Driving device and driving method

Abstract

The embodiment of the invention provides a driving device which comprises three phases of bridge arms, each phase of bridge arm comprises an upper switch tube and a lower switch tube which are connected in series, the source end of the upper switch tube is connected to a power supply voltage end, and the drain end of the lower switch tube is connected to a grounding end through a sampling resistor. The drain end of the upper switch tube is connected with the source end of the lower switch tube and is used for being connected to a motor, and the gate end of the upper switch tube and the gate end of the lower switch tube are used for receiving control signals; at least one first capacitor is connected between the source end of the upper switch tube and the drain end of the lower switch tube.

Description

Driving device and driving method Technical Field

[0001] The present application relates to the field of circuit technology, and more specifically, to a driving device and a driving method. Background Art

[0002] Motors are driven by a drive device. Currently, most commonly used drive devices use switching transistors (e.g., metal-oxide-semiconductor (MOS) transistors) to control the on / off power supply to the motor. For motor drives, interference typically comes from two sources: one source of interference comes from the spike surge response generated by the constant on / off switching of the switching transistor, which in turn generates electromagnetic interference that can affect the normal operation of the motor; the other source of interference comes from power supply ripple and noise.

[0003] Summary of the Invention

[0004] In one aspect, an embodiment of the present application provides a driving device, comprising: a three-phase bridge arm, each phase bridge arm comprising an upper switch tube and a lower switch tube connected in series, the source terminal of the upper switch tube being connected to the power supply voltage terminal, the drain terminal of the lower switch tube being connected to the ground terminal via a sampling resistor, the drain terminal of the upper switch tube being connected to the source terminal of the lower switch tube and being used to be connected to the motor, the gate terminal of the upper switch tube and the gate terminal of the lower switch tube being used to receive a control signal; wherein, at least one first capacitor is also connected between the source terminal of the upper switch tube and the drain terminal of the lower switch tube.

[0005] In some implementations, the at least one first capacitor includes two or more capacitors.

[0006] In some implementations, two or more capacitors are connected in series.

[0007] In some implementations, the two or more capacitors can be the same or different.

[0008] In some implementations, the driving device according to the embodiment of the present application further includes: a second capacitor connected to the power supply voltage terminal and the ground terminal.

[0009] In some implementations, the second capacitor is an electrolytic capacitor or a supercapacitor.

[0010] In some implementations, the driving device according to the embodiment of the present application further includes: a third capacitor connected to the power supply voltage terminal and the ground terminal.

[0011] In some implementations, the driving device according to the embodiment of the present application further includes: a first resistor and a fourth capacitor connected in series to the source terminal and the drain terminal of the upper switch tube.

[0012] In some implementations, the driving device according to the embodiment of the present application further includes: a second resistor and a fifth capacitor connected in series between the source terminal and the drain terminal of the lower switch tube.

[0013] In some implementations, the upper switch tube and the lower switch tube are metal oxide semiconductor transistors.

[0014] According to the driving device of the embodiment of the present application, by providing a capacitor between the source terminal of the upper switch tube and the drain terminal of the lower switch tube, electromagnetic interference can be effectively reduced, electromagnetic sensitivity (EMS) can be improved, and noise interference can be weakened. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly describes the drawings involved in the embodiments of the present application. For those skilled in the art, other drawings can also be obtained based on these drawings without creative work. In the drawings:

[0016] FIG1 shows a circuit diagram of a driving device according to an embodiment of the present application.

[0017] FIG2 shows a printed circuit board (PCB) layout of a driving device according to an embodiment of the present application.

[0018] FIG3 shows a PCB layout of a driving device according to an embodiment of the present application.

[0019] FIG4 shows a schematic diagram of an application of a driving device according to an embodiment of the present application. DETAILED DESCRIPTION

[0020] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, scheme, and advantages of the present application clearer, the details of the present application are further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. For those skilled in the art, the present application can be implemented without some of the details in these specific details. The following description of the embodiments is only for providing a better understanding of the present application by illustrating the examples of the present application.

[0021] It should be noted that, in this article, relational terms such as first, second, third, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. In addition, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, and the process, method, article or equipment including a series of elements includes not only these elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the presence of additional elements in the process, method, article or equipment including the elements.

