Dynamic gate drive resistance adjustment apparatus and method, three-phase full-bridge circuit, and vehicle

Abstract

The application relates to a dynamic gate driving resistance adjusting device and method, a three-phase full-bridge circuit and a vehicle, which comprise a master control unit, a driving chip and a driving resistance; the driving resistance comprises a first variable resistance and a second variable resistance; the driving chip has a first output end and a second output end; the first variable resistance is electrically connected between the first output end and a control end of an external power device, and the second variable resistance is electrically connected between the second output end and the control end of the external power device; the master control unit determines target resistance values of the first variable resistance and the second variable resistance, and issues resistance adjusting instructions to the first variable resistance and the second variable resistance; the first variable resistance and the second variable resistance are adjusted to the corresponding target resistance values based on the resistance adjusting instructions; when the switch action state is on, the driving chip is internally connected to the first output end; when the switch action state is off, the driving chip is internally connected to the second output end. The application realizes digital and dynamic adjustment of the driving resistance.

Description

Technical Field

[0001] This invention relates to the field of drive control technology for motor drives, specifically to a dynamic gate drive resistor adjustment device and method, a three-phase full-bridge circuit, and a vehicle. Background Technology

[0002] When a power device IGBT (or SiC) turns on, if the turn-on speed is too fast (i.e., the rate of rise of the drive voltage du / dt is too high), an excessively high current spike will be generated. Conversely, when it turns off, its collector (drain) current decreases rapidly, generating an extremely high rate of current change (-di / dt). Due to the presence of parasitic inductance (L) in the circuit, this current abrupt change is counteracted, generating an induced electromotive force Vs = L * di / dt according to Lenz's law. The direction of this induced voltage is consistent with the power supply voltage. The superposition of these two voltages results in a spike in the voltage Vce (Vds) across the IGBT (or SiC) that is much higher than the DC bus voltage.

[0003] Although the underlying mechanisms of current and voltage spikes generated by IGBTs and SiCs are different, both can be controlled within a safe range by matching the value of the drive resistor to change the rate of voltage change (du / dt) during turn-on and the rate of current change (di / dt) during turn-off. This optimizes switching losses during switching on and off, thereby improving system efficiency.

[0004] Currently, in the field of electric drive for new energy vehicles, the gate drive resistor scheme for IGBT and silicon carbide (SiC) power devices mainly adopts the fixed resistor method. The core of the fixed resistor method is to select one or a set of fixed resistor values ​​based on the rated current of the power device, the gate charge (Qg), and the recommended values ​​in the datasheet, and then using data obtained through double-pulse testing. These fixed resistor values ​​are connected in series in the gate drive circuit to suppress turn-on current spikes and turn-off voltages. This scheme has advantages such as simple structure, low cost, and high reliability. Its main technical feature is using resistance to limit the peak value of the gate charging and discharging current, thereby achieving a balance between switching speed, switching losses, electromagnetic interference, and voltage overshoot caused by parasitic inductance. However, the drawback of the fixed resistor method is its lack of flexibility. Once selected, its switching characteristics (such as du / dt, di / dt) are fixed and cannot be dynamically adjusted according to system operating conditions. In high-frequency applications or when using high-speed devices such as SiC, a fixed switching speed may generate excessive voltage stress under certain operating conditions, while under other operating conditions, it may fail to fully utilize the low-loss potential of the device, resulting in the system efficiency not approaching optimization.

[0005] Therefore, it is necessary to develop a new dynamic gate drive resistor adjustment device and method, a three-phase full-bridge circuit, and a vehicle. Summary of the Invention

[0006] The purpose of this invention is to provide a dynamic gate drive resistor adjustment device and method, a three-phase full-bridge circuit and a vehicle, which can realize digital and dynamic adjustment of the drive resistor.

[0007] In a first aspect, the present invention provides a dynamic gate drive resistor adjustment device, comprising a main control unit, a drive chip, and a drive resistor; wherein the drive resistor comprises a first variable resistor and a second variable resistor.

