CN113715690A - Power supply system and control method thereof - Google Patents
Power supply system and control method thereof Download PDFInfo
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- CN113715690A CN113715690A CN202111014369.4A CN202111014369A CN113715690A CN 113715690 A CN113715690 A CN 113715690A CN 202111014369 A CN202111014369 A CN 202111014369A CN 113715690 A CN113715690 A CN 113715690A
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- 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
- B60L58/25—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 controlling the electric load
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of DC power input into DC power output
- H02M3/02—Conversion of DC power input into DC power output without intermediate conversion into AC
- H02M3/04—Conversion of DC power input into DC power output without intermediate conversion into AC by static converters
- H02M3/06—Conversion of DC power input into DC power output without intermediate conversion into AC by static converters using resistors or capacitors, e.g. potential divider
- H02M3/07—Conversion of DC power input into DC power output without intermediate conversion into AC by static converters using resistors or capacitors, e.g. potential divider using capacitors charged and discharged alternately by semiconductor devices with control electrode, e.g. charge pumps
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of DC power input into DC power output
- H02M3/22—Conversion of DC power input into DC power output with intermediate conversion into AC
- H02M3/24—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters
- H02M3/28—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC
- H02M3/325—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/33569—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
-
- 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
- B60L2210/00—Converter types
- B60L2210/10—DC to DC converters
-
- 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
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Charge And Discharge Circuits For Batteries Or The Like (AREA)
- Electric Propulsion And Braking For Vehicles (AREA)
Abstract
The invention discloses a power supply system and a control method thereof, wherein the power supply system is a system for supplying power to a low-voltage electric appliance system in an electric automobile, and comprises the following steps: the DC/DC isolation module comprises a charge pump and a DC/DC isolation module, wherein the charge pump comprises N charging capacitors, at least one charging capacitor is used as a power supply capacitor of the DC/DC isolation module, and the charge pump is connected with a power battery and a power system controller of the electric automobile. According to the implementation scheme, when the temperature of the power battery is low, the charge pump heating mode can be started, the charge pump is controlled by the power system controller to alternately charge and discharge so as to enable the power battery to generate heat to realize self-heating, and in the DC/DC working mode, the capacitor in the charge pump is reused as the charging capacitor, so that an integrated charge pump and a DC/DC isolation module are formed, structural components and line connection of the system are reduced to a certain extent, and the overall volume and cost of the power system are reduced.
Description
Technical Field
The invention relates to the field of automobile power supplies, in particular to a power supply system and a control method thereof.
Background
In recent years, various electric vehicles such as pure electric vehicles, hybrid electric vehicles and plug-in hybrid electric vehicles have been developed rapidly, and tend to gradually replace fuel vehicles. A battery, an auxiliary system thereof, a module such as an on-vehicle DC/DC module, and the like play an indispensable role in an electric vehicle as a core component or an important component of a strong electric system of the electric vehicle.
The auxiliary system of the battery can be a battery heating structure. As is well known, a power battery is the core of an electric vehicle and provides energy for a main drive motor. However, the low-temperature performance of the battery pack is poor, and the battery pack needs to be preheated by a battery heating structure before being used at low temperature, so that the power battery can reach a proper working temperature and keep stable working performance.
However, the battery auxiliary system and the on-board DC/DC generally have larger volume, mass and heat dissipation requirements, and a protective relay needs to be added between the power battery and the auxiliary system and between the power battery and the on-board DC/DC, which causes the whole power supply system of the vehicle to be bulky and complex, the circuit to be complicated and complicated, and additional cost to be increased.
Disclosure of Invention
In view of this, the present invention provides a power supply system and a control method thereof, so as to overcome the problems of large volume and high cost of the power supply system in the prior art.
In order to achieve the purpose, the invention provides the following technical scheme:
a power supply system for a system for supplying power to a low-voltage electrical machine system in an electric vehicle, the power supply system comprising:
the charge pump comprises N charging capacitors, N is more than or equal to 2, at least one charging capacitor is used as a power supply capacitor of the DC/DC isolation module, and the charge pump is connected with a power battery and a power system controller of the electric automobile.
Optionally, the two power supply capacitors are connected in series when starting the DC/DC function, and the two power supply capacitors provide isolation voltages in different directions for the high-voltage side of the DC/DC isolation module.
Optionally, the number of the power supply capacitor is one, a first voltage stabilizing switch and a second voltage stabilizing switch are arranged between the charge pump and the power battery, the first voltage stabilizing switch and the second voltage stabilizing switch are arranged on the same pole of the power battery, and the power supply capacitor provides isolation voltage for the high-voltage side of the DC/DC isolation module.
Optionally, a circuit between switches in the DC/DC isolation module forms a single-ended forward isolation circuit on the high-voltage side of the DC/DC isolation module; the input side of the single-ended forward isolation circuit is connected with the power supply capacitor, and the output side of the single-ended forward isolation circuit is connected with a primary side coil of a transformer in the DC/DC isolation module.
Optionally, a circuit between switches in the DC/DC isolation module forms a full-bridge isolation circuit on a high-voltage side of the DC/DC isolation module, an input side of the full-bridge isolation circuit is connected to the power supply capacitor, and an output side of the full-bridge isolation circuit is connected to a primary winding of a transformer in the DC/DC isolation module.
