CN113972706B - Vehicle, energy conversion device and control method thereof - Google Patents
Vehicle, energy conversion device and control method thereof Download PDFInfo
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- CN113972706B CN113972706B CN202010716979.8A CN202010716979A CN113972706B CN 113972706 B CN113972706 B CN 113972706B CN 202010716979 A CN202010716979 A CN 202010716979A CN 113972706 B CN113972706 B CN 113972706B
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- 238000006243 chemical reaction Methods 0.000 title claims abstract description 41
- 238000000034 method Methods 0.000 title claims abstract description 38
- 238000010438 heat treatment Methods 0.000 claims abstract description 115
- 238000004146 energy storage Methods 0.000 claims abstract description 94
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 48
- 229910052742 iron Inorganic materials 0.000 claims abstract description 22
- 238000007599 discharging Methods 0.000 claims description 57
- 238000004804 winding Methods 0.000 claims description 29
- 238000013507 mapping Methods 0.000 claims description 13
- 230000003828 downregulation Effects 0.000 claims description 3
- 230000002222 downregulating effect Effects 0.000 claims 1
- 230000001276 controlling effect Effects 0.000 abstract description 17
- 230000001105 regulatory effect Effects 0.000 abstract description 10
- 239000000779 smoke Substances 0.000 abstract description 5
- 230000008859 change Effects 0.000 abstract description 3
- 239000003990 capacitor Substances 0.000 description 29
- 230000008569 process Effects 0.000 description 13
- 238000010586 diagram Methods 0.000 description 11
- 230000007423 decrease Effects 0.000 description 8
- 229910000976 Electrical steel Inorganic materials 0.000 description 7
- 230000007935 neutral effect Effects 0.000 description 6
- 230000020169 heat generation Effects 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 238000011217 control strategy Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000005291 magnetic effect Effects 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 230000001360 synchronised effect Effects 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 239000003302 ferromagnetic material Substances 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 230000000391 smoking effect Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000001960 triggered effect Effects 0.000 description 1
Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/007—Regulation of charging or discharging current or voltage
- H02J7/007188—Regulation of charging or discharging current or voltage the charge cycle being controlled or terminated in response to non-electric parameters
- H02J7/007192—Regulation of charging or discharging current or voltage the charge cycle being controlled or terminated in response to non-electric parameters in response to temperature
- H02J7/007194—Regulation of charging or discharging current or voltage the charge cycle being controlled or terminated in response to non-electric parameters in response to temperature of the battery
-
- 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
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0068—Battery or charger load switching, e.g. concurrent charging and load supply
-
- 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
- H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
- H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
- H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
- H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/53—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/537—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
- H02M7/5387—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
- H02M7/53871—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current
-
- 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
- H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
- H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
- H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
- H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/53—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/537—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
- H02M7/539—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters with automatic control of output wave form or frequency
- H02M7/5395—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters with automatic control of output wave form or frequency by pulse-width modulation
-
- 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)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Electric Propulsion And Braking For Vehicles (AREA)
- Secondary Cells (AREA)
Abstract
The technical scheme includes that the energy conversion device comprises a bridge arm converter, a motor and an energy storage element, wherein the motor and the energy storage element are connected with a battery to form a battery heating circuit, when a battery heating instruction is acquired, the control method comprises the steps of controlling the bridge arm converter by taking initial charge and discharge frequency as target charge and discharge frequency of the battery heating circuit, enabling the battery and the energy storage element to charge and discharge so as to enable the battery to be self-heated, acquiring temperature parameters of the motor, adjusting target charge and discharge frequency of the battery heating circuit according to the temperature parameters of the motor, and controlling the bridge arm converter to adjust current flowing through the battery heating circuit according to the target charge and discharge frequency so as to adjust iron loss of the motor. According to the application, the bridge arm converter is regulated according to the change of the temperature parameter of the motor, so that the iron loss of the motor is controlled, and the phenomena of light heating and heavy smoke emission of the motor caused by the increase of the heating time in the self-heating process of the battery are avoided.
Description
Technical Field
The application relates to the technical field of vehicles, in particular to a vehicle, an energy conversion device and a control method thereof.
Background
With the widespread use of new energy, batteries can be applied in various fields as a power source. The battery is used as a power source in different environments, and the performance of the battery is also affected. For example, the performance of a battery in a low-temperature environment is considerably degraded from that of a battery in a normal temperature environment. For example, the discharge capacity of a battery at zero temperature may decrease with a decrease in temperature. At-30 ℃, the discharge capacity of the battery is substantially 0, resulting in the battery being unusable. In order to be able to use the battery in a low temperature environment, it is necessary to preheat the battery before using the battery.
As shown in fig. 1, in the prior art, the bridge arm converter 101, the motor 102 and the battery 103 are included, when the battery 103 is in a discharging process, the transistor VT1 and the transistor VT6 in the bridge arm converter 101 are triggered to be simultaneously turned on, current flows out of the positive electrode of the battery 103, passes through the transistor VT1 and the transistor VT6 and two stator inductances of the motor 102, returns to the negative electrode of the battery 103, the current rises, energy is stored in the two stator inductances, and when the battery 103 is in a charging process, as shown in fig. 2, the transistor VT1 and the transistor VT6 are simultaneously turned off, the current returns to the battery 102 from the two stator inductances of the motor 102 and the bridge arm converter 101 through two bleeder diodes VD4 and VD3, and the current drops. The two processes are repeated, the battery is in a rapid charge and discharge alternating state, and the internal resistance of the battery causes a large amount of internal heat to be generated, so that the temperature is rapidly increased. However, in the prior art, during the control process of the motor, as the charge and discharge frequency of the battery is fixed, the motor generates heat or smoke along with the increase of the heating time of the battery, which can cause great damage to the motor and seriously affect the service life of the motor, and meanwhile, the noise generated by the motor is also very large and seriously affect the driving feeling of a driver.
Disclosure of Invention
The application aims to provide a vehicle, an energy conversion device and a control method thereof, wherein the iron loss of a motor can be regulated by regulating a bridge arm converter according to the temperature parameter of the motor, so that the problems of heat generation, smoke generation and high noise of the motor in the battery heating process are avoided.
