Switching control circuit, motor drive system and vehicle

Abstract

This invention discloses a switch control circuit, a motor drive system, and a vehicle. The switch control circuit controls the on / off state of a switch module and includes a control module, a comparison module, a sampling module, and a negative feedback module. The control module generates a reference voltage signal and a first control signal, and transmits them to the comparison module. The sampling module acquires the voltage change signal at the first terminal of the switch module and transmits it to the first terminal of the comparison module. The comparison module generates a second control signal based on the reference voltage signal, the control signal, and the voltage change signal. The negative feedback module adjusts the steepness of the rising and falling edges of the second control signal. This invention enables dynamic adjustment of the voltage switching speed of the switch module by changing the characteristic parameters of the reference voltage signal and the first control signal through the control module. This overcomes the noise interference problem caused by the large voltage change rate of the bus voltage in existing drive systems, and helps reduce EMI noise.

Description

Technical Field

[0001] This invention relates to the field of circuit technology, and in particular to a switch control circuit, a motor drive system, and a vehicle. Background Technology

[0002] Currently, electric motors are widely used in instrumentation, automated production, national defense, and aerospace. In the application of electric motors, the drive system, as a key component for energy conversion or transfer, is a primary focus for designers.

[0003] In the existing technology, the drive system needs to continuously turn the high voltage of the bus on and off by controlling the switch. During this process, the bus voltage will generate violent voltage fluctuations and the voltage change rate dV / dt of the bus voltage is too large, thus causing electromagnetic interference (EMI) noise interference problems. Summary of the Invention

[0004] This invention provides a switch control circuit, a motor drive system, and a vehicle to reduce EMI noise.

[0005] According to one aspect of the present invention, a switch control circuit is provided for controlling the on / off state of a switch module, comprising a control module, a comparison module, a sampling module, and a negative feedback module;

[0006] The first terminal of the control module is connected to the first terminal of the comparison module, and the second terminal of the control module is connected to the second terminal of the comparison module; the control module is used to generate a reference voltage signal and transmit the reference voltage signal to the first terminal of the comparison module through the first terminal of the control module, and to generate a first control signal and transmit the first control signal to the second terminal of the comparison module through the second terminal of the control module.

[0007] The sampling module is connected between the first terminal of the comparison module and the first terminal of the switching module; the sampling module is used to acquire the voltage change signal at the first terminal of the switching module and transmit the voltage change signal to the first terminal of the comparison module.

[0008] The third terminal of the comparison module is connected to the second terminal of the switch module; the comparison module is used to generate a second control signal based on the reference voltage signal, the control signal and the voltage change signal, so as to control the on / off state of the switch module;

[0009] The negative feedback module is connected between the second end and the third end of the comparison module; the negative feedback module is used to adjust the steepness of the rising and falling edges of the second control signal.

[0010] Optionally, the switching module includes an inductor, a bus capacitor, an insulated gate bipolar transistor (IGBT), and a diode;

[0011] The diode is connected in parallel between the collector and emitter of the IGBT;

[0012] The gate of the IGBT is connected to the second terminal of the switching module, the collector of the IGBT is connected to the first terminal of the switching module, and the emitter of the IGBT is connected to the negative terminal of the bus capacitor.

[0013] The positive terminal of the bus capacitor is connected to the first terminal of the inductor;

[0014] The second end of the inductor is connected to the collector of the IGBT.

[0015] Optionally, the negative feedback module includes a first resistor and a first capacitor;

[0016] The first end of the first resistor is connected to the second end of the comparison module, and the second end of the first resistor is connected to the negative end of the first capacitor.

[0017] The positive terminal of the first capacitor is connected to the third terminal of the comparison module.

[0018] Optionally, it also includes:

[0019] The second resistor is connected between the first terminal of the control module and the first terminal of the comparison module.

[0020] Optionally, it also includes:

[0021] A third resistor is connected between the second terminal of the control module and the second terminal of the comparison module.

[0022] Optionally, it also includes:

[0023] A fourth resistor is connected between the third terminal of the comparator module and the second terminal of the switch module.

