Grid and source electrode feedback parallel current sharing circuit and method for power device of energy storage converter

Abstract

The invention provides an energy storage converter power device gate-source feedback parallel current sharing circuit and method, and belongs to the technical field of power electronics. Transient current balance during parallel connection of the power devices is realized, so that the risk that part of the devices are damaged due to bearing of overlarge current stress is avoided, the service life of the devices is effectively prolonged, and the reliability of the whole power electronic system is improved. Meanwhile, the stable current balance can also reduce electromagnetic interference caused by current imbalance, and the anti-interference capability of the system is improved. The active grid control technology can dynamically adjust the current change rate according to the actual current condition, so that the switching speeds of the parallel power devices are better matched, the energy loss in the switching process is reduced, and the efficiency of the system is improved. In addition, the stable current balance is beneficial to improving the dynamic response performance of the system, reducing ripples of output voltage and current, and improving the electric energy quality and the overall performance of the system.

Description

Technical Field

[0001] The present invention belongs to the field of power electronics technology, and specifically relates to current balancing technology in parallel applications of power devices, and is particularly suitable for the parallel use of power devices such as power switching tubes, and is widely used in electric vehicle power systems, industrial motor drives, power system power conversion, and other occasions that require high power density and high reliability. Background Art

[0002] In order to meet the high power requirements of energy storage converters, high-power device parallel technology has become a common solution. For example, in some medium and large energy storage systems, multiple high-power devices such as insulated gate bipolar transistors (IGBTs) or silicon carbide metal oxide semiconductor field effect transistors (power switch tubes) are often used in parallel. However, this parallel connection method faces many challenges. There are certain differences in the manufacturing process of high-power devices. Even for devices produced in the same batch, their parameters such as on-resistance and threshold voltage are difficult to be completely consistent. In addition, circuit parasitic parameters, such as line inductance and capacitance, will have a significant impact on current distribution in parallel circuits. The combined effect of these factors leads to the phenomenon of current imbalance between parallel high-power devices in actual operation.

[0003] Current imbalance can cause a series of serious problems for energy storage converters. Current imbalance is particularly prominent during switching transients. Some devices that bear large currents will generate excessive heat, resulting in increased junction temperature. In this state for a long time, the aging speed of the device is accelerated, greatly increasing the risk of device damage, thereby reducing the reliability of the energy storage converter. Moreover, current imbalance will also cause additional energy loss, reduce the overall conversion efficiency of the system, and increase the operating cost of the system. At present, the existing driving technology has certain limitations for the current imbalance problem of high-power devices in parallel. Although passive methods such as device screening can select devices with relatively close parameters, this method is costly, time-consuming and labor-intensive, and lacks practicality in large-scale production and application scenarios. Symmetrical circuit layout is limited by the physical structure of the actual circuit board, and it is difficult to achieve complete symmetry, especially when multiple high-power devices are connected in parallel, it is almost impossible to ensure that the parasitic parameters of each device are completely consistent. Although coupled inductors can suppress dynamic current imbalance to a certain extent, they are large in size, and as the number of parallel devices increases, the number and cost of inductors required will increase significantly. Among active methods, traditional active gate driver (AGD) technology also has some problems. Some AGD methods require high-bandwidth current sensors, which not only increases the system cost, but also places higher requirements on the installation and layout of the sensors. Some AGD methods have a slow response speed and cannot adapt to the needs of fast switching of high-power devices, resulting in large current imbalance during switching transients. In addition, some AGD methods have complex control circuits and are difficult to expand to multiple parallel devices, which limits their application scope in actual energy storage converter projects. In summary, in energy storage converters, the current imbalance problem of high-power devices in parallel seriously affects system performance and reliability. Existing drive technologies are difficult to effectively solve these problems. Therefore, a new and efficient drive optimization technology is urgently needed to improve this situation. Summary of the invention

[0004] In view of the current imbalance problem existing in the existing power device parallel technology, especially the reliability reduction and efficiency loss caused by the transient current imbalance of the switch when the power switch tubes are connected in parallel, the present invention provides a current balancing technology that is simple, efficient, fast in response and easy to expand to multiple parallel devices, so as to achieve transient current balance when the power devices are connected in parallel, and improve the reliability and overall performance of the system.