A control method of a power supply system is applied to a power supply system controller, the power supply system controller is positioned in a power system of an electric automobile, and the power system comprises the following steps: power supply system, power battery and power supply system controller, power supply system includes: the DC/DC isolation module comprises a charge pump and a DC/DC isolation module, wherein the charge pump comprises N charging capacitors, N is more than or equal to 2, at least one charging capacitor is used as a power supply capacitor of the DC/DC isolation module, and the charge pump is connected with the power battery and the power system controller; the DC/DC isolation module supplies power to a low-voltage electrical system; the method comprises the following steps:
acquiring the temperature of the power battery;
if the temperature of the power battery is lower than a preset temperature value, controlling to start a heating function;
when the heating function is started, the on-off state of a switch in the charge pump is controlled, and charging and discharging between the power battery and the charge pump are realized;
detecting that the temperature of the power battery reaches the preset temperature value, closing a heating function and starting a DC/DC function;
and when the DC/DC function is started, controlling the switch state of the switch in the charge pump and the switch state of the switch in the DC/DC isolation module so that the power supply capacitor provides isolation voltage for the high-voltage side of the DC/DC isolation module.
Optionally, the number of the power supply capacitors is two, and the control of the switch state of the switch in the charge pump and the switch state of the switch in the DC/DC isolation module includes:
controlling the switch state of a switch in the charge pump so as to enable the two power supply capacitors to be connected in series;
and controlling the switch state of a switch in the DC/DC isolation module so that the two power supply capacitors alternately provide isolation voltages in different directions for the high-voltage side of the DC/DC isolation module.
Optionally, the power supply capacitor is one, a first voltage stabilizing switch and a second voltage stabilizing switch are arranged between the charge pump and the power battery, the first voltage stabilizing switch and the second voltage stabilizing switch are arranged at the same pole of the power battery, and control the on-off state of a switch in the charge pump and the on-off state of a switch in the DC/DC isolation module, including:
controlling the switching states of the first voltage stabilizing switch and the second voltage stabilizing switch and the switching state of a switch in the charge pump so as to enable the power supply capacitor to output a stable voltage;
controlling a switch state of a switch in the DC/DC isolation module to cause the supply capacitor to provide an isolation voltage for a high voltage side of the DC/DC isolation module.
Optionally, controlling the switching states of the first voltage stabilizing switch and the second voltage stabilizing switch and the switching state of the switch in the charge pump, so that the supply capacitor can output a stable voltage, includes:
under the condition that the isolation voltage is smaller than the voltage of the power battery, controlling a first voltage stabilizing switch to be closed, and enabling a power supply capacitor to output a stable voltage by controlling the switching frequency of a charging switch of the power supply capacitor in the charge pump;
or,
under the condition that the isolation voltage is greater than the voltage of the power battery, controlling a charging switch of the first voltage stabilizing switch and another non-power supply capacitor in the charge pump except the power supply capacitor to be closed so as to charge the non-power supply capacitor; the first voltage stabilizing switch and a charging switch of the non-power supply capacitor are controlled to be switched off, and the second voltage stabilizing switch and a switch of the power supply capacitor are controlled to be switched on, so that the power supply capacitor is charged; and the power supply capacitor can output stable voltage by alternately executing the frequency of the two states.
Optionally, the method further includes:
acquiring an instantaneous acceleration or recovery braking energy instruction;
and controlling to close the DC/DC function, and controlling the power supply capacitor of the charge pump to provide instant energy to realize instant acceleration, or controlling the power supply capacitor of the charge pump to absorb braking energy.
As can be seen from the above technical solutions, compared with the prior art, an embodiment of the present invention discloses a power supply system and a control method thereof, where the power supply system supplies power to a low-voltage electrical device system in an electric vehicle, and the power supply system includes: the charge pump comprises N charging capacitors, N is more than or equal to 2, at least one charging capacitor is used as a power supply capacitor of the DC/DC isolation module, and the charge pump is connected with a power battery and a power system controller of the electric automobile. According to the implementation scheme, when the temperature of the power battery is low, the charge pump heating mode can be started, the charge pump is controlled by the power system controller to alternately charge and discharge so as to enable the power battery to generate heat to realize self-heating, and in the DC/DC working mode, the capacitor in the charge pump is reused as the charging capacitor, so that an integrated charge pump and a DC/DC isolation module are formed, structural components and line connection of the system are reduced to a certain extent, and the overall volume and cost of the power system are reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a schematic structural arrangement diagram of a power supply system according to an embodiment of the present invention;
fig. 2 is a schematic circuit diagram of a charge pump according to an embodiment of the present invention;
fig. 3 is a schematic circuit diagram of a power supply system according to an embodiment of the disclosure;
fig. 4 is a schematic circuit diagram of another power supply system according to the embodiment of the disclosure;
FIG. 5 is a schematic circuit diagram of a third power system according to an embodiment of the disclosure;
FIG. 6 is a flowchart illustrating a method for controlling a power system according to an embodiment of the present invention;
FIG. 7 is a schematic block diagram of a power system according to an embodiment of the present disclosure;
fig. 8 is a flowchart illustrating a complete implementation of a control method of a power supply system according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Fig. 1 is a schematic structural arrangement diagram of a power supply system according to an embodiment of the present invention, where the power supply system is a system for supplying power to a low-voltage electrical device system in an electric vehicle, and as shown in fig. 1, the power supply system may include: the charge pump 10 comprises N charging capacitors, N is more than or equal to 2, at least one charging capacitor is used as a power supply capacitor of the DC/DC isolation module 20, and the charge pump 10 is connected with a power battery and a power system controller of the electric automobile.
The positive electrode of the charge pump 10 is connected to the positive electrode of the power battery, the negative electrode of the charge pump 10 is connected to the negative electrode of the power battery, the charge pump 10 includes at least two capacitors and at least three first switches, and the at least three first switches can control the at least two capacitors to be in different connection states under different switch states.
The power system controller is respectively connected with the power battery and the charge pump 10, and is configured to control the operating state of the charge pump 10 according to the operating state information of the power battery, where the operating state of the charge pump 10 includes charging, discharging, and disconnection.