[0008] The driver chip has a first output terminal and a second output terminal;

[0009] The first variable resistor is electrically connected between the first output terminal and the external power device control terminal, and the second variable resistor is electrically connected between the second output terminal and the external power device control terminal;

[0010] The main control unit is signal-connected to the driver chip, and the main control unit is configured to:

[0011] Determine the target resistance values ​​of the first variable resistor and the second variable resistor, and issue resistance adjustment commands to the first variable resistor and the second variable resistor;

[0012] The first and second variable resistors are adjusted to their corresponding resistance values ​​based on the resistance adjustment command;

[0013] The driver chip has an internal switching action path:

[0014] When the switch is in the ON state, the driver chip is internally connected to the first output terminal;

[0015] When the switch is in the off state, the driver chip is internally connected to the second output terminal.

[0016] In the above technical solution, the present invention realizes the digital and dynamic adjustment of the driving resistor, which can overcome the problem of insufficient flexibility of using a fixed resistor for the turn-on and turn-off of power devices. By using two variable resistors, a first variable resistor and a second variable resistor, respectively corresponding to the turn-on and turn-off conditions, the slow response and resistance value matching lag caused by frequent resistance value switching of a single variable resistor at high switching frequencies can be avoided. It can quickly respond to meet the switching action requirements of the power device, and provide a timely and accurate resistance value during the turn-on and turn-off processes. At the same time, the optimal resistance value can be configured independently to meet the different requirements of suppressing peak current during turn-on and suppressing peak voltage during turn-off, thereby optimizing system efficiency. Moreover, the two variable resistors work independently without interference and can be accurately adjusted according to the instructions of the main control unit, effectively reducing adjustment errors, enhancing the accuracy and stability of dynamic adjustment, improving the switching trajectory optimization effect, power device reliability and system EMI performance. Furthermore, the resistance value can be independently and flexibly adjusted according to real-time bus voltage, load current and other operating conditions (refer to the double pulse test data of the power device), improving the system adaptability and achieving global performance optimization across the entire voltage range and different operating points.

[0017] One possible implementation also includes an isolation unit;

[0018] If the driver chip is a driver chip with integrated isolation function, the isolation unit includes a first isolation device and a second isolation device. The main control unit communicates with the first variable resistor through the first isolation device, and the main control unit also communicates with the second variable resistor through the second isolation device.

[0019] In the above technical solution, the communication isolation between the main control unit and the two variable resistors is achieved through isolation units, which avoids interference between high and low voltage signals and ensures the accuracy and stability of the transmission of resistance adjustment commands.

[0020] One possible implementation also includes an isolation unit;

[0021] If the driver chip is a driver chip without integrated isolation function, the isolation unit is a third isolation device;

[0022] The main control unit communicates with the first variable resistor, the second variable resistor, and the driver chip via a third isolation device.

[0023] In the above technical solution, the communication isolation between the main control unit and the two variable resistors and the driver chip is realized by the isolation unit, which avoids interference between high and low voltage signals and ensures the accuracy and stability of the transmission of resistance adjustment commands.

[0024] In one possible implementation, the first variable resistor includes at least one digital potentiometer, and if the first variable resistor includes multiple digital potentiometers, the digital potentiometers are connected in parallel.

[0025] In one possible implementation, the first variable resistor includes at least one digital potentiometer and at least one fixed resistor, with the digital potentiometer and the fixed resistor connected in parallel.

[0026] In one possible implementation, the second variable resistor includes at least one digital potentiometer, and if the second variable resistor includes multiple digital potentiometers, the digital potentiometers are connected in parallel.

[0027] In one possible implementation, the second variable resistor includes at least one digital potentiometer and at least one fixed resistor, with the digital potentiometer and the fixed resistor connected in parallel.

[0028] Secondly, the dynamic gate drive resistor adjustment method of the present invention is applied to the dynamic gate drive resistor adjustment device of the present invention, and the method includes the following steps:

[0029] The main control unit determines the target resistance values ​​required for the first and second variable resistors;

[0030] The main control unit sends resistance adjustment commands corresponding to the target resistance values ​​to the first and second variable resistors.

