Overcurrent protection circuit, chip, three-phase motor and electronic device

Abstract

Embodiments of the present application provide an overcurrent protection circuit, a chip, a three-phase motor and an electronic device. The overcurrent protection circuit comprises an amplification module, a comparison module and a digital-to-analog conversion module. The amplification module is used to connect a three-phase circuit and amplify an electrical signal; the comparison module comprises a plurality of input channels, the plurality of input channels are connected with the amplification module respectively, and the comparison module is used to select different circuit input channels to be turned on according to the flow direction of phase current; the digital-to-analog conversion module is connected with the comparison module, and the digital-to-analog conversion module is used to adjust and output a reference voltage. According to the overcurrent protection circuit in the embodiments of the present application, it can be applied to the three-phase circuit of the three-phase motor, and in the freewheeling area of the PWM wave of the three-phase motor, the overcurrent protection circuit in the embodiments can implement better overcurrent protection and can perform full-process overcurrent protection on the three-phase motor.

Description

Technical Field

[0001] This application relates to the field of electronic manufacturing technology, specifically to an overcurrent protection circuit, a chip, a three-phase motor, and electronic equipment. Background Technology

[0002] Three-phase motors based on Field Oriented Control (FOC) technology have been widely applied and popularized. These motors have overcurrent protection circuits that can provide safety protection for the entire motor system in the event of a sudden dangerous situation, minimizing damage and extending the system's lifespan. Currently, an adder is typically used to sum the three currents in the three-phase circuit and compare the summed current with a preset threshold to determine if the motor is experiencing overcurrent, thus providing overcurrent protection. However, in the zero-vector region of the three-phase motor's space vector (PWM), because the motor phase currents freewheel between the lower arms of the inverter bridge, the total voltage sums to zero, making protection impossible. Therefore, how to provide full-range overcurrent protection for three-phase motors is a problem that urgently needs to be solved. Summary of the Invention

[0003] In view of the above problems, embodiments of this application provide an overcurrent protection circuit, a chip, a three-phase motor, and an electronic device to solve the above technical problems.

[0004] In a first aspect, embodiments of this application provide an overcurrent protection circuit for connecting a three-phase circuit. The overcurrent protection circuit includes an amplification module, a comparator module, and a reference voltage module. The amplification module is used to connect to the three-phase circuit and amplify the electrical signal. The comparator module includes multiple input channels, each connected to the amplification module. The comparator module is used to select different circuit input channels to conduct according to the direction of phase current flow. The reference voltage module is connected to the comparator module and is used to adjust and output a reference voltage.

[0005] According to the overcurrent protection circuit in this embodiment, it can be applied to the three-phase circuit of a three-phase motor. By connecting an amplification module to each phase of the three-phase circuit and outputting the amplified electrical signal to multiple input channels of a comparison module, the comparison module can select different input channels to conduct based on the direction of the phase current in the three-phase circuit. Finally, a reference voltage module outputs a reference voltage to provide overcurrent protection for the circuit. Compared to the first example in the related art, the overcurrent protection circuit in this embodiment only requires one comparison module and one reference voltage converter to provide overcurrent protection for the three-phase circuit. By reducing the number of comparison modules and reference voltage converters, the cost can be reduced. Compared to the second example in the related technology, the related technology cannot achieve full-range overcurrent protection in the freewheeling region of the PWM wave of the three-phase motor. However, in the embodiment of this application, the comparison module can select different circuit input channels to be turned on according to the direction of the phase current in the three-phase circuit. Finally, the reference voltage module outputs a reference voltage to provide overcurrent protection for the circuit. Therefore, the overcurrent protection circuit in this embodiment can implement full-range overcurrent protection to provide better overcurrent protection for the three-phase motor.

[0006] Furthermore, the overcurrent protection circuit according to the embodiments of this application may also have the following technical features:

[0007] In some embodiments of this application, the comparison module includes a data selector and a comparator, wherein the data selector includes a plurality of the input channels, the input terminal of the data selector is connected to the output terminal of the amplification module, and the output terminal of the data selector is connected to the comparator.

[0008] In some embodiments of this application, the plurality of input channels include at least one first channel and a plurality of second channels, and the amplification module includes:

[0009] The first phase amplifier circuit has its output terminal connected to the first channel and one of the plurality of second channels;

[0010] The output of the second phase amplifier circuit is connected to the first channel and one of the plurality of second channels;

[0011] The third phase amplifier circuit has its output terminal connected to the first channel and one of the plurality of second channels.

[0012] In some embodiments of this application, the first channel is turned on in the ripple zone of the space vector PWM wave, and in the freewheeling zone of the space vector PWM wave, the comparator selects one of the multiple second channels to be turned on according to the direction of the phase current.