In the process of researching the technical scheme of the invention, the inventor finds that a separate DC/DC module is required to be added to the power supply system for supplying power to the low-voltage equipment of the vehicle in the prior art. However, the separately added DC/DC module is large in volume and high in cost. Therefore, in the embodiment of the present invention, at least two capacitors in the charge pump are designed to be multiplexed, so that the capacitors can be applied to the charge pump in the charge pump operation mode and applied to the DC/DC module in the DC/DC operation mode.
The charge pump and the DC/DC isolation module can be integrated together in design because the charging capacitor in the charge pump can be multiplexed as the power supply capacitor of the DC/DC isolation module. The operation mode of the power supply system may include, but is not limited to, a battery heating mode and a DC/DC function, which correspond to the heating function and the DC/DC function of the power battery, respectively. When the heating function of the power battery is started, the power supply system controller controls the on-off state of a first switch in the charge pump to realize charging and discharging between the power battery and the charge pump; when the DC/DC function is started, the power supply system controller controls the switching state of the first switch in the charge pump and the switching state of the switch in the DC/DC isolation module, so that the power supply capacitor provides isolation voltage for the high-voltage side of the DC/DC isolation module.
Fig. 2 is a schematic circuit structure diagram of a charge pump according to an embodiment of the present invention, in a specific implementation, the charge pump may be formed by connecting a plurality of capacitors and a plurality of switches and other components (in fig. 2, two capacitors (C1 and C2) and three first switches (S1, S2, and S3) are taken as examples), the capacitors are used as energy storage elements, and by controlling the opening and closing of each first switch, a connection manner between the capacitors may be changed, so that conversion of output voltages at two ends of the charge pump is achieved.
The invention does not limit the quantity of switches and capacitors to the circuit structure of the charge pump, can increase the capacitors with any group number, and only needs to add the switches to form a corresponding charge-discharge loop. The first switch in the charge pump can be realized by high-power semiconductor switch components such as MOSFET, IGBT and the like, and in addition, the current carrying capacity can be enlarged by increasing the number of the MOSFET in parallel connection.
Before the vehicle is started, the temperature of the power battery can be obtained, the current battery temperature is compared with the preset lowest temperature at which the power battery can normally work, and if the current battery temperature is lower than the lowest temperature, the working performance of the power battery at the current temperature is poor. Therefore, in order to ensure that the operating performance of the power battery is at a high level, the battery heating function needs to be activated.
Specifically, in conjunction with fig. 2, in the first operating state of the charge pump, S1 and S3 are closed, and S2 is open; in the second working state of the charge pump, S1 and S3 are opened, and S2 is closed; and under the working mode of the charge pump, the first working state and the second working state are alternately switched.
It can be seen that when the switches S1, S3 are closed and S2 is open, the capacitors C1 and C2 are connected in parallel, and the charge pump is in a low voltage state; when the switches S1, S3 are open and S2 is closed, the capacitors C1 and C2 are connected in series and the charge pump is in a high voltage state.
When the power supply system controller controls the charge pump to work in a low-voltage state, the power battery discharges and the charge pump charges; when the power supply system controller controls the charge pump to work in a high-voltage state, the charge pump discharges electricity, and the power battery charges. The power supply system controller controls the charge pump to work in a low-voltage state and a high-voltage state alternately, so that the power battery can work in a discharging state and a charging state alternately, and the self-heating of the power battery can be realized.
In this embodiment, the heating of the power battery is realized by the charge pump, and the processes of charging the charge pump by the power battery and discharging the power battery by the charge pump can be alternately realized by controlling the on and off states of the corresponding switches in the charge pump, so that positive and negative pulse currents are generated on the power battery. The power supply system disclosed by the embodiment can automatically heat the power battery at any time and any place according to needs without the aid of external source-containing equipment, and great convenience is brought to users.
Further, the charge pump self-heating has a faster heating speed, a higher heating efficiency, and a smaller volume than an external heating structure such as a PTC structure or a heat pump.
The power supply system can start a charge pump heating mode when the temperature of a power battery is low, the charge pump is controlled by the power supply system controller to alternately charge and discharge so as to enable the power battery to generate heat to realize self-heating, and under the DC/DC working mode, a capacitor in the charge pump is reused as a charging capacitor, so that an integrated charge pump and a DC/DC isolation module are formed, structural components and line connection of the system are reduced to a certain extent, and the overall volume and cost of the power supply system are reduced.
Fig. 3 is a schematic circuit diagram of a power supply system according to an embodiment of the disclosure, and in conjunction with fig. 3, the DC/DC isolation module may include at least two second switches (S4 and S5) and a transformer, where the at least two second switches and the transformer and the at least two capacitors in the charge pump are configured as a DC/DC module.
The second switch is not specifically referred to as a switch of a type different from that of the first switch, and may be a switch of the same type as that of the first switch or a switch of a type different from that of the first switch, as required.
The scheme shown in fig. 3 adopts an isolated half-bridge DC/DC module, only two switching elements are added on the basis of the charge pump to realize the DC/DC function, and the DC/DC module and the energy storage element of the charge pump share two high-voltage large-capacity capacitors and two switches, so that compared with the existing design of independently adding the DC/DC module, the size and cost of the system are further reduced.
After the power battery reaches a temperature range suitable for working in a self-heating mode, or when the temperature of the power battery is originally in the temperature range suitable for working, the vehicle can directly utilize a power supply system to realize a DC/DC function after being started. Specific implementations may be, but are not limited to, the following two:
1. the two capacitors of the charge pump are combined to form an isolated half-bridge DC/DC, as shown in FIG. 3.
When the power supply system starts the DC/DC function, the two power supply capacitors (such as C1 and C2 in FIG. 3) are connected in series when the DC/DC function is started, and the two power supply capacitors can provide isolation voltages in different directions for the high-voltage side of the DC/DC isolation module.