[0024] Optionally, the sampling module includes a second capacitor;

[0025] The negative terminal of the second capacitor is connected to the first terminal of the comparison module, and the positive terminal of the second capacitor is connected to the first terminal of the switching module.

[0026] Optionally, the control module is a microcontroller unit (MCU), and the comparison module is a comparator.

[0027] According to another aspect of the present invention, a motor drive system is provided, including the switch control circuit described in any embodiment of the present invention.

[0028] According to another aspect of the present invention, a vehicle is provided that integrates the motor drive system described in any embodiment of the present invention.

[0029] The technical solution of this invention involves a control module generating a reference voltage signal and a first control signal, which are then transmitted to a comparison module. A sampling module acquires the voltage change signal at the first terminal of the switching module and transmits this signal to the comparison module. The comparison module generates a second control signal based on the reference voltage signal, the control signal, and the voltage change signal to control the switching on / off state of the switching module. A negative feedback module connected between the second and third terminals of the comparison module adjusts the steepness of the rising and falling edges of the second control signal. Therefore, this invention can dynamically adjust the voltage switching speed of the switching module, overcoming the EMI noise interference problem caused by the large voltage change rate of the bus voltage during continuous switching of high-voltage bus voltage in existing drive systems, thus helping to reduce EMI noise.

[0030] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a structural diagram of a switch control circuit provided in an embodiment of the present invention;

[0033] Figure 2 This is a waveform diagram of a first control signal provided in an embodiment of the present invention;

[0034] Figure 3 This is a waveform diagram of a second control signal provided in an embodiment of the present invention;

[0035] Figure 4 This is a structural diagram of another switch control circuit provided in an embodiment of the present invention;

[0036] Figure 5 This is an EMI frequency domain diagram of an existing IGBT drive circuit system;

[0037] Figure 6This is an EMI frequency domain diagram of a switch control circuit provided in an embodiment of the present invention;

[0038] Figure 7 This is a functional logic diagram of a motor drive system provided in an embodiment of the present invention. Detailed Implementation

[0039] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0040] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0041] Figure 1 This is a structural diagram of a switch control circuit provided in an embodiment of the present invention. See also... Figure 1 The switch control circuit is used to control the on / off state of the switch module 200, and includes a control module 110, a comparison module 120, a sampling module 130, and a negative feedback module 140.

[0042] The first terminal of the control module 110 is connected to the first terminal of the comparison module 120, and the second terminal of the control module 110 is connected to the second terminal of the comparison module 120. The control module 110 is used to generate a reference voltage signal and transmit the reference voltage signal to the first terminal of the comparison module 120 through the first terminal of the control module 110, and to generate a first control signal and transmit the first control signal to the second terminal of the comparison module 120 through the second terminal of the control module 110.

[0043] The sampling module 130 is connected between the first terminal of the comparison module 120 and the first terminal of the switch module 200; the sampling module 130 is used to collect the voltage change signal of the first terminal of the switch module 200 and transmit the voltage change signal to the first terminal of the comparison module 120.

[0044] The third terminal of the comparison module 120 is connected to the second terminal of the switch module 200; the comparison module 120 is used to generate a second control signal based on the reference voltage signal, the control signal and the voltage change signal, so as to control the switching of the switch module 200.

[0045] The negative feedback module 140 is connected between the second terminal and the third terminal of the comparison module 120; the negative feedback module 140 is used to adjust the steepness of the rising and falling edges of the second control signal.

[0046] In this context, the switching module 200 refers to one or more switching transistors of any type, or a circuit containing such switching transistors. For example, the switching module 200 may be an Insulated Gate Bipolar Transistor (IGBT). The control module 110 may be a microcontroller, a system-on-a-chip (SoC), or a programmable logic controller (PLC), etc. Optionally, the control module 110 may employ a microcontroller unit (MCU). The sampling module 130 may be a sampling resistor, a sampling capacitor, or a combined sampling circuit; the comparison module 120 may be a microcontroller, etc. Optionally, the comparison module 120 may employ a comparator. In this case, the first terminal of the comparison module 120 refers to the non-inverting terminal of the comparator, the second terminal refers to the inverting terminal of the comparator, and the third terminal refers to the output terminal of the comparator.