[0013] In some embodiments of this application, the overcurrent protection circuit further includes an adder, the input of which is connected to the first phase amplifier circuit, the second phase amplifier circuit and the third phase amplifier circuit respectively, and the output of which is connected to the first channel.

[0014] In some embodiments of this application, the reference voltage module outputs a first threshold voltage in the ripple zone of the space vector PWM wave.

[0015] In some embodiments of this application, the three-phase circuit includes a first-phase circuit, a second-phase circuit, and a third-phase circuit; in the freewheeling region of the space vector PWM wave, when one of the first-phase circuit, the second-phase circuit, and the third-phase circuit is a first-direction current and the other two are second-direction currents, the reference voltage module outputs a second threshold reference voltage; when two of the first-phase circuit, the second-phase circuit, and the third-phase circuit are first-direction currents and the other is a second-direction current, the reference voltage module outputs a third threshold reference voltage; wherein the direction of the first-direction current is opposite to the direction of the second-direction current.

[0016] In some embodiments of this application, the second channel includes a first sub-channel, a second sub-channel, and a third sub-channel, wherein the first sub-channel is connected to the first phase circuit, the second sub-channel is connected to the second phase circuit, and the third sub-channel is connected to the third phase circuit.

[0017] In some embodiments of this application, the first sub-channel is turned on when the current directions of the second phase circuit and the third phase circuit are the same, the current direction of the second phase circuit is opposite to the current direction of the first phase circuit, and the current direction of the third phase circuit is opposite to the current direction of the first phase circuit.

[0018] In some embodiments of this application, the second sub-channel is turned on when the current directions of the first phase circuit and the third phase circuit are the same, the current direction of the first phase circuit is opposite to the current direction of the second phase circuit, and the current direction of the third phase circuit is opposite to the current direction of the second phase circuit.

[0019] In some embodiments of this application, the third sub-channel is turned on when the current directions of the first phase circuit and the second phase circuit are the same, the current direction of the first phase circuit is opposite to the current direction of the third phase circuit, and the current direction of the second phase circuit is opposite to the current direction of the third phase circuit.

[0020] Secondly, embodiments of this application also propose a chip including the overcurrent protection circuit of any embodiment of the first aspect.

[0021] Thirdly, embodiments of this application also propose a three-phase motor, including the overcurrent protection circuit in any embodiment of the first aspect.

[0022] Fourthly, embodiments of this application also provide an electronic device, including a device body and a chip disposed on the device body as described in the third aspect embodiment.

[0023] These or other aspects of this application will become more apparent from the description of the following embodiments. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A circuit diagram of a three-phase circuit, the first example in the related art, is shown;

[0026] Figure 2 A circuit diagram of a three-phase circuit, as shown in the second example of the related art, is illustrated.

[0027] Figure 3 A structural block diagram of an overcurrent protection circuit in one embodiment of this application is shown;

[0028] Figure 4 A structural block diagram of an overcurrent protection circuit according to another embodiment of this application is shown;

[0029] Figure 5 A circuit diagram of an overcurrent protection circuit according to an embodiment of this application is shown;

[0030] Figure 6 The waveform diagram of the phase current of the overcurrent protection circuit in an embodiment of this application is shown;

[0031] Figure 7 A timing diagram of the space vector PWM of the overcurrent protection circuit in an embodiment of this application is shown;

[0032] Figure 8 The diagram shows the current flow direction of the space vector PWM ripple zone in an embodiment of the overcurrent protection circuit of this application. Figure 6 (Central I Zone);

[0033] Figure 9 This application shows a current flow diagram of the freewheeling region of the space vector PWM of the overcurrent protection circuit in an embodiment of the present application. Figure 6 (Central I Zone);

[0034] Figure 10 The diagram shows the current flow direction of the space vector PWM ripple zone in an embodiment of the overcurrent protection circuit of this application. Figure 6 (Central VI Zone);

[0035] Figure 11 This application shows a current flow diagram of the freewheeling region of the space vector PWM of the overcurrent protection circuit in an embodiment of the present application. Figure 6 (Central VI Zone);

[0036] Figure 12 The diagram shows the current flow direction of the space vector PWM ripple zone in an embodiment of the overcurrent protection circuit of this application. Figure 6 (Central II Zone);

[0037] Figure 13 This application shows a current flow diagram of the freewheeling region of the space vector PWM of the overcurrent protection circuit in an embodiment of the present application. Figure 6 (Central II Zone). Detailed Implementation

[0038] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0039] To enable those skilled in the art to better understand the solutions of this application, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0040] In the embodiments of this application, it should be noted that, in this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0041] Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0042] In the description of the embodiments of this application, the words "example" or "for example" are used to indicate exemplification, illustration, or description. Any embodiment or design described as "example" or "for example" in the embodiments of this application is not to be construed as being more preferred or having more advantages than another embodiment or design. The use of the words "example" or "for example" is intended to present relative concepts in a clear manner.