The present application has been achieved in view of the above, and a first aspect of the present application provides a control method of an energy conversion device, characterized in that the energy conversion device includes:
The system comprises a bridge arm converter, a motor and an energy storage element, wherein the bridge arm converter, the motor and the energy storage element are connected with a battery to form a battery heating circuit;
the control method comprises the following steps:
when a battery heating instruction is acquired, the bridge arm converter is controlled by taking the initial charge and discharge frequency as the target charge and discharge frequency of the battery heating circuit, so that the battery and the energy storage element are charged and discharged, and the battery is self-heated;
Acquiring a temperature parameter of the motor, and adjusting a target charge-discharge frequency of the battery heating circuit according to the temperature parameter of the motor;
And controlling the bridge arm converter to adjust the current flowing through the battery heating circuit according to the target charge-discharge frequency so as to adjust the iron loss of the motor.
A second aspect of the present application provides an energy conversion device comprising:
The system comprises a bridge arm converter, a motor and an energy storage element, wherein the bridge arm converter, the motor and the energy storage element are connected with a battery to form a battery heating circuit;
The energy conversion device further comprises a control module for:
when a battery heating instruction is acquired, the bridge arm converter is controlled by taking the initial charge and discharge frequency as the target charge and discharge frequency of the battery heating circuit, so that the battery and the energy storage element are charged and discharged, and the battery is self-heated;
Acquiring a temperature parameter of the motor, and adjusting a target charge-discharge frequency of the battery heating circuit according to the temperature parameter of the motor;
And controlling the bridge arm converter to adjust the current flowing through the battery heating circuit according to the target charge-discharge frequency so as to adjust the iron loss of the motor.
A third aspect of the application provides a vehicle comprising the energy conversion device of the second aspect.
The technical scheme includes that the energy conversion device comprises a bridge arm converter, a motor and an energy storage element, wherein the motor and the energy storage element are connected with a battery to form a battery heating circuit, when a battery heating instruction is acquired, the control method comprises the steps of controlling the bridge arm converter by taking initial charge and discharge frequency as target charge and discharge frequency of the battery heating circuit, enabling the battery and the energy storage element to charge and discharge so as to enable the battery to be self-heated, acquiring temperature parameters of the motor, adjusting target charge and discharge frequency of the battery heating circuit according to the temperature parameters of the motor, and controlling the bridge arm converter to adjust current flowing through the battery heating circuit according to the target charge and discharge frequency so as to adjust iron loss of the motor. According to the application, the bridge arm converter is regulated according to the change of the temperature parameter of the motor, so that the iron loss of the motor is controlled, and the phenomena of light heating and heavy smoke emission of the motor caused by the increase of the heating time in the self-heating process of the battery are avoided.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a current flow diagram of a motor control circuit provided in the prior art;
FIG. 2 is another current flow diagram of a motor control circuit provided by the prior art;
Fig. 3 is a circuit diagram of an energy conversion device according to a first embodiment of the present application;
FIG. 4 is another circuit diagram of an energy conversion device according to a first embodiment of the present application;
FIG. 5 is another circuit diagram of an energy conversion device according to a first embodiment of the present application;
Fig. 6 is a flowchart of a control method of an energy conversion device according to a first embodiment of the present application;
fig. 7 is a flowchart of a control method step S10 of an energy conversion device according to an embodiment of the present application;
Fig. 8 is a specific flowchart of step S20 in a control method of an energy conversion device according to a first embodiment of the present application;
fig. 9 is a specific flowchart of step S30 in a control method of an energy conversion device according to a first embodiment of the present application;
FIG. 10 is another circuit diagram of an energy conversion device according to a first embodiment of the present application;
FIG. 11 is a current flow diagram of an energy conversion device according to an embodiment of the present application;
FIG. 12 is another current flow diagram of an energy conversion device according to an embodiment of the present application;
FIG. 13 is another current flow diagram of an energy conversion device according to an embodiment of the present application;
FIG. 14 is another current flow diagram of an energy conversion device according to a second embodiment of the present application;
Fig. 15 is another current flow diagram of an energy conversion device according to a second embodiment of the present application.
Detailed Description
The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.
In order to illustrate the technical scheme of the application, the following description is made by specific examples.
An embodiment of the present application provides an energy conversion device, including:
The bridge arm converter, the motor and the energy storage element are connected with the battery to form a battery heating circuit.
As a first embodiment of the connection relationship among the bridge arm inverter, the motor, and the energy storage element, as shown in fig. 3, the energy conversion device includes:
The first ends of all the bridge arms of the bridge arm converter 101 are commonly connected to form a first bus end, and the second ends of all the bridge arms of the bridge arm converter 101 are commonly connected to form a second bus end;
the energy storage device comprises an energy storage element C1, wherein a first end of the energy storage element C1 is connected with a first converging end, and a second end of the energy storage element C1 is connected with a second converging end;
The first end of the motor 102 is respectively connected with the middle points of all phases of bridge arms of the bridge arm converter 101, the second end of the motor 102 is commonly connected with the positive electrode of the battery 103, and the negative electrode of the battery 103 is connected with the first converging end;
the bridge arm converter 101 includes M bridge arms, a first end of each of the M bridge arms is commonly connected to form a first bus end of the bridge arm converter 101, a second end of each of the M bridge arms is commonly connected to form a second bus end of the bridge arm converter 101, each bridge arm includes two power switch units connected in series, the power switch units may be of a transistor, an IGBT, a MOS transistor and other device types, a midpoint of each bridge arm is formed between the two power switch units, the motor includes M phase windings, a first end of each phase winding in the M phase windings is connected with a midpoint of each bridge arm in a group of M bridge arms in a one-to-one correspondence manner, a second end of each phase winding in the M phase windings is commonly connected to form a neutral point, and the neutral point is connected with a positive electrode of the battery 103.
