ub)/Ua; a is a target current amplitude of a current waveform, f is a current frequency, B is a target current average value, R is the sum of internal resistances of the first battery pack and the second battery pack, ua is a voltage of the first battery pack, ub is a voltage of the second battery pack, and y is a target duty ratio.
Under the conditions provided by this embodiment, a and B may be obtained from step S124 in the target current waveform function, the current frequency f is a fixed frequency, for example, 800Hz, and the target duty ratio y may be obtained by substituting into the target current waveform function, where the target current waveform is in stage B as shown in fig. 5.
Since the maximum charging power of the second battery pack is increased along with the temperature of the second battery pack, when the maximum charging power of the second battery pack is increased, the target current average value is also increased, and therefore, the duty ratio is also changed.
And S126, controlling the bridge arm converter according to the target duty ratio to enable the first battery pack, the bridge arm converter, the motor winding and the second battery pack to form different current loops, charging the second battery pack according to the target current average value, and heating the second battery pack according to the target current amplitude value.
The control of the bridge arm converter according to the target duty ratio to charge and discharge the first battery pack and the second battery pack means that the control of the bridge arm converter according to the target duty ratio enables a first heating and charging circuit formed by the bridge arm converter, a motor winding and the second battery pack and a second heating and charging circuit formed by the bridge arm converter and the second battery pack to work alternately.
The technical effects of this embodiment are: when one of the first battery pack and the second battery pack is detected to be at a lower temperature and cannot be started, the duty ratio is obtained according to the battery parameters of the first battery pack and the second battery pack, the bridge arm converter is controlled to heat and charge the first battery pack or the second battery pack according to the duty ratio, and the first battery pack or the second battery pack is started.
As an implementation manner, for step S102, an application environment of the present embodiment is that the battery temperature is within a preset temperature range, and at this time, the second battery pack is heated and charged, and the battery parameters of the first battery pack and the battery parameters of the second battery pack are obtained, including:
the maximum discharging current and the maximum charging power of the first battery pack are obtained, and the temperature, the maximum discharging current and the maximum charging power of the second battery pack are obtained.
As an embodiment, as shown in fig. 7, step S102 includes:
and S127, when the temperature of the second battery pack is not lower than a second preset temperature value and lower than a third preset temperature value, acquiring a target current average value of a target current waveform of the current loop according to the maximum charging power of the first battery pack and the maximum charging power of the second battery pack, and acquiring a target current amplitude value of the target current waveform of the current loop according to the maximum charging and discharging current of the first battery pack and the maximum charging and discharging current of the second battery pack.
The temperature of the second battery pack is not lower than the second preset temperature value and lower than the third preset temperature means that the battery has a certain temperature, for example, 15 ℃, and at this time, the second battery pack can be charged while still having a heating requirement.
In step S127, obtaining a target current average value of a target current waveform of the current loop according to the maximum charging power of the first battery pack and the maximum charging power of the second battery pack includes:
and obtaining a target current average value according to the smaller maximum charging power in the maximum charging power of the first battery pack and the maximum charging power of the second battery pack.
And when the temperature of the second battery pack reaches the lowest temperature which meets the maximum charging power of the second battery pack, the maximum charging power of the second battery pack is kept unchanged when the temperature of the second battery pack rises, and the target current average value is also kept unchanged.
And S128, acquiring a target duty ratio according to the target current average value, the target current amplitude and the target current waveform function.
Wherein the target current waveform function is y = ((a x sin (2 x pi f x t) + B) x R + Ub)/Ua; a is a target current amplitude of a current waveform, f is a current frequency, B is a target current average value, R is the sum of internal resistances of the first battery pack and the second battery pack, ua is a voltage of the first battery pack, ub is a voltage of the second battery pack, and y is a target duty ratio.
Under the conditions provided by this embodiment, a and B may be obtained from step S124 in the target current waveform function, and the current frequency f is a fixed frequency, for example, 800Hz, and is brought into the target current waveform function to obtain the target duty ratio y, where the target current waveform is shown as stage C in fig. 5.
And S129, controlling the bridge arm converter according to the target duty ratio to enable the first battery pack, the bridge arm converter, the motor winding and the second battery pack to form different current loops, charging the second battery pack according to the target current average value, and heating the second battery pack according to the target current amplitude value.
The control of the bridge arm converter according to the target duty ratio to charge and discharge the first battery pack and the second battery pack means that the control of the bridge arm converter according to the target duty ratio enables a first heating and charging circuit formed by the bridge arm converter, a motor winding and the second battery pack and a second heating and charging circuit formed by the motor winding, the bridge arm converter and the second battery pack to work alternately; due to the internal resistance in the second battery pack, when the heating discharging process and the heating charging process are executed, the current flowing in and out of the second battery pack can enable the internal resistance of the second battery pack to generate heat, so that the temperature of the second battery pack is increased, and meanwhile, the second battery pack is charged.