And (3) opening the switches S1 and S3 to make S2 normally closed, wherein the capacitors C1 and C2, the switches S4 and S5 and the power battery form a primary side circuit of the isolation half-bridge type DC/DC. The capacitors C1 and C2 have the same capacitance value and withstand voltage, and when the switch S2 is closed, the two capacitors C1 and C2 share half of the bus voltage respectively. The bus capacitors C1 and C2 are generally large in capacitance value, and stable voltage division can be achieved. In the scheme, S2 is closed all the time, so the voltage on the capacitors C1 and C2 is the power battery voltage of 1/2 all the time. When S4 is conducted, S5 is disconnected, the voltage at two ends of the capacitor C1 is transmitted to the secondary side, S4 is disconnected when S5 is conducted, the voltage at two ends of the capacitor C2 is transmitted to the secondary side, the direct current voltage is converted into pulse alternating current voltage through the alternating conduction of S4 and S5, and the pulse alternating current voltage passes through a transformer, secondary side rectifier diodes (right side D1, D2, D3 and D4 in the figure 3) and a filter circuit to provide stable direct current output voltage for a low-voltage load. The output voltage can be adjusted by adjusting the duty ratio of the switch conducting signal. In the implementation scheme, the voltage borne by the switch tubes S4 and S5 is the voltage of the power battery.
For example: the primary side input voltage of the transformer is Ui 100V, the transformer transformation ratio N1/N2 is 100/15, the upper and lower switching elements are alternately conducted, the direct current voltage of the primary side is converted into pulse alternating current voltage and transmitted to the secondary side, the amplitude of the pulse alternating current voltage of the secondary side is +/-15V, the pulse alternating current voltage is converted into positive pulse at the input port of the LC filter circuit through diode rectification, and if two switching tubes are assumedThe total time of conduction is ton, the period is T, the average value of the output voltage is 15 × ton/T, the defined duty ratio D is ton/T, the output voltage Uo is Ui × N2/N1 × D, Uo is V in fig. 3OUT1Or VOUT2. If the duty ratio is 0.8, the average value of the output voltage is 12V, and a stable dc voltage can be obtained through the LC filter circuit (right side L1 and C3 or L2 and C4 in fig. 3).
It should be noted that fig. 3 is only a basic example of an implementation, the low-voltage side may adopt a full-wave rectification mode in fig. 3, and may also adopt a full-bridge rectification mode, a half-wave rectification mode, and the like, and the high-voltage side may add a resonant capacitor, an inductor, and other elements to form a soft switching circuit such as an LLC, and the like, so as to reduce switching loss. The secondary side output can realize different voltage outputs on the low-voltage side by adding a plurality of windings with different turns.
2. And combining the charge pump with the isolation DC/DC to form a two-stage DC/DC device, wherein the first stage of charge pump DC/DC can realize regulated DC/DC with adjustable output voltage, and the second stage of isolation DC/DC realizes high-low voltage isolation.
In another implementation, the power supply capacitor is one, a first voltage stabilizing switch and a second voltage stabilizing switch are arranged between the charge pump and the power battery, the first voltage stabilizing switch and the second voltage stabilizing switch are arranged on the same pole of the power battery, and the power supply capacitor provides isolation voltage for the high-voltage side of the DC/DC isolation module. When the DC/DC function is started, the power supply system controller controls the switching states of the first voltage stabilizing switch and the second voltage stabilizing switch and the switching state of the first switch in the charge pump so that the power supply capacitor can output stable voltage, and controls the switching states of the switches in the DC/DC isolation module so that the power supply capacitor provides isolation voltage for the high-voltage side of the DC/DC isolation module.
In this implementation, S2 remains open throughout the DC/DC mode of operation. The charge pump comprises a first capacitor C1 and a second capacitor C2, and the power supply system comprises: the first voltage stabilizing switch and the second voltage stabilizing switch are respectively a voltage stabilizing switch connected between the anode of the power battery and the first end of the first capacitor and a voltage stabilizing switch connected between the anode of the power battery and the second end of the first capacitor, so that the output voltage at the two ends of the second capacitor C2 (power supply capacitor) can be adjusted through related circuit control. Fig. 4 is a schematic circuit structure diagram of another power supply system disclosed in the embodiment of the present invention, fig. 5 is a schematic circuit structure diagram of a third power supply system disclosed in the embodiment of the present invention, and the circuit structures shown in fig. 4 and fig. 5 both include the two voltage stabilizing switches, except that the isolated DC/DC part in the two diagrams is implemented differently, the implementation in fig. 4 is a single-ended forward implementation, and the implementation in fig. 5 is a full-bridge circuit implementation, but the isolated DC/DC part may also be implemented in other implementations such as a single-ended flyback implementation, a half-bridge circuit implementation, and the like. Corresponding to fig. 4, the circuit between the switches in the DC/DC isolation module forms a single-ended forward isolation circuit on the high-voltage side of the DC/DC isolation module; the input side of the single-ended forward isolation circuit is connected with the power supply capacitor, and the output side of the single-ended forward isolation circuit is connected with a primary side coil of a transformer in the DC/DC isolation module. Corresponding to fig. 5, the circuit between the switches in the DC/DC isolation module forms a full-bridge isolation circuit on the high-voltage side of the DC/DC isolation module, the input side of the full-bridge isolation circuit is connected to the power supply capacitor, and the output side of the full-bridge isolation circuit is connected to the primary winding of the transformer in the DC/DC isolation module.
In a specific implementation, first, any voltage value in the range of 0 to twice the bus voltage of the power battery can be obtained on the capacitor C2 by using the first stage charge pump. The output voltage reference value Vref is preset, and can be divided into two modes of voltage boosting and voltage reducing according to the magnitude of the voltage reference value, which are respectively described as follows:
in a step-down mode, that is, in a case where the output voltage reference value of the second capacitor is smaller than the voltage of the power battery, the process of charging the second capacitor by controlling the power battery and the process of independently discharging the second capacitor to the transformer side are alternately performed, so that the output voltage value of the second capacitor is maintained at the voltage reference value.