When m=3, the bridge arm converter 101 is a three-phase inverter, the three-phase inverter includes three bridge arms, the first end of each bridge arm in the three bridge arms is commonly connected to form a first bus end of the bridge arm converter 101, the second end of each bridge arm in a group of three bridge arms is commonly connected to form a second bus end of the bridge arm converter 101, the three-phase inverter includes 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, the first power switch unit and the fourth power switch unit form a first bridge arm, the second power switch unit and the fifth switch unit form a second bridge arm, the third power switch unit and the sixth switch unit form a third bridge arm, one end of the first power switch unit, the third power switch unit and one end of the fifth power switch unit are commonly connected to form a first bus end of the three-phase inverter, and one end of the second power switch unit, the fourth power switch unit and the sixth power switch unit are commonly connected to form a second bus end of the three-phase inverter.
The motor 102 includes three-phase windings, a first end of each phase winding in the three-phase windings is connected with a midpoint of each path of bridge arm in the three-path bridge arm in a one-to-one correspondence manner, a second end of each phase winding in the three-phase windings is connected together to form a neutral point, a first end of a first phase winding of the motor 102 is connected with the midpoint of the first path of bridge arm, a first end of a second phase winding of the motor 102 is connected with the midpoint of the second path of bridge arm, and a first end of a third phase winding of the motor 102 is connected with the midpoint of the third path of bridge arm.
The first power switch unit in the three-phase inverter 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 motor is a three-phase four-wire system, which can be a permanent magnet synchronous motor or an asynchronous motor, and the three-phase winding is connected at one point and is connected with the positive electrode of the battery 103.
In another embodiment, as shown in fig. 4, the energy conversion device further comprises a first switch module 104 and a second switch module 105. The first end of the first switch module 104 is connected to the first end of the energy storage element C1, the second end of the first switch module 104 is connected to the positive electrode of the battery 103, and the second switch module 105 is connected between the neutral point of the motor 102 and the positive electrode or the negative electrode of the battery 103.
The first switch module 104 is used for switching on or switching off the battery 103 and the energy storage element C1 according to the control signal, so that the battery 103 charges or stops charging the energy storage element C1, and the second switch module 105 is used for switching on or switching off the motor 102 and the battery 103 according to the control signal, so that the battery 103 outputs electric energy to the motor 102 or stops outputting electric energy.
In this embodiment, the bridge arm converter 101 in the battery heating circuit, the three-phase inverter in the motor driving circuit of the vehicle and the motor can be multiplexed to the motor 102, and the energy storage module multiplexes the bus capacitance of the motor driving circuit, and uses different functions of the same module. Through the arrangement of the first switch module 104 and the second switch module 105, components are multiplexed to realize multiple function switching, the utilization rate of the bridge arm converter 101 and the motor 102 is increased, and the cost is saved.
When the first switch module 104 is turned on and the second switch module 105 is turned off, the battery 103, the first switch module 104, the bridge arm converter 101, the energy storage element C1, and the motor 102 form a motor driving circuit, and at this time, the bridge arm converter 101 is controlled to output power from the motor.
When the first switch module 104 is turned off and the second switch module 105 is turned on, the battery 103, the second switch module 105, the motor 102, the bridge arm converter 101, and the energy storage element C1 form a battery heating circuit, and at this time, the bridge arm converter 101 is controlled to charge and discharge the battery 101 and the energy storage element C1 to heat the battery.
When the first switch module 104 is turned off and the second switch module 105 is turned on, fig. 4 may be equivalent to fig. 3, where the first bus end of the bridge arm converter 101 is connected to the first end of the energy storage element C1, the second bus end of the bridge arm converter 101 is connected to the second end of the energy storage element C1, the first end of the motor 102 is connected to the bridge arm converter 101, the second end of the motor 102 is connected to the first end of the battery 101, and the second end of the battery 103 is connected to the second bus end of the bridge arm converter 101, so as to form a battery heating circuit.
The battery heating circuit comprises a discharging loop and a charging loop, wherein the discharging loop is used for discharging the energy storage element C1 through the motor 102 and the bridge arm converter 101 by the battery 103, at the moment, current flows out of the battery 103, the current flows into the energy storage element C1 through the motor 102 and the bridge arm converter 101 to charge the energy storage element C1, the charging loop is used for charging the battery 103 through the motor and the bridge arm converter 101 by the energy storage element C1, at the moment, the current flows out of the energy storage element C1, the current flows into the battery 103 through the bridge arm converter 101 and the motor 102, and because of internal resistance in the battery 103, the internal resistance of the battery 103 generates heat due to the fact that the current flows in and out of the battery 103 in the working process of the discharging loop and the charging loop, and then the temperature of the battery 103 is increased.
When the battery heating circuit works, the battery 103, the motor 102 and the bridge arm converter 101 form a discharging energy storage loop, the battery 103, the motor 102, the bridge arm converter 101 and the energy storage element C1 form a discharging energy release loop, the energy storage element C1, the bridge arm converter 101, the motor 102 and the battery 103 form a charging energy storage loop, and the motor 102, the battery 103 and the bridge arm converter 101 form a charging energy release loop.
The discharging loop comprises a discharging energy storage loop and a discharging energy release loop, the charging loop comprises a charging energy storage loop and a charging energy release loop, when the discharging energy storage loop is controlled to work through the bridge arm converter 101, the battery 103 outputs electric energy to enable the windings of the motor to store energy, when the discharging energy release loop is controlled to work through the bridge arm converter 101, the battery 103 discharges and the windings of the motor release energy to charge the energy storage element C1, when the charging energy storage loop is controlled to work through the bridge arm converter 101, the energy storage element C1 discharges to charge the battery 103, the windings of the motor 102 store energy, and when the charging energy release loop is controlled to work through the bridge arm converter 101, the windings of the motor 102 release energy to charge the battery 103. In addition, the current value flowing through the battery heating circuit is regulated by controlling the duty ratio of the PWM control signal of the bridge arm converter 101, namely, the control duty ratio is equivalent to the control of the conduction time of the upper bridge arm and the lower bridge arm, and the current in the battery heating circuit is increased or reduced after the conduction time of the upper bridge arm or the lower bridge arm is controlled to be prolonged or shortened, so that the heating power generated by the battery 103 can be regulated.