The technical effects of this embodiment lie in: when one of the first battery pack and the second battery pack is detected to be at a certain temperature, the duty ratio is obtained according to the battery parameters of the first battery pack and the second battery pack, the bridge arm converter is controlled to heat and charge the first battery pack or the second battery pack according to the duty ratio, and the heating and charging of the first battery pack or the second battery pack are achieved.
As an implementation manner, for step S102, the application environment of this implementation manner is that the battery temperature is within the preset temperature range but the external environment temperature is low, and the obtaining of the battery parameter of the first battery pack and the battery parameter of the second battery pack includes:
acquiring the maximum discharge current and the maximum charge power of a first battery pack, and acquiring the temperature, the maximum discharge current and the maximum charge power of a second battery pack;
step S102 includes:
step S130, when the temperature of the second battery pack reaches the optimal charging temperature and the environmental temperature is lower than a fourth preset temperature value, obtaining a target current average value of a target current waveform of the current loop according to the maximum charging power of the first battery pack and the maximum charging power of the second battery pack.
And S131, when the temperature of the second battery pack is detected to be lower than the optimal charging temperature, acquiring a target current amplitude according to the corresponding relation between the temperature and the target current amplitude, and acquiring a target duty ratio according to the target current average value, the target current amplitude and a target current waveform function.
When the temperature of the battery reaches the optimal charging temperature, the battery needs to be heated in a heat preservation mode due to the fact that the environment temperature is low. At this time, the current value corresponding to the maximum charging power is taken as the average value of the self-heating current. The optimal temperature of the battery is taken as a control target, the temperature of the battery is monitored in real time and taken as a feedback value of PID closed-loop control, the amplitude of the self-heating current is controlled in real time, and the optimal temperature of the battery is kept, wherein the target current waveform is shown as a stage D in fig. 5.
And S132, controlling the bridge arm converter according to the target duty ratio to enable the first battery pack, the bridge arm converter, the motor winding and the second battery pack to form different current loops so as to heat and charge the second battery pack, and meanwhile, maintaining the temperature of the second battery pack at the optimal charging temperature.
The technical effects of this embodiment are: when one of the first battery pack and the second battery pack is detected to be at a certain temperature and the ambient temperature is low, the duty ratio is obtained according to the battery parameters of the first battery pack and the second battery pack, the duty ratio is adjusted according to the temperature of the battery packs, the bridge arm converter is controlled to heat and charge the first battery pack or the second battery pack according to the duty ratio, and the temperature of the first battery pack or the second battery pack is maintained.
In step S102, as an embodiment, the battery temperature is the optimum charging temperature in the application environment of the present embodiment, and heating is not required.
As shown in fig. 9, step S102 includes:
s133, when the temperature of the second battery pack reaches the optimal charging temperature and heating is not needed, controlling the target current amplitude to be gradually reduced, and enabling the duty ratio of the bridge arm converter to be a fixed value;
s134, controlling the bridge arm converter according to the duty ratio of the bridge arm converter to charge and discharge the first battery pack and the second battery pack so as to charge the second battery pack;
and S135, when the second battery pack is detected to be in a full-charge state, reducing the duty ratio to 0.
In the above steps, when the battery temperature is the optimal charging temperature and heating is not needed, the self-heating current amplitude of the battery is gradually reduced until the self-heating current amplitude is zero. As shown in stage E of fig. 5, the charging current waveform is the same as the conventional charging waveform. As shown in stage F of fig. 5, the charging completion charging current is gradually reduced to 0, and the charging process is completed.
The present application is specifically described below by way of a specific circuit configuration:
as shown in fig. 10, firstly, N lines of a motor are added to be led out, a second capacitor C2 is connected, and then switching of a contactor can realize torque output in a normal driving state, direct current charging in a parking state and battery charging in the parking state, and can heat the battery during battery charging. The battery heating function is mainly to realize the rapid charging and discharging between the first battery pack and the second battery pack by controlling the high-frequency switch of the IGBT of the bridge arm converter, and the heating purpose of the battery is realized by emitting a large amount of heat inside the battery due to the existence of the internal resistance of the battery.
As shown in fig. 10, the energy conversion device includes an arm converter 101, a motor winding, a first capacitor C1, a second capacitor C2, a switch K1, a switch K2, a switch K3, a switch K4, a switch K5, a resistor R, a first battery pack 103, and a second battery pack 104, wherein a positive electrode of the first battery pack 103 is connected to a first end of the resistor R and a first end of the switch K2, a second end of the resistor R is connected to a first end of the switch K3, a second end of the switch K3 is connected to a second end of the switch K2, a first end of the first capacitor C1, and a first bus end of the arm converter 101, a midpoint of three paths of the arm converter 101 is respectively connected to three-phase windings of the motor winding, a connection point of the three-phase windings of the motor winding is connected to the first end of the switch K1, a second end of the switch K1 is connected to a first end of the second capacitor C2 and a positive electrode of the second battery pack 104, a second end of the second capacitor C2 is connected to a second bus end of the arm converter 101, a second end of the first capacitor C1, a second end of the switch K4, a negative electrode of the switch K5, and a second terminal of the second battery pack 104.