[0031] The first variable resistor and the second variable resistor receive the resistance adjustment command and adjust themselves to the corresponding target resistance values;

[0032] The driver chip switches its internal connection path according to the switch's operating state: when the switch is in the open state, it is internally connected to the first output terminal and outputs a drive signal to the external power device control terminal through the first variable resistor; when the switch is in the closed state, it is internally connected to the second output terminal and outputs a drive signal to the external power device control terminal through the second variable resistor.

[0033] The method for confirming the target resistance value is as follows:

[0034] The main control unit acquires the current bus voltage, load demand current, and junction temperature change rate of the power devices;

[0035] The main control unit queries a preset lookup table based on the current bus voltage and the load demand current to obtain the initial value of the target resistance.

[0036] After the power device completes initialization and enters normal switching operation, the main control unit dynamically adjusts the target resistance value based on the real-time collected actual load current and the junction temperature change rate. If the junction temperature change rate of the power device is greater than the first rate threshold, the target resistance value is reduced according to a preset ratio. If the junction temperature change rate of the power device is less than the second rate threshold, the target resistance value is increased according to a preset ratio. The preset reference table is a table showing the correspondence between bus voltage, load demand current and target resistance value, and the first rate threshold is greater than the second rate threshold.

[0037] Thirdly, the three-phase full-bridge circuit described in this invention employs the dynamic gate drive resistor adjustment device as described in this invention.

[0038] Fourthly, the vehicle described in this invention employs a three-phase full-bridge circuit as described in this invention. Attached Figure Description

[0039] Figure 1 This is one of the circuit block diagrams of the dynamic gate drive resistor adjustment device in the embodiments of this application;

[0040] Figure 2 This is a second circuit block diagram of the dynamic gate drive resistor adjustment device in the embodiments of this application;

[0041] Figure 3 This is one of the circuit block diagrams of the first variable resistor in the embodiments of this application;

[0042] Figure 4 This is a second circuit block diagram of the first variable resistor in the embodiments of this application;

[0043] Figure 5 This is the third circuit block diagram of the third variable resistor in the embodiments of this application;

[0044] Figure 6 The fourth circuit block diagram of the third variable resistor in the embodiments of this application;

[0045] Figure 7 This is a flowchart of the dynamic gate drive resistor adjustment method in the embodiments of this application;

[0046] Figure 8 This is a schematic block diagram of the three-phase full-bridge circuit in the embodiments of this application;

[0047] Figure 9 This is a schematic diagram of the vehicle in the embodiments of this application. Detailed Implementation

[0048] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.

[0049] like Figure 1 and Figure 2 As shown, a dynamic gate drive resistor adjustment device includes a main control unit, a drive chip, and a drive resistor; wherein the drive resistor includes a first variable resistor and a second variable resistor. The drive chip has a first output terminal and a second output terminal; the first variable resistor is electrically connected between the first output terminal and the control terminal of an external power device, and the second variable resistor is electrically connected between the second output terminal and the control terminal of the external power device. The main control unit is signal-connected to the drive chip.

[0050] The main control unit is configured to: determine the target resistance values ​​of the first variable resistor and the second variable resistor, and issue resistance adjustment commands to the first variable resistor and the second variable resistor. The first variable resistor and the second variable resistor are adjusted to the corresponding target resistance values ​​based on the resistance adjustment commands.

[0051] The driver chip has an internal switching action path: when the switch is in the open state, the driver chip is internally connected to the first output terminal; when the switch is in the closed state, the driver chip is internally connected to the second output terminal.

[0052] This device enables digital and dynamic adjustment of the drive resistor, overcoming the lack of flexibility in power devices that share a fixed resistor for both turn-on and turn-off.

[0053] The function of a drive resistor is to suppress the peak current when power devices are turned on and the peak voltage when they are turned off. If a single variable resistor (such as a digital potentiometer) is used to perform both the turn-on and turn-off drive functions, although the resistance value can be adjusted according to the real-time status of the system, in high switching frequency scenarios, the digital potentiometer has insufficient response speed when switching between turn-on and turn-off, and it is difficult to quickly provide an appropriate resistance value.