In the process of controlling the operation of the discharging circuit and the charging circuit, the discharging energy storage circuit, the discharging energy release circuit, the charging energy storage circuit and the charging energy release circuit in the discharging circuit can be controlled to operate sequentially, the current value flowing through the battery heating circuit can be adjusted by controlling the duty ratio of the PWM control signal of the bridge arm converter 101, the discharging energy storage circuit and the discharging energy release circuit in the discharging circuit can be controlled to be alternately conducted for discharging, the charging energy storage circuit and the charging energy release circuit in the charging circuit can be controlled to be alternately conducted for discharging, and the current value flowing through the discharging circuit and the charging circuit can be respectively adjusted by controlling the duty ratio of the PWM control signal of the bridge arm converter 101.
In the present embodiment, the bridge arm converter 101 is controlled to operate the battery heating circuit, the battery 103 in the discharging circuit is caused to discharge the energy storage element C1, the energy storage element C1 in the charging circuit is caused to charge the battery 103, and the temperature of the battery 103 is further increased, and the bridge arm converter 101 is controlled to adjust the current in the self-heating circuit of the battery 103, so that the heating power generated by the battery 103 can be adjusted.
As shown in fig. 5, in a second embodiment of the connection relationship among the bridge arm converter 101, the motor 102 and the energy storage element, the first bus terminal of the bridge arm converter 101 is connected to the positive electrode of the battery 103, the second bus terminal of the bridge arm converter 101 is connected to the negative electrode of the battery 103, the first terminal of the motor 102 is connected to the bridge arm converter 101, the second terminal of the motor 102 is connected to the first terminal of the energy storage element C2, and the second terminal of the energy storage element C2 is connected to the second bus terminal of the bridge arm converter 101, thereby forming a battery heating circuit.
The difference between the present embodiment and the above embodiment is that the connection manner between the modules is different, and the specific structure of each module is the same, which can be referred to the above embodiment and will not be described herein again.
The battery heating circuit comprises a discharging loop and a charging loop, wherein the discharging loop is used for discharging the energy storage element C2 through the bridge arm converter 101 and the motor 102 by the battery 103, at the moment, current flows out of the battery 103, flows into the energy storage element C2 through the bridge arm converter 101 and the motor 102 to charge the energy storage element C2, the charging loop is used for charging the battery 103 through the motor 102 and the bridge arm converter 101 by the energy storage element C2, at the moment, current flows out of the energy storage element C2, flows into the battery 103 through the motor 102 and the bridge arm converter 101, and because of internal resistance in the battery 103, the internal resistance of the battery is generated by the inflow and outflow of the current in the process of the discharging loop and the charging loop, and the temperature of the battery 103 is further increased.
As shown in fig. 6, the control method includes step S10, step S20, and step S30, and the specific steps are as follows:
and S10, when a battery heating instruction is acquired, controlling and controlling the bridge arm converter by taking the initial charge and discharge frequency as the target charge and discharge frequency of the battery heating circuit, so that the battery and the energy storage element are charged and discharged, and the battery is self-heated.
The battery heating instruction is an instruction for enabling the battery and other modules to form a heating circuit and generate heat, and when the battery heating instruction is obtained, the bridge arm converter, the motor winding and the energy storage element are connected with the battery to form a battery heating circuit in a working state, and the bridge arm converter is controlled through initial charge and discharge frequency to enable the battery heating circuit to be in the working state, wherein the initial charge and discharge frequency can be determined through a plurality of preset charge and discharge frequencies of the battery.
The step of controlling the bridge arm converter with the initial charge and discharge frequency in the step S10 further includes obtaining the initial charge and discharge frequency before the step of charging and discharging the battery and the energy storage element, as shown in fig. 7, the step of obtaining the initial charge and discharge frequency includes steps S101, S102, S103 and S104, and specifically includes the following steps:
And S101, acquiring a plurality of charge and discharge frequencies of the battery.
In step S101, the charge and discharge frequency of the battery may be a plurality of values, for example, 50HZ, 95HZ, 250HZ, etc. There is a correspondence between the charge-discharge frequency of the battery and the current effective value of the battery heating circuit, for example, the charge-discharge frequency is 50HZ corresponding to the current effective value of 50A, the charge-discharge frequency is 95HZ corresponding to the current effective value of 60A, the charge-discharge frequency is 250HZ corresponding to the current effective value of 80A, and so on.
S102, controlling a bridge arm converter by adjusting the duty ratio of a PWM control signal under each charge and discharge frequency of the battery to obtain a current effective value corresponding to each charge and discharge frequency.
The charging and discharging frequencies of the battery are different and correspond to the current effective values in different battery heating circuits, and the duty ratios of different PWM control signals under the same charging and discharging frequency of the battery also correspond to the current effective values of different battery heating circuits, so that the charging and discharging frequency of the battery is kept unchanged, the current effective values flowing through the battery heating circuits can be adjusted by adjusting the duty ratios of the PWM control signals, and the current effective values can be recorded by a current sensor.
And S103, obtaining a current effective value corresponding to each charge and discharge frequency, and obtaining a current-frequency mapping table.
And S104, obtaining a maximum current effective value according to the current effective value, and taking the charge-discharge frequency corresponding to the maximum current effective value as an initial charge-discharge frequency.
Wherein the PWM control signal duty cycle is adjusted at each charge-discharge frequency in turn, for example, the PWM control signal duty cycle may be adjusted by gradually increasing or decreasing the PWM control signal duty cycle conversion amount. And further obtaining a plurality of current effective values corresponding to each charge-discharge frequency, and obtaining a current-frequency mapping table, wherein the current effective values in the current-frequency mapping table correspond to the charge-discharge frequency. The current effective values in the current-frequency mapping table are sequenced to obtain maximum current effective values, and the corresponding charging and discharging frequency is obtained according to the maximum current effective values to serve as initial charging and discharging frequency.
The technical effect of the embodiment is that the duty ratio of the PWM control signal is regulated under each charge-discharge frequency to obtain the effective value of the current, and then the corresponding charge-discharge frequency is obtained according to the effective value of the maximum current as the initial charge-discharge frequency, so that the battery heating circuit can perform self-heating of the battery at the charge-discharge frequency close to the resonance frequency point, and the battery heating circuit can achieve ideal self-heating effect due to the maximum current value output by the battery at the resonance frequency point
S20, acquiring temperature parameters of the motor, and adjusting target charge and discharge frequency of the battery heating circuit according to the temperature parameters of the motor.