[0043] Furthermore, in the embodiments of this application, "multiple" refers to two or more. Therefore, in the embodiments of this application, "multiple" can also be understood as "at least two". "At least one" can be understood as one or more, such as one, two, or more. For example, including at least one means including one, two, or more, and is not limited to which ones are included. For example, including at least one of A, B, and C, then it could include A, B, C, A and B, A and C, B and C, or A and B and C.

[0044] It should be noted that in the embodiments of this application, "and / or" describes the relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. In addition, the character " / ", unless otherwise specified, generally indicates that the associated objects before and after it are in an "or" relationship.

[0045] It should be noted that in the embodiments of this application, "connection" can be understood as electrical connection. The connection between two electrical components can be a direct or indirect connection between the two electrical components. For example, the connection between A and B can be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components.

[0046] Currently, three-phase motors based on Field Oriented Control (FOC) technology have been widely applied and popularized. During motor operation, response speed, operational stability, energy consumption, and noise are key concerns. In addition, the motor's protection system, much like a car's braking system, provides safety protection for the entire motor system in sudden dangerous situations, minimizing damage and extending the system's lifespan. Among the many protection mechanisms, overcurrent protection is the most common and crucial protection system in motor systems.

[0047] Currently, there are usually two methods for overcurrent protection of motor systems. Here, we take the commonly used 3-resistor sampling FOC system as an example.

[0048] like Figure 1 As shown in the first example, the three-phase circuit of the motor system includes upper bridge arm switching devices Q1, Q2, and Q3, and lower bridge arm switching devices Q4, Q5, and Q6. Sampling resistors R1, R2, and R3 are provided on the lower bridge arm. Amplifiers OPA_0, OPA_1, and OPA_2 are connected to each sampling resistor. The other end of each amplifier is connected to two comparators CMP_0 and CMP_1, and two reference voltage transformers DAC_0 and DAC_1. In this illustration, only the current amplification and protection of one phase of the three-phase motor circuit is shown as an example. Amplifiers OPA_1 and OPA_2 in the illustration are also connected to two comparators and two reference voltage transformers, but are not shown in the figure. It can be understood that by using two comparators and two reference voltage transformers in each phase of the three-phase motor circuit for upper and lower threshold judgments—that is, a total of six comparators and six reference voltage transformers—effective current monitoring and protection can be implemented throughout the entire time period. However, this method, due to the large number of comparators and reference voltage transformers used, is often not adopted in cost-sensitive applications.

[0049] like Figure 2As shown in the second example, to reduce costs, an adder composed of R4, R5, and R6 is used, and the electrical signal is input to the positive terminal of comparator CMP_0. That is, this method uses an adder to sum the three currents of the three-phase circuit and compares the summed current with a preset threshold to determine if the motor is experiencing overcurrent, thus providing overcurrent protection. Although this method effectively reduces the number of analog components and has been widely used, in the zero-vector region of the space vector PWM wave, because the motor phase current freewheels between R1, R2, and R3, V0 + V1 + V2 = 0. In other words, this method cannot provide protection in the freewheeling region of the space vector PWM wave. Since this method cannot achieve full-range overcurrent protection, there are certain safety hazards. How to provide low-cost, full-range overcurrent protection for three-phase motors is a problem that urgently needs to be solved.

[0050] In view of this, such as Figure 3 and Figure 4 As shown, an embodiment of the first aspect of this application proposes an overcurrent protection circuit for connecting a three-phase circuit to provide low-cost, full-range overcurrent protection for a three-phase motor.

[0051] In the embodiments of this application, the overcurrent protection circuit includes an amplification module 10, a comparison module 20, and a reference voltage module 30. The amplification module 10 is used to connect to the three-phase circuit and amplify the electrical signal; the comparison module 20 includes multiple input channels 210, which are respectively connected to the amplification module 10, and the comparison module 20 is used to select different input channels 210 to conduct according to the direction of phase current flow; the reference voltage module 30 is connected to the comparison module 20, and the reference voltage module 30 is used to adjust and output a reference voltage.

[0052] In this embodiment, the amplification module 10 can be an OPA (Operational Amplifier), which can be implemented separately by discrete devices or integrated into a semiconductor chip; there is no particular limitation here. The amplification module 10 is connected to a three-phase circuit that requires overcurrent protection. For example, the amplification module 10 can be connected to... Figure 5 The sampling resistor 40 in the three-phase circuit is located across its terminals. The comparison module 20 may include a data selector 21 (Multiplexer, MUX) and a comparator 22 (Comparator, CMP), where, for example... Figure 4As shown, the data selector 21 includes multiple circuit input channels 210, and each of the multiple circuit input channels 210 is connected to the amplification module 10. The other end of the data selector 21 is connected to the comparator 22. In the embodiments of this application, the comparator 22 can select different circuit input channels 210 according to the direction of the motor phase current to provide individual overcurrent protection for different circuits. The reference voltage module 30 can be a DAC (Digital-to-Analog Converter), which can convert the input binary digital quantity into an analog quantity and output it in the form of voltage or current. In this embodiment, the reference voltage module 30 is used to adjust and output a reference voltage, which can also be called a reference threshold voltage. When the actual voltage in the circuit used for overcurrent protection is higher than the reference voltage, the circuit can be cut off to provide overcurrent protection.