The bridge arm converter 101 comprises a first power switch unit, a second power switch unit, a third power switch unit, a fourth power switch unit, a fifth power switch unit and a sixth power switch unit, wherein the first power switch unit and the fourth power switch unit form a first bridge arm, the third power switch unit and the sixth power switch unit form a second bridge arm, the fifth power switch unit and the second power switch unit form a third bridge arm, one ends of the first power switch unit, the third power switch unit and the fifth power switch unit are connected in common and form a first current collecting end of the bridge arm converter 101, one ends of the second power switch unit, the fourth power switch unit and the sixth power switch unit are connected in common and form a second current collecting end of the bridge arm converter 101, a first phase winding of a motor winding is connected with a midpoint of the first bridge arm, a second phase winding of the motor winding is connected with a midpoint of the second bridge arm, and a third phase winding of the motor winding is connected with a midpoint of the third bridge arm.
The first power switch unit in the bridge arm converter 101 comprises a first upper bridge arm VT1 and a first upper bridge diode VD1, the second power switch unit comprises a second lower bridge arm VT2 and a second lower bridge diode VD2, the third power switch unit comprises a third upper bridge arm VT3 and a third upper bridge diode VD3, the fourth power switch unit comprises a fourth lower bridge arm VT4 and a fourth lower bridge diode VD4, the fifth power switch unit comprises a fifth upper bridge arm VT5 and a fifth upper bridge diode VD5, the sixth power switch unit comprises a sixth lower bridge arm VT6 and a sixth lower bridge diode VD6, the three-phase alternating current motor is a three-phase four-wire system, can be a permanent magnet synchronous motor or an asynchronous motor, and a neutral line is led out from a connection midpoint of three-phase windings.
Under the normal drive line mode, switch K1, K5 disconnection, first electric capacity C1 is between the generating line positive negative pole, and first electric capacity C1 can effectually play the stabilized busbar voltage, absorbs ripple electric current's effect, improves the output efficiency of IGBT operational reliability and battery package. According to the torque requirement of the whole vehicle, the controller controls the IGBT to realize the output of the motor torque and meet the running function of the whole vehicle.
Under the VTOV mode of the whole vehicle, the switches K1 and K5 are closed, then the first capacitor C1 is connected between the positive electrode and the negative electrode of the bus, one end of the second capacitor C2 is connected to the negative electrode of the bus, and the other end of the second capacitor C2 is connected to the point N of the motor through the switch K1. The controller realizes the rapid alternate charging and discharging of the first battery pack and the second battery pack through the control of the IGBT, so that the battery packs continuously have current output or input, and because of the existence of the internal resistance of the battery, a large amount of heat is emitted inside the battery, and the temperature of the battery is rapidly increased. The controller controls the switching action of the three-phase bridge arm, so that continuous and rapid charging and discharging can be carried out between the first battery pack and the second battery pack, and due to the existence of the internal resistance of the battery packs, a large amount of heat is generated to rapidly heat the battery packs.
The duty cycle determines the increase in current per battery charge-discharge cycle and also decreases, i.e. determines the direction of change of current, specifically: the duty ratio of the lower bridge arm is increased, so that the discharging current of the second battery pack is increased, or the charging current of the second battery pack is reduced; the duty ratio of the lower bridge arm is reduced, so that the discharging current of the second battery pack is reduced, or the charging current of the second battery pack is increased. By means of a plurality of successive duty cycle adjustments, it is possible to control not only the maximum and minimum values of the current but also the shape of the current. The VTOV can realize self-heating of sine current waveform, self-heating while charging of sine current waveform and direct current charging. On the whole, the first battery pack and the second battery pack perform energy interaction, and the change of the charge and discharge current of the second battery pack is reflected on the charge and discharge current of the first battery pack.
The four typical working modes of the whole vehicle are as follows:
the first working mode is as follows: only heat is applied.
Scene: under the extreme low temperature environment, under the condition that first battery package or second battery package need heat, and the second battery package can't charge, only heat. Such as shown in stage a of fig. 5.
The control method comprises the following steps: and controlling the average value of the charging current to be zero, and controlling the self-heating power by controlling the frequency and the amplitude of the current.
And a second working mode: charging and heating.
Scene: and under the condition that the ambient temperature is low, the second battery pack allows charging, and the first battery pack or the second battery pack needs to be heated, charging and heating are carried out. Such as stages B and C of fig. 5.