[0054] To address the aforementioned issues with a single variable resistor, this device employs two independent variable resistors: a first variable resistor adapted for turn-on operation and a second variable resistor adapted for turn-off operation. This independent dual-resistor configuration avoids the response lag and untimely resistance matching problems caused by frequent resistance value switching of a single variable resistor during high-frequency switching. It enables rapid response to meet the switching requirements of power devices such as IGBTs and SiC, providing precisely matched drive resistors during both turn-on and turn-off processes. The two variable resistors can be independently set to optimal resistance values ​​to meet the differentiated requirements of suppressing current spikes during turn-on and voltage spikes during turn-off, thereby optimizing system efficiency. For example, a small resistor is used to quickly establish the gate voltage during the initial turn-on phase, switching to a larger resistor as the Miller plateau approaches to suppress current spikes (di / dt) and voltage overshoot (dv / dt). This significantly improves the reliability of power devices and the system's electromagnetic compatibility without excessively sacrificing switching speed. Furthermore, the two variable resistors operate independently without interference, allowing for precise resistance adjustment based on the main control unit's resistance adjustment commands. This reduces adjustment errors, improves the accuracy and stability of dynamic adjustment, and optimizes the switching trajectory. Simultaneously, the device can also independently and flexibly adjust based on real-time bus voltage, load current, and power device temperature parameters, enhancing its adaptability and achieving global performance optimization across the entire voltage range and at different operating points.

[0055] In one possible embodiment, the main control unit uses an MCU as the core of the device control. The MCU collects the bus voltage, load current and power device temperature parameters in real time. Based on the bus voltage, load current and power device temperature parameters, it determines the turn-on resistance value (i.e., the resistance value of the first variable resistor) and the turn-off resistance value (i.e., the resistance value of the second variable resistor). At the same time, it generates PWM control signals and sends resistance adjustment commands to the first variable resistor and the second variable resistor through a communication protocol.

[0056] like Figure 1 As shown, in one possible embodiment, a dynamic gate drive resistor adjustment device further includes an isolation unit. If the driver chip has an isolation function, the isolation unit includes a first isolation device and a second isolation device. The main control unit communicates with the first variable resistor through the first isolation device, and also communicates with the second variable resistor through the second isolation device. This application achieves communication isolation between the main control unit and the two variable resistors through the isolation units, avoiding interference from high and low voltage signals and ensuring the accuracy and stability of the resistance adjustment command transmission.

[0057] For example, the first isolation device and the second isolation device are digital isolators, which respectively realize electrical isolation between the control unit and the first variable resistor and the second variable resistor, ensuring safe isolation between the low-voltage control side and the high-voltage power side, and avoiding high-voltage interference from affecting the main control unit and command transmission.

[0058] like Figure 2 As shown, in one possible embodiment, a dynamic gate drive resistor adjustment device further includes an isolation unit; if the driver chip does not have isolation functionality, the isolation unit includes a third isolation device; the main control unit communicates with the first variable resistor, the second variable resistor, and the driver chip respectively through the third isolation device. This application achieves communication isolation between the main control unit and the two variable resistors and the driver chip through the isolation unit, avoiding interference from high and low voltage signals and ensuring the accuracy and stability of the resistance adjustment command transmission.

[0059] For example, the third isolation device is a digital isolator, which realizes electrical isolation between the MCU and the first variable resistor, the second variable resistor, and the driver chip, respectively, to ensure safe isolation between the low-voltage control side and the high-voltage power side, and to avoid high-voltage interference affecting the main control unit and command transmission.

[0060] like Figure 3 and Figure 4 As shown, in one possible embodiment, the first variable resistor includes at least one digital potentiometer, and if the first variable resistor includes multiple digital potentiometers, the digital potentiometers are connected in parallel.

[0061] For example, the first variable resistor is a digital potentiometer connected in series between the first output terminal of the driver chip and the gate of the power device. The digital potentiometer adjusts its own resistance value according to the resistance adjustment command of the main control unit to control the turn-on speed of the power device (i.e., the adjustment of the resistance value of the first variable resistor is completed before switching).