[0053] According to the overcurrent protection circuit in this embodiment, it can be applied to the three-phase circuit of a three-phase motor. By connecting the amplification module 10 to each phase of the three-phase circuit, and outputting the amplified electrical signal to multiple circuit input channels 210 of the comparison module 20, the comparison module 20 can select different circuit input channels 210 to conduct according to the direction of the phase current in the three-phase circuit. Finally, the reference voltage module 30 outputs a reference voltage to provide overcurrent protection for the circuit. Compared with the first example in the related art, the overcurrent protection circuit in this embodiment can provide overcurrent protection for the three-phase circuit with only one comparison module 20 and one reference voltage module 30. By reducing the number of comparison modules 20 and reference voltage modules 30, the cost can be reduced. Compared to the second example in the related technology, the related technology cannot achieve full-range overcurrent protection in the freewheeling region of the PWM wave of the three-phase motor. However, in the embodiment of this application, the comparison module 20 can select different circuit input channels 210 to be turned on according to the flow direction of the phase current in the three-phase circuit. Finally, the reference voltage module 30 outputs a reference voltage to provide overcurrent protection for the circuit. Therefore, the overcurrent protection circuit in this embodiment can implement full-range overcurrent protection to provide better overcurrent protection for the three-phase motor.

[0054] In some embodiments of this application, the comparison module 20 includes a data selector 21 and a comparator 22. The data selector 21 includes multiple input channels 210. The input terminal of the data selector 21 is connected to the output terminal of the amplification module 10, and the output terminal of the data selector 21 is connected to the comparator 22. In this embodiment, the comparison module 20 may include a data selector 21 (Multiplexer, MUX) and a comparator 22 (Comparator, CMP), wherein, as... Figure 4As shown, the data selector 21 includes multiple circuit input channels 210, and the multiple circuit input channels 210 are respectively connected to the amplification module 10. The other end of the data selector 21 is connected to the comparator 22. In the embodiments of this application, the comparator 22 can select different circuit input channels 210 according to the direction of the motor phase current to provide individual overcurrent protection for different circuits.

[0055] In some embodiments of this application, the plurality of input channels 210 include at least one first channel 211 and a plurality of second channels 212, and the amplification module 10 includes a first phase amplifier circuit 110, a second phase amplifier circuit 120 and a third phase amplifier circuit 130, wherein the output terminal of the first phase amplifier circuit 110 is connected to one of the first channel 211 and the plurality of second channels 212; the output terminal of the second phase amplifier circuit 120 is connected to one of the first channel 211 and the plurality of second channels 212; and the output terminal of the third phase amplifier circuit 130 is connected to one of the first channel 211 and the plurality of second channels 212.

[0056] In this embodiment, the plurality of input channels 210 include at least one first channel 211 and a plurality of second channels 212. For example, a plurality of operational amplifiers are connected to the first channel 211 via adders, and the plurality of operational amplifiers are respectively connected to the plurality of second channels 212; in the ripple region of the space vector PWM wave, the first channel 211 is turned on, and in the freewheeling region of the space vector PWM wave, the comparator 22 selects one of the plurality of second channels 212 to be turned on according to the direction of the phase current.

[0057] like Figure 5 As shown, in one embodiment of this application, the overcurrent protection circuit is used to connect a three-phase circuit. For example, the three-phase circuit includes a first-phase circuit, a second-phase circuit, a third-phase circuit, and at least three sampling resistors 40 for sampling the current of the first-phase circuit, the second-phase circuit, and the third-phase circuit. The number of amplification modules 10 is at least three, and the three amplification modules 10 are respectively connected to the two ends of the three sampling resistors 40.

[0058] exist Figure 5In this diagram, VBUS is the power supply terminal 60. The three-phase circuit includes a first-phase circuit, a second-phase circuit, and a third-phase circuit. The first-phase circuit, shown in the diagram, can be a U-phase circuit, including switching devices Q1 and Q4, and a sampling resistor R1. The second-phase circuit, shown in the diagram, can be a V-phase circuit, including switching devices Q2 and Q5, and a sampling resistor R2. The third-phase circuit, shown in the diagram, can be a W-phase circuit, including switching devices Q3 and Q6, and a sampling resistor R3. Amplifier OPA_0 is connected across the sampling resistor R1, amplifier OPA_1 is connected across the sampling resistor R2, and amplifier OPA_2 is connected across the sampling resistor R3. The output terminals of amplifiers OPA_0, OPA_1, and OPA_2 are respectively connected to multiple circuit input channels 210 of the data selector 21. In this embodiment, by setting multiple amplification modules 10 and connecting the input terminals of each amplification module 10 to the sampling resistors, overcurrent protection can be provided for each circuit.