The control method comprises the following steps: the average current is controlled to be I1, and the charging power and the self-heating power are controlled by controlling the frequency and the amplitude of the charging current.
And a third working mode: and maintaining stable charging.
Scene: in the case where the ambient temperature is not particularly low, the battery temperature is maintained at a certain target temperature. And charging is performed. As in stage D of fig. 5.
Maintaining the temperature and charging: and regulating by taking the temperature of the battery as a control target, and regulating the heating power by combining the charging power.
The working mode is four: only charging.
Scene: when the temperature of the battery is higher, the second battery pack is only charged under the condition that the first battery pack and the second battery pack do not need to be heated. Such as stages E and F of fig. 5.
The control method comprises the following steps: and controlling the output voltage of the first battery pack to be higher than that of the second battery pack, and only charging the second battery pack.
The charging and heating process between electric automobiles is explained, and the charging waveform control method of the whole automobile comprises the following steps:
1. the charging self-heating waveform control method comprises the following steps:
the method comprises the following steps: the method comprises the following steps: and acquiring the voltages of the first battery pack and the second battery pack, and assuming that the voltage of the first battery pack is Ua =600V, the voltage of the second battery pack is Ub =320V, and the sum of the internal resistances of the first battery pack and the second battery pack is R.
Step two: the IGBT duty cycle of the bridge arm converter is controlled by controlling the modulation waveform, assuming that the modulation waveform is y = ((a = (2 × pi × f × t) + B) × R + Ub)/Ua. A is a target current amplitude of a current waveform, f is a current frequency, B is a target current average value, R is the sum of internal resistances of the first battery pack and the second battery pack, ua is a voltage of the first battery pack, ub is a voltage of the second battery pack, and y is a target duty ratio.
Step three: the output voltage of the first battery pack is 600 x y, and the voltage difference between the first battery pack and the second battery pack is 600 x y-320.
Step four: the sum of the internal resistances of the first battery pack and the second battery pack is R, namely, the charging self-heating waveform is (600 x y-320)/R. The voltage difference waveform and the current waveform are shown in fig. 11.
2. And (3) temperature detection: the temperature of the inductor, the motor, the IGBT and the battery is monitored in real time, and the safety of the charging and heating process is guaranteed.
The specific implementation case of the whole vehicle VTOV heating and charging control method mainly comprises two stages:
and (3) a system design stage: the first battery pack is positioned on the vehicle A, and the second battery pack is positioned on the vehicle B.
When the VTOV of the whole vehicle is charged and heated, the temperature rise rate of the battery is related to the amplitude and the frequency of a current waveform, and according to the implementation case, the fixed self-heating current waveform frequency is preferably selected to be 800Hz by combining simulation and test according to the battery characteristics. The power of the heating is then controlled by controlling the amplitude of the self-heating current waveform.
The first battery pack of the vehicle A and the CAN communication information of the vehicle B are interactively designed, the vehicle A and the vehicle B acquire the voltage, the temperature, the maximum charging and discharging current, the maximum charging and discharging power, the heating requirement and other information of the batteries of the two vehicles through CAN communication, and direct-current charging protocol interactive messages are designed.
A first heating strategy: under the condition that the temperature of the battery is extremely low, such as minus 40 ℃, the BMS of at least one of the A car and the B car has the heating requirement. And at the moment, the maximum charging and discharging currents of the A vehicle and the B vehicle are obtained through the messages. The amplitude of self-heating can be controlled according to the maximum charging and discharging current of the vehicle, the self-heating is carried out by the maximum current which can be borne by the vehicle, the self-heating power maximization is realized, twice of the smaller value of the maximum charging and discharging current of the vehicle A and the vehicle B at the moment is taken as the current amplitude of the VTOV self-heating of the whole vehicle, the amplitude of the alternating current is twice of the current value due to the fact that the amplitude of the alternating current is positive and negative, the self-heating current amplitude is taken as a control target, the amplitude of the self-heating current of the whole vehicle is controlled through a PID closed loop, and the maximum power heating is carried out on a battery of the whole vehicle. And the temperature and various parameters of the battery are monitored in real time, so that the safety of the heating process is ensured. As shown in stage a of fig. 5.
And (2) heating strategy two: at lower battery temperatures, such as-20 ℃, the battery can be charged at low power, still with heating requirements. Taking the minimum value m of the maximum charging and discharging current of the A vehicle and the B vehicle at the moment, obtaining the maximum charging power n of the A vehicle and the B vehicle at the moment (the charging power of the battery is different at different temperatures, the charging power is 0 at an extremely low temperature, namely charging and discharging are not carried out, for example, in the stage A), taking the current value corresponding to the smaller value in the charging and discharging power as the self-heating current average value, taking the self-heating current amplitude of the whole vehicle VTOV as 2 x (m-n), taking the self-heating current amplitude and the current average value as control targets, and controlling the amplitude and the average value of the self-heating current of the whole vehicle through a PID closed loop. Along with the increase of the temperature of the battery, the charge and discharge power of the battery also changes, and the average value of the self-heating current is gradually increased until the maximum charge power of the battery is reached. And the temperature and various parameters of the battery are monitored in real time, so that the safety of the heating process is ensured. As shown in phase B of fig. 5, both the self-heating current magnitude and the current average value are varied during this process.