[0022] As mentioned above, for the motor drive circuit device, part of the interference comes from the spike surge response generated by the continuous switching of the switch tube. The electromagnetic interference generated by the spike surge response will affect the normal operation of the motor; another part of the interference comes from the ripple and noise of the power supply.

[0023] One existing solution involves placing a capacitor between the drain and source of each switching tube in the driver device so that the spike generated when the switching tube is rapidly turned off is absorbed by the capacitor, thereby reducing electromagnetic interference and ensuring that the motor can operate normally when the switching tube is rapidly turned off. However, this solution has a very limited effect on suppressing high-frequency interference generated by the power supply.

[0024] Another existing solution involves placing a capacitor between the positive terminal of the drive device's power supply voltage and ground to absorb the hookback voltage generated by the motor, thereby preventing damage to the switching tube in the lower bridge arm of the drive device due to the hookback voltage possibly exceeding the upper limit of the switching tube's tolerance. However, for many systems with limitations such as spatial structure and printed circuit board (PCB) design, this solution causes the loop area from the positive terminal of the power supply voltage to ground to be too wide and the loop path to be too long, making the capacitor unable to effectively absorb the voltage.

[0025] In view of the above, embodiments of the present application provide a driving device and a driving method that can effectively suppress high-frequency noise without increasing the loop area. The driving device and the driving method according to embodiments of the present application are described in detail below with reference to FIG1 to FIG4 .

[0026] FIG1 shows a schematic circuit diagram of a drive device according to an embodiment of the present application. As shown in FIG1 , the drive device 100 according to an embodiment of the present application includes: a three-phase bridge arm, each phase bridge arm including an upper switch tube and a lower switch tube connected in series, the source terminal of the upper switch tube being connected to the supply voltage terminal, the drain terminal of the lower switch tube being connected to the ground terminal via a sampling resistor, the drain terminal of the upper switch tube being connected to the source terminal of the lower switch tube and being connected to the motor, and the gate terminal of the upper switch tube and the gate terminal of the lower switch tube being used to receive a control signal; wherein, at least one first capacitor is further connected between the source terminal of the upper switch tube and the drain terminal of the lower switch tube.

[0027] More specifically, as shown in FIG1 , the first phase bridge arm includes an upper switch tube M1 and a lower switch tube M4 connected in series. The source terminal of the upper switch tube M1 is connected to the power supply voltage terminal Vcc, and the drain terminal of the lower switch tube M4 is connected to the ground terminal GND via the sampling resistor R7. The drain terminal of the upper switch tube M1 is connected to the source terminal of the lower switch tube M4 and is used to be connected to a motor (not shown in the figure). The gate terminal of the upper switch tube M1 and the gate terminal of the lower switch tube M4 are used to receive a control signal (for example, from the pre-driver module U1). At least one first capacitor (such as the series-connected capacitors C8 and C14 shown in the figure) is also connected between the source terminal of the upper switch tube M1 and the drain terminal of the lower switch tube M4.

[0028] Similarly, the second-phase bridge arm includes an upper switch tube M2 and a lower switch tube M5 connected in series. The source terminal of the upper switch tube M2 is connected to the power supply voltage terminal Vcc, and the drain terminal of the lower switch tube M5 is connected to the ground terminal GND via the sampling resistor R8. The drain terminal of the upper switch tube M2 is connected to the source terminal of the lower switch tube M5 and is used to connect to the motor (not shown in the figure). The gate terminal of the upper switch tube M2 and the gate terminal of the lower switch tube M5 are used to receive a control signal (for example, from the pre-driver module U1); wherein, at least one first capacitor (as shown in the figure, the series-connected capacitors C10 and C16) is also connected between the source terminal of the upper switch tube M2 and the drain terminal of the lower switch tube M5.

[0029] Similarly, the third-phase bridge arm includes an upper switch tube M3 and a lower switch tube M6 connected in series. The source terminal of the upper switch tube M3 is connected to the power supply voltage terminal Vcc, and the drain terminal of the lower switch tube M6 is connected to the ground terminal GND via the sampling resistor R9. The drain terminal of the upper switch tube M3 is connected to the source terminal of the lower switch tube M6 and is used to be connected to the motor (not shown in the figure). The gate terminal of the upper switch tube M3 and the gate terminal of the lower switch tube M6 are used to receive a control signal (for example, from the pre-driver module U1); wherein, at least one first capacitor (as shown in the figure, the series-connected capacitors C12 and C18) is also connected between the source terminal of the upper switch tube M3 and the drain terminal of the lower switch tube M6.