Specifically, buck mode (Vref < VBAT, VBAT being the power cell voltage): s4 remains closed throughout the buck mode. The voltage on the capacitor C2 is monitored at all times and the voltage measurement VC2 on the capacitor C2 is compared with Vref, two thresholds Vref1 and Vref2 can be set, Vref1< Vref 2. If VC2 < Vref1, S1 is closed to charge the capacitor C2. If VC2 is greater than or equal to Vref2, switch S1 is turned off and the capacitor discharges outwards independently. By reasonably selecting the voltage reference value and controlling the switching frequency of S1, stable DC voltage output can be realized at two ends of the capacitor C2.
In a boost mode, namely under the condition that the voltage reference value of the second capacitor is larger than the voltage of the power battery, the output voltage of the second capacitor is maintained at the voltage reference value by controlling the power battery to charge only the first capacitor and controlling the power battery to be connected with the first capacitor in series and simultaneously alternately executing the process of charging the second capacitor, wherein the second capacitor is independently discharged to the side of the transformer during the process that the power battery charges only the first capacitor.
Specifically, boost mode (VBAT < Vref <2 VBAT):
1) s4 and S3 are closed, and the power battery charges the first capacitor C1.
2) S4 is disconnected from S3, S5 is closed from S1, and the energy stored in the first capacitor C1 is transferred to the second capacitor C2 to be output to the load.
3) In the process of step 2), if VC2 is greater than or equal to Vref, S5 and S1 are opened, the second capacitor C2 discharges outwards independently, and S4 and S3 can be closed at this time, and the power battery charges the first capacitor C1 to supplement part of energy. If VC2 < Vref, then close S5 and S1, continue to supply energy to the second capacitor C2 and supply power to the outside. By reasonably selecting the voltage threshold Vref and the switching frequency of the switching tube, stable voltage output can be realized across the second capacitor C2.
For example: assuming that VBAT is 400V and Vref is 500V, in step 1), the first capacitor C1 is charged to 400V, then S4 and S3 are opened, and S5 and S1 are closed, the voltage across the left and right ends of the second capacitor C2 is 800V, the second capacitor C2 is charged with 800V, S5 and S1 are opened when the voltage across the second capacitor C2 is greater than 500V, power is supplied to the load by the second capacitor C2, the electric quantity on the second capacitor C2 is consumed, the voltage across the second capacitor C2 drops, S5 and S1 are closed again when the voltage across the second capacitor C2 is less than 500V, the second capacitor C2 is charged by the power supply and the first capacitor C1, the voltage across the second capacitor C2 rises, and the process is repeated. The higher the switching frequency in this process, the lower the amplitude of the voltage fluctuation across the second capacitor C2.
In addition, two upper and lower thresholds may be set, for example, when the voltage is greater than 505V, the second capacitor C2 is discharged alone, and when the voltage is less than 495V, the second capacitor C2 is charged.
And the low-voltage isolation output is realized by utilizing the next-stage DC/DC device after the voltage regulation control of the first-stage charge pump. In the implementation of fig. 4, when the DC/DC mode is turned on, the switch S6 is closed, and the DC voltage is converted into a pulsed ac voltage by periodically switching the switch S7, and the pulsed ac voltage is transmitted to the secondary side by the transformer, half-wave rectified by the diodes D2 and D3, and filtered by the filter circuit (including the inductor L1 and the capacitor C3) and then output. One winding of the transformer and a diode D1 form a magnetic reset circuit, when the switch S7 is switched off, the transformer exciting current flows back to the power supply and gradually drops to zero, and the magnetic bias phenomenon of the transformer is prevented. The regulation of the output voltage is achieved by adjusting the duty cycle of the on signal of switch S7.
In the implementation of fig. 5, switches S6, S7, S8 and S9 form an isolated full-bridge DC/DC primary circuit, one group is S6 and S9, and the other group is S7 and S8, the DC voltage is converted into a pulse ac voltage by alternately turning on the two groups of switches, and the pulse ac voltage is transmitted to the secondary side, and power is supplied to the low-voltage load through rectifier diodes (right side D1, D2, D3 and D4 in fig. 5) and filter circuits (right side L11 and C3, and L2 and C4 in fig. 5). The output voltage is adjusted by adjusting the duty ratio of the switch conducting signal.
In the schemes shown in fig. 4 and 5, in the DC/DC mode, first a charge pump structure is used to implement a first step-up/step-down DC/DC, and then a first-step isolation DC/DC is used to implement high-low voltage isolation. Therefore, the first-stage DC/DC can be used for realizing voltage stabilization and compensating the influence of the change of the state of charge of the power battery on the primary side input voltage of the DC/DC. The primary side voltage can be increased according to actual requirements, the primary side current and power consumption are reduced, and the method is suitable for application occasions requiring high efficiency. Or the primary voltage is reduced according to the requirement, so that the requirement on the voltage-resistant grade of the transformer is reduced, and the requirements on insulating materials, the number of turns of the coil, the turn-to-turn distance and the like are reduced. Therefore, the invention is beneficial to regulating the primary voltage of the transformer according to actual requirements, thereby providing more choices for the design of the transformer.
According to the power supply system, the original vehicle DC/DC module and the battery heating device are integrated, the volume of the power supply system is not obviously increased compared with that of the original vehicle DC/DC module, and external heating devices such as a PTC heating plate are omitted. The combined device can simultaneously realize two functions of battery heating and DC/DC, and the volume and the cost are greatly reduced compared with the prior scheme. And because the integration level of the power supply system is higher, the direct current bus copper bar/cable, the high-voltage relay, the heat dissipation device and the like can be shared, and the overall volume and the cost of the system can be further reduced.