[0059] In some embodiments of this application, the amplification module 10 includes at least an operational amplifier (OPA). The input terminal of the OPA is connected to both ends of the sampling resistor 40, and the output terminal of the OPA is connected to the circuit input channel 210 of the data selector 21. In this embodiment, the operational amplifier is referred to as the OPA (Operational Amplifier), which can be implemented separately by discrete devices or integrated into a semiconductor chip. The input terminal of the OPA is connected to a resistor to acquire electrical signals from a three-phase circuit requiring overcurrent protection. Please refer to... Figure 5 In this embodiment, the first phase amplifier circuit 110 amplifies the signal across the sampling resistor R1, and its output is connected to one of the first channel 211 and multiple second channels 212. The second phase amplifier circuit 120 amplifies the signal across the sampling resistor R2, and its output is also connected to one of the first channel 211 and multiple second channels 212. The third phase amplifier circuit 130 amplifies the signal across the sampling resistor R3, and its output is connected to one of the first channel 211 and multiple second channels 212. Thus, the comparator 22 can select one of the first channel 211 or multiple second channels 212 to conduct according to the direction of the phase current, and adjusts and outputs a reference voltage through the reference voltage module 30 to provide overcurrent protection for circuits requiring overcurrent protection.

[0060] In some embodiments of this application, the overcurrent protection circuit further includes an adder. The input terminals of the adder are connected to the first phase amplifier circuit 110, the second phase amplifier circuit 120, and the third phase amplifier circuit 130, respectively, and the output terminal of the adder is connected to the first channel 211. In this embodiment, the adder may include resistors R4, R5, and R6 connected to the output terminal of the amplifier module 10, and the output terminal of the adder is connected to the first channel 211. Thus, in the ripple region of the space vector PWM wave, the first channel 211 is turned on to provide overcurrent protection in the ripple region. In the freewheeling region of the space vector PWM wave, the comparator 22 turns on one of the multiple second channels 212 according to the direction of the circuit phase current.

[0061] In some embodiments of this application, the first channel is turned on in the ripple zone of the space vector PWM wave, and in the freewheeling zone of the space vector PWM wave, the comparator selects one of the multiple second channels to be turned on according to the direction of the phase current.

[0062] In this embodiment, the circuit input channel 210 includes a first channel 211 and a second channel 212. One end of the first channel 211 is connected to an operational amplifier via an adder, and one end of each of the multiple second channels 212 is connected to an operational amplifier in each circuit. For example, when there are three operational amplifiers, one end of each operational amplifier is connected to a second channel 212, and the operational amplifier is connected to the first channel 211 via an adder. Thus, in the ripple zone of the space vector PWM wave, the first channel 211 is turned on to provide overcurrent protection in the ripple zone. In the freewheeling zone of the space vector PWM wave, the comparator 22 turns on one of the multiple second channels 212 according to the direction of the circuit phase current.

[0063] To clearly illustrate the beneficial effects of the embodiments of this application, the implementation process of the embodiments of this application is described in detail below. It should be noted that the following is only one example of the embodiments of this application. Those skilled in the art can make corresponding adjustments or changes based on the embodiments of this application, and the adjusted or changed implementation methods are also within the protection scope of this application.

[0064] like Figure 6 The figure shown is a waveform diagram of the phase current of the three-phase circuit in an embodiment of this application, where line lv represents... Figure 5 The current waveform of the middle V phase circuit, line lw is Figure 5 The current waveform of the W-phase circuit, line lu is Figure 5 The current waveform of the U-phase circuit.

[0065] like Figure 7 As shown, Figure 6The timing diagram of space vector PWM in region I is shown. PWM_U, PWM_V, and PWM_W represent the drive signals of the upper arms of the inverter bridge in the three-phase circuit. T0 represents one of the zero vector regions, i.e., the freewheeling region of the lower arm. T1 represents the ripple generation region of the space vector PWM.

[0066] It should be noted that, Figure 7 Only illustrative examples are shown. Figure 6 The timing diagram of space vector PWM in region I, of course, Figure 7 The square wave in the timing diagram of the space vector PWM can also have other forms; no special limitations are made here, and it is only used as an example for illustration. Furthermore, Figure 6 Each current partition can include multiple space vector PWM cycles, and the shape of each space vector PWM can be different. For ease of understanding, Figure 6 and Figure 7 The waveforms shown are merely examples and do not constitute a specific limitation on this application.