[0030] It should be understood that for each phase bridge arm, the at least one first capacitor may not be limited to the two capacitors shown in the figure, but may be more or fewer capacitors. It should also be understood that the multiple first capacitors can reduce the failure caused by the short circuit of a single capacitor and increase the reliability and stability of the system. However, the at least one first capacitor of the present application may not be limited to the series connection shown in the figure, but may also be connected in parallel, for example. The capacitors in the at least one first capacitor may be the same or different capacitors. The impedance values ​​of the sampling resistors R7, R8, and R9 are usually relatively small, for example, less than 5m Ω.

[0031] In some implementations, for each phase bridge arm, the driving device 100 further includes: a second capacitor connected to the power supply voltage terminal and the ground terminal.

[0032] Specifically, as shown in FIG1 , for the first-phase bridge arm, the driving device 100 further includes a second capacitor C1 connected between the power supply voltage terminal Vcc and the ground terminal GND. For the second-phase bridge arm, the driving device 100 further includes a second capacitor C3 connected between the power supply voltage terminal Vcc and the ground terminal GND. For the third-phase bridge arm, the driving device 100 further includes a second capacitor C5 connected between the power supply voltage terminal Vcc and the ground terminal GND.

[0033] In some implementations, the second capacitors C1, C3, and C5 for each phase bridge arm can be electrolytic capacitors (as shown in FIG1 ) or supercapacitors. The second capacitors C1, C3, and C5 are used to store energy. When the drive circuit experiences high instantaneous power consumption, they can temporarily store the released energy, stabilize the supply voltage, and improve voltage stability.

[0034] In some implementations, for each phase bridge arm, the driving device 100 further includes: a third capacitor connected between the power supply voltage terminal and the ground terminal.

[0035] Specifically, as shown in FIG1 , for the first-phase bridge arm, the driving device 100 further includes: a third capacitor C2 connected between the power supply voltage terminal Vcc and the ground terminal GND. For the second-phase bridge arm, the driving device 100 further includes: a third capacitor C4 connected between the power supply voltage terminal Vcc and the ground terminal GND. For the third-phase bridge arm, the driving device 100 further includes: a third capacitor C6 connected between the power supply voltage terminal Vcc and the ground terminal GND.

[0036] In some implementations, for each phase bridge arm, the driving device 100 further includes: a first resistor and a fourth capacitor connected in series to the source terminal and the drain terminal of the upper switch tube.

[0037] Specifically, as shown in FIG1 , for the first-phase bridge arm, the driver device 100 further includes: a first resistor R1 and a fourth capacitor C7 connected in series to the source and drain terminals of the upper switch M1. The first resistor R1 and the fourth capacitor C7 serve as a buffer circuit for the upper switch M1. For the second-phase bridge arm, the driver device 100 further includes: a first resistor R2 and a fourth capacitor C9 connected in series to the source and drain terminals of the upper switch M2. The first resistor R2 and the fourth capacitor C9 serve as a buffer circuit for the upper switch M2. For the third-phase bridge arm, the driver device 100 further includes: a first resistor R3 and a fourth capacitor C11 connected in series to the source and drain terminals of the upper switch M3. The first resistor R3 and the fourth capacitor C11 serve as a buffer circuit for the upper switch M3.

[0038] In some implementations, for each phase bridge arm, the driving device 100 further includes: a second resistor and a fifth capacitor connected in series between the source terminal and the drain terminal of the lower switch tube.

[0039] Specifically, as shown in FIG1 , for the first-phase bridge arm, the driver device 100 further includes: a second resistor R4 and a fifth capacitor C13 connected in series between the source and drain terminals of the lower switch M4. The second resistor R4 and the fifth capacitor C13 serve as a buffer circuit for the lower switch M4. For the second-phase bridge arm, the driver device 100 further includes: a second resistor R5 and a fifth capacitor C15 connected in series between the source and drain terminals of the lower switch M5. The second resistor R5 and the fifth capacitor C15 serve as a buffer circuit for the lower switch M5. For the third-phase bridge arm, the driver device 100 further includes: a second resistor R6 and a fifth capacitor C17 connected in series between the source and drain terminals of the lower switch M6. The second resistor R6 and the fifth capacitor C17 serve as a buffer circuit for the lower switch M6.