Wherein the temperature parameters of the motor include motor rotor temperature and motor stator temperature.
As shown in fig. 8, as an embodiment, adjusting the target charge-discharge frequency of the battery heating circuit according to the temperature parameter of the motor in step S20 includes:
And S201, when at least one of the temperature of the motor rotor and the temperature of the motor stator reaches a preset temperature value, acquiring a current effective value of the battery heating circuit under the current temperature parameter of the motor.
When the temperature of the motor rotor reaches a preset temperature value or the temperature of the motor stator reaches a preset temperature value or both the temperature of the motor rotor and the temperature of the motor stator reach a preset temperature value, the fact that the temperature of the motor is too high at the moment is indicated, the iron loss of the motor is too large, the temperature of the motor needs to be adjusted, and the current effective value of the battery heating circuit at the moment is detected. The preset temperature value of the motor rotor can be the same as or different from the preset temperature value of the motor stator, and can be set according to actual requirements.
Step S202, the current effective value is adjusted down by a current difference delta I.
And the effective value of the current is adjusted downwards according to a preset current difference delta I.
And S203, taking the charging and discharging frequency corresponding to the effective value of the current after the down regulation as a target charging and discharging frequency based on a current-frequency mapping table.
The corresponding relation between the current effective value and the charging and discharging frequency is stored in the current-frequency mapping table, and the corresponding target charging and discharging frequency is searched in the current-frequency mapping table according to the current effective value after the current is adjusted downwards.
And S30, controlling the bridge arm converter to adjust the current flowing through the battery heating circuit according to the target charge and discharge frequency so as to adjust the iron loss of the motor.
And under the target charging and discharging frequency, acquiring a corresponding PWM control signal according to the reduced current effective value, controlling the bridge arm converter according to the PWM control signal, and enabling the current to reach the current effective value by adjusting the duty ratio of the PWM control signal.
In the initial stage of self-heating of the battery, for example, as shown in fig. 3, the initial charge-discharge frequency of the battery heating circuit approaches to the resonance frequency point, and when the resonance frequency point of the battery heating circuit is 760HZ, that is, the charge-discharge frequency of the battery is 760HZ, the heating current value output by the battery is 259A at the maximum. However, as the battery heating time increases, when the battery is continuously heated at the current value, hysteresis and eddy current phenomena occur in the iron core (ferromagnetic material) of the motor under the action of the alternating magnetic field, and the iron core loss occurs in the motor under the action of the hysteresis and the eddy current phenomena. The iron core loss can cause unnecessary heating or smoking of the motor rotor and the stator silicon steel sheet in the self-heating process of the battery, so that the motor is damaged.
The iron loss per unit weight is expressed as follows:
wherein P Fe is iron loss, unit W/Kg, The iron loss coefficient, f is the charge and discharge frequency of the battery, beta is the frequency index, the value of the frequency index is in the range of 1.2-1.6, the frequency index varies with the steel content of the silicon steel sheet, B m is the amplitude of the alternating-current magnetic flux component, and the formula indicates the iron loss of each kilogram of silicon steel sheet when B m =1T, f =50 HZ, and the value of the iron loss is in the range of 1.05-2.5.
As can be seen from the formula of the iron loss, the iron loss of the motor is strongly related to the charge-discharge frequency of the battery, and the iron core loss of the motor increases exponentially with the increase of the charge-discharge frequency of the battery. Therefore, when at least one of the rotor and the stator silicon steel sheets of the motor has serious heat generation, the current effective value is reduced by a current difference delta I, for example, the current difference delta I is 22A, the current effective value 259A is 237A after being reduced by 22A based on a current-frequency mapping table, and the current effective value 237A corresponds to 666HZ of charge and discharge frequency, and 666HZ is taken as the target charge and discharge frequency. The heating phenomenon of the motor is improved by adopting a mode of adjusting the charge and discharge frequency of the battery. The heating power of the battery is in direct proportion to the internal resistance of the battery, and the internal resistance of the battery is in direct proportion to the charge and discharge frequency. Therefore, the heating power of the battery is also in direct proportion to the charge and discharge frequency, but the heating power and the charge and discharge frequency are weakly related. Therefore, when the motor heats seriously, the charging and discharging frequency of the battery is adjusted, and the heating power of the battery is not greatly influenced.
As shown in fig. 9, as an embodiment, the switching of the upper and lower arms of the arm converter is controlled by adjusting the duty ratio of the PWM control signal in step S30, including:
S301, acquiring the switching frequency of the bridge arm converter, and acquiring the number of charge and discharge cycles of the bridge arm converter according to the switching frequency of the bridge arm converter and the charge and discharge frequency of the battery.
The switching frequency of the bridge arm converter is preset in the battery management system, a corresponding relation exists between the switching frequency of the bridge arm converter and the charging and discharging frequency of the battery, the bridge arm converter is continuously acted for N times in the charging and discharging period of one battery, and the number of the charging and discharging periods of the bridge arm converter is obtained according to the ratio of the switching frequency of the bridge arm converter to the charging and discharging frequency of the battery.
S302, the duty ratio of the PWM control signal is adjusted according to the number of charge and discharge cycles of the bridge arm converter.
The duty ratio of the PWM control signal may be adjusted in various manners, and may be adjusted according to a plurality of duty ratios corresponding to the charge/discharge frequency of the battery, or may be adjusted stepwise according to a duty ratio variation.
The duty ratio of the control signal is changed according to a preset comparison value, and the number of charge and discharge cycles is counted by a counter to gradually adjust the duty ratio, so that the current value of the battery heating circuit reaches the current effective value.
Further, after the step of taking the charge-discharge frequency corresponding to the effective value of the target current as the target charge-discharge frequency, the method further includes:
after the preset time, if at least one of the temperature of the motor rotor and the temperature of the motor stator still reaches the preset temperature value, continuously reducing the current effective value by a current difference delta I, and taking the charging and discharging frequency corresponding to the continuously reduced current effective value as the target charging and discharging frequency.
The specific control manner is referred to step S201 to step S203, and will not be described herein.