[0047] It is understood that the reference voltage signal refers to a reference signal with a certain voltage value, and the first control signal can be a pulse width modulation (PWM) signal. It is also understood that since both the reference voltage signal and the first control signal are generated by the control module 110, the voltage value of the reference voltage signal, as well as the frequency, amplitude, duty cycle, and other characteristic parameters of the first control signal, are adjustable, and this embodiment of the invention does not impose any limitations on these aspects. For example, the voltage value of the reference voltage signal can be -1V, 2V, 5V, or 10V, etc. Furthermore, the voltage change signal refers to the rate of change of the bus voltage, dV / dt, and the second control signal is used to control the on / off state of the switching module 200; the second control signal can be a PWM signal.

[0048] Based on this, the working principle of the switch control circuit provided in this embodiment is as follows:

[0049] The control module 110 generates a reference voltage signal and a first control signal, and transmits the reference voltage signal and the first control signal to the comparison module 120; the sampling module 130 acquires the voltage change signal at the first terminal of the switch module 200, and transmits the voltage change signal to the comparison module 120; the comparison module 120 generates a second control signal based on the reference voltage signal, the control signal and the voltage change signal, and then controls the switching on and off of the switch module 200; the negative feedback module 140 connected between the second terminal and the third terminal of the comparison module 120 adjusts the steepness of the rising edge and falling edge of the second control signal.

[0050] For example, Figure 2 This is a waveform diagram of a first control signal provided in an embodiment of the present invention. Figure 3 This is a waveform diagram of a second control signal provided in an embodiment of the present invention. See also... Figure 2 and Figure 3 The negative feedback module can significantly improve the steepness of the rising and falling edges of the second control signal, which is beneficial to reducing EMI noise.

[0051] See also Figure 2 and Figure 3 As can be seen, T represents the period of the first control signal and the second control signal, D represents the duty cycle of the first control signal and the second control signal, and tr represents the time of the rising edge or falling edge of the first control signal and the second control signal.

[0052] In summary, the embodiments of the present invention can dynamically adjust the voltage switching speed of the switching module by changing the characteristic parameters of the reference voltage signal and the first control signal through the control module. This overcomes the EMI noise interference problem caused by the large voltage change rate of the bus voltage during the continuous switching of the high voltage of the bus by the control switch in the existing drive system, and is beneficial to reducing EMI noise.

[0053] Based on the above embodiments, the specific settings of other circuit structures in the switching module, negative feedback module, sampling module and switching control circuit are described below, but these are not intended to limit the present invention.

[0054] Figure 4 This is a structural diagram of another switch control circuit provided in an embodiment of the present invention. See also... Figure 4 Optionally, the switching module 200 includes an inductor L1, a bus capacitor C1, an insulated-gate bipolar transistor (IGBT), and a diode. The diode is connected in parallel between the collector and emitter of the IGBT. The gate of the IGBT is connected to the second terminal of the switching module 200, the collector of the IGBT is connected to the first terminal of the switching module, and the emitter of the IGBT is connected to the negative terminal of the bus capacitor C1. The positive terminal of the bus capacitor C1 is connected to the first terminal of the inductor L1. The second terminal of the inductor L1 is connected to the collector of the IGBT.

[0055] In this configuration, IGBTs and diodes can form an IGBTD, and inductor L1 is used to simulate a motor load.

[0056] See also Figure 4 Optionally, the negative feedback module 140 includes a first resistor R2 and a first capacitor C3. A first terminal of the first resistor R2 is connected to a second terminal of the comparator module 120, and a second terminal of the first resistor R2 is connected to the negative terminal of the first capacitor C3. The positive terminal of the first capacitor C3 is connected to a third terminal of the comparator module 120.

[0057] In this circuit, the first resistor R2 is the negative feedback resistor, and the first capacitor C3 is the negative feedback capacitor. It is understood that the negative feedback module 140, composed of the first resistor R2 and the first capacitor C3, also has a filtering function. It can filter the second control signal output from the third terminal of the comparison module 120 before transmitting it to the second terminal of the comparison module 120, further reducing EMI noise.