The power supply system is described in detail in the embodiment disclosed in the present invention, and next, the present invention also discloses a control method of the power supply system, and a detailed description is given below of a specific embodiment.
Fig. 6 is a flowchart of a control method of a power supply system according to an embodiment of the present invention, which is applied to a power supply system controller, where the power supply system controller is located in a power system of an electric vehicle, and the power system includes: power supply system, power battery and power supply system controller, power supply system includes: the DC/DC isolation module comprises a charge pump and a DC/DC isolation module, wherein the charge pump comprises N charging capacitors, N is more than or equal to 2, at least one charging capacitor is used as a power supply capacitor of the DC/DC isolation module, and the charge pump is connected with the power battery and the power system controller; the DC/DC isolation module supplies power to a low-voltage electrical system. Referring to fig. 6, the control method of the power supply system may include:
step 601: and acquiring the temperature of the power battery.
The method comprises the steps of presetting the lowest temperature at which the power battery can normally work as a preset temperature value, acquiring temperature information of the power battery through a temperature sensor arranged in the power battery, comparing the acquired temperature information with the preset temperature value, and judging whether the power battery needs to be preheated at low temperature or not. It can be understood that the preset temperature value can also be set to be higher than the lowest temperature at which the power battery can normally work, and specifically the preset temperature value can be set according to actual requirements.
Step 602: and if the temperature of the power battery is lower than a preset temperature value, controlling to start a heating function.
Step 603: and when the heating function is started, the on-off state of a switch in the charge pump is controlled, so that the charging and discharging between the power battery and the charge pump are realized.
And determining that the self-heating function needs to be started in the case that the temperature is lower than a preset temperature value. Referring to fig. 3, when the self-heating function is activated, the switches S4 and S5 are kept off, and the power battery is directly connected to the charge pump, so that the capacitor and the power battery are alternately charged and discharged by controlling the alternate on and off of S1, S3 and S2, and heat is generated. And when S1 and S3 are closed and S2 is opened, the two capacitors are connected in parallel, and the power battery discharges to the capacitors. When S1 and S3 are disconnected and S2 is closed, the two capacitors are connected in series and discharge to the power battery. The control circuit is repeatedly switched between the two states, and pulse current can be generated on the power battery.
If the circuit structure shown in fig. 4 is adopted, S5 and S6 need to be kept open and S4 needs to be closed when the self-heating function is started; with the circuit configuration shown in fig. 5, when the self-heating function is activated, S5 to S9 need to be kept open, and S4 needs to be closed. The remaining control method of the self-heating phase is identical to the implementation of fig. 3.
Step 604: and when the temperature of the power battery reaches the preset temperature value, closing the heating function and starting the DC/DC function.
After the temperature of the power battery reaches a preset temperature value, the working performance of the power battery is determined to be ensured, the power battery does not need to be heated any more, the heating function can be closed, and the DC/DC function is started.
Step 605: and when the DC/DC function is started, controlling the switch state of the switch in the charge pump and the switch state of the switch in the DC/DC isolation module so that the power supply capacitor provides isolation voltage for the high-voltage side of the DC/DC isolation module.
The specific implementation of the DC/DC function can be referred to the description of the relevant parts in the foregoing embodiment of the power system, and will not be repeated herein.
According to the control method of the power supply system, when the temperature of the power battery is low, the charge pump heating mode can be started, the charge pump is controlled by the power supply system controller to alternately charge and discharge so that the power battery can generate heat to realize self-heating, and in the DC/DC working mode, the capacitor in the charge pump is reused as the charging capacitor, so that the integrated charge pump and the DC/DC isolation module are formed, structural components and line connection of the system are reduced to a certain extent, and the overall volume and cost of the power supply system are reduced.
In one implementation, if there are two supply capacitors in the power supply system, the controlling the switch states of the switches in the charge pump and the switches in the DC/DC isolation module may include: controlling the switch state of a switch in the charge pump so as to enable the two power supply capacitors to be connected in series; and controlling the switch state of a switch in the DC/DC isolation module so that the two power supply capacitors alternately provide isolation voltages in different directions for the high-voltage side of the DC/DC isolation module.
In one implementation, the method includes that a power supply capacitor in a power supply system is one, a first voltage stabilizing switch and a second voltage stabilizing switch are arranged between the charge pump and the power battery, and the first voltage stabilizing switch and the second voltage stabilizing switch are arranged at the same pole of the power battery, and control a switching state of a switch in the charge pump and a switching state of a switch in the DC/DC isolation module, and the method may include: controlling the switching states of the first voltage stabilizing switch and the second voltage stabilizing switch and the switching state of a switch in the charge pump so as to enable the power supply capacitor to output a stable voltage; controlling a switch state of a switch in the DC/DC isolation module to cause the supply capacitor to provide an isolation voltage for a high voltage side of the DC/DC isolation module.
Specifically, controlling the switching states of the first voltage stabilizing switch and the second voltage stabilizing switch and the switching state of the switch in the charge pump so that the supply capacitor can output a stable voltage may include: under the condition that the isolation voltage is smaller than the voltage of the power battery, controlling a first voltage stabilizing switch to be closed, and enabling a power supply capacitor to output a stable voltage by controlling the switching frequency of a charging switch of the power supply capacitor in the charge pump; or, under the condition that the isolation voltage is greater than the voltage of the power battery, controlling a charging switch of the first voltage stabilizing switch and another non-power supply capacitor in the charge pump except the power supply capacitor to be closed so as to charge the non-power supply capacitor; the first voltage stabilizing switch and a charging switch of the non-power supply capacitor are controlled to be switched off, and the second voltage stabilizing switch and a switch of the power supply capacitor are controlled to be switched on, so that the power supply capacitor is charged; and the power supply capacitor can output stable voltage by alternately executing the frequency of the two states.