In this embodiment, in order to avoid serious heat generation of the motor, when the temperature of the motor rotor or the stator silicon steel sheet reaches a certain set value, the effective current value is adjusted downwards in real time, and then the charging and discharging frequency is adjusted to reduce the iron loss of the motor, and the corresponding optimal battery heating current value is obtained according to the adjusted charging and discharging frequency, and the subsequent battery heating is performed according to the value.
The first embodiment of the application provides a control method of an energy conversion device, the energy conversion device comprises a bridge arm converter, a motor and an energy storage element, the motor and the energy storage element are connected with a battery to form a battery heating circuit, and the control method comprises the steps of obtaining a vehicle state; when the state of the vehicle is in a heating mode, the bridge arm converter is controlled to regulate the current flowing through the battery heating circuit, so that the battery and the energy storage element are charged and discharged to enable the battery to be self-heated, the temperature parameter of the motor is obtained, and the bridge arm converter is regulated according to the temperature parameter of the motor to regulate the iron loss of the motor. According to the application, the bridge arm converter is regulated according to the change of the temperature parameter of the motor, so that the iron loss of the motor is controlled, and the phenomena of light heating and heavy smoke emission of the motor caused by the increase of the heating time in the self-heating process of the battery are avoided.
The present embodiment will be specifically described by a specific circuit configuration:
As shown in fig. 10, the energy conversion device includes a bridge arm converter 101, a motor 102, a first switch module 104, a second switch module 105, a bus capacitor C1, an energy storage capacitor C2, and a switch K4, where the first switch module 104 includes a switch K2, a switch K3, and a resistor R, the second switch module 105 includes a switch K1, a positive electrode of the battery 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 capacitor C1, and a first bus end of the bridge arm converter 101, a midpoint of a three-way bridge arm of the bridge arm converter 101 is respectively connected to three coils of the motor 102, a connection point of the three coils of the motor 102 is connected to a first end of the switch K1, a second end of the switch K1 is connected to a first end of the energy storage capacitor C2, and a second end of the energy storage capacitor C2 is connected to a second end of the bridge arm converter 101, a second end of the bus capacitor C1, and a second end of the switch K4.
The bridge arm converter 101 includes 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, where 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 commonly connected and form a first bus end of the bridge arm converter, one ends of the second power switch unit, the fourth power switch unit and the sixth power switch unit are commonly connected and form a second bus end of the bridge arm converter, a first phase coil of the motor 102 is connected with a midpoint of the first bridge arm, a second phase coil of the motor 102 is connected with a midpoint of the second bridge arm, and a third phase coil of the motor 102 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 connecting midpoint of the three-phase coils.
As shown in fig. 11, when the energy conversion device performs the pre-charging of the bus capacitor, the pre-charging is controlled by opening the switch K2, performing the pre-charging preparation, closing the switches K3 and K4, starting the pre-charging of the bus capacitor C1, raising the voltage on the bus capacitor C1 to a value close to the voltage of the battery 103 by the battery 103, closing the switch K2, opening the switch K3, completing the pre-charging process, and ending the whole process if the voltage of the bus capacitor C1 fails to reach the determined value.
When the bridge arm converter 101 is controlled to enter a high-frequency control mode, a formal heating flow is entered, and in the battery heating process, an IGBT switch is continuously acted for N times in a battery charging and discharging period by adopting a control mode of high switching frequency, so that the IGBT switch frequency is N times of the battery charging and discharging frequency. The control of charge and discharge current and capacitance voltage values is realized by controlling the duty ratio, and the battery self-heating process comprises the following four working states:
The first stage is a discharging energy storage loop operation, as shown in fig. 12, when the upper bridge arm of the bridge arm converter 101 is turned on, the current flowing out from the positive electrode of the battery 103 is combined with the current flowing out from the bus capacitor C1 through the switch K2, and then flows back to the negative electrode of the battery 103 and the bus capacitor C1 through the upper bridge arm (the first upper bridge arm VT1, the third upper bridge arm VT3 and the fifth upper bridge arm VT 5), the motor 102, the switch K1 and the energy storage capacitor C2 of the bridge arm converter 101, and the current is continuously increased, and in this process, the battery 103 and the bus capacitor C1 discharge outwards, so that the voltage of the energy storage capacitor C2 is continuously increased.
The second stage is a discharge energy release circuit, as shown in fig. 13, the upper bridge arm of the bridge arm converter 101 is opened, the lower bridge arm is closed, current flows out from a connection point of the three-phase coil of the motor 102, flows to the positive electrode of the energy storage capacitor C2 through the switch K1, and then flows back to the three-phase coil of the motor 102 through the lower bridge arm (the second lower bridge diode VD2, the fourth lower bridge diode VD4 and the sixth lower bridge diode VD 6) of the bridge arm converter 101 respectively, the current is continuously reduced, the voltage of the energy storage capacitor C2 is continuously increased, and when the current is reduced to zero, the voltage of the capacitor C2 reaches the maximum value. Meanwhile, since the output current of the battery 103 decreases, the voltage at both ends of the battery 102 increases, and the bus capacitor C1 is continuously charged, and the current gradually decreases as the voltage of the capacitor bus C1 increases.
In the third stage, as shown in fig. 14, the lower bridge arm of the bridge arm converter 101 is disconnected, the current flows out from the positive electrode of the energy storage capacitor C2, flows into the motor 102 through the switch K1, flows into the positive electrode of the bus capacitor C1 and the battery 103 through the upper bridge arm (the first upper bridge diode VD1, the third upper bridge diode VD3 and the fifth upper bridge diode VD 5) of the bridge arm converter 101 after passing through the three-phase coil of the motor 102, and finally flows back to the negative electrode of the energy storage capacitor C2.
In the fourth stage, the charging and energy releasing circuit works, as shown in fig. 15, the lower bridge arm of the bridge arm converter 101 is controlled to be conducted, current flows out from the three-phase coil of the motor 102, flows through the lower bridge arm (the second lower bridge arm VT2, the fourth lower bridge arm VT4 and the sixth lower bridge arm VT 6) of the bridge arm converter 101 respectively, flows to the negative electrode of the energy storage capacitor C2, finally flows to the neutral point of the motor 102 through the switch K1, and the voltage of the energy storage capacitor C2 is continuously reduced, and the current is also continuously reduced. At the same time, since the charging current of the battery 103 decreases, the voltage across the battery 103 decreases, the bus capacitor C1 starts to charge the battery 103, and the current gradually decreases to zero as the voltage of the bus capacitor C1 decreases.