[0058] See also Figure 4 Optionally, it also includes a second resistor Rf, which is connected between the first terminal of the control module 110 and the first terminal of the comparison module 120.

[0059] The second resistor Rf is a balancing resistor used to balance the offset current between the first and second terminals of comparator Op, so as to balance the voltage between the first and second terminals of comparator Op and reduce the offset voltage.

[0060] See also Figure 4 Optionally, it also includes a third resistor Ri, which is connected between the second terminal of the control module 110 and the second terminal of the comparison module 120.

[0061] The third resistor, Ri, is a matching resistor used to match the input and output impedances of the comparator Op.

[0062] See also Figure 4 Optionally, it also includes a fourth resistor Rg, which is connected between the third terminal of the comparator module 120 and the second terminal of the switch module 200.

[0063] The fourth resistor, Rg, is the driving resistor used to drive the IGBT.

[0064] See also Figure 4 Optionally, the sampling module 130 includes a second capacitor Cv. The negative terminal of the second capacitor Cv is connected to the first terminal of the comparison module 120, and the positive terminal of the second capacitor Cv is connected to the first terminal of the switching module 200.

[0065] The second capacitor Cv is a sampling capacitor used to collect the voltage at the collector of the IGBT, which is the rate of change of the bus voltage, dV / dt.

[0066] Based on this, the working principle of the switch control circuit provided in this embodiment is as follows:

[0067] The control module 110 generates a reference voltage signal and a first control signal. The reference voltage signal is transmitted to the non-inverting input of the comparator Op through the second resistor Rf, and the first control signal is transmitted to the inverting input of the comparator Op through the third resistor Ri. The second capacitor Cv collects the voltage change signal at the first terminal of the switching module 200 and transmits the voltage change signal to the non-inverting input of the comparator Op. The comparator Op generates a second control signal based on the reference voltage signal, the control signal, and the voltage change signal, thereby controlling the switching module 200 to turn on and off. The first resistor R2 and the first capacitor C3 connected between the inverting input and the output terminal of the comparator Op adjust the steepness of the rising and falling edges of the second control signal.

[0068] For example, Figure 5 This is an EMI frequency domain diagram of an existing IGBT drive circuit system. Figure 6 This is an EMI frequency domain diagram of a switch control circuit provided in an embodiment of the present invention. See also... Figure 5 and Figure 6 After the switch is turned off, the phase noise slope of the existing IGBT drive circuit system is -48 dB / decade, while the phase noise slope of the switch control circuit provided in this embodiment of the invention is -60 dB / decade. Therefore, compared with the existing IGBT drive circuit system, the switch control circuit provided in this embodiment of the invention can significantly reduce EMI noise.

[0069] In summary, the embodiments of the present invention can dynamically adjust the voltage switching speed of the IGBT by changing the characteristic parameters of the reference voltage signal and the first control signal through the control module. This overcomes the EMI noise interference problem caused by the large voltage change rate of the bus voltage during the continuous switching of the high voltage of the bus by the control switch in the existing drive system, and is beneficial to reducing EMI noise.

[0070] It should be noted that the first resistor R2, the second resistor Rf, the third resistor Ri, and the fourth resistor Rg can be any type of resistor, such as a surface-mount resistor; the first capacitor C3 and the second capacitor Cv can be any type of capacitor, such as a foil polypropylene capacitor. For the above embodiments, the characteristic parameters of each component in the switch control circuit can be adaptively adjusted according to the actual application scenario of the switch control circuit, and the embodiments of the present invention do not impose any limitations in this regard.

[0071] This invention also provides a motor drive system, including the switch control circuit provided in any embodiment of this invention.

[0072] For example, Figure 7 This is a functional logic diagram of a motor drive system provided in an embodiment of the present invention. See also... Figure 7 The input signal, Input PWM, is converted into a reference signal Vref by the switching control circuit. The reference signal Vref and the feedback signal V from the power IGBT are then used together. CE After conversion, the input is given to the power control circuit, which adaptively generates a drive signal V. GE It drives the power IGBT to switch on and off, thereby supplying power to electrical loads such as motors.