And (3) heating strategy III: when the battery temperature reaches the lowest value that can satisfy the maximum charging power, such as 15 ℃, under the condition that the heating requirement still exists. And at the moment, the maximum charging and discharging current m and the charging and discharging power n of the vehicle A and the vehicle B are obtained through messages. And taking a smaller value m in the maximum charging and discharging currents of the A vehicle and the B vehicle, taking a current value corresponding to the smaller value in the charging and discharging power of the two vehicles as a self-heating current average value n, taking the amplitude of the self-heating current of the whole vehicle VTOV as 2 x (m-n), taking the amplitude of the self-heating current and the average value n as control targets, and controlling the amplitude and the average value of the self-heating current of the whole vehicle through a PID closed loop. And the temperature and various parameters of the battery are monitored in real time, so that the safety of the heating process is ensured. As shown in stage C of fig. 5. In the process, the value of the current average value n is constant, and the value of m is variable.
And (4) heating strategy four: when the temperature of the battery reaches the optimal charging temperature, the battery needs to be heated in a heat preservation manner due to the low ambient temperature. At this time, the current value corresponding to the maximum charging power is taken as the average value of the self-heating current. The optimal temperature of the battery is taken as a control target, the temperature of the battery is monitored in real time and taken as a feedback value of PID closed-loop control, the amplitude of the self-heating current is controlled in real time, and the optimal temperature of the battery is kept. As shown in stage D of fig. 4.
And (4) heating strategy five: when the temperature of the battery is the optimal charging temperature and heating is not needed, the self-heating current amplitude of the battery is gradually reduced until the self-heating current amplitude is zero. As shown in stage E of fig. 5, the charging current waveform is the same as the conventional charging waveform. As shown in stage F of fig. 5, the charging current is gradually decreased to 0 to complete the charging process.
A debugging control stage:
first, vehicle B has a charging demand.
Step one, the vehicles a and B are connected through the dc charging line at the dc charging port, as shown in fig. 12, the power battery in the vehicle a corresponds to the first battery pack in fig. 10, and the power battery in the vehicle B corresponds to the second battery pack in fig. 10.
And step two, the vehicle A and the vehicle B perform information interaction through CAN communication, firstly, the vehicle A acquires the battery voltage of the vehicle B, the battery voltage of the vehicle A is compared with the battery voltage of the vehicle A, and if the battery voltage of the vehicle A is higher than the battery voltage of the vehicle B and the direct-current charging protocol interaction CAN be successfully completed, the next charging process is performed.
And step three, the vehicle A acquires information such as battery temperature, maximum charging current, maximum discharging current, maximum charging power, heating requirement and the like of the vehicle B.
And step four, if the battery temperature of the vehicle B is too low, a heating requirement exists, and charging cannot be performed, adjusting the duty ratio of a three-phase bridge arm of the vehicle A bridge arm converter according to the acquired battery temperature, the maximum charging current and the maximum discharging current of the vehicle A and the vehicle B, and controlling the waveform and the amplitude of the charging current of the vehicle B, as shown in the waveform of the phase A of fig. 5. The battery of the B vehicle is only heated.
And step five, after a period of heating, the battery temperature of the vehicle B continuously rises, and charging is allowed, then the three-phase bridge arm duty ratio of the vehicle A bridge arm converter is adjusted in real time according to the battery temperatures, the maximum charging current and the maximum discharging current of the vehicle A and the vehicle B, and the charging current and the waveform of the vehicle B are controlled, as shown in the stage B of fig. 5. The charging power of the B car is continuously improved, and meanwhile, the battery is heated.
Step six, when the charge and discharge power of the vehicle A and the vehicle B reaches the maximum value, the three-phase bridge arm duty ratio of the vehicle A bridge arm converter is adjusted in real time according to the battery temperature, the maximum charge current and the maximum discharge current of the vehicle A and the vehicle B, and the charge current and the waveform of the vehicle B are controlled, as shown in stage C of fig. 5. The charging power of the vehicle B is constant, and the battery is heated.
And step seven, as the battery temperature of the vehicle B rises and the heating power requirement is reduced, adjusting the three-phase bridge arm duty ratio of the vehicle A-axle arm converter in real time according to the battery temperature, the maximum charging current and the maximum discharging current of the vehicle A and the vehicle B, and controlling the charging current and the waveform of the vehicle B, as shown in the stage D of fig. 5. The charging power of the B vehicle is constant, the amplitude of the self-heating waveform of the battery is reduced, and the temperature of the battery is stabilized.