[0040] The buffer circuit of switch M1 absorbs the current and spike voltage stored in the inductor and capacitor components, thereby reducing the spike voltage generated when switch M1 is turned on and off. For switch M1, adjusting the first resistor R1 and the fourth capacitor C7 can absorb the ringing and feedback voltage generated by the source and drain terminals of switch M1. For the other switches M2, M3, M4, M5, and M6, their corresponding buffer circuits perform similar functions and are not further described here.

[0041] It should be understood that for each phase bridge arm, the second capacitor, the third capacitor, and the fourth capacitor can be the same or different. The second capacitor, the third capacitor, and the fourth capacitor can also be the same or different between each phase bridge arm. The first resistor can also be the same or different between each phase bridge arm.

[0042] In some implementations, for each phase bridge arm, the upper switch tubes M1 , M2 , and M3 and the lower switch tubes M4 , M5 , and M6 may be metal oxide semiconductor (MOS) transistors.

[0043] According to the driving device of the embodiment of the present application, by providing a capacitor between the source terminal of the upper switching tube and the drain terminal of the lower switching tube, electromagnetic interference caused by the frequent switching of the switching tube can be effectively reduced, thereby improving electromagnetic sensitivity (EMS) and absorbing power supply ripple and noise. In addition, by adding bypass capacitors at the supply voltage terminal and the ground terminal, power supply ripple and noise can be further absorbed.

[0044] The driving device according to the embodiment of the present application can be applied to a system requiring a driving module, such as but not limited to an electronic power steering system of a vehicle.

[0045] FIG2 shows an application diagram of a driving device according to an embodiment of the present application. As shown in FIG2 , in this application, the driving device according to an embodiment of the present application is used as a driving module 203 as shown in the figure. In this application, the microcontroller unit (MCU) 201 of the vehicle sends a control signal to the pre-driving module 202. The pre-driving module 202 generates a pre-driving signal for controlling the conduction or shutoff of the switch tubes of each phase bridge arm of the driving module 203 according to the control signal sent by the MCU 201. Then, the driving module 203 generates a driving signal by turning on or off the switch tubes of each phase bridge arm to drive the motor 204 to operate. The sampling module 205 samples the voltage or current signal of the motor 204 and feeds it back to the MCU 201, and then the MCU 201 generates an appropriate control signal.

[0046] The driver circuit (including the three-phase bridge arms) is typically integrated into a printed circuit board (PCB). Due to the nature of the driver circuit, all components must be located together in a single PCB. Because the driver circuit generates significant heat, the backside of the PCB is typically not used for other components and is used solely for heat dissipation to improve circuit stability and reliability.

[0047] The pre-drive signal sent by the pre-drive module 202 is generally a pulse width modulation (PWM) wave, which carries abundant high-frequency components on the rising edge of the PWM wave. Due to the influence of components and PCB spatial structure, there is no way to absorb this high-frequency component through PCB design.

[0048] According to the drive device of the embodiment of the present application, on the one hand, capacitors C1, C2, C3, C4, C5, and C6 are placed at the power supply voltage terminal. Since capacitors have the characteristic of "passing high frequencies and blocking low frequencies", these capacitors provide a low-impedance return path for high-frequency noise, allowing high-frequency noise to quickly return to the ground terminal, reducing interference noise flowing into the loop, and improving the electromagnetic immunity (EMS) of the system. In practice, the second capacitors C1, C3, and C5 have a significant suppressive effect on motor ripple noise, but their ability to suppress high-frequency power supply noise is limited. Therefore, they are used in conjunction with the third capacitors C2, C4, and C6.