In other embodiments, the control method of the power supply system may further include, in addition to the above steps: acquiring an instantaneous acceleration or recovery braking energy instruction; and controlling to close the DC/DC function, and controlling the power supply capacitor of the charge pump to provide instant energy to realize instant acceleration, or controlling the power supply capacitor of the charge pump to absorb braking energy.
For a better understanding of the specific implementation, an exemplary implementation is given below:
fig. 7 is a schematic block diagram of a power supply system disclosed in the embodiment of the present invention, and fig. 8 is a complete implementation flowchart of a control method of the power supply system disclosed in the embodiment of the present invention. Referring to fig. 7, the connection relationship between the power system of the automobile and the power battery, the power system controller, the low-voltage electrical system and other key elements on the automobile is shown. The power System controller generally refers to a Battery Management System (BMS), and the power System controller monitors the operating states of the power Battery, such as voltage, current, temperature, and the like, in real time during the operation of the System, and sends a control signal to the power System according to the feedback information of the power Battery, and receives the feedback signal of the power System to control the activation and deactivation of the self-heating function of the charge pump and the DC/DC function. And the power battery is connected with the power supply system through a high-voltage relay. The isolated DC/DC can provide multiple isolated outputs, and the low-voltage side output can charge the low-voltage storage battery and supply power for the low-voltage electric system on the vehicle. In addition, the power supply system controller can also control the charge pump circuit to instantaneously release energy or absorb energy according to the running state of the vehicle, so as to control the instantaneous acceleration of the vehicle or recover the braking energy. The Vehicle driving state may be obtained from a Vehicle Control Unit (VCU).
Referring to fig. 8, in one specific implementation, a method for controlling a power supply system may include:
in step S1, before the vehicle is started, the operating state information such as the battery temperature is acquired.
And step S2, if the temperature of the battery is lower than the preset temperature value, starting a self-heating function of the charge pump, generating positive and negative pulse current on the power battery, and heating the battery by using the self internal resistance of the power battery.
And step S3, monitoring the battery voltage and current information at any time in the heating process, and stopping the self-heating process of the charge pump if the voltage and the current exceed the set safety threshold values. The specific implementation method comprises the following steps:
the method comprises the steps of presetting safe threshold values of working voltage and current of a power battery, reading voltage and current information of the power battery by a power system controller system at any time in the working process of the power battery, disconnecting S1, S2 and S3 in the figure 3 if the voltage and the current of the battery exceed the preset safe threshold values, disconnecting a high-voltage relay and stopping self-heating of the power battery.
And step S4, stopping the self-heating function of the charge pump when the temperature reaches a preset temperature value, and starting the DC/DC function to supply power for the low-voltage electrical system.
And step S5, if the vehicle needs to accelerate instantaneously or recover the braking energy in the running process, providing instantaneous energy or absorbing the braking energy through the charge pump energy storage element.
It should be noted that, during the implementation of step S5, the DC/DC function is suspended, and the low-voltage battery is used to store energy to supply power to the low-voltage electrical system. Specifically, in the process of starting or instantaneously accelerating the automobile, the vehicle controller collects an accelerator pedal signal and sends a corresponding signal to the power system controller, the power system controller controls the charge pump switch S2 to be closed, S1 and S3 are disconnected, the two capacitors are connected in series at two ends of the power battery to supply power to the outside, at the moment, the maximum discharge voltage can reach twice the voltage of the bus of the battery (S1 and S3 are closed, and when S2 is disconnected, the capacitors are firstly connected in parallel at two ends of the power battery to charge, the voltage on each capacitor after being fully charged is equal to the voltage of the bus of the battery, then S1 and S3 are disconnected, S2 is disconnected, the two capacitors are connected in series, the voltage at two ends of the series branch is twice the voltage of the bus of the battery), and if the conditions of the motor controller and the motor allow the instantaneous acceleration capability of the electric automobile to be greatly improved. After the acceleration process is completed, S2 is turned off, and the energy storage capacitor stops supplying power to the outside.
When the automobile runs downhill or brakes, the vehicle control unit collects a brake pedal signal, starts a regenerative braking process and sends a corresponding signal to the power supply system controller, the power supply system controller controls the charge pump switch S2 to be switched off, S1 and S3 to be switched on, and the two capacitors are connected in parallel at two ends of the power battery to store energy, so that the recovery of regenerative braking energy is realized. And (5) disconnecting S1 and S3 after braking is finished, and stopping the energy storage process. The scheme can avoid repeated charging of the lithium ion battery in the regenerative braking process, and can realize energy recovery under any SOC of the lithium ion battery.
Since the transient acceleration or braking process is short, the self-heating part and the isolation transformer part can be disconnected in the process (such as the disconnection of S4 and S5 in FIG. 3), and the required electric quantity of the low-voltage electric system is provided by the low-voltage storage battery. During the process of instantaneous acceleration or braking, the switching states of several switching tubes S1, S2 and S3 need to be switched, and when the DC/DC function is realized, the states of the switching tubes are fixed, taking FIG. 3 as an example, S1 and S3 are always open, S2 is always closed, and S4 and S5 are repeatedly turned on and off to realize the DC/DC function. If the connection is not broken during transient acceleration or braking, it may interfere with the system operation and even cause a hazard. For example, if S4 and S3 are conducted simultaneously, the two ends of the power battery are shorted by the paths formed by S2, S3 and S4, and a large current is generated instantaneously to cause fire. This is avoided by disconnecting the connection.