[0067] Please refer to Figure 6 and Figure 7 At the zero point of the PWM waveform, the three-phase current of the motor can be read using an ADC (Analog-to-Digital Converter) to determine the direction of the three-phase current flow. The current flowing into the stator winding 70 of the motor is pre-defined as positive (+), and the current flowing out of the stator winding 70 is pre-defined as negative (-). Figure 6 Taking region I as an example, the current Iu in phase U is positive, the current Iv in phase V is negative, and the current Iw in phase W is negative. Please refer to... Figure 8 , Figure 8 The dashed arrow in the middle is Figure 6 The current flow direction in the space vector PWM waveform generation region under the current direction in region I is as follows: At this time, current flows into the motor from switching device Q1 and out from switching devices Q5 and Q6. This allows the first channel 211 to conduct. In other words, when the PWM wave is in... Figure 7 When ISR1 is applied, the first channel 211 is turned on. When the three-phase circuit is in the freewheeling region, please refer to... Figure 9 , Figure 9 The dashed arrow in the middle is Figure 6In the current direction of the space vector PWM waveform generation region under the current direction of region I, switching devices Q1, Q2, and Q3 are all off. Due to inertia, the current still flows from the motor into switching devices Q5 and Q6, and then into the motor from Q4. The entire circuit is in a freewheeling state. In the freewheeling region of the space vector PWM, since the three-phase motor phase currents freewheel between R1, R2, and R3, the voltage after the sum of the three is zero. At this time, one of the second channels 212 can be selected to be turned on. That is to say, when the PWM wave is in the freewheeling region... Figure 7 When ISR2 is applied, one of the second channels 212 is turned on to provide overcurrent protection for the corresponding circuit.

[0068] In some embodiments of this application, in the ripple zone of the space vector PWM wave, the reference voltage module 30 outputs a first threshold voltage. In this embodiment, the first threshold voltage is related to the supply voltage, the resistance value of the sampling resistors, the gain of the operational amplifier, the bias voltage, and the setting value of the overcurrent protection point. For example, assuming the microcontroller's supply voltage is 'a', the resistance value of each of the three sampling resistors is 'b', the gain of the operational amplifier is 'c', the output DC bias voltage is 1 / 2*a, and the overcurrent protection point setting value is 'd', the value of the first threshold voltage is:

[0069] DAC_MT (DAC middle threshold)=1 / 2*a+1 / 3*(b*c*d).

[0070] For example, assuming the microcontroller's supply voltage is 5 volts, the three sampling resistors are all 0.05 ohms, the operational amplifier's gain is 10, the output DC bias voltage is 1 / 2 * 5 volts, or 2.5 volts, and the overcurrent protection point is set to 3 amps, the first threshold voltage is:

[0071] DAC_MT=2.5+1 / 3*(0.05*3*10)=3.0V.

[0072] In some embodiments of this application, the three-phase circuit includes a first-phase circuit, a second-phase circuit, and a third-phase circuit. In the freewheeling region of the space vector PWM wave, when one of the first-phase circuit, the second-phase circuit, and the third-phase circuit is a first-direction current and the other two are second-direction currents, the reference voltage module 30 outputs a second threshold reference voltage. When two of the first-phase circuit, the second-phase circuit, and the third-phase circuit are first-direction currents and the other is a second-direction current, the reference voltage module 30 outputs a third threshold reference voltage. The direction of the first-direction current is opposite to the direction of the second-direction current.

[0073] In this embodiment, the second threshold voltage is related to the supply voltage, the resistance value of the sampling resistors, the gain of the operational amplifier, the bias voltage, and the setting value of the overcurrent protection point. For example, assuming the microcontroller's supply voltage is 'a', the resistance value of each of the three sampling resistors is 'b', the operational amplifier's gain is 'c', the output DC bias voltage is 1 / 2*a, and the overcurrent protection point is set to 'd', the value of the second threshold voltage is:

[0074] DAC_LT(DAC low threshold)=1 / 2*ab*c*d.

[0075] For example, assuming the microcontroller's supply voltage is 5 volts, the three sampling resistors are all 0.05 ohms, the operational amplifier's gain is 10, the output DC bias voltage is 1 / 2 * 5 volts, or 2.5 volts, and the overcurrent protection point is set to 3 amps, the second threshold voltage value is:

[0076] DAC_LT=2.5-0.05*3*10=1.0V.

[0077] The third threshold voltage is related to the supply voltage, the resistance value of the sampling resistors, the gain of the operational amplifier, the bias voltage, and the overcurrent protection setting. For example, assuming the microcontroller's supply voltage is 'a', the resistance value of all three sampling resistors is 'b', the operational amplifier's gain is 'c', the output DC bias voltage is 1 / 2*a, and the overcurrent protection setting is 'd', the value of the third threshold voltage is:

[0078] DAC_HT (DAC high threshold)=1 / 2*a+b*c*d.