[0049] Figure 3 shows the PCB layout of a drive device according to an embodiment of the present application. As shown in Figure 3, the drive circuit is arranged in the lower left part of the PCB. Capacitors C1, C3, and C5 are generally large in size, and their placement on the PCB is greatly affected by the spatial structure of the PCB. Therefore, they are arranged in the upper right part of the PCB, farther away from the drive circuit, together with capacitors C2, C4, and C6. Sampling resistors R7, R8, and R9 can be packaged as, for example, 2512 or 3920 and are arranged on the back of the PCB. In the figure, the pre-driver module and MCU are set in the lower right part of the PCB, and some connectors or other components can be set in the upper left part.

[0050] As shown in Figure 3, for capacitors C1, C2, C3, C4, C5, and C6, the loop area from the power supply voltage terminal Vcc to the ground terminal GND is large, and the return path is long, which cannot effectively absorb the high-frequency noise introduced by the frequent on-off of the switching tube.

[0051] Therefore, on the other hand, the driving device according to the embodiment of the present application adds a first capacitor C8, C14, C10, C16, C12, and C18 low-pass filter to provide a low-impedance leakage path for high-frequency noise, so that high-frequency noise and high-order harmonics leak to the system ground terminal in advance, thereby reducing the interference flowing into the system, effectively suppressing the interference noise, and improving the EMS performance of the system.

[0052] More specifically, according to the relevant theories of electromagnetic technology, there is the following formula

[0053] Where E represents the electric field strength, S represents the loop area, I represents the current, f represents the frequency of the pre-drive signal, and D represents the distance between loops. Generally speaking, once the PCB design is finalized, I, f, and D remain constant. Therefore, the larger the loop area S, the greater the spatially radiated electric field strength E. Therefore, by reducing the loop area S, spatial radiation can be reduced and the noise propagation path can be shortened.

[0054] Figure 4 shows the PCB layout of a driver device according to an embodiment of the present application. Figure 4 specifically illustrates the layout of the driver circuitry. As can be seen, capacitors C8, C14, C10, C16, C12, and C18 are placed near the switching transistors, reducing the return path and loop area, thereby effectively absorbing high-frequency noise.

[0055] Therefore, according to the driving device of the embodiment of the present application, by adding capacitors C8, C14, C10, C16, C12, and C18 to the source terminal of the upper switch and the drain terminal of the lower switch, an AC leakage circuit for high-frequency noise is provided, which suppresses high-frequency noise, improves EMS performance, and reduces the loop area and return path, thereby reducing spatial radiation and weakening noise interference.

[0056] The above disclosure is only some specific embodiments of the present application, and the present application is not limited to the specific structures described above and shown in the drawings. Those skilled in the art will understand that the scope of protection of the present application is not limited thereto, but rather various equivalent modifications or replacements are conceivable within the technical scope disclosed in the present application, and these equivalent modifications or replacements are all included in the scope of protection of the present application.

Claims

1. A driving device comprising: A three-phase bridge arm, each phase bridge arm includes an upper switch tube and a lower switch tube connected in series, a source terminal of the upper switch tube is connected to a power supply voltage terminal, a drain terminal of the lower switch tube is connected to a ground terminal via a sampling resistor, a drain terminal of the upper switch tube is connected to a source terminal of the lower switch tube and is used to be connected to a motor, and a gate terminal of the upper switch tube and a gate terminal of the lower switch tube are used to receive a control signal; Wherein, at least one first capacitor is connected between the source terminal of the upper switch tube and the drain terminal of the lower switch tube.

2. The driving device according to claim 1, wherein: The at least one first capacitor includes two or more capacitors.

3. The driving device according to claim 2, wherein: The two or more capacitors are connected in series.

4. The driving device according to claim 3, wherein: The two or more capacitors may be the same or different.

5. The driving device according to claim 1, further comprising: A second capacitor is connected between the supply voltage terminal and the ground terminal.

6. The driving device according to claim 5, wherein: The second capacitor is an electrolytic capacitor or a super capacitor.

7. The driving device according to claim 5, further comprising: a third capacitor connected between the supply voltage terminal and the ground terminal.

8. The driving device according to claim 1, further comprising: A first resistor and a fourth capacitor connected in series are connected to the source terminal and the drain terminal of the upper switch tube.

9. The driving device according to claim 8, further comprising: A second resistor and a fifth capacitor connected in series are connected to the source terminal and the drain terminal of the lower switch tube.

10. The driving device according to claim 1, wherein The upper switch tube and the lower switch tube are metal oxide semiconductor transistors.

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