Step eight, when the vehicles A and B have no heating requirements, adjusting the three-phase bridge arm duty ratio of the vehicle A bridge arm converter in real time according to the battery temperatures, the maximum charging current and the maximum discharging current of the vehicles A and B, and controlling the charging current and the waveform of the vehicle B, as shown in stage E of fig. 5. And the amplitude of the self-heating waveform of the B vehicle is gradually reduced until the amplitude is zero, and the battery of the B vehicle is charged by direct current.
Step nine, as the battery capacity of the vehicle B increases, the charging power gradually decreases, as shown in stage E of fig. 5.
And step ten, monitoring the state parameters of the vehicle A and the vehicle B in real time in the whole VTOV process, and ensuring the safety of the VTOV process.
When the first battery pack is used for heating and/or charging the second battery pack, the current of the current loop flows as follows:
as shown in fig. 13, when the lower arm of the arm converter is turned off and the upper arm is turned on, the current starts from the positive electrode of the first battery pack 103, and charges the second battery pack 104 through the upper arm (the first upper diode VD1, the third upper diode VD3, and the fifth upper diode VD 5) of the arm converter 101 and the motor winding.
As shown in fig. 14, when the lower arm of the arm converter 101 is turned on, a current flows from the motor winding, passes through the lower arms (the second lower arm VT2, the fourth lower arm VT4, and the sixth lower arm VT 6) of the arm converter 101, flows from the second to the negative electrode of the battery pack 104, and the current increases continuously.
When the second battery pack heats and/or charges the first battery pack, the current of the current loop flows as follows:
as shown in fig. 15, when the lower arm of the arm converter 101 is turned on, a current flows out from the negative electrode of the second battery pack 103, passes through the motor winding and the lower arm of the arm converter 101 (the second lower diode VD2, the fourth lower diode VD4, and the sixth lower diode VD 6), and flows back to the positive electrode of the second battery pack.
As shown in fig. 16, when the lower arm of the arm converter 101 is controlled to be open, the upper arm is controlled to be closed, and the upper arm of the arm converter 101 is controlled to be open, the current starts from the positive electrode of the second battery pack 104 and the motor winding, and the positive electrode of the first battery pack 103 is charged after passing through the motor winding and the upper arm (the first upper arm VT1, the third upper arm VT3, and the fifth upper arm VT 5) of the arm converter 101.
Compared with the prior art, the circuit structure and the control method are changed, the three-phase bridge arm control is the same, the current vector inside the motor is zero, no torque pulsation exists, in addition, the current waveform can be improved through the high switching frequency control of the IGBT of the bridge arm converter, the requirements of the system on the current amplitude, the frequency and the waveform are met, and finally, the influence of the first capacitor C1 in the energy interaction process of the vehicle power battery A and the vehicle power battery is effectively relieved due to the fact that the capacitance value of the first capacitor C1 is small.
The above embodiments are merely for illustrating the technical solutions of the present application, rather than to a limitation thereof; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the embodiments of the present application, and they should be construed as being included in the present application.

Claims (10)

1. An energy conversion device, characterized in that the energy conversion device comprises:
the bridge arm converter is characterized in that first ends of all paths of bridge arms of the bridge arm converter are connected together to form a first bus end, and second ends of all paths of bridge arms of the bridge arm converter are connected together to form a second bus end;
a first battery pack, a first polarity end of which is connected with the first bus bar end, and a second polarity end of which is connected with the second bus bar end;
a second battery pack;
a first end of a motor winding of the motor is connected with the bridge arm converter, a second end of the motor winding is connected with a neutral point in common and is connected with a first polarity end of a second battery pack, and a second polarity end of the second battery pack is connected with a second bus end of the bridge arm converter;
the controller is used for acquiring battery parameters of the first battery pack and battery parameters of the second battery pack, controlling the bridge arm converter according to the battery parameters of the first battery pack and the battery parameters of the second battery pack, and enabling the first battery pack, the bridge arm converter, the motor winding and the second battery pack to form different current loops so as to heat and/or charge the first battery pack or heat and/or charge the second battery pack.
2. The energy conversion device of claim 1, further comprising:
an inductor connected between a neutral point of the motor winding and the second battery pack.
3. A control method of the energy conversion apparatus according to claim 1, characterized in that the control method comprises:
acquiring battery parameters of the first battery pack and battery parameters of the second battery pack;
and controlling the bridge arm converter according to the battery parameters of the first battery pack and the second battery pack to enable the first battery pack, the bridge arm converter, the motor winding and the second battery pack to form different current loops so as to heat and/or charge the first battery pack or heat and/or charge the second battery pack.