[0079] For example, assuming the microcontroller's supply voltage is 5 volts, the three sampling resistors are all 0.05 ohms, the operational amplifier's gain is 10, the output DC bias voltage is 1 / 2 * 5 volts, or 2.5 volts, and the overcurrent protection point is set to 3 amps, the third threshold voltage value is:

[0080] DAC_HT=2.5+0.05*3*10=4.0V.

[0081] Table 1 below shows the relationship between the current range and the first threshold voltage, the second threshold voltage, and the third threshold voltage:

[0082] Zone I + - - DAC_LT Zone II + + - DAC_HT Zone III - + - DAC_LT Zone IV - + + DAC_HT V Zone - - + DAC_LT VI Zone + - + DAC_HT

[0083] Table 1

[0084] Please refer to Table 1 above. Figure 6When the PWM wave of the circuit freewheels in region I, the U-phase current is positive, and the V-phase and W-phase currents are negative. At this time, the reference voltage module 30 (DAC) can output the second threshold voltage DAC_LT. When the PWM wave of the circuit freewheels in region II, the U-phase and V-phase currents are positive, and the W-phase current is negative. At this time, the reference voltage module 30 (DAC) can output the third threshold voltage DAC_HT. It should be noted that when the PWM wave of the circuit is in the ripple generation region, the reference voltage module 30 (DAC) can output the first threshold voltage DAC_MT.

[0085] In some embodiments of this application, the second channel 212 includes a first sub-channel 2121, a second sub-channel 2122, and a third sub-channel 2123. The first sub-channel 2121 is connected to the first phase circuit, the second sub-channel 2122 is connected to the second phase circuit, and the third sub-channel 2123 is connected to the third phase circuit. In this embodiment, the first sub-channel 2121, the second sub-channel 2122, and the third sub-channel 2123 are respectively connected to the first phase circuit, the second phase circuit, and the third phase circuit of the circuit, so as to switch different second channels 212 when the PWM wave of the circuit is in freewheeling mode, thereby providing overcurrent protection for the circuit.

[0086] In some embodiments of this application, the first sub-channel 2121 is turned on when the current directions of the second phase circuit and the third phase circuit are the same, the current direction of the second phase circuit is opposite to the current direction of the first phase circuit, and the current direction of the third phase circuit is opposite to the current direction of the first phase circuit.

[0087] In this embodiment, please refer to Figure 8 and Figure 9 ,exist Figure 8 and Figure 9 In the diagram, assume that phase U is the first phase, phase V is the second phase, and phase W is the third phase. Operational amplifier OPA_0 is connected to the sampling resistor R1 of the first phase, operational amplifier OPA_1 is connected to the sampling resistor R2 of the second phase, and operational amplifier OPA_2 is connected to the sampling resistor R3 of the third phase. Figure 8 In the circuit, when the circuit is generating waveforms, current flows from switching device Q1 into motor 70, and then from motor 70 through switching devices Q5 and Q6. At this time, the first channel 211 is turned on. Figure 9 In the circuit, when the circuit is in freewheeling mode, the current flowing through the switching device R4 is equal to the sum of the currents flowing through the switching devices R5 and R6. Therefore, at this time, the operational amplifier OPA_0 connected to the first phase circuit is turned on. That is to say, the data selector 21 switches to the first sub-channel 2121 to be turned on as the positive input.

[0088] In some embodiments of this application, the second sub-channel 2122 is turned on when the current directions of the first phase circuit and the third phase circuit are the same, the current directions of the first phase circuit and the second phase circuit are opposite, and the current direction of the third phase circuit is opposite to the current direction of the second phase circuit.

[0089] In this embodiment, please refer to Figure 10 and Figure 11 ,exist Figure 10 and Figure 11 In the diagram, assume that phase U is the first phase, phase V is the second phase, and phase W is the third phase. Operational amplifier OPA_0 is connected to the sampling resistor R1 of the first phase, operational amplifier OPA_1 is connected to the sampling resistor R2 of the second phase, and operational amplifier OPA_2 is connected to the sampling resistor R3 of the third phase. Figure 10 In the circuit, when the circuit is generating waveforms, current flows from switching devices Q1 and Q3 into motor 70, and then from motor 70 through switching device Q5. At this time, the first channel 211 is turned on. Figure 11 In the circuit, when the circuit is in freewheeling mode, the current flowing through the switching device R5 is equal to the sum of the currents flowing through the switching devices R4 and R6. Therefore, the operational amplifier OPA_1 connected to the second phase circuit is turned on at this time. That is to say, the data selector 21 switches to the second sub-channel 2122 to be turned on as the positive input.

[0090] In some embodiments of this application, the third sub-channel 2123 is turned on when the current directions of the first phase circuit and the second phase circuit are the same, the current direction of the first phase circuit is opposite to the current direction of the third phase circuit, and the current direction of the second phase circuit is opposite to the current direction of the third phase circuit.