Through the four processes, the battery is continuously and rapidly charged and discharged, and a large amount of heat is generated due to the existence of the internal resistance of the battery, so that the battery is rapidly heated.
The control strategy provided by the application, which can adjust the charge and discharge frequency in real time, controls the IGBT through software so as to realize the self-heating function of the battery, and specifically comprises the following steps:
step 1, according to the hardware circuit of the connection system shown in fig. 11, the functions of all the components are guaranteed to be good.
Step 2, given the IGBT switching frequency of the system, the switching frequency is generally fixed, the corresponding period number in the program is calculated, and the period number is calculated by a program software algorithm.
And 3, determining the initial charge and discharge frequency of the system according to the system design requirements and the simulation analysis result.
And 4, calculating an initial duty ratio according to the input and output voltage level and combining the control principle of a hardware circuit of the current system.
And 5, calculating a counter of the control period configuration controller according to the step 2, and determining a comparison value of the counter according to the duty ratio value calculated in the step 4, wherein the comparison value can also be set according to historical data and is used for changing the duty ratio of the control signal.
And 6, applying a control signal to a three-phase bridge arm of the bridge arm converter (the control of the three-phase bridge arm is consistent), and changing the charge and discharge current value by adjusting the duty ratio to achieve the charge and discharge function of the battery.
And 7, monitoring state parameters such as the temperature of a motor rotor, the temperature of a motor stator silicon steel sheet, a three-phase current value, a battery charge and discharge current value, a capacitor C1 side current value, a battery two-end voltage value, a C1 capacitor two-end voltage value, a motor and IGBT temperature and the like at all times in the charge and discharge process.
And 8, continuously monitoring the temperature of the motor rotor and the temperature of the silicon steel sheet of the motor stator, and reducing the charge and discharge frequency of the battery by one gear when any one of the two temperatures reaches a temperature set value T (for example, if the original charge and discharge frequency is 830HZ, the algorithm reduces the charge and discharge frequency to 760 HZ). And outputting a corresponding maximum output current value under the regulated battery charging and discharging frequency by the battery current, and outputting the current by the subsequent battery heating.
And 9, setting the duty ratio according to the adjusted charge and discharge frequency again, so that the system outputs the maximum heating current value of the battery under the updated charge and discharge frequency of the battery. Subsequent battery heating will perform battery self-heating at this current value.
And 10, after the charge and discharge are completed, gradually reducing the charge and discharge current value of the battery until the charge and discharge current value is 0 by reducing the duty ratio of the three-phase IGBT control signal, and ending the charge and discharge process of the battery.
The debugging step is that after the current flows out from the charging pile, the current flows into the motor through the motor to charge and discharge the battery. The above control strategy is described based on the system hardware configuration shown in fig. 10, but is not limited to the above hardware configuration, and is applicable to other cases of similar configurations.
The second embodiment of the present invention also provides an energy conversion device, including:
the bridge arm converter, the motor and the energy storage element are connected with the battery to form a battery heating circuit;
The energy conversion device further comprises a control module for:
When a battery heating instruction is acquired, the initial charge and discharge frequency is used as a target charge and discharge frequency of a battery heating circuit to control a bridge arm converter, so that the battery and an energy storage element are charged and discharged to enable the battery to be self-heated, a temperature parameter of a motor is acquired, the target charge and discharge frequency of the battery heating circuit is adjusted according to the temperature parameter of the motor, and the bridge arm converter is controlled to adjust current flowing through the battery heating circuit according to the target charge and discharge frequency so as to adjust the iron loss of the motor.
The specific control manner of the controller may refer to the above control method, and will not be described herein.
The bridge arm converter comprises N-phase bridge arms, the motor comprises N-phase windings, and the N-phase bridge arms are connected with the N-phase windings in a one-to-one correspondence manner.
In one embodiment, the bridge arm converter is formed by connecting a motor, an energy storage element and a battery, and the battery heating circuit specifically comprises a first end of an N-phase bridge arm which is commonly connected to form a first bus end, the first bus end is connected with the first end of the energy storage element, a second end of the N-phase bridge arm is commonly connected to form a second bus end, the second bus end is connected with the second end of the energy storage element, the first ends of N-phase windings are respectively connected to the midpoints of the N-phase bridge arm in a one-to-one correspondence manner, the second ends of the N-phase windings are connected to the positive electrode of the battery, and the negative electrode of the battery is connected to the second bus end.
In another embodiment, the bridge arm converter, the motor, the energy storage element and the battery are connected to form a battery heating circuit specifically includes:
the first ends of the N-phase bridge arms are connected together to form a first bus end, the first bus end is connected with the positive electrode of the battery, the second ends of the N-phase bridge arms are connected together to form a second bus end, the second bus end is connected with the negative electrode of the battery, the first ends of the N-phase windings are respectively connected to the midpoints of the N-phase bridge arms in a one-to-one correspondence mode, the second ends of the N-phase windings are connected to the first ends of the energy storage elements, and the second ends of the energy storage elements are connected to the second bus end.
The third embodiment of the present invention also provides a vehicle, including the energy conversion device provided in the first embodiment.
The foregoing embodiments are merely for illustrating the technical solution of the present application, but not for limiting the same, and although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that the technical solution described in the foregoing embodiments may be modified or substituted for some of the technical features thereof, and that these modifications or substitutions should not depart from the spirit and scope of the technical solution of the embodiments of the present application and should be included in the protection scope of the present application.
Claims (9)
1. A control method of an energy conversion device, characterized in that the energy conversion device comprises:
The system comprises a bridge arm converter, a motor and an energy storage element, wherein the bridge arm converter, the motor and the energy storage element are connected with a battery to form a battery heating circuit;
the control method comprises the following steps:
when a battery heating instruction is acquired, acquiring a plurality of charging and discharging frequencies of the battery;
Controlling the bridge arm converter by adjusting the duty ratio of a PWM control signal under each charge and discharge frequency of the battery to obtain a current effective value corresponding to each charge and discharge frequency;
obtaining the current effective value corresponding to each charge-discharge frequency to obtain a current-frequency mapping table;
taking the charge-discharge frequency corresponding to the maximum current value in the current-frequency mapping table as an initial charge-discharge frequency;
Controlling the bridge arm converter by taking the initial charge-discharge frequency as the target charge-discharge frequency of a battery heating circuit, so that the battery and the energy storage element are charged and discharged, and the battery is self-heated;
Acquiring a temperature parameter of the motor, and adjusting a target charge-discharge frequency of the battery heating circuit according to the temperature parameter of the motor;
And controlling the bridge arm converter to adjust the current flowing through the battery heating circuit according to the target charge-discharge frequency so as to adjust the iron loss of the motor.
2. The control method of claim 1, wherein the acquiring the temperature parameter of the motor comprises:
and acquiring the temperature of a motor rotor and the temperature of a motor stator in the motor.
3. The control method according to claim 2, wherein the adjusting the target charge-discharge frequency of the battery heating circuit according to the temperature parameter of the motor includes:
When at least one of the motor rotor temperature and the motor stator temperature reaches a preset temperature value, acquiring a current effective value of the battery heating circuit under the current temperature parameter of the motor;
Down-regulating the current effective value by a current difference delta I;
And taking the charging and discharging frequency corresponding to the current effective value after the down regulation as a target charging and discharging frequency based on the current-frequency mapping table.
4. The control method according to claim 3, wherein after the step of setting the charge/discharge frequency corresponding to the current effective value after the down-regulation as the target charge/discharge frequency, further comprising:
After the preset time, if at least one of the temperature of the motor rotor and the temperature of the motor stator still reaches the preset temperature value, continuously reducing the current effective value by a current difference delta I, and taking the charging and discharging frequency corresponding to the continuously reduced current effective value as a target charging and discharging frequency.
5. The control method of claim 4, wherein controlling the bridge arm converter to regulate current flowing through the battery heating circuit according to the target charge-discharge frequency comprises:
acquiring the switching frequency of the bridge arm converter, and acquiring the number of charge and discharge cycles of the bridge arm converter according to the switching frequency of the bridge arm converter and the target charge and discharge frequency of the battery;
and adjusting the duty ratio of the PWM control signal according to the number of charge and discharge cycles of the bridge arm converter so as to adjust the current flowing through the battery heating circuit.
6. The control method of claim 1, wherein the bridge arm converter, the motor, the energy storage element and the battery are connected to form a battery heating circuit specifically comprises a first end of an N-phase bridge arm commonly connected to form a first bus end, the first bus end is connected to the first end of the energy storage element, a second end of the N-phase bridge arm commonly connected to form a second bus end, the second bus end is connected to the second end of the energy storage element, the first ends of N-phase windings are respectively connected to midpoints of the N-phase bridge arm in a one-to-one correspondence manner, the second ends of the N-phase windings are connected to positive poles of the battery, and negative poles of the battery are connected to the second bus end.
7. The control method according to claim 1, wherein the bridge arm converter, the motor, the energy storage element, and the battery are connected to form a battery heating circuit specifically includes:
the first ends of the N-phase bridge arms are connected together to form a first bus end, the first bus end is connected with the positive electrode of the battery, the second ends of the N-phase bridge arms are connected together to form a second bus end, the second bus end is connected with the negative electrode of the battery, the first ends of the N-phase windings are connected to the midpoints of the N-phase bridge arms in a one-to-one correspondence mode respectively, the second ends of the N-phase windings are connected to the first ends of the energy storage elements, and the second ends of the energy storage elements are connected to the second bus ends.
8. An energy conversion device, characterized in that the energy conversion device comprises:
The system comprises a bridge arm converter, a motor and an energy storage element, wherein the bridge arm converter, the motor and the energy storage element are connected with a battery to form a battery heating circuit;
The energy conversion device further comprises a control module for:
when a battery heating instruction is acquired, acquiring a plurality of charging and discharging frequencies of the battery;
Controlling the bridge arm converter by adjusting the duty ratio of a PWM control signal under each charge and discharge frequency of the battery to obtain a current effective value corresponding to each charge and discharge frequency;
obtaining the current effective value corresponding to each charge-discharge frequency to obtain a current-frequency mapping table;
taking the charge-discharge frequency corresponding to the maximum current value in the current-frequency mapping table as an initial charge-discharge frequency;
Controlling the bridge arm converter by taking the initial charge-discharge frequency as the target charge-discharge frequency of a battery heating circuit, so that the battery and the energy storage element are charged and discharged, and the battery is self-heated;
Acquiring a temperature parameter of the motor, and adjusting a target charge-discharge frequency of the battery heating circuit according to the temperature parameter of the motor;
And controlling the bridge arm converter to adjust the current flowing through the battery heating circuit according to the target charge-discharge frequency so as to adjust the iron loss of the motor.
9. A vehicle characterized in that it comprises the energy conversion device according to claim 8.
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| CN111404247A (en) * | 2020-06-04 | 2020-07-10 | 比亚迪股份有限公司 | Battery energy processing device and method and vehicle |
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| CN111347926B (en) * | 2018-12-21 | 2022-04-15 | 比亚迪股份有限公司 | Power battery charging and discharging device, vehicle and heating device |
| CN110962631B (en) * | 2018-12-29 | 2020-11-17 | 宁德时代新能源科技股份有限公司 | Battery heating system and control method thereof |
| CN112356738B (en) * | 2019-06-24 | 2022-04-22 | 宁德时代新能源科技股份有限公司 | Motor controller, vehicle control unit, battery management system and control method |
| CN111391718B (en) * | 2020-06-04 | 2020-10-23 | 比亚迪股份有限公司 | Battery energy processing device and method and vehicle |
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| CN109823234A (en) * | 2019-04-23 | 2019-05-31 | 上海汽车集团股份有限公司 | A kind of control method of drive system, drive system and new-energy automobile |
| CN210225008U (en) * | 2019-08-15 | 2020-03-31 | 比亚迪股份有限公司 | Energy conversion device and vehicle |
| CN111404247A (en) * | 2020-06-04 | 2020-07-10 | 比亚迪股份有限公司 | Battery energy processing device and method and vehicle |
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