[0062] like Figure 5 and Figure 6 As shown, in one possible embodiment, the first variable resistor includes at least one digital potentiometer and at least one fixed resistor, with the digital potentiometer and the fixed resistor connected in parallel.

[0063] In one possible embodiment, the second variable resistor includes at least one digital potentiometer, and if the second variable resistor includes multiple digital potentiometers, the digital potentiometers are connected in parallel.

[0064] For example, the second variable resistor is a digital potentiometer connected in series between the second output terminal of the driver chip and the gate of the power device. The digital potentiometer adjusts its own resistance value according to the resistance adjustment command of the main control unit to control the turn-off speed of the power device (i.e., to complete the adjustment of the resistance value of the second variable resistor before switching).

[0065] In one possible embodiment, the second variable resistor includes at least one digital potentiometer and at least one fixed resistor, with the digital potentiometer and the fixed resistor connected in parallel.

[0066] The three-phase full-bridge circuit includes six power devices. This application only shows the drive circuit structure of one of the power devices. The drive circuit structures of the other five power devices are the same as those of the power device. Each of them is independently configured with a corresponding first variable resistor and a second variable resistor to realize the digital dynamic adjustment of the turn-on and turn-off drive resistors of all power devices in the three-phase full-bridge circuit. This ensures that each power device can independently adapt to the optimal resistance value according to its own switching conditions, so that the entire three-phase full-bridge circuit has fast response capability, good switching performance and system efficiency at high switching frequencies, and improves the overall operational reliability and EMI performance.

[0067] like Figure 7 As shown in the embodiments of this application, a dynamic gate drive resistor adjustment method is applied to the dynamic gate drive resistor adjustment device as described in the embodiments of this application. The method includes the following steps:

[0068] The main control unit determines the target resistance values ​​required for the first and second variable resistors.

[0069] The main control unit sends resistance adjustment commands corresponding to the target resistance values ​​to the first and second variable resistors.

[0070] The first and second variable resistors receive resistance adjustment commands and are adjusted to their respective target resistance values.

[0071] The driver chip switches its internal connection path according to the switch's operating state: when the switch is in the open state, it is internally connected to the first output terminal and outputs a drive signal to the external power device control terminal through the first variable resistor; when the switch is in the closed state, it is internally connected to the second output terminal and outputs a drive signal to the external power device control terminal through the second variable resistor.

[0072] In this embodiment of the application, the method for confirming the target resistance value is as follows:

[0073] The main control unit acquires the current bus voltage, load demand current, and junction temperature change rate of the power devices;

[0074] The main control unit queries a preset lookup table based on the current bus voltage and the load demand current to obtain the initial value of the target resistance.

[0075] After the power device completes initialization and enters normal switching operation, the main control unit dynamically adjusts the target resistance value based on the real-time collected actual load current and the junction temperature change rate. If the junction temperature change rate of the power device is greater than the first rate threshold, the target resistance value is reduced according to a preset ratio. If the junction temperature change rate of the power device is less than the second rate threshold, the target resistance value is increased according to a preset ratio. The preset reference table is a table showing the correspondence between bus voltage, load demand current and target resistance value, and the first rate threshold is greater than the second rate threshold.

[0076] In this embodiment, the current bus voltage and load demand current are obtained by querying a preset lookup table through calibration. The combination of different bus voltages, different load demand currents, and different power device junction temperature rates is matched with the corresponding optimal target resistance value and a data table (i.e., preset lookup table) is established.

[0077] like Figure 8 As shown in the embodiments of this application, a three-phase full-bridge circuit adopts the dynamic gate drive resistor adjustment device as described in the embodiments of this application.

[0078] like Figure 9 As shown in the embodiments of this application, a vehicle adopts a three-phase full-bridge circuit as described in the embodiments of this application.