[0005] In order to achieve the above object, the technical solution provided by the present invention is as follows:

[0006] In the first aspect, the present invention provides a gate-source feedback parallel current sharing circuit for power devices of an energy storage converter, comprising a gate-source feedback circuit main circuit, a gate drive circuit of a power switch tube and an active gate control circuit, wherein the gate-source feedback circuit main circuit is composed of a DC voltage , a freewheeling diode D and a load inductor L are connected in parallel to form a branch, and the two power devices are marked as and The parallel branch, and the source inductance in the parallel branch and And parasitic inductance and Composition; power devices Branch Road , , The power devices are connected in series. Branch Road , , It is also a series relationship in sequence; the connection method of the gate-source feedback circuit is a DC voltage , a branch consisting of a freewheeling diode D and a load inductor L in parallel, and a power device Branch and power switch tube The branches formed by the parallel connection of the branches are connected in series in sequence;

[0007] The gate drive circuit includes the gate resistor , source resistance and drive voltage pulse ; The gate drive circuit is connected in such a way that the gate of each power device is connected through a gate resistor Connect to the drive voltage source , the source is connected in series with a source resistor The drain is then connected to a branch consisting of a freewheeling diode D and a load inductor L in parallel;

[0008] Active gate control circuit includes a bipolar junction transistor and ,resistance and , diodes VD1 and VD2; the active gate control circuit is connected to the power device The gate Connect one end of diode VD1, and the other end of diode VD1 is connected to bipolar junction transistor The collector of a bipolar junction transistor The base connection of the power device The source S1 of the bipolar junction transistor The emitter connection resistance ,resistance Connecting power devices Source S2 of power device The gate Connect one end of diode VD2, and diode VD1 to bipolar junction transistor The collector of a bipolar junction transistor The base connection of the power device The source S1 of the bipolar junction transistor The emitter connection resistance One end of the resistor The other end of the power device The source S2.

[0009] Furthermore, the active gate control circuit is based on the feedback work of the gate-source feedback circuit main circuit to the power device, including:

[0010] when Opening faster than hour, work, make The gate current decreases, and the formula for reducing the current is:

[0011]

[0012] in, for The absorbed current, for The source inductor voltage at for The source inductor voltage at is the base-emitter conduction voltage of the bipolar junction transistor;

[0013] when Opening faster than When Q2 works, The gate current decreases, and the formula for reducing the current is:

[0014]

[0015] in, for The absorbed current, for The source inductor voltage at for The source inductor voltage at It is the base-emitter conduction voltage of a bipolar junction transistor.

[0016] Furthermore, the resistance of the active gate control circuit and The design satisfies the following formula:

[0017]

[0018] in, for The source inductor voltage at for The source inductor voltage at is the base-emitter conduction voltage of the bipolar junction transistor, It is the maximum output current required by the active gate control circuit.

[0019] In a second aspect, the present invention provides a method for current sharing by gate-source feedback in parallel with power devices of an energy storage converter, which is applied to the current sharing circuit for gate-source feedback in parallel with power devices of an energy storage converter as in the first aspect, and comprises the following steps:

[0020] S1: The active gate control circuit monitors the voltage across the source inductor of the power device in real time to obtain the power device , The rate of change of current in the two branches;

[0021] S2: , The source inductor voltage of the branch and With reference voltage For comparison, > , The current change rate is large. > , The current change rate is large;

[0022] S3: Active gate control circuit works, controlling , The gate current is > , Active gate control circuit generates sink current reduce The gate current at > , Active gate control circuit generates sink current reduce The gate current at

[0023] S4: The turn-on and turn-off speeds are adjusted by feedback from the source resistor. and When the power device is working, the source current Flow through the source resistor and , resulting in a pressure drop and ; and It is introduced into the gate drive circuit as a feedback signal, interacting with the gate voltage to adjust and The turn-on and turn-off speeds are adjusted to the equilibrium state.

[0024] Furthermore, in S1, the current change rate is calculated as follows:

[0025]

[0026] in and They are , is the source inductor voltage, They are , The rate of change of current in the two branches, is the source inductance.

[0027] Furthermore, in S2, the calculation formula of the reference voltage is as follows:

[0028]

[0029] in is the amount of source inductance of all parallel devices, For the The source inductor voltage.

[0030] Furthermore, in S3, the absorption current generated by the active gate control circuit and The calculation formula is as follows:

[0031]

[0032] in, and Indicates power device and The voltage across the source inductor, It is the reference voltage across the source inductor of the power device; is the base-emitter conduction voltage of the bipolar junction transistor; and It is the resistor connected between the emitter of the bipolar junction transistor and the source of the power device.

[0033] Furthermore, in S4, adjust and The turn-on and turn-off speeds include:

[0034] and These two voltage drops are introduced into the gate drive circuit as feedback signals and interact with the gate voltage. and The pressure drop calculation formula is as follows:

[0035]

[0036] when Compare When the conduction is fast, The source inductor voltage Greater than The source inductor voltage ,exist Current is generated between , current Direction is from source Point to source Point, current Flow , resulting in a pressure drop and , will make The gate-source voltage Reduce the conduction speed and slow down, The calculation formula is expressed as:

[0037]

[0038] is the driving voltage, will make The gate-source voltage As the conduction speed increases, The calculation formula is expressed as:

[0039]

[0040] The conduction speed gradually slows down, and The conduction speed of the and The conduction speeds are close to the same.

[0041] Furthermore, the resistance value of the source resistor is selected according to the rated current, switching speed and desired current balance accuracy of the power device, and the source resistor is calculated according to the following formula:

[0042]

[0043] in, is the source resistance value, is the rated current of the power device, is the power device threshold voltage, is the current rise time, is the allowable current unbalance.

[0044] Furthermore, the source inductance Used to detect the current change rate, its detection voltage must meet the minimum requirements for the normal operation of the feedback circuit. The feedback circuit in the active gate control circuit is based on a bipolar junction transistor. The source inductance detection voltage must meet certain requirements. The base-emitter conduction voltage of the bipolar junction transistor is , the peak currents of the two parallel power switches are and , the average quiescent current is , the current rise time is , is the peak current mismatch ratio, and Rising at a constant slope, the current rise rate and , the calculation formula is:

[0045]

[0046] For current sinking circuits, when Opening faster than ,at this time > , the necessary conditions for normal operation are:

[0047]

[0048] Substituting the current rise rate expression into the above formula, we can get the calculation formula of the minimum source inductance:

[0049]

[0050] Bandwidth of a bipolar junction transistor The calculation formula is:

[0051]

[0052] in is the current rise time.

[0053] Furthermore, when there is a difference in source inductance hour, The current change rate The calculation formula is:

[0054]

[0055] The voltage difference caused by the source inductance is less than , the formula is:

[0056]

[0057] in is the average quiescent current, is the current rise time, is the source inductance difference, is the base-emitter conduction voltage.

[0058] In summary, the present invention provides a gate-source feedback parallel current-sharing circuit and method for power devices of an energy storage converter. By achieving transient current balance when power devices are connected in parallel, the risk of damage to some devices due to excessive current stress is avoided, the service life of the devices is effectively extended, and the reliability of the entire power electronic system is improved. At the same time, stable current balance can also reduce electromagnetic interference caused by current imbalance and improve the anti-interference ability of the system. Active gate control technology can dynamically adjust the current change rate according to the actual current conditions, so that the switching speed of parallel power devices is more matched, reducing energy loss during the switching process and improving the efficiency of the system. In addition, stable current balance helps to improve the dynamic response performance of the system, reduce the ripple of output voltage and current, and improve the power quality and overall performance of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0060] Figure 1 A schematic diagram of a gate-source feedback parallel current-sharing circuit for power devices of an energy storage converter provided in an embodiment of the present invention;

[0061] Figure 2 A schematic diagram of an active gate control circuit provided by an embodiment of the present invention;

[0062] Figure 3 A current comparison diagram of the turn-on phase before the current balancing method is used according to an embodiment of the present invention;

[0063] Figure 4 A current comparison diagram of the turn-on phase after using the current balancing method provided by an embodiment of the present invention;

[0064] Figure 5 A current comparison diagram of the shutdown phase before the current balancing method is used according to an embodiment of the present invention;

[0065] Figure 6 A current comparison diagram of the shutdown phase after using the current balancing method provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0066] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0067] The embodiment of the present invention provides a current-sharing circuit for power devices of an energy storage converter with gate-source feedback in parallel. The circuit adopts a power device parallel circuit structure based on source resistance feedback and active gate control circuit control, such as Figure 1 The gate-source feedback circuit of the power device in parallel in this embodiment is composed of a gate-source feedback circuit main circuit, a gate drive circuit of the power switch tube, and an active gate control circuit; the gate-source feedback circuit main circuit is composed of a DC voltage , the branch consisting of the freewheeling diode D and the load inductor L in parallel, and the two power switch tubes are marked as for The parallel branch, source inductance and and parasitic inductance and Composition, including power devices Branch Road , , The power devices are connected in series. Branch Road , , The gate-source feedback circuit main circuit connection method is a DC voltage , a branch consisting of a freewheeling diode D and a load inductor L in parallel, and a power device Branch and power switch tube The branches formed by the parallel connection of the branches are connected in series in sequence; the gate drive circuit includes a gate resistor and , source resistance , and drive voltage pulse ; The gate drive circuit is connected in such a way that the gate of each power device is connected through a gate resistor and connected to the driving voltage source , the source is connected in series with a source resistor The drain is then connected to a branch consisting of a freewheeling diode D and a load inductor L in parallel.

[0068] The principle of active gate control circuit is as follows Figure 2 As shown, the active gate control circuit includes a bipolar junction transistor and ,resistance and , diodes VD1 and VD2; the connection method of the active gate control circuit is Active gate control circuit for power devices The gate Connect one end of diode VD1, and the other end of diode VD1 is connected to bipolar junction transistor The collector of a bipolar junction transistor The base connection of the power device Source , bipolar junction transistor The emitter connection , Connecting power devices The source S2; Active gate control circuit for power devices The gate Connect one end of diode VD2, and diode VD1 to bipolar junction transistor The collector of a bipolar junction transistor The base connection of the power device The source S1 of the bipolar junction transistor The emitter connection One end of The other end of the power device The source S2.

[0069] The embodiment of the present invention also provides a method for current sharing by gate-source feedback parallel connection of power devices of an energy storage converter, the steps of which are as follows:

[0070] S1, the active gate control circuit monitors the voltage across the source inductor of the power device in real time, and obtains , The current change rate of the two branches; the calculation formula for the current change rate obtained by the source inductance is expressed as:

[0071] (1)

[0072] in and They are , is the source inductor voltage, They are , The rate of change of current in the two branches, is the source inductance;

[0073] S2, , The source inductor voltage of the branch and With reference voltage For comparison, a bipolar junction transistor in an active gate control circuit and Will and and Compare, when > , The current change rate is large. > , The current change rate is large; the two power devices , Parallel control strategy, The active gate control circuit of equal , The active gate control circuit of equal In the control strategy of connecting multiple power devices in parallel, an average control strategy is adopted to calculate the average value of the source inductance of all parallel devices. The average value calculation formula is expressed as:

[0074] (2)

[0075] Using it as a reference signal, according to each device and The gate drive current is adjusted based on the comparison result so that the current change rate of each device approaches the average value.

[0076] S3, active gate control circuit operation control , The gate current is > ,at this time The current change rate is greater than the reference value and needs to be reduced The gate current at Active gate control circuit generates sink current reduce The gate current at > ,at this time The current change rate is greater than the reference value and needs to be reduced The gate current at Active gate control circuit generates sink current reduce The gate current at .

[0077] In a further embodiment, the active gate control circuit generates a sink current and The calculation formula is expressed as:

[0078] (2)

[0079] in, and Indicates power device and The voltage across the source inductor reflects the rate of change of the source current. It is the reference voltage across the source inductor of the power device, which is used to compare with the actual detected voltage across the source inductor to determine whether the current changes too fast; It is the base-emitter conduction voltage of the bipolar junction transistor. It is the voltage drop between the base and the emitter when the bipolar junction transistor is working normally. This voltage value plays an important role in calculating the absorption current because it determines the degree of current absorption together with the voltage across the source inductance and the reference voltage. and The resistor is used to determine the relationship between the absorption current and the voltage difference. The size of the resistor affects the adjustment effect of the absorption current on the gate drive current.

[0080] S4, adjusts the turn-on and turn-off speeds through source resistance feedback. and When the power device is working, the source current Flow through the source resistor and , resulting in a pressure drop and .

[0081] In a further embodiment, and The pressure drop calculation formula is expressed as:

[0082] (4)

[0083] and This voltage drop is introduced into the gate drive circuit as a feedback signal and interacts with the gate voltage; Compare When the conduction is fast, The source inductor voltage Greater than The source inductor voltage ,exist Current is generated between , current The direction is from the source Point flows to the source point S2, the current Flow , resulting in a pressure drop and , will make The gate-source voltage Reduce the conduction speed and slow down, The calculation formula is expressed as:

[0084] (5)

[0085] is the driving voltage, will make The gate-source voltage Reduce the conduction speed faster, The calculation formula is expressed as:

[0086] (6)

[0087] The conduction speed gradually slows down, and The conduction speed of the and The conduction speed is almost the same, so that the source current is adjusted to a balanced state.

[0088] In some other embodiments of the present invention, some design methods of important parameters are also provided, including:

[0089] The source resistance is calculated according to the following formula:

[0090] (7)

[0091] in, is the source resistance value, is the rated current of the power device, is the power device threshold voltage, is the current rise time, To allow for the amount of current imbalance, the power capacity of the source resistor is selected based on the operating current and voltage of the power device to ensure that it will not be damaged by overheating during normal operation and overload conditions;

[0092] Source Inductance Used to detect the current change rate, its detection voltage must meet the minimum requirements for the normal operation of the feedback circuit. The feedback circuit in the active gate control circuit is based on a bipolar junction transistor. The source inductance detection voltage must meet certain requirements. The base-emitter conduction voltage of the bipolar junction transistor is , the peak currents of the two parallel power switches are and , the average quiescent current is , the current rise time is , is the peak current mismatch ratio, and Rising at a constant slope, the current rise rate and , the calculation formula is:

[0093] (8)

[0094] For current sinking circuits, when Opening faster than ,at this time > The necessary conditions for its normal operation are:

[0095] (9)

[0096] Substituting the current rise rate expression into the above formula, we can get the calculation formula of the minimum source inductance:

[0097] (10)

[0098] Bandwidth of a bipolar junction transistor The calculation formula is:

[0099] (11)

[0100] in is the current rise time.

[0101] When there is a difference in source inductance hour, The current change rate The calculation formula is:

[0102] (12)

[0103] The voltage difference caused by the source inductance is less than , the formula is:

[0104] (13)

[0105] in is the average quiescent current, is the current rise time, is the source inductance difference, is the base-emitter conduction voltage.

[0106] Active gate control circuit resistance and The design needs to meet:

[0107] (14)

[0108] in and Indicates power device and The voltage across the source inductor, is the base-emitter conduction voltage of the bipolar junction transistor, It is the maximum output current required by the active gate control circuit.

[0109] Figure 3-6 The results of the application of a gate-source feedback parallel current-sharing circuit and method for energy storage converter power devices in a specific circuit are presented. These results were obtained by oscilloscope measurement, which showed that when this current-sharing method was not used, the current-sharing circuit was and The branch current on and , and also shows that after adopting this current balancing method, the turn-on stage and the turn-off stage and The branch current on and By comparing these waveforms, it can be clearly seen that the current imbalance in the turn-on and turn-off stages is significantly reduced after using this current balancing method. The formula is:

[0110] (15)

[0111] in is the current imbalance, and They are and The branch current on for and The maximum value of .

[0112] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A gate-source feedback parallel current sharing circuit for power devices of an energy storage converter, comprising a gate-source feedback circuit main circuit, a gate drive circuit of a power switch tube and an active gate control circuit, characterized in that: The main circuit of the gate-source feedback circuit consists of a DC voltage , a freewheeling diode D and a load inductor L are connected in parallel to form a branch, and the two power devices are marked as and The parallel branch, and the source inductance in the parallel branch and And parasitic inductance and Composition; power devices Branch Road , , The power devices are connected in series. Branch Road , , The gate-source feedback circuit is connected in series with the DC voltage , a branch consisting of a freewheeling diode D and a load inductor L in parallel, and a power device Branch and power switch tube The branches formed by the parallel connection of the branches are connected in series in sequence; The gate drive circuit includes a gate resistor , source resistance and drive voltage pulse The gate drive circuit is connected in such a way that the gate of each power device is connected through a gate resistor. Connect to the drive voltage source , the source is connected in series with a source resistor The drain is then connected to a branch consisting of a freewheeling diode D and a load inductor L in parallel; The active gate control circuit includes a bipolar junction transistor and ,resistance and , diodes VD1 and VD2; the connection mode of the active gate control circuit is a power device The gate Connect one end of diode VD1, and the other end of diode VD1 is connected to bipolar junction transistor The collector of a bipolar junction transistor The base connection of the power device The source of S1, bipolar junction transistor The emitter connection resistance ,resistance Connecting power devices Source S2 of power device The gate Connect one end of diode VD2, and diode VD1 to bipolar junction transistor The collector of a bipolar junction transistor The base connection of the power device The source of S1, bipolar junction transistor The emitter connection resistance One end of the resistor The other end of the power device The source S2.

2. The energy storage converter power device gate-source feedback parallel current sharing circuit according to claim 1, characterized in that: The active gate control circuit is based on the feedback work of the gate-source feedback circuit main circuit to the power device, including: when Opening faster than hour, work, make The gate current decreases, and the formula for reducing the current is: in, for The absorbed current, for The source inductor voltage at for The source inductor voltage at is the base-emitter conduction voltage of the bipolar junction transistor; when Opening faster than When Q2 works, The gate current decreases, and the formula for reducing the current is: in, for The absorbed current, for The source inductor voltage at for The source inductor voltage at It is the base-emitter conduction voltage of a bipolar junction transistor.

3. The energy storage converter power device gate-source feedback parallel current sharing circuit according to claim 1, characterized in that: The active gate control circuit resistance and The design satisfies the following formula: in, for The source inductor voltage at for The source inductor voltage at is the base-emitter conduction voltage of the bipolar junction transistor, It is the maximum output current required by the active gate control circuit.

4. A method for current sharing by gate-source feedback in parallel with power devices of an energy storage converter, applied to the current sharing circuit by gate-source feedback in parallel with power devices of an energy storage converter as claimed in any one of claims 1 to 3, characterized in that: The steps include: S1: The active gate control circuit monitors the voltage across the source inductor of the power device in real time to obtain the power device , The rate of change of current in the two branches; S2: , The source inductor voltage of the branch and With reference voltage For comparison, > , The current change rate is large. > , The current change rate is large; S3: Active gate control circuit works, controlling , The gate current is > , Active gate control circuit generates sink current reduce The gate current at > , Active gate control circuit generates sink current reduce The gate current at S4: The turn-on and turn-off speeds are adjusted by feedback from the source resistor. and When the power device is working, the source current Flow through the source resistor and , resulting in a pressure drop and ; and It is introduced into the gate drive circuit as a feedback signal, interacting with the gate voltage to adjust and The turn-on and turn-off speeds are adjusted to the equilibrium state.

5. A method for current sharing by gate-source feedback parallel connection of power devices of energy storage converter according to claim 4, characterized in that: In S1, the current change rate is calculated as follows: in and They are , is the source inductor voltage, They are , The rate of change of current in the two branches, is the source inductance.

6. A method for parallel current sharing of power devices of energy storage converters by gate-source feedback according to claim 4, characterized in that: In S2, the calculation formula of the reference voltage is as follows: in is the amount of source inductance of all parallel devices, For the The source inductor voltage.

7. A method for current sharing by gate-source feedback parallel connection of power devices of energy storage converter according to claim 4, characterized in that: In S3, the active gate control circuit generates a sink current and The calculation formula is as follows: in, and Indicates power device and The voltage across the source inductor, It is the reference voltage across the source inductor of the power device; is the base-emitter conduction voltage of the bipolar junction transistor; and It is the resistor connected between the emitter of the bipolar junction transistor and the source of the power device.

8. A method for current sharing by gate-source feedback in parallel of power devices of energy storage converter according to claim 4, characterized in that: In S4, adjust and The turn-on and turn-off speeds include: and These two voltage drops are introduced into the gate drive circuit as feedback signals and interact with the gate voltage. and The pressure drop calculation formula is as follows: when Compare When the conduction is fast, The source inductor voltage Greater than The source inductor voltage ,exist Current is generated between , current Direction is from source Point to source Point, current Flow , resulting in a pressure drop and , will make The gate-source voltage Reduce the conduction speed and slow down, The calculation formula is expressed as: is the driving voltage, will make The gate-source voltage As the conduction speed increases, The calculation formula is expressed as: The conduction speed gradually slows down, and The conduction speed of the and The conduction speeds are close to the same.

9. A method for current sharing by gate-source feedback parallel connection of power devices of energy storage converter according to claim 4, characterized in that: The resistance value of the source resistor is selected according to the rated current, switching speed and desired current balance accuracy of the power device. The source resistor is calculated according to the following formula: in, is the source resistance value, is the rated current of the power device, is the power device threshold voltage, is the current rise time, is the allowable current unbalance.

10. A method for current sharing by gate-source feedback parallel connection of power devices in energy storage converter according to claim 4, characterized in that: Source Inductance It is used to detect the rate of change of current. Its detection voltage must meet the minimum requirement for the normal operation of the feedback circuit. The feedback circuit in the active gate control circuit is based on a bipolar junction transistor. The base-emitter conduction voltage of the bipolar junction transistor is , the peak currents of the two parallel power switches are and , the average quiescent current is , the current rise time is , is the peak current mismatch ratio, and Rising at a constant slope, the current rise rate and , the calculation formula is: For current sinking circuits, when Opening faster than ,at this time > , the necessary conditions for normal operation are: Substituting the current rise rate expression into the above formula, we can get the calculation formula of the minimum source inductance: Bandwidth of a bipolar junction transistor The calculation formula is: in is the current rise time.

11. A method for current sharing by gate-source feedback parallel connection of power devices in energy storage converter according to claim 10, characterized in that: When there is a difference in source inductance hour, The current change rate The calculation formula is: The voltage difference caused by the source inductance is less than , the formula is: in is the average quiescent current, is the current rise time, is the source inductance difference, is the base-emitter conduction voltage.

Images