[0073] This embodiment adds a voltage switching speed detection step to the motor drive system. The input PWM signal is converted using a switching control circuit, and the converted reference signal Vref is compared with the feedback signal V from the power IGBT. CE After being combined with the input power control circuit, the power control circuit adaptively generates the drive signal V. GE To drive the power IGBT to switch on and off, due to the feedback signal V of the power IGBT. CE Since the data is acquired synchronously, the motor drive system has strong real-time performance. Furthermore, in the early stages of electromagnetic interference experiments, this application can calibrate the switching speed of the power IGBT and record the calibrated data in a database. During the experiment, simply retrieving data from the database ensures that the final experimental results meet the test standards.

[0074] Therefore, this embodiment can dynamically adjust the voltage switching speed of the IGBT in a closed loop during product iteration, thereby reducing EMI noise; through the settings of the host computer software, the hardware iteration time and cost caused by electromagnetic interference experiments can be reduced.

[0075] This invention also provides a vehicle including the motor drive system provided in any embodiment of this invention. Its technical principle and implementation effect are similar, and will not be described again.

[0076] It should be noted that the motor drive system provided in any embodiment of the present invention can also be applied to fields such as machinery and ships.

[0077] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0078] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A switching control circuit, characterized by comprising: Used to control the on / off state of the switching module, including a control module, a comparison module, a sampling module, and a negative feedback module; The first terminal of the control module is connected to the first terminal of the comparison module, and the second terminal of the control module is connected to the second terminal of the comparison module; the control module is used to generate a reference voltage signal and transmit the reference voltage signal to the first terminal of the comparison module through the first terminal of the control module, and to generate a first control signal and transmit the first control signal to the second terminal of the comparison module through the second terminal of the control module. The sampling module is connected between the first terminal of the comparison module and the first terminal of the switching module; the sampling module is used to acquire the voltage change signal at the first terminal of the switching module and transmit the voltage change signal to the first terminal of the comparison module; wherein, the voltage change signal is a signal reflecting the rate of voltage change; The third terminal of the comparison module is connected to the second terminal of the switch module; the comparison module is used to generate a second control signal based on the reference voltage signal, the first control signal and the voltage change signal, so as to control the on / off state of the switch module; The negative feedback module is connected between the second end and the third end of the comparison module; the negative feedback module is used to adjust the steepness of the rising and falling edges of the second control signal.

2. The switch control circuit according to claim 1, characterized in that, The switching module includes an inductor, a bus capacitor, an insulated gate bipolar transistor (IGBT), and a diode. The diode is connected in parallel between the collector and emitter of the IGBT; The gate of the IGBT is connected to the second terminal of the switching module, the collector of the IGBT is connected to the first terminal of the switching module, and the emitter of the IGBT is connected to the negative terminal of the bus capacitor. The positive terminal of the bus capacitor is connected to the first terminal of the inductor; The second end of the inductor is connected to the collector of the IGBT.

3. The switch control circuit of claim 1, wherein The negative feedback module includes a first resistor and a first capacitor; The first end of the first resistor is connected to the second end of the comparison module, and the second end of the first resistor is connected to the negative end of the first capacitor. The positive terminal of the first capacitor is connected to the third terminal of the comparison module.

4. The switch control circuit of claim 1, wherein Also includes: The second resistor is connected between the first terminal of the control module and the first terminal of the comparison module.

5. The switch control circuit of claim 1, wherein Also includes: A third resistor is connected between the second terminal of the control module and the second terminal of the comparison module.

6. The switch control circuit of claim 1, wherein Also includes: A fourth resistor is connected between the third terminal of the comparator module and the second terminal of the switch module.

7. The switch control circuit of claim 1, wherein The sampling module includes a second capacitor; The negative terminal of the second capacitor is connected to the first terminal of the comparison module, and the positive terminal of the second capacitor is connected to the first terminal of the switching module.

8. The switch control circuit of claim 1, wherein The control module uses a microcontroller unit (MCU), and the comparison module uses a comparator.

9. An electric motor drive system characterized by comprising: Includes the switch control circuit as described in any one of claims 1-8.

10. A vehicle characterized by comprising: It integrates the motor drive system as described in claim 9.

Images