[0079] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A dynamic gate drive resistor adjustment device, characterized in that, It includes a main control unit, a driver chip, and a driver resistor; wherein the driver resistor includes a first variable resistor and a second variable resistor; The driver chip has a first output terminal and a second output terminal; The first variable resistor is electrically connected between the first output terminal and the external power device control terminal, and the second variable resistor is electrically connected between the second output terminal and the external power device control terminal; The main control unit is signal-connected to the driver chip, and the main control unit is configured to: Determine the target resistance values ​​of the first variable resistor and the second variable resistor, and issue resistance adjustment commands to the first variable resistor and the second variable resistor; The first and second variable resistors are adjusted to their corresponding resistance values ​​based on the resistance adjustment command; The driver chip has an internal switching action path: When the switch is in the ON state, the driver chip is internally connected to the first output terminal; When the switch is in the off state, the driver chip is internally connected to the second output terminal.

2. The dynamic gate drive resistor adjustment device according to claim 1, characterized in that, It also includes isolation units; If the driver chip is a driver chip with integrated isolation function, the isolation unit includes a first isolation device and a second isolation device. The main control unit communicates with the first variable resistor through the first isolation device, and the main control unit also communicates with the second variable resistor through the second isolation device.

3. The dynamic gate drive resistor adjustment device according to claim 1, characterized in that, It also includes isolation units; If the driver chip is a driver chip without integrated isolation function, the isolation unit is a third isolation device; The main control unit communicates with the first variable resistor, the second variable resistor, and the driver chip via a third isolation device.

4. The dynamic gate drive resistor adjustment device according to claim 1, characterized in that, The first variable resistor includes at least one digital potentiometer. If the first variable resistor includes multiple digital potentiometers, the digital potentiometers are connected in parallel.

5. The dynamic gate drive resistor adjustment device according to claim 1, characterized in that, The first variable resistor includes at least one digital potentiometer and at least one fixed resistor, with each digital potentiometer and each fixed resistor connected in parallel.

6. The dynamic gate drive resistor adjustment device according to claim 1, characterized in that, The second variable resistor includes at least one digital potentiometer. If the second variable resistor includes multiple digital potentiometers, the digital potentiometers are connected in parallel.

7. The dynamic gate drive resistor adjustment device according to claim 1, characterized in that, The second variable resistor includes at least one digital potentiometer and at least one fixed resistor, with each digital potentiometer and each fixed resistor connected in parallel.

8. A method for adjusting the dynamic gate drive resistor, characterized in that, The method applied to the dynamic gate drive resistor adjustment device as described in any one of claims 1 to 7 includes the following steps: The main control unit determines the target resistance values ​​required for the first and second variable resistors; The main control unit sends resistance adjustment commands corresponding to the target resistance values ​​to the first and second variable resistors. The first variable resistor and the second variable resistor receive the resistance adjustment command and adjust themselves to the corresponding target resistance values; The driver chip switches its internal connection path according to the switch's operating state: when the switch is in the open state, it is internally connected to the first output terminal and outputs a drive signal to the external power device control terminal through the first variable resistor; when the switch is in the closed state, it is internally connected to the second output terminal and outputs a drive signal to the external power device control terminal through the second variable resistor. The method for confirming the target resistance value is as follows: The main control unit acquires the current bus voltage, load demand current, and junction temperature change rate of the power devices; The main control unit queries a preset lookup table based on the current bus voltage and the load demand current to obtain the initial value of the target resistance. After the power device completes initialization and enters normal switching operation, the main control unit dynamically adjusts the target resistance value based on the real-time collected actual load current and the junction temperature change rate. If the junction temperature change rate of the power device is greater than the first rate threshold, the target resistance value is reduced according to a preset ratio. If the junction temperature change rate of the power device is less than the second rate threshold, the target resistance value is increased according to a preset ratio. The preset reference table is a table showing the correspondence between bus voltage, load demand current and target resistance value, and the first rate threshold is greater than the second rate threshold.

9. A three-phase full-bridge circuit, characterized in that, The dynamic gate drive resistor adjustment device as described in any one of claims 1 to 7 is used.

10. A vehicle, characterized in that, The three-phase full-bridge circuit as described in claim 9 is adopted.

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