4. The control method of claim 3, wherein the obtaining the battery parameters of the first battery pack and the battery parameters of the second battery pack comprises:
acquiring the maximum discharge current of the first battery pack, and acquiring the temperature and the maximum discharge current of the second battery pack;
the controlling the bridge arm converter according to the battery parameters of the first battery pack and the battery parameters of the second battery pack to enable the first battery pack, the bridge arm converter, the motor winding and the second battery pack to form different current loops so as to heat and/or charge the second battery pack comprises:
when the temperature of the second battery pack is lower than a first preset temperature value, acquiring a target current amplitude of a target current waveform of the current loop according to the maximum charge-discharge current of the first battery pack and the maximum charge-discharge current of the second battery pack;
obtaining a target duty ratio according to the target current amplitude and a target current waveform function;
and controlling the bridge arm converter according to the target duty ratio to enable the first battery pack, the bridge arm converter, the motor winding and the second battery pack to form different current loops so as to heat the second battery pack.
5. The control method of claim 4, wherein obtaining the target current amplitude of the target current waveform of the current loop according to the maximum charging and discharging current of the first battery pack and the maximum charging and discharging current of the second battery pack comprises:
and obtaining a smaller current value in the maximum charging and discharging current of the first battery pack and the maximum charging and discharging current of the second battery pack, and performing doubling operation on the smaller current value to obtain a target current amplitude of a target current waveform of the current loop.
6. The control method according to claim 3, wherein the obtaining the battery parameter of the first battery pack and the battery parameter of the second battery pack comprises:
acquiring the maximum discharge current and the maximum charge power of the first battery pack, and acquiring the temperature, the maximum discharge current and the maximum charge power of the second battery pack;
the controlling the bridge arm converter according to the battery parameters of the first battery pack and the battery parameters of the second battery pack to enable the first battery pack, the bridge arm converter, the motor winding and the second battery pack to form different current loops so as to heat and/or charge the second battery pack comprises the following steps:
when the temperature of the second battery pack is not lower than a first preset temperature value and lower than a second preset temperature value, acquiring a target current average value of a target current waveform of the current loop according to the maximum charging power of the first battery pack and the maximum charging power of the second battery pack, and acquiring a target current amplitude value of the target current waveform of the current loop according to the maximum charging and discharging current of the first battery pack and the maximum charging and discharging current of the second battery pack;
obtaining a target duty ratio according to the target current average value, the target current amplitude and a target current waveform function;
and controlling the bridge arm converter according to the target duty ratio to enable the first battery pack, the bridge arm converter, the motor winding and the second battery pack to form different current loops, charging the second battery pack according to the target current average value, and heating the second battery pack according to the target current amplitude value.
7. The control method of claim 3, wherein the obtaining the battery parameters of the first battery pack and the battery parameters of the second battery pack comprises:
acquiring the maximum discharge current and the maximum charge power of the first battery pack, and acquiring the temperature, the maximum discharge current and the maximum charge power of the second battery pack;
the controlling the bridge arm converter according to the battery parameters of the first battery pack and the battery parameters of the second battery pack to enable the first battery pack, the bridge arm converter, the motor winding and the second battery pack to form different current loops so as to heat and/or charge the second battery pack comprises:
when the temperature of the second battery pack is not lower than a second preset temperature value and lower than a third preset temperature value, obtaining a target current average value of a target current waveform of the current loop according to the maximum charging power of the first battery pack and the maximum charging power of the second battery pack, and obtaining a target current amplitude value of the target current waveform of the current loop according to the maximum charging and discharging current of the first battery pack and the maximum charging and discharging current of the second battery pack;
obtaining a target duty ratio according to the target current average value, the target current amplitude and a target current waveform function;
and controlling the bridge arm converter according to the target duty ratio to enable the first battery pack, the bridge arm converter, the motor winding and the second battery pack to form different current loops, charging the second battery pack according to the target current average value, and heating the second battery pack according to the target current amplitude value.
8. The control method according to claim 6 or 7, wherein the obtaining a target current average value of a target current waveform of the current loop according to the maximum charging power of the first battery pack and the maximum charging power of the second battery pack comprises:
obtaining a target current average value according to the smaller maximum charging power of the first battery pack and the maximum charging power of the second battery pack;
the obtaining of the target current amplitude of the target current waveform of the current loop according to the maximum charging and discharging current of the first battery pack and the maximum charging and discharging current of the second battery pack includes:
and obtaining a smaller current value in the maximum charging and discharging current of the first battery pack and the maximum charging and discharging current of the second battery pack, and carrying out difference operation and doubling operation on the smaller current value and the target current average value to obtain a target current amplitude of a target current waveform of the current loop.