[0091] In this embodiment, please refer to Figure 12 and Figure 13 ,exist Figure 12 and Figure 13 In the diagram, assume that phase U is the first phase, phase V is the second phase, and phase W is the third phase. Operational amplifier OPA_0 is connected to the sampling resistor R1 of the first phase, operational amplifier OPA_1 is connected to the sampling resistor R2 of the second phase, and operational amplifier OPA_2 is connected to the sampling resistor R3 of the third phase. Figure 12 In the circuit, when the circuit is generating waveforms, current flows from switching devices Q1 and Q2 into motor 70, and then from motor 70 through switching device Q6. At this time, the first channel 211 is turned on. Figure 13In the circuit, when the circuit is in freewheeling mode, the current flowing through the switching device R6 is equal to the sum of the currents flowing through the switching devices R4 and R5. Therefore, at this time, the operational amplifier OPA_2 connected to the third phase circuit is turned on. That is to say, the data selector 21 switches to the third sub-channel 2123 to be turned on as the positive input.

[0092] Table 2 below shows the relationship between the current range and the first threshold voltage, the second threshold voltage, the third threshold voltage, and the voltage input channel of comparator 22:

[0093] Zone I + - - <![CDATA[V0 (first sub-channel)]]> DAC_LT Zone II + + - <![CDATA[V2 (third sub-channel)]]> DAC_HT Zone III - + - <![CDATA[V1 (second sub-channel)]]> DAC_LT Zone IV - + + <![CDATA[V0 (first sub-channel)]]> DAC_HT V Zone - - + <![CDATA[V2 (third sub-channel)]]> DAC_LT VI Zone + - + <![CDATA[V1 (second sub-channel)]]> DAC_HT

[0094] Table 2

[0095] Please refer to Table 2 above. Figure 6 When the PWM wave of the circuit continues in region I, the U-phase current is positive, and the V-phase and W-phase currents are negative. At this time, comparator 22 can switch the second channel 212 to the first sub-channel 2121. Figure 8 When the PWM wave of the circuit is freewheeling in region II, the U-phase current and V-phase current are positive, and the W-phase current is negative. At this time, the comparator 22 can switch the second channel 212 to the third sub-channel 2123. Figure 8 The reference voltage module 30 (DAC) can output the third threshold voltage DAC_HT. Other regions of the PWM wave in the circuit are similar to the above example and will not be described again. In summary, in this embodiment, one of the second channels 212 can be selected according to the relationships in Table 2. Figure 8 The V0, V1, or V2 in the input are turned on to serve as positive inputs.

[0096] In some embodiments of this application, the data selector 21 can be an internal component of the comparator 22. That is, the comparator 22 can be a comparator 22 that supports multiple input channel selection for data selection, or the data selector 21 can be a component of the comparator 22. In this way, it is not necessary to introduce more components, thereby achieving the purpose of full-range overcurrent protection. In other embodiments, the data selector 21 and the comparator 22 can also be two independent components.

[0097] It should be understood that the above-described embodiments are merely preferred implementations of the present application, and are not the only limitation on the waveform of the PWM wave of the three-phase circuit in the present application. Therefore, those skilled in the art can flexibly set the waveform of the PWM wave based on the actual application scenario on the basis of the embodiments of the present application.

[0098] An embodiment of the second aspect of this application provides a chip including the overcurrent protection circuit of any embodiment of the first aspect.

[0099] In this embodiment, the chip includes the overcurrent protection circuit of any embodiment of the first aspect. The chip (Integrated Circuit, IC) can be, but is not limited to, a SOC (System on Chip) chip or a SIP (System in Package) chip. In this embodiment, since the chip includes the overcurrent protection circuit of any embodiment of the first aspect, it also possesses the beneficial effects of any embodiment of the first aspect. Specifically, the chip in this embodiment can be applied to the three-phase circuit of a three-phase motor. By connecting the amplification module 10 to each phase of the three-phase circuit, and outputting the amplified electrical signal to multiple circuit input channels 210 of the comparison module 20, the comparison module 20 can select different circuit input channels 210 to conduct according to the direction of the phase current in the three-phase circuit. Finally, the reference voltage module 30 outputs a reference voltage to provide overcurrent protection for the circuit. Compared to the first example in the related art, the overcurrent protection circuit in this embodiment can provide overcurrent protection for a three-phase circuit using only one comparator module 20 and one reference voltage module 30. By reducing the number of comparator modules 20 and reference voltage modules 30, costs can be reduced. Compared to the second example in the related art, which cannot achieve full-range overcurrent protection in the freewheeling region of the PWM wave of a three-phase motor, the comparator module 20 in this embodiment can select different circuit input channels 210 to conduct according to the direction of phase current in the three-phase circuit. Finally, the reference voