A supercapacitor and battery hybrid power system and charging control method

Abstract

The present invention discloses a supercapacitor and battery hybrid power system and charging control method, belonging to the technical field of hybrid power systems. The system of the present invention includes: a supercapacitor array, a battery array, a parallel charging and discharging DC / DC converter, a supercapacitor parallel bus, and a battery parallel bus. The charging control method includes: a battery serial charging control method and a supercapacitor parallel charging control method. In the present invention, the supercapacitor provides burst power, and the battery mainly discharges at a constant current to supplement the power output of the supercapacitor, thereby preventing battery capacity decay caused by burst power and extending the battery life.

Description

Technical Field

[0001] The present invention relates to the technical field of hybrid power systems, and more particularly, to a supercapacitor and battery hybrid power system and a charging control method. Background Art

[0002] In recent years, the demand for fuel has continued to rise sharply, and air pollution has become increasingly serious. In particular, the amount of CO2 produced by automobile emissions has continued to increase, which has caused abnormal changes in the global climate. Energy depletion and environmental pollution have become problems that need to be urgently solved in today's society. The development of electric vehicles is the most direct and effective way to alleviate this problem. Although electric vehicles have obvious advantages in environmental protection, energy saving, and cleanliness, they also have many disadvantages. In a sense, the success or failure of electric vehicles depends first on battery technology.

[0003] Supercapacitors have the characteristics of high power density, high charge and discharge efficiency and long cycle life. They are suitable for repeated charging and discharging and high current charging and discharging, and can meet the sudden power requirements of electric vehicles such as starting, accelerating and climbing. However, there are currently problems with low single-cell capacity and large parameter discreteness. They cannot be directly operated in parallel. If balancing technology is not adopted, they cannot be operated in series, and it is difficult to form a large-capacity supercapacitor group.

[0004] Lithium batteries have a high energy density, allowing large numbers of individual cells to be connected in series or parallel to form large-capacity battery packs to meet the continuous power demands of electric vehicles. However, lithium batteries have the problem of reduced cycle life due to high current discharge. When lithium batteries are used in large quantities, due to the differences in cell capacity, the smallest cell will be discharged or fully charged first, which will limit the continued charging or discharging of other cells. To avoid this problem, active balancing technology must be adopted. Electric vehicles have a large number of lithium batteries. To simplify management, they are usually connected in parallel first and then in series. However, the terminal voltage of the batteries after parallel connection is the same, which limits the application of balancing technology to individual cells. Moreover, to avoid circulating currents after parallel connection, a complex battery screening process is required to connect batteries with consistent parameters in parallel. However, after long-term use, the capacity loss and shortened life caused by circulating currents cannot be avoided.

[0005] The existing technology is to connect supercapacitors (SC) in series to form a supercapacitor group, and lithium batteries in parallel and then in series to form a lithium battery group. There are two ways to connect the supercapacitor group and the lithium battery group: direct parallel connection and passive connection via inductor, and active connection via power converter. Direct parallel and passive connection methods have been eliminated. The Bat / UC structure, in which lithium batteries are connected in parallel with supercapacitors via power converters, is not conducive to continuous power output, while the UC / Bat structure, in which supercapacitors are connected in parallel with lithium batteries via power converters, is not conducive to sudden power output. Summary of the Invention

[0006] In order to solve the above problems, the present invention proposes a supercapacitor and battery hybrid power system, which includes:

[0007] Supercapacitor array, battery array, parallel charging and discharging DC / DC converter, supercapacitor parallel bus and battery parallel bus;

[0008] The supercapacitor array includes g×h supercapacitor units, wherein g is the number of rows of the supercapacitor array, h is the number of columns of the supercapacitor array, and g and h can be any integers;

[0009] The battery array includes i×j battery cells, wherein i is the number of rows of the battery array, j is the number of columns of the battery array, and i and j can be any integers;

[0010] The parallel charge and discharge DC / DC converter includes g supercapacitor ports and i battery ports, and is an isolated DC / DC converter with g+i output / input ports;

[0011] The supercapacitor ports of g parallel charge-discharge DC / DC converters are respectively connected to g supercapacitor parallel busbars, and each supercapacitor parallel busbar is connected to the parallel ports of h supercapacitor units in each row of the supercapacitor array;

[0012] The battery ports of i parallel charge and discharge DC / DC converters are respectively connected to i battery parallel bus bars, and each battery parallel bus bar is connected to the parallel ports of j battery units in each row of the battery array.

[0013] Optionally, the parallel charging and discharging DC / DC converter is composed of a bidirectional full-bridge phase-shifted DC / DC conversion circuit with g+i ports sharing a single magnetic circuit and a high-frequency transformer with g+i windings.

[0014] Optionally, the supercapacitor unit includes one serial port and one parallel port;

[0015] The serial ports of g supercapacitor units are connected in series to form a supercapacitor unit string, and h supercapacitor unit strings are connected in parallel to form the supercapacitor array.

[0016] Optionally, the supercapacitor unit includes one supercapacitor and one series-parallel conversion unit;

[0017] The series-parallel conversion unit includes a non-isolated DC / DC converter and a capacitor;

[0018] The non-isolated DC / DC converter in the supercapacitor unit includes one supercapacitor port and one bus port;

[0019] The two ends of the supercapacitor are connected to the supercapacitor port of the non-isolated DC / DC converter in the supercapacitor unit;

[0020] The two ends of the capacitor are connected to the bus port of the non-isolated DC / DC converter in the supercapacitor unit;

[0021] The two ends of the supercapacitor become the serial ports of the supercapacitor unit, and the bus port of the non-isolated DC / DC converter in the supercapacitor unit becomes the parallel port of the supercapacitor unit.

[0022] Optionally, the non-isolated DC / DC converter in the series-parallel conversion unit is a non-isolated Buck / Boost bidirectional half-bridge DC / DC converter.

[0023] Optionally, the battery unit includes one serial port and one parallel port;

[0024] The serial ports of i battery units are connected in series to form a battery unit string, and j battery units are connected in parallel to form the battery array;

[0025] The j battery cells are connected in series to a battery array serial charging circuit and then connected to a charger.

[0026] Optionally, the battery unit includes 1 battery and 1 series-parallel conversion unit;

[0027] The series-parallel conversion unit includes a non-isolated DC / DC converter and a capacitor;

[0028] The non-isolated DC / DC converter in the battery unit includes one battery port and one bus port;

[0029] The two ends of the battery are connected to the battery port of the non-isolated DC / DC converter in the battery unit;

[0030] The two ends of the capacitor are connected to the bus port of the non-isolated DC / DC converter in the battery unit;

[0031] The two ends of the battery become the serial ports of the battery unit, and the bus port of the non-isolated DC / DC converter in the battery unit becomes the parallel port of the battery unit.

[0032] Optionally, the non-isolated DC / DC converter in the series-parallel conversion unit is a non-isolated Buck / Boost bidirectional half-bridge DC / DC converter.

[0033] The present invention also proposes a control method for serially charging batteries in the above system, wherein the battery management system participates in the charging control, including:

[0034] S1. Start the supercapacitor and battery hybrid system. When the voltage U2 of the battery parallel bus reaches the initial working voltage U 02 Then, start the charger;

[0035] S2. The battery management system sets the serial charging current I of the charger to the battery array in the supercapacitor and battery hybrid system. TBa ;

[0036] S3. The battery management system sets the balancing current I of the battery port of the non-isolated DC / DC converter of each battery cell in the battery array of the supercapacitor and battery hybrid system. Ba ;

[0037] S4. Parallel charge and discharge DC / DC converters maintain the same voltage U2 for each battery parallel bus;

[0038] S5. If the average voltage of each battery parallel bus is U A2 Higher than the initial operating voltage U of the battery parallel bus 02 , the battery management system reduces the serial charging current I TBa ;

[0039] S6. If the average voltage of each battery parallel busbar is U A2 Lower than the initial operating voltage U of the battery parallel bus 02 , the battery management system increases the serial charging current I TBa .

[0040] Optionally, S2 to S6 can be operated cyclically or in parallel.

[0041] The present invention also proposes a control method for parallel charging of supercapacitors in the above-mentioned system. The system is placed in an electric vehicle, and the vehicle control system and battery management system of the electric vehicle participate in the charging control, including:

[0042] L1. Start the supercapacitor and battery hybrid system, and the voltage U1 of the supercapacitor parallel bus reaches the initial working voltage U 01 , the voltage U2 of the battery parallel bus reaches the initial working voltage U 02 ;

[0043] L2. The vehicle control system sets the parallel discharge current I of the battery port of the non-isolated DC / DC converter in each battery cell in the battery array. Ba, the parallel discharge current I of each battery port of the parallel charge and discharge DC / DC converter D1 , the parallel charging current I of the bus port of the non-isolated DC / DC converter in each supercapacitor unit in the supercapacitor array D2 The parallel charging current I of the supercapacitor port of the non-isolated DC / DC converter in each supercapacitor unit in the supercapacitor array SC ;

[0044] L3. The battery management system adjusts the parallel discharge current I of the battery port of the non-isolated DC / DC converter in each battery cell in the battery array. Ba ;

[0045] L4. Parallel charging and discharging DC / DC converters maintain the parallel bus voltage U2 of each battery constant at U 02 , maintain the same voltage U1 of each supercapacitor parallel bus;

[0046] L5. The battery management system adjusts the parallel charging current I of the supercapacitor port of the non-isolated DC / DC converter in each supercapacitor unit in the supercapacitor array. SC ;

[0047] L6. If the average voltage of each supercapacitor parallel bus is U A1 Lower than the initial working voltage U of the supercapacitor parallel bus 01 The vehicle control system increases the parallel discharge current I of the battery port of the non-isolated DC / DC converter in each battery cell in the battery array. Ba , and according to I Ba Adjustment I D1 , I D2 and I SC ;

[0048] L7. If the average voltage of each supercapacitor parallel bus is U A1 Higher than the initial working voltage U of the supercapacitor parallel bus 01 The vehicle control system reduces the parallel discharge current I of the battery port of the non-isolated DC / DC converter in each battery unit in the battery array. Ba , and according to I Ba Adjustment I D1 , I D2 and I SC .

[0049] Optionally, L2 to L7 can be operated cyclically or in parallel.

[0050] Optionally, the vehicle control system in L2 sets the parallel discharge current I of the battery port of the non-isolated DC / DC converter in each battery unit in the battery array.Ba , specifically including:

[0051] M1. The vehicle control system sets the parallel discharge current I of the battery port of the non-isolated DC / DC converter in each battery cell in the battery array. Ba The initial value of

[0052] M2. If the state of charge of the supercapacitor array is C SC In C SC1 ≥C SC ≥C SC2 , I Ba is a constant value;

[0053] M3. If C SC In C SC <C SC2 , I Ba C SC In C SC1 ≥C SC ≥C SC2 The fixed increment gradually increases based on the constant value at the time;

[0054] M4. If C SC In C SC >C SC1 , I Ba C SC In C SC1 ≥C SC ≥C SC2 The fixed increment gradually decreases based on the constant value at the time;

[0055] M5. If C SC In C SC <C SC2 or C SC >C SC1 After that, restore to C SC In C SC1 ≥C SC ≥C SC2 When C SC =C SC1 or C SC =C SC2 The current value I Ba , as the new C SC In C SC1 ≥C SC ≥C SC2 constant value when .

[0056] Among them, C SC1 and C SC2 There are two gears of the state of charge of the supercapacitor array, and C SC1 >C SC2 .

[0057] Optionally, M2 to M5 can be operated cyclically or in parallel.

[0058] This invention uses supercapacitors to provide short-term, sudden power needs for electric vehicles, such as starting, accelerating, and climbing. It also absorbs and stores energy recovered during deceleration, braking, and braking, while using batteries to provide stable, continuous power. The battery discharge current uses a constant value or a constant, incremental value based on a constant value, mitigating battery capacity degradation caused by short-term, sudden power needs and extending the battery's service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 This is a structural diagram of a supercapacitor and battery hybrid power system of the present invention;

[0060] Figure 2 Schematic diagram of external connections of a parallel charge and discharge DC / DC converter according to a first embodiment of the present invention;

[0061] Figure 3 1 is a structural diagram of a parallel charge and discharge DC / DC converter according to a first embodiment of the present invention;

[0062] Figure 4 A structural diagram of a supercapacitor unit according to a first embodiment of the present invention;

[0063] Figure 5 is a structural diagram of a battery unit according to a first embodiment of the present invention;

[0064] Figure 6 A structural diagram of a supercapacitor and battery hybrid system according to a second embodiment of the present invention;

[0065] Figure 7 A structural diagram of a control system for serial charging of batteries in a supercapacitor and battery hybrid system according to a third embodiment of the present invention;

[0066] Figure 8 A flowchart of a process for serially charging batteries of a supercapacitor and battery hybrid system according to a third embodiment of the present invention;

[0067] Figure 9 A structural diagram of a control system for parallel charging of supercapacitors of a hybrid system of supercapacitors and batteries for electric vehicles according to a fourth embodiment of the present invention;

[0068] Figure 10 A flowchart of a program for setting the parallel discharge current of the battery ports of the non-isolated DC / DC converters in the battery array for a vehicle control system according to a fourth embodiment of the present invention;

[0069] Figure 11 A flowchart of a process for parallel charging of supercapacitors of a supercapacitor and battery hybrid system according to a fourth embodiment of the present invention;

[0070] Among them: 101 is a supercapacitor array; 102 is a battery array; 103 is a supercapacitor unit; 104 is a battery unit; 105 is a supercapacitor array serial discharge circuit; 106 is a battery array serial charging circuit; 107 is an electrical load; 108 is a charger; 109 is a parallel charge and discharge DC / DC converter; 111 is a supercapacitor parallel bus; 112 is a battery parallel bus; 113 is a supercapacitor; 114 is a battery; 115 is a series-parallel conversion unit; 116 is a non-isolated DC / DC converter; 117 is a capacitor. DETAILED DESCRIPTION

[0071] Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to provide a thorough and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments shown in the accompanying drawings is not intended to limit the present invention. In the accompanying drawings, identical elements are denoted by the same reference numerals.

[0072] Unless otherwise specified, the terms used herein (including technical terms) have the meanings commonly understood by those skilled in the art. In addition, it is understood that terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0073] The present invention provides a supercapacitor and battery hybrid power system, such as Figure 1 Shown, including:

[0074] Supercapacitor array, battery array, parallel charging and discharging DC / DC converter, supercapacitor parallel bus and battery parallel bus;

[0075] The supercapacitor array includes g×h supercapacitor units, wherein g is the number of rows of the supercapacitor array, h is the number of columns of the supercapacitor array, and g and h can be any integers;

[0076] The battery array includes i×j battery cells, wherein i is the number of rows of the battery array, and j is the number of columns of the battery array. i and j can be any integers;

[0077] The parallel charge and discharge DC / DC converter includes g supercapacitor ports and i battery ports, and is an isolated DC / DC converter with g+i output / input ports;

[0078] The supercapacitor ports of g parallel charge-discharge DC / DC converters are respectively connected to g supercapacitor parallel busbars, and each supercapacitor parallel busbar is connected to the parallel ports of h supercapacitor units in each row of the supercapacitor array;

[0079] The battery ports of i parallel charging and discharging DC / DC converters are respectively connected to i battery parallel bus bars, and each battery parallel bus bar is connected to the parallel ports of j battery units in each row of the battery array.

[0080] The parallel charging and discharging DC / DC converter is composed of a bidirectional full-bridge phase-shifted DC / DC conversion circuit with g+i ports sharing a single magnetic circuit and a high-frequency transformer with g+i windings.

[0081] The specific implementation is as follows:

[0082] Supercapacitor array 101 , battery array 102 , supercapacitor array serial discharge circuit 105 , battery array serial charge circuit 106 , parallel charge and discharge DC / DC converter 109 .

[0083] Supercapacitor array 101 is composed of g × h (rows × columns) supercapacitor units 103, where g and h can be arbitrary integers. Each supercapacitor unit includes one serial port and one parallel port. The serial ports of g supercapacitor units 103 are first connected in series to form a supercapacitor unit string, and the h supercapacitor unit strings are then connected in parallel to form supercapacitor array 101.

[0084] Battery array 102 consists of i×j (rows×columns) battery cells 104, where i and j can be arbitrary integers. Each battery cell includes one serial port and one parallel port. The serial ports of i battery cells 104 are first connected in series to form a battery cell string, and j battery cell strings are then connected in parallel to form battery array 102.

[0085] In addition to electric vehicles, the hybrid system of supercapacitors and batteries can also be used in other power systems that need to meet short-term, sudden power demands. The h parallel supercapacitor cells in supercapacitor array 101 are connected in series to a supercapacitor array serial discharge circuit 105, which is then connected to a power load 107, which in an electric vehicle is the drive motor controller. The j parallel battery cells in battery array 102 are connected in series to a battery array serial charging circuit 106, which is then connected to a charger 108, which in an electric vehicle can be an onboard charger or an off-board charger using a conductive charging port.

[0086] Since the parallel charge and discharge DC / DC converter 109 is a multi-port isolated DC / DC converter, the number of rows g of the supercapacitor array 101 may not be equal to the number of rows i of the battery array 102; the number of columns h of the supercapacitor array 101 may not be equal to the number of columns j of the battery array 102; the total capacity of the supercapacitor array 101 may not be equal to the total capacity of the battery array 102; and the output voltage of the supercapacitor array 101 may not be equal to the output voltage of the battery array 102.

[0087] It is recommended that supercapacitors use double-layer supercapacitors with optimal charge and discharge power performance; it is recommended that batteries use lithium-ion batteries, but various electrochemical batteries such as lead-carbon, sodium-sulfur, and sodium-nickel can also be used; in order to simplify the complexity of the control strategy, it is recommended that the supercapacitors in the supercapacitor array 101 be of the same model, and it is recommended that the batteries in the battery array 102 be of the same model.

[0088] The non-isolated DC / DC converter in the supercapacitor unit and the non-isolated DC / DC converter in the battery unit are both non-isolated Buck / Boost bidirectional half-bridge DC / DC converters.

[0089] The parallel charging and discharging DC / DC converter is composed of a bidirectional full-bridge phase-shifted DC / DC conversion circuit with g+i ports sharing a single magnetic circuit and a high-frequency transformer with g+i windings.

[0090] The system of the present invention also proposes a control method for serial charging of batteries in a supercapacitor and battery hybrid system, in which the battery management system participates in the charging control;

[0091] The method comprises the following steps:

[0092] S1. The supercapacitor and battery hybrid system is turned on, and the voltage U2 of the battery parallel bus reaches the initial operating voltage U 02 , the charger is turned on;

[0093] S2. The battery management system sets the serial charging current I of the charger to the battery array. TBa ;

[0094] S3. The battery management system sets the balancing current I of the battery port of the non-isolated DC / DC converter in each battery cell in the battery array. Ba ;

[0095] S4. Parallel charge and discharge DC / DC converters maintain the same voltage U2 for each battery parallel bus;

[0096] S5. If the average voltage of each battery parallel bus is UA2 Higher than the initial operating voltage U of the battery parallel bus 02 , the battery management system reduces the serial charging current I TBa ;

[0097] S6. If the average voltage of each battery parallel busbar is U A2 Lower than the initial operating voltage U of the battery parallel bus 02 , the battery management system increases the serial charging current I TBa ;

[0098] Steps S2 to S6 are executed in a loop or in parallel.

[0099] The system of the present invention is applied to electric vehicles and a control method for parallel charging of supercapacitors in a hybrid system of supercapacitors and batteries for electric vehicles is also proposed. The vehicle control system and battery management system participate in the charging control.

[0100] The steps include:

[0101] L1. The supercapacitor and battery hybrid system is turned on, and the voltage U1 of the supercapacitor parallel bus reaches the initial operating voltage U 01 , the voltage U2 of the battery parallel bus reaches the initial working voltage U 02 ;

[0102] L2. The vehicle control system sets the parallel discharge current I of the battery port of the non-isolated DC / DC converter in each battery cell in the battery array. Ba , the parallel discharge current I of each battery port of the parallel charge and discharge DC / DC converter D1 , the parallel charging current I of the bus port of the non-isolated DC / DC converter in each supercapacitor unit in the supercapacitor array D2 The parallel charging current I of the supercapacitor port of the non-isolated DC / DC converter in each supercapacitor unit in the supercapacitor array SC ;

[0103] L3. The battery management system adjusts the parallel discharge current I of the battery port of the non-isolated DC / DC converter in each battery cell in the battery array. Ba ;

[0104] L4. Parallel charging and discharging DC / DC converters maintain the parallel bus voltage U2 of each battery constant at U 02 , maintain the same voltage U1 of each supercapacitor parallel bus;

[0105] L5. The battery management system adjusts the parallel charging current I of the supercapacitor port of the non-isolated DC / DC converter in each supercapacitor unit in the supercapacitor array. SC ;

[0106] L6. If the average voltage of each supercapacitor parallel bus is U A1 Lower than the initial working voltage U of the supercapacitor parallel bus 01 The vehicle control system increases the parallel discharge current I of the battery port of the non-isolated DC / DC converter in each battery cell in the battery array. Ba , and according to I Ba Adjustment I D1 , I D2 and I SC ;

[0107] L7. If the average voltage of each supercapacitor parallel bus is U A1 Higher than the initial working voltage U of the supercapacitor parallel bus 01 The vehicle control system reduces the parallel discharge current I of the battery port of the non-isolated DC / DC converter in each battery unit in the battery array. Ba , and according to I Ba Adjustment I D1 , I D2 and I SC ;

[0108] Steps L2 to L7 are executed cyclically or in parallel.

[0109] In step L2, the vehicle control system sets the parallel discharge current I of the battery port of the non-isolated DC / DC converter in each battery unit in the battery array. Ba , including the following steps:

[0110] M1. The vehicle control system sets the parallel discharge current I of the battery port of the non-isolated DC / DC converter in each battery cell in the battery array. Ba The initial value of

[0111] M2. If the state of charge of the supercapacitor array is C SC In C SC1 ≥C SC ≥C SC2 , I Ba is a constant value;

[0112] M3. If C SC In C SC <C SC2 , I Ba C SC In C SC1 ≥C SC≥C SC2 The fixed increment gradually increases based on the constant value at the time;

[0113] M4. If C SC In C SC >C SC1 , I Ba C SC In C SC1 ≥C SC ≥C SC2 The fixed increment gradually decreases based on the constant value when

[0114] M5. If C SC In C SC <C SC2 or C SC >C SC1 After that, restore to C SC In C SC1 ≥C SC ≥C SC2 When C SC =C SC1 or C SC =C SC2 The current value I Ba , as the new C SC In C SC1 ≥C SC ≥C SC2 Constant value when

[0115] Steps M2 to M5 are executed cyclically or in parallel;

[0116] Among them, C SC1 and C SC2 There are two gears for the state of charge of the supercapacitor array, C SC1 >C SC2 .

[0117] Figure 2 FIG. 1 is a schematic diagram of external connections of a parallel charge and discharge DC / DC converter according to a first embodiment of the present invention. Figure 2 As shown, the parallel charge and discharge DC / DC converter 109 has g supercapacitor charging ports and i battery discharging ports.

[0118] The positive and negative busbars of the supercapacitor parallel busbars 111 extend from the positive and negative ends of each supercapacitor charging port; the positive and negative busbars of each pair of supercapacitor parallel busbars 111 are respectively connected to the positive and negative ends of the parallel ports of the h supercapacitor units 103 in each row of the supercapacitor array 101. Figure 2 They are SC1+, SC2+ to SCg+ and SC1-, SC2- to SCg- respectively.

[0119] The positive and negative busbars of the battery parallel busbar 112 extend from the positive and negative ends of each battery discharge port; the positive and negative busbars of each pair of battery parallel busbars 112 are respectively connected to the positive and negative ends of the parallel ports of j battery cells 104 in each row of the battery array 102. Figure 2 They are Ba1+, Ba2+ to Bai+ and Ba1-, Ba2- to Bai- respectively.

[0120] Figure 3 FIG is a structural diagram of a parallel charge and discharge DC / DC converter according to a first embodiment of the present invention. Figure 3 As shown, the parallel charge and discharge DC / DC converter 109 is an isolated DC / DC converter with g+i output / input ports, and is composed of a bidirectional full-bridge phase-shifted DC / DC conversion circuit with g+i ports sharing a single magnetic circuit and a high-frequency transformer with g+i windings.

[0121] Since the capacitor 117 is connected in parallel between the supercapacitor parallel bus 111 and the battery parallel bus 112 , the parallel charge and discharge DC / DC converter 109 is a voltage source bidirectional DC / DC converter.

[0122] Figure 4 FIG. 1 is a structural diagram of a supercapacitor unit according to a first embodiment of the present invention. Figure 4 As shown, supercapacitor unit 103 includes supercapacitor 113 and series-parallel conversion unit 115. Series-parallel conversion unit 115 includes non-isolated DC / DC converter 116 and capacitor 117. Non-isolated DC / DC converter 116 includes one supercapacitor port and one bus port. Non-isolated DC / DC converter 116 is a non-isolated Buck / Boost bidirectional half-bridge DC / DC converter.

[0123] The two ends of the supercapacitor 113 are connected to the supercapacitor ports of the non-isolated DC / DC converter 116 in the series-parallel conversion unit 115; the two ends of the capacitor 117 are connected to the bus ports of the non-isolated DC / DC converter 116 in the series-parallel conversion unit 115; the two ends of the supercapacitor 113 become the serial ports of the supercapacitor unit 103, and the bus ports of the non-isolated DC / DC converter 116 in the series-parallel conversion unit 115 become the parallel ports of the supercapacitor unit 103.

[0124] It is recommended that the supercapacitor 113 be a double-layer supercapacitor, and the capacitor 117 be an electrolytic capacitor. The capacity of the capacitor is recommended to be determined based on the capacity of the supercapacitor and the performance of the hybrid system. The capacity of the capacitor 117 is recommended to be 3% to 5% of the capacity of the supercapacitor 113.

[0125] Figure 5FIG. 1 is a structural diagram of a battery unit according to a first embodiment of the present invention, Figure 5 As shown, battery unit 104 includes a battery 114 and a series-parallel conversion unit 115. Series-parallel conversion unit 115 includes a non-isolated DC / DC converter 116 and a capacitor 117. Non-isolated DC / DC converter 116 includes one supercapacitor port and one bus port. Non-isolated DC / DC converter 113 is a non-isolated Buck / Boost bidirectional half-bridge DC / DC converter.

[0126] The two ends of the battery 114 are connected to the battery ports of the non-isolated DC / DC converter 116 in the series-parallel conversion unit 115; the two ends of the capacitor 117 are connected to the bus ports of the non-isolated DC / DC converter 116 in the series-parallel conversion unit 115; the two ends of the battery 114 become the serial ports of the battery unit 104, and the bus ports of the non-isolated DC / DC converter 116 in the series-parallel conversion unit 115 become the parallel ports of the battery unit 104.

[0127] The electrical structure of the series-parallel conversion unit 115 in the supercapacitor unit 103 is the same as that of the series-parallel conversion unit 115 in the battery unit 104 , but the internal electrical parameters of the two series-parallel conversion units need to be related to the electrical design of the hybrid system.

[0128] Figure 6 FIG. 1 is a structural diagram of a supercapacitor and battery hybrid system according to a second embodiment of the present invention, as shown in FIG. Figure 6 As shown, Figure 1 The illustrated ultracapacitor and battery hybrid system can also serve as a subsystem of a larger hybrid system. Ultracapacitor subarrays 101 are connected in series to form a larger ultracapacitor array; battery subarrays 102 are connected in series to form an even larger battery array. All ultracapacitor subarrays 101 are connected in series to an ultracapacitor array serial discharge circuit 105, which is then connected to an electrical load 107. All battery subarrays 102 are connected in series to a battery array serial charging circuit 106, which is then connected to a charger 108.

[0129] Figure 7 This diagram shows the structure of a control system for serial battery charging in a supercapacitor and battery hybrid system according to a third embodiment of the present invention. Serial battery charging is a key operating objective of the hybrid system and includes parallel balancing of the batteries within the hybrid system. The serial battery charging system for the supercapacitor and battery hybrid system includes a battery array 102, a battery array serial charging circuit 106, a charger 108, a battery parallel bus 112, a parallel charging and discharging DC / DC converter 109, and a battery management system.

[0130] like Figure 7 As shown in the control system structure diagram, the meaning of each component unit is as follows: 108 link - charger; 114 link - battery; 116 link - non-isolated DC / DC converter in the battery unit; 109 link - parallel charging and discharging DC / DC converter; BMS link - battery management system; comparison point 2: battery port of the non-isolated DC / DC converter in the battery unit; comparison point U2: capacitor of the series-parallel conversion unit in the battery unit, the voltage across the capacitor is the battery parallel bus voltage U2.

[0131] Description of the control system structure diagram:

[0132] When the supercapacitor and battery hybrid system is started, the voltage U2 of each battery parallel bus 112 connected to the i battery discharge ports of the parallel charge and discharge DC / DC converter 109 reaches the initial working voltage U 02 After that, the hybrid system starts to work with the participation of the battery management system. The initial working voltage U 02 , it is recommended to be in the optimal operating point with the highest efficiency of the hybrid system.

[0133] exist Figure 7 In the embodiment, the charger 108 is controlled by the battery management system, and the battery array 102 is serially charged through the battery array serial charging circuit 106. The serial charging current is I TBa The non-isolated DC / DC converter 116 in the battery array 102, under the control of the battery management system, inputs (or outputs) a balancing current I from the battery 114 according to the balancing state of each battery. Ba and outputs a current I to the battery parallel bus 112 (or inputs a current I from the battery parallel bus 112). EBa Since the capacitor 117 is connected in parallel between the battery parallel bus 112, the non-isolated DC / DC converter 116 outputs (or inputs) a current I to the battery parallel bus 112. EBa After that, the voltage U2 of the battery parallel bus 112 will increase (or decrease).

[0134] After the hybrid system is started, the parallel charge and discharge DC / DC converter 109 maintains the voltage U2 of each battery parallel bus 112 to be the same, so as to achieve voltage balance and consistency of each battery parallel bus. A2 After that, the parallel charge and discharge DC / DC converter 109 inputs current from the battery parallel bus through the battery port to reduce the voltage of the battery parallel bus; when the voltage of a battery parallel bus is lower than the average voltage UA2 Afterwards, the parallel charge and discharge DC / DC converter 109 outputs current to the battery parallel bus 112 through the battery port, thereby increasing the voltage of the battery parallel bus.

[0135] The parallel charge and discharge DC / DC converter 109 achieves the balance of input and output power of each battery port through a transformer with a single magnetic circuit and i windings shared by the DC / DC conversion circuits of i ports, thereby maintaining the voltage U2 of each battery parallel bus balanced and consistent.

[0136] During the battery charging process, the capacity C of each battery in the battery array 102 is Ba Unbalanced, in the later stage of battery charging, individual batteries in the battery array have a unified serial charging current I TBa Under the action of the battery, the battery will reach the fully charged state in advance. The battery management system adjusts the balancing current I of each battery according to the state of charge (SOC) of each battery. Ba , so that all batteries in the battery array 102 are fully charged at the same time. When the battery capacity is small and the charging speed needs to be slowed down, the non-isolated DC / DC converter 116 inputs current from the battery 114, Figure 5 I in Ba Is positive, the actual charging current of the battery I RBa When the battery capacity is large and the charging speed needs to be accelerated, the non-isolated DC / DC converter 116 outputs current to the battery 114, Figure 5 I in Ba is negative, the actual charging current of the battery I RBa Increase. It can be expressed by formula (1):

[0137] I RBa =I TBa -I Ba (1)

[0138] Where: I RBa is the actual charging current of the battery, I TBa is the serial charging current of the battery, I Ba is the balancing current of the battery.

[0139] At the end of battery charging, all batteries are about to reach a fully charged state. In order to prevent the charging current from exceeding the battery's tolerance, the actual charging current I of the battery needs to be reduced. RBa If the algorithm of the battery management system causes the balanced current I Ba Increase, resulting in the average voltage U of each battery parallel bus A2 Higher than the initial working voltage U02 , the battery management system reduces the serial charging current I TBa , thereby reducing the actual battery charging current I RBa purpose.

[0140] In the early stage of battery charging, the battery management system tends to increase the actual charging current I of the battery within the range permitted by the battery's tolerance. RBa If the algorithm of the battery management system causes each non-isolated DC / DC converter 116 in the battery array 102 to output a balancing current I Ba Increase, resulting in the average voltage U of each battery parallel bus A2 Lower than the initial operating voltage U 02 , the battery management system increases the serial charging current I of the battery array 102 TBa , thereby increasing the actual charging current I RBa purpose.

[0141] Figure 8 A flowchart of a process for serially charging batteries of a supercapacitor and battery hybrid system according to a third embodiment of the present invention is shown in FIG. Figure 8 As shown, battery serial charging includes the following steps:

[0142] S1. The supercapacitor and battery hybrid system is turned on, and the voltage U2 of the battery parallel bus reaches the initial operating voltage U 02 , the charger is turned on;

[0143] S2. The battery management system sets the serial charging current I of the charger to the battery array. TBa ;

[0144] S3. The battery management system actively balances each battery in the battery array and sets the battery balancing current I of the battery port of the non-isolated DC / DC converter in each battery unit in the battery array. Ba ;

[0145] S4. Parallel charge and discharge DC / DC converters maintain the same voltage U2 for each battery parallel bus;

[0146] S5. If the average voltage of each battery parallel bus is U A2 Higher than the initial operating voltage U of the battery parallel bus 02 , the battery management system reduces the serial charging current I TBa ;

[0147] S6. If the average voltage of each battery parallel busbar is U A2 Lower than the initial operating voltage U of the battery parallel bus02 , the battery management system increases the serial charging current I TBa .

[0148] Steps S2 to S6 are executed in a loop or in parallel.

[0149] Figure 9 This is a structural diagram of a control system for parallel charging of supercapacitors in a hybrid system of supercapacitors and batteries for electric vehicles according to a fourth embodiment of the present invention. Parallel charging of supercapacitors is the operating purpose of the hybrid system, including parallel discharge of batteries within the hybrid system. The battery parallel charging system of the hybrid system of supercapacitors and batteries includes: a supercapacitor array 101, a battery array 102, a supercapacitor parallel bus 111, a battery parallel bus 112, a parallel charging and discharging DC / DC converter 109, a supercapacitor array serial discharge circuit 105, an electrical load 107 (a drive motor controller in an electric vehicle), a vehicle control system, and a battery management system.

[0150] like Figure 9 As shown in the figure, the meaning of each component unit in the control system structure diagram is as follows: 114 link - battery; Ba116 link - non-isolated DC / DC converter in the battery unit; 109 link - parallel charge and discharge DC / DC converter; SC116 link - non-isolated DC / DC converter in the supercapacitor unit; 107 link - drive motor controller of the electric vehicle; 113 link - supercapacitor; VCS link - vehicle control system; BMS link - battery management system; comparison point 1: supercapacitor port of the non-isolated DC / DC converter in the supercapacitor unit; comparison point U1: capacitor of the series-parallel conversion unit in the supercapacitor unit, the voltage across the capacitor is the supercapacitor parallel bus voltage U1; comparison point U2: capacitor of the series-parallel conversion unit in the battery unit, the voltage across the capacitor is the battery parallel bus voltage U2.

[0151] Description of the control system structure diagram:

[0152] When the supercapacitor and battery hybrid system is started, the voltage U1 of each supercapacitor parallel bus 111 connected to the g supercapacitor ports of the parallel charging and discharging DC / DC converter 109 reaches the initial working voltage U 01 , the voltage U2 of each battery parallel bus 112 connected to the i battery ports of the parallel charge and discharge DC / DC converter 109 reaches the initial working voltage U 02 After that, the hybrid system starts to work with the participation of the vehicle control system and the battery management system. The initial working voltage U 01 The initial operating voltage U of the battery parallel bus 11202 , it is recommended to be at the optimal operating point for the highest hybrid system efficiency. After the electric vehicle is running, the supercapacitor array 101 outputs power to the drive motor controller through the supercapacitor array serial discharge circuit 105 to drive the vehicle. When the electric vehicle decelerates, brakes, or applies the brake, the drive motor controller sends the recovered energy back to the supercapacitor array 101 through the supercapacitor array serial discharge circuit 105.

[0153] exist Figure 9 In the process, the non-isolated DC / DC converter 116 in the battery array 102 is controlled by the vehicle control system, and the parallel discharge current I Ba , obtains energy from the battery 114, and inputs the energy output by the battery into the battery parallel bus 112; the parallel charge and discharge DC / DC converter 109 inputs the parallel discharge current I through the battery port under the control of the vehicle control system. D1 , obtains energy from the battery parallel bus 112. At the same time, the parallel charge and discharge DC / DC converter transfers the energy on the battery parallel bus 112 to the supercapacitor parallel bus 111 through the supercapacitor port. The non-isolated DC / DC converter 116 in the supercapacitor array 101, under the control of the vehicle control system, passes the parallel charging current I D2 Energy is obtained from the supercapacitor parallel bus 111, and the parallel charging current I SC The energy on the supercapacitor parallel bus 111 is input into the supercapacitor 115 .

[0154] The parallel discharge current I of the battery port of the non-isolated DC / DC converter 116 in the battery array 102 Ba , the parallel discharge current I of the battery port of the parallel charge and discharge DC / DC converter 109 D1 , the parallel charging current I of the bus port of the non-isolated DC / DC converter 116 in the supercapacitor array 101 D2 and the parallel charging current I of the supercapacitor port of the non-isolated DC / DC converter 116 in the supercapacitor array 101 UC After the electric vehicle is running, it is controlled by the vehicle control system; during the battery discharge process, in order to make each battery in the battery array 102 reach the discharge cut-off state at the same time, during the supercapacitor discharge process, in order to make each supercapacitor in the supercapacitor array 101 reach the discharge cut-off state at the same time, I Ba and I SC It is also controlled by the battery management system.

[0155] The parallel discharge current I of each battery set by the vehicle control system BaThe vehicle control system sets the parallel discharge current I of each battery parallel busbar. D1 The parallel charging current I of each supercapacitor unit set by the vehicle control system is the same. D2 The parallel charging current I of each supercapacitor set by the vehicle control system is the same. UC are the same; however, the battery management system actively balances each battery in the battery array, and the I Ba Added battery management system adjustment increment I MBa Afterwards, each I Ba Become different; the battery management system actively balances each supercapacitor in the supercapacitor array, and SC Added battery management system adjustment increment I MSC Afterwards, each I SC Become different.

[0156] The initial current I when the electric vehicle starts running Ba , I D1 , I D2 and I SC The following relationship exists, which can be expressed by equations (2), (3) and (4):

[0157] i·j·U Ba I Ba =η1·i·U2·I D1 (2)

[0158] Where: i is the number of rows of the battery array, j is the number of columns of the battery array, U Ba is the battery port voltage of the non-isolated DC / DC converter in the battery array, I Ba is the parallel discharge current of the battery port of the non-isolated DC / DC converter in the battery array, η1 is the efficiency conversion coefficient of the non-isolated DC / DC converter in the battery array, U2 is the parallel bus voltage of the battery, I D1 It is the parallel discharge current of the battery port of the parallel charge and discharge DC / DC converter.

[0159] i·U2·I D1 =η2·g·h·U1·I D2 (3)

[0160] Where: i is the number of rows in the battery array, U2 is the parallel bus voltage of the battery, I D1 is the parallel discharge current of the battery port of the parallel charge and discharge DC / DC converter, η2 is the efficiency conversion coefficient of the parallel charge and discharge DC / DC converter, g is the number of rows of the supercapacitor array, h is the number of columns of the supercapacitor array, U1 is the supercapacitor parallel bus voltage, ID2 is the parallel charging current of the bus port of the non-isolated DC / DC converter in the supercapacitor array.

[0161] U1·I D2 =η3·U SC I SC (4)

[0162] Where: U1 is the supercapacitor parallel bus voltage, I D2 is the parallel charging current of the bus port of the non-isolated DC / DC converter in the supercapacitor array; η3 is the efficiency conversion coefficient of the non-isolated DC / DC converter in the supercapacitor array, U SC is the supercapacitor port voltage of the non-isolated DC / DC converter in the supercapacitor array, I SC is the parallel charging current of the supercapacitor ports of the non-isolated DC / DC converter in the supercapacitor array.

[0163] Figure 10 The flowchart of the program for setting the parallel discharge current of the battery port of the non-isolated DC / DC converter in the battery array according to the fourth embodiment of the vehicle control system of the present invention is as follows. Figure 10 As shown in the figure, when the electric vehicle starts to drive, the vehicle control system sets the parallel discharge current I of the battery port of the non-isolated DC / DC converter in the battery array according to the historical data of the electric vehicle's driving route and the driving data of similar electric vehicles on the same route. Ba The initial value of Figure 10 Middle I Ba The initial value is I Ba0 , and based on I Ba and formulas (2), (3) and (4), set I D1 , I D2 and I SC .

[0164] After the electric vehicle is running, in order to extend the service life of the battery in the battery array, the vehicle control system sets the parallel discharge current I Ba It is a constant value or a fixed incremental value based on a constant value. Figure 10 Middle I Ba The constant value is I CBa , I Ba The fixed increment gradient value based on the constant value of I CBa ±δΔt, using the following control method:

[0165] The state of charge (SOC) of the supercapacitor array in electric vehicles is divided into two levels: charging target state C SC1 and accelerated charging state CSC2 The optimal state of charge of an electric vehicle before starting and while driving is the target state of charge. Since energy needs to be recovered during deceleration, braking, and braking, C SC1 Not too large; C SC1 and C SC2 It should be formulated according to the capacity of the supercapacitor, the capacity of the battery and the performance of the hybrid system, such as C SC1 85% SOC, C SC2 It is 60% SOC.

[0166] If the state of charge C of the supercapacitor array in the electric vehicle SC In C SC1 ≥C SC ≥C SC2 , the battery is in constant current charging state, Figure 10 Middle I Ba is a constant value I CBa If C SC In C SC <C SC2 , I Ba C SC In C SC1 ≥C SC ≥C SC2 The fixed increment gradually increases based on the constant value when Figure 10 Middle I Ba For I CBa +δΔt (where δ is the fixed increment gradient coefficient, which is a constant, and Δt is C SC In C SC <C SC2 duration of time); if C SC In C SC >C SC1 , I Ba C SC In C SC1 ≥C SC ≥C SC2 The fixed increment gradually decreases based on the constant value when Figure 10 Middle I Ba For I CBa -δΔt (where δ is the fixed increment gradient coefficient, which is a constant, and Δt is C SC In C SC >C SC1 duration of time); if C SC In C SC <C SC2 or C SC >C SC1 After that, restore to C SC1 ≥C SC ≥C SC2 When CSC C SC =C SC1 or C SC =C SC2 The current value I Ba , as the new C SC In C SC1 ≥C SC ≥C SC2 The constant value I CBa , Figure 10 In, when C SC =C SC1 or C SC =C SC2 I Ba For I CBa +δΔt or I CBa -δΔt (where δ is the fixed increment gradient coefficient, which is a constant, and Δt is C SC In C SC <C SC2 When or C SC >C SC1 duration of time), the I Ba As a new I CBa .

[0167] exist Figure 9 In the example, after the electric vehicle is running, the battery management system adjusts the parallel discharge current I of the battery port of the non-isolated DC / DC converter 116 in the battery array given by the vehicle control system according to the difference in the state of charge (SOC) of each battery 114 in the battery array 102. Ba When the SOC of the battery array is low, reduce the parallel discharge current I of the battery with low capacity Ba , causing each battery in battery array 102 to reach a discharge cutoff state simultaneously, thereby maximizing battery capacity utilization. Because capacitor 117 is connected in parallel between parallel battery buses 112, as the output current from non-isolated DC / DC converter 116 to parallel battery buses 112 decreases, voltage U2 of parallel battery buses 112 also decreases.

[0168] The parallel charge and discharge DC / DC converter 109 adjusts the parallel discharge current I of the i battery ports. D1 , maintain the voltage of each battery parallel bus 112 constant at U 02 When the voltage U2 of a battery parallel bus is lower than U 02 After that, the parallel discharge current I D1 It also decreases accordingly, causing the voltage U2 of the battery parallel bus to rise.

[0169] The parallel charge and discharge DC / DC converter 109 maintains the voltage U1 of each supercapacitor parallel bus 111 to be the same by adjusting the output current of g supercapacitor ports, thereby achieving voltage balance and consistency of each supercapacitor parallel bus. A1 After that, the parallel charge and discharge DC / DC converter 109 reduces the output current of the supercapacitor port, so that the voltage U1 of the supercapacitor parallel bus drops; when the voltage U1 of a supercapacitor parallel bus is lower than the average voltage U1 of the supercapacitor parallel bus A1 After that, the parallel charge-discharge DC / DC converter 109 increases the output current of the supercapacitor port, so that the voltage U1 of the supercapacitor parallel bus rises.

[0170] During the supercapacitor discharge process, the capacity C of each supercapacitor in the supercapacitor array 101 is SC Unbalanced. In the later stage of supercapacitor discharge, individual supercapacitors in the supercapacitor array have a unified serial discharge current I TSC The battery management system adjusts the parallel charging current I of each supercapacitor according to the state of charge (SOC) of each supercapacitor. SC , so that each supercapacitor in the supercapacitor array 101 reaches the discharge cut-off state at the same time. TSC Supplying power output to the electric vehicle, it is not controlled by the battery management system. The non-isolated DC / DC converter 116 in the supercapacitor array 101 increases the parallel charging current I of the supercapacitor port. SC , to compensate for the actual output current I RSC The deficiency can be expressed by public notice (5):

[0171] I RSC =I TSC -I SC (5)

[0172] Where: I RSC is the actual discharge current of the supercapacitor, I TSC is the serial discharge current of the supercapacitor, I SC is the parallel charging current of the supercapacitor.

[0173] At the end of supercapacitor discharge, all supercapacitors are about to reach the discharge cut-off state. In order to prevent the discharge current from exceeding the supercapacitor's tolerance, the actual discharge current I of the supercapacitor needs to be reduced. RSC If the algorithm of the battery management system causes the parallel charging current I SCIncrease, resulting in the average voltage U of the supercapacitor parallel bus A1 Lower than the initial operating voltage U 01 The vehicle control system increases the parallel discharge current I of the battery port of the non-isolated DC / DC converter in the battery array 102 Ba .

[0174] When an electric vehicle encounters short-term, sudden power demands such as starting, accelerating, and climbing, the capacity imbalance of each supercapacitor in the supercapacitor array 101 increases, and the battery management system tends to increase the parallel charging current I SC , maintain the capacity balance of supercapacitors in the supercapacitor array. If the battery management system algorithm causes the parallel charging current I SC Increase, resulting in the average voltage U of the supercapacitor parallel bus A1 Lower than the initial operating voltage U 01 The vehicle control system increases the parallel discharge current I of the battery port of the non-isolated DC / DC converter in the battery array 102 Ba .

[0175] During the driving process of the electric vehicle, when encountering energy recovery needs such as deceleration, braking, and braking, the capacity imbalance of each supercapacitor in the supercapacitor array 101 increases, and the battery management system tends to reduce the parallel charging current I input by the non-isolated DC / DC converter 116 in the supercapacitor array 101 to the supercapacitor SC , maintain the capacity balance of supercapacitors in the supercapacitor array. If the battery management system algorithm causes the parallel charging current I SC Reduced, resulting in the average voltage U of the supercapacitor parallel bus A1 Higher than the initial working voltage U 01 The vehicle control system reduces the parallel discharge current I of the battery port of the non-isolated DC / DC converter in the battery array 102 Ba .

[0176] Figure 11 A flowchart of a process for parallel charging of supercapacitors of a supercapacitor and battery hybrid system according to a fourth embodiment of the present invention is shown in FIG. Figure 11 As shown, the parallel charging of supercapacitors includes the following steps:

[0177] L1. The supercapacitor and battery hybrid system is turned on, and the voltage U1 of the supercapacitor parallel bus reaches the initial operating voltage U 01 , the voltage U2 of the battery parallel bus reaches the initial working voltage U 02 ;

[0178] L2. The vehicle control system sets the parallel discharge current I of the battery port of the non-isolated DC / DC converter in the battery array. Ba , parallel discharge current I of the battery port of the parallel charge and discharge DC / DC converter D1 , the parallel charging current I of the bus port of the non-isolated DC / DC converter in the supercapacitor array D2 The parallel charging current I of the supercapacitor port of the non-isolated DC / DC converter in the supercapacitor array SC ;

[0179] L3. The battery management system actively balances each battery in the battery array and adjusts the parallel discharge current I of the battery port of the non-isolated DC / DC converter in the battery array to the battery. Ba , given by the vehicle control system I Ba Added battery management system adjustment increment I MBa ;

[0180] L4. Parallel charge and discharge DC / DC converters maintain the voltage U2 of each battery parallel bus constant at U 02 , maintain the same voltage U1 of each supercapacitor parallel bus;

[0181] L5. The battery management system actively balances each supercapacitor in the supercapacitor array and adjusts the parallel charging current I of the supercapacitor port of the non-isolated DC / DC converter in the supercapacitor array. SC , given by the vehicle control system I SC Added battery management system adjustment increment I MSC ;

[0182] L6. If the average voltage of each supercapacitor parallel bus is U A1 Lower than the initial working voltage U of the supercapacitor parallel bus 01 The vehicle control system increases the parallel discharge current I of the battery port of the non-isolated DC / DC converter in the battery array. Ba , and according to I Ba Adjustment I D1 , I D2 and I SC ;

[0183] L7. If the average voltage of each supercapacitor parallel bus is U A1 Higher than the initial working voltage U of the supercapacitor parallel bus 01 The vehicle control system reduces the parallel discharge current I of the battery port of the non-isolated DC / DC converter in the battery array. Ba , and according to I Ba Adjustment ID1 , I D2 and I SC .

[0184] Steps L2 to L7 are executed cyclically or in parallel.

[0185] The technical solution of this invention uses supercapacitors to provide short-term, sudden power demands for electric vehicles, such as starting, accelerating, and climbing. It also absorbs and stores energy recovered during deceleration, braking, and braking, while using batteries to provide stable, continuous power. The battery discharge current adopts a constant value or a constant-incremental, gradually changing value based on a constant value, mitigating battery capacity degradation caused by short-term, sudden power demands and extending the battery's service life.

[0186] The battery management system of the present invention controls the non-isolated DC / DC converter within each supercapacitor unit in the supercapacitor array and the non-isolated DC / DC converter within each battery unit in the battery array. During the parallel charging of the supercapacitor array and the parallel discharging of the battery array, personalized battery management can be performed for each supercapacitor and battery in the array. At the same time, the parallel charging and discharging DC / DC converters, which serve as the intermediate link between the parallel charging of the supercapacitor array and the parallel discharging of the battery array, are not controlled by the battery management system and independently perform voltage equalization or constant voltage control on each supercapacitor charging port and battery discharging port, thereby simplifying the control strategy.

[0187] At the end of the battery array's charging process, the present invention automatically reduces the charging current of batteries with low capacity through the non-isolated DC / DC converter assigned to each battery cell. At the end of the battery array's discharging process, the present invention automatically reduces the discharge current of batteries with low capacity through the non-isolated DC / DC converter assigned to each battery cell. At the end of the supercapacitor array's discharging process, the present invention automatically reduces the discharge current of supercapacitors with low capacity through the non-isolated DC / DC converter assigned to each supercapacitor cell. This achieves capacity balancing between supercapacitors and batteries during the charging and discharging process, allowing each supercapacitor or battery to reach full charge or discharge cutoff simultaneously. This prevents premature termination of charging or discharging due to individual supercapacitors or batteries with low capacity, thereby fully utilizing the energy storage capacity of the supercapacitors or batteries.

[0188] The present invention uses a high-frequency transformer with a single magnetic circuit and multiple windings in a parallel charging DC / DC converter, thereby achieving energy sharing between different charging and discharging circuits during the parallel charging and discharging process of a supercapacitor and a battery, improving the flexibility of control modes such as discharge, charging, voltage equalization, and constant voltage, and simplifying the complexity of the control strategy. In addition, the multi-winding transformer isolates the various charging and discharging circuits from each other, isolates the correlation between the control pulses of electronic switching devices in different parallel circuits, and significantly reduces the complexity of the control strategy.

[0189] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code. The scheme in the embodiment of the present application can be implemented in various computer languages, for example, object-oriented programming language Java and literal translation scripting language JavaScript, etc.

[0190] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0191] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0192] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0193] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0194] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A supercapacitor and battery hybrid system, comprising: Supercapacitor array, battery array, parallel charging and discharging DC / DC converter, supercapacitor parallel bus and battery parallel bus; The supercapacitor array includes g×h supercapacitor units, wherein g is the number of rows of the supercapacitor array, h is the number of columns of the supercapacitor array, and g and h are arbitrary integers; The battery array includes i×j battery cells, wherein i is the number of rows of the battery array, j is the number of columns of the battery array, and i and j are arbitrary integers; The parallel charge and discharge DC / DC converter includes g supercapacitor ports and i battery ports, and is an isolated DC / DC converter with g+i output / input ports; The supercapacitor ports of g parallel charge-discharge DC / DC converters are respectively connected to g supercapacitor parallel busbars, and each supercapacitor parallel busbar is connected to the parallel ports of h supercapacitor units in each row of the supercapacitor array; The battery ports of i parallel charge-discharge DC / DC converters are respectively connected to i battery parallel bus bars, and each battery parallel bus bar is connected to the parallel ports of j battery cells in each row of the battery array; The supercapacitor unit includes a supercapacitor and a series-parallel conversion unit; The series-parallel conversion unit includes a non-isolated DC / DC converter and a capacitor; The non-isolated DC / DC converter in the supercapacitor unit includes one supercapacitor port and one bus port; The two ends of the supercapacitor are connected to the supercapacitor port of the non-isolated DC / DC converter in the supercapacitor unit; The two ends of the capacitor are connected to the bus port of the non-isolated DC / DC converter in the supercapacitor unit; The two ends of the supercapacitor become the serial ports of the supercapacitor unit, and the bus port of the non-isolated DC / DC converter in the supercapacitor unit becomes the parallel port of the supercapacitor unit; The battery unit includes a battery and a series-parallel conversion unit; The series-parallel conversion unit includes a non-isolated DC / DC converter and a capacitor; The non-isolated DC / DC converter in the battery unit includes one battery port and one bus port; The two ends of the battery are connected to the battery port of the non-isolated DC / DC converter in the battery unit; The two ends of the capacitor are connected to the bus port of the non-isolated DC / DC converter in the battery unit; The two ends of the battery become the serial ports of the battery unit, and the bus port of the non-isolated DC / DC converter in the battery unit becomes the parallel port of the battery unit.

2. The system according to claim 1, wherein the parallel charging and discharging DC / DC converter is composed of a bidirectional full-bridge phase-shifted DC / DC conversion circuit with g+i ports sharing a single magnetic circuit and a high-frequency transformer with g+i windings.

3. The system according to claim 1, wherein the supercapacitor unit comprises one serial port and one parallel port; in, The serial ports of g supercapacitor units are connected in series to form a supercapacitor unit string, and h supercapacitor unit strings are connected in parallel to form the supercapacitor array.

4. The system according to claim 1, wherein the non-isolated DC / DC converter in the series-parallel conversion unit in the supercapacitor unit is a non-isolated Buck / Boost bidirectional half-bridge DC / DC converter.

5. The system according to claim 1, wherein the battery unit comprises one serial port and one parallel port; in, The serial ports of i battery units are connected in series to form a battery unit string, and j battery unit strings are connected in parallel to form the battery array; The j battery cells are connected in series to a battery array serial charging circuit and then connected to a charger. 6 . The system according to claim 1 , wherein the non-isolated DC / DC converter in the series-parallel conversion unit in the battery unit is a non-isolated Buck / Boost bidirectional half-bridge DC / DC converter.

7. A control method for serial charging of batteries using the system according to any one of claims 1 to 6, wherein a battery management system participates in the charging control, comprising: S1. Start the supercapacitor and battery hybrid system. When the voltage U2 of the battery parallel bus reaches the initial working voltage U 02 Then, start the charger; S2. The battery management system sets the serial charging current I of the charger to the battery array in the supercapacitor and battery hybrid system. TBa ; S3. The battery management system sets the balancing current I of the battery port of the non-isolated DC / DC converter of each battery cell in the battery array of the supercapacitor and battery hybrid system. Ba ; S4. Parallel charge and discharge DC / DC converters maintain the same voltage U2 for each battery parallel bus; S5. If the average voltage of each battery parallel bus is U A2 Higher than the initial operating voltage U of the battery parallel bus 02 , the battery management system reduces the serial charging current I TBa ; S6. If the average voltage of each battery parallel busbar is U A2 Lower than the initial operating voltage U of the battery parallel bus 02 , the battery management system increases the serial charging current I TBa .

8. The method according to claim 7, wherein steps S2 to S6 can be operated cyclically or in parallel.

9. A control method for parallel charging of supercapacitors using the system according to any one of claims 1 to 6, wherein the system is installed in an electric vehicle, and the vehicle control system and battery management system of the electric vehicle participate in the charging control, comprising: L1. Start the supercapacitor and battery hybrid system, and the voltage U1 of the supercapacitor parallel bus reaches the initial working voltage U 01 , the voltage U2 of the battery parallel bus reaches the initial working voltage U 02 ; L2. The vehicle control system sets the parallel discharge current I of the battery port of the non-isolated DC / DC converter in each battery cell in the battery array. Ba , the parallel discharge current I of each battery port of the parallel charge and discharge DC / DC converter D1 , the parallel charging current I of the bus port of the non-isolated DC / DC converter in each supercapacitor unit in the supercapacitor array D2 The parallel charging current I of the supercapacitor port of the non-isolated DC / DC converter in each supercapacitor unit in the supercapacitor array SC ; L3. The battery management system adjusts the parallel discharge current I of the battery port of the non-isolated DC / DC converter in each battery cell in the battery array. Ba ; L4. Parallel charging and discharging DC / DC converters maintain the parallel bus voltage U2 of each battery constant at U 02 , maintain the same voltage U1 of each supercapacitor parallel bus; L5. The battery management system adjusts the parallel charging current I of the supercapacitor port of the non-isolated DC / DC converter in each supercapacitor unit in the supercapacitor array. SC ; L6. If the average voltage of each supercapacitor parallel bus is U A1 Lower than the initial working voltage U of the supercapacitor parallel bus 01 The vehicle control system increases the parallel discharge current I of the battery port of the non-isolated DC / DC converter in each battery cell in the battery array. Ba , and according to I Ba Adjustment I D1 , I D2 and I SC ; L7. If the average voltage of each supercapacitor parallel bus is U A1 Higher than the initial working voltage U of the supercapacitor parallel bus 01 The vehicle control system reduces the parallel discharge current I of the battery port of the non-isolated DC / DC converter in each battery unit in the battery array. Ba , and according to I Ba Adjustment I D1 , I D2 and I SC . 10 . The method according to claim 9 , wherein the steps L2 to L7 can be operated cyclically or in parallel.

11. The method according to claim 9, wherein the vehicle control system in L2 sets the parallel discharge current I of the battery port of the non-isolated DC / DC converter in each battery unit in the battery array. Ba , specifically including: M1. The vehicle control system sets the parallel discharge current I of the battery port of the non-isolated DC / DC converter in each battery cell in the battery array. Ba The initial value of M2. If the state of charge of the supercapacitor array is C SC In C SC1 ≥C SC ≥C SC2 , I Ba is a constant value; M3. If C SC In C SC <C SC2 , I Ba C SC In C SC1 ≥C SC ≥C SC2 The fixed increment gradually increases based on the constant value at the time; M4. If C SC In C SC >C SC1 , I Ba C SC In C SC1 ≥C SC ≥C SC2 The fixed increment gradually decreases based on the constant value at the time; M5. If C SC In C SC <C SC2 or C SC >C SC1 After that, restore to C SC In C SC1 ≥C SC ≥C SC2 When C SC =C SC1 or C SC =C SC2 The current value I Ba , as the new C SC In C SC1 ≥C SC ≥C SC2 Constant value when Among them, the C SC1 and C SC2 There are two gears of the state of charge of the supercapacitor array, and C SC1 >C SC2 . 12 . The method according to claim 11 , wherein the steps M2 to M5 can be operated cyclically or in parallel.

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