9. The control method of claim 3, wherein the obtaining the battery parameters of the first battery pack and the battery parameters of the second battery pack comprises:
acquiring the maximum discharge current and the maximum charging power of the first battery pack, acquiring the temperature, the maximum discharge current and the maximum charging power of the second battery pack;
the controlling the bridge arm converter according to the battery parameters of the first battery pack and the battery parameters of the second battery pack to enable the first battery pack, the bridge arm converter, the motor winding and the second battery pack to form different current loops so as to heat and/or charge the second battery pack comprises the following steps:
when the temperature of the second battery pack reaches the optimal charging temperature and the ambient temperature is lower than a fourth preset temperature, acquiring a target current average value of a target current waveform of the current loop according to the maximum charging power of the first battery pack and the maximum charging power of the second battery pack;
when the temperature of the second battery pack is detected to be lower than the optimal charging temperature, acquiring a target current amplitude according to the corresponding relation between the temperature and the target current amplitude, and acquiring a target duty ratio according to the target current average value, the target current amplitude and a target current waveform function;
and controlling the bridge arm converter according to a target duty ratio to enable the first battery pack, the bridge arm converter, the motor winding and the second battery pack to form different current loops so as to heat and charge the second battery pack and simultaneously maintain the temperature of the second battery pack at the optimal charging temperature.
10. The control method according to claim 3, wherein the controlling the bridge arm inverter according to the battery parameters of the first battery pack and the battery parameters of the second battery pack to make the first battery pack, the bridge arm inverter, the motor winding, and the second battery pack form different current loops to realize heating and/or charging of the second battery pack comprises:
when the temperature of the second battery pack reaches the optimal charging temperature and does not need heating, controlling the target current amplitude to be gradually reduced, and enabling the duty ratio of the bridge arm converter to be a fixed value;
controlling the bridge arm converter according to the duty ratio of the bridge arm converter to enable the first battery pack, the bridge arm converter, the motor winding and the second battery pack to form different current loops so as to charge the second battery pack;
and when the second battery pack is detected to be in a full state, reducing the duty ratio to 0.
CN202110352503.5A 2021-03-31 2021-03-31 Energy conversion device and control method thereof Pending CN115139854A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110352503.5A CN115139854A (en) 2021-03-31 2021-03-31 Energy conversion device and control method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110352503.5A CN115139854A (en) 2021-03-31 2021-03-31 Energy conversion device and control method thereof

Publications (1)

Publication Number Publication Date
CN115139854A true CN115139854A (en) 2022-10-04

Family

ID=83405061

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110352503.5A Pending CN115139854A (en) 2021-03-31 2021-03-31 Energy conversion device and control method thereof

Country Status (1)

Country Link
CN (1) CN115139854A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024109887A1 (en) * 2022-11-25 2024-05-30 比亚迪股份有限公司 Energy conversion device and vehicle

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024109887A1 (en) * 2022-11-25 2024-05-30 比亚迪股份有限公司 Energy conversion device and vehicle

Similar Documents

Publication Publication Date Title
CN110971173B (en) Charging method of power battery, motor control circuit and vehicle
CN111660875B (en) Vehicle, energy conversion device, and control method therefor
CN111347900B (en) Vehicle, motor control circuit and power battery charging and heating method
CN113752908B (en) Vehicle, energy conversion device, and control method therefor
CN102470760B (en) Secondary battery temperature-increasing control apparatus and vehicle including the same, and secondary battery temperature-increasing control method
CN111347936B (en) Vehicle and power battery heating method and device thereof
CN113119801B (en) Vehicle, energy conversion device, and control method therefor
CN113752875B (en) Vehicle battery heating device and method and vehicle
CN112977171A (en) Electric automobile and power battery pulse heating system
CN113119802B (en) Vehicle, energy conversion device, and control method therefor
CN113752912B (en) Vehicle, energy conversion device, and control method therefor
CN111404246B (en) Battery energy processing device and method and vehicle
CN113085516B (en) Power battery pulse heating system and heating method of electric automobile
CN113844334B (en) Vehicle, energy conversion device, and control method therefor
CN114079400A (en) Motor control circuit, vehicle and battery self-heating control method
CN212579628U (en) Energy conversion device and vehicle
CN113119804B (en) Energy conversion device, control method, vehicle, and readable storage medium
CN113972707A (en) Vehicle, energy conversion device, and control method therefor
CN113752911A (en) Energy processing device and method and vehicle
CN115139854A (en) Energy conversion device and control method thereof
CN111355434B (en) Motor control circuit, vehicle and heating method thereof
CN113928183B (en) Vehicle, energy conversion device, and control method therefor
CN115648966A (en) Motor controller, control unit, electric drive system and electric vehicle
CN113752914A (en) Control method and device of energy conversion device and vehicle
CN218640706U (en) Heating circuit based on grouping battery and electric vehicle

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