In the implementation, besides the functions of the charge pump heating, the DC/DC function and the like, the charge pump circuit can be controlled to instantaneously release energy or absorb energy according to the running state of the vehicle, so that the automobile is controlled to instantaneously accelerate or recover braking energy. Specifically, instantaneous acceleration energy is provided for the automobile through the energy storage capacitor or regenerative braking energy is recycled, the maximum amplification voltage in the instantaneous discharging stage can reach twice of the voltage of the power battery, and the damage to the power battery caused by frequent repeated charging can be avoided in the energy recycling stage. And the energy storage system (namely the capacitor) of the device is directly connected with the power battery, and energy recovery can be realized only by switching on and off part of switch tubes in the control circuit in the energy recovery stage so as to change the connection mode of the circuit, so that the control is simpler, the recovered energy can be timely stored in the capacitor, and the power battery cannot be damaged due to insufficient response.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
It is further noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in Random Access Memory (RAM), memory, Read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A power supply system, wherein the power supply system is a system for supplying power to a low-voltage electrical device system in an electric vehicle, and the power supply system comprises:
the charge pump comprises N charging capacitors, N is more than or equal to 2, at least one charging capacitor is used as a power supply capacitor of the DC/DC isolation module, and the charge pump is connected with a power battery and a power system controller of the electric automobile.
2. The power supply system of claim 1, wherein the two supply capacitors are connected in series when a DC/DC function is enabled, the two supply capacitors providing isolation voltages in different directions to the high voltage side of the DC/DC isolation module.
3. The power supply system according to claim 1, wherein the supply capacitor is one, a first voltage stabilizing switch and a second voltage stabilizing switch are arranged between the charge pump and the power battery, the first voltage stabilizing switch and the second voltage stabilizing switch are arranged on the same pole of the power battery, and the supply capacitor provides an isolation voltage for a high-voltage side of the DC/DC isolation module.
4. The power supply system of claim 3, wherein the circuit between the switches in the DC/DC isolation module forms a single-ended forward isolation circuit on the high-voltage side of the DC/DC isolation module; the input side of the single-ended forward isolation circuit is connected with the power supply capacitor, and the output side of the single-ended forward isolation circuit is connected with a primary side coil of a transformer in the DC/DC isolation module.
5. The power supply system of claim 3, wherein the circuits between the switches in the DC/DC isolation module form a full-bridge isolation circuit on the high-voltage side of the DC/DC isolation module, the input side of the full-bridge isolation circuit is connected to the supply capacitor, and the output side of the full-bridge isolation circuit is connected to the primary winding of the transformer in the DC/DC isolation module.
6. A control method of a power supply system is applied to a power supply system controller, the power supply system controller is positioned in a power system of an electric automobile, and the power system comprises the following steps: power supply system, power battery and power supply system controller, power supply system includes: the DC/DC isolation module comprises a charge pump and a DC/DC isolation module, wherein the charge pump comprises N charging capacitors, N is more than or equal to 2, at least one charging capacitor is used as a power supply capacitor of the DC/DC isolation module, and the charge pump is connected with the power battery and the power system controller; the DC/DC isolation module supplies power to a low-voltage electrical system; the method comprises the following steps:
acquiring the temperature of the power battery;
if the temperature of the power battery is lower than a preset temperature value, controlling to start a heating function;
when the heating function is started, the on-off state of a switch in the charge pump is controlled, and charging and discharging between the power battery and the charge pump are realized;
detecting that the temperature of the power battery reaches the preset temperature value, closing a heating function and starting a DC/DC function;
and when the DC/DC function is started, controlling the switch state of the switch in the charge pump and the switch state of the switch in the DC/DC isolation module so that the power supply capacitor provides isolation voltage for the high-voltage side of the DC/DC isolation module.
7. The control method of claim 6, wherein the supply capacitors are two, and controlling the switch states of the switches in the charge pump and the switches in the DC/DC isolation module comprises:
controlling the switch state of a switch in the charge pump so as to enable the two power supply capacitors to be connected in series;
and controlling the switch state of a switch in the DC/DC isolation module so that the two power supply capacitors alternately provide isolation voltages in different directions for the high-voltage side of the DC/DC isolation module.
8. The control method according to claim 6, wherein the supply capacitor is one, a first voltage stabilizing switch and a second voltage stabilizing switch are arranged between the charge pump and the power battery, the first voltage stabilizing switch and the second voltage stabilizing switch are arranged on the same pole of the power battery, and the control method controls the switch state of the switch in the charge pump and the switch state of the switch in the DC/DC isolation module, and comprises the following steps:
controlling the switching states of the first voltage stabilizing switch and the second voltage stabilizing switch and the switching state of a switch in the charge pump so as to enable the power supply capacitor to output a stable voltage;
controlling a switch state of a switch in the DC/DC isolation module to cause the supply capacitor to provide an isolation voltage for a high voltage side of the DC/DC isolation module.
9. The method of claim 8, wherein controlling the switching states of the first and second switches and the switch in the charge pump to enable the supply capacitor to output a stable voltage comprises:
under the condition that the isolation voltage is smaller than the voltage of the power battery, controlling a first voltage stabilizing switch to be closed, and enabling a power supply capacitor to output a stable voltage by controlling the switching frequency of a charging switch of the power supply capacitor in the charge pump;
or,
under the condition that the isolation voltage is greater than the voltage of the power battery, controlling a charging switch of the first voltage stabilizing switch and another non-power supply capacitor in the charge pump except the power supply capacitor to be closed so as to charge the non-power supply capacitor; the first voltage stabilizing switch and a charging switch of the non-power supply capacitor are controlled to be switched off, and the second voltage stabilizing switch and a switch of the power supply capacitor are controlled to be switched on, so that the power supply capacitor is charged; and the power supply capacitor can output stable voltage by alternately executing the frequency of the two states.
10. The control method according to any one of claims 6 to 9, characterized by further comprising:
acquiring an instantaneous acceleration or recovery braking energy instruction;
and controlling to close the DC/DC function, and controlling the power supply capacitor of the charge pump to provide instant energy to realize instant acceleration, or controlling the power supply capacitor of the charge pump to absorb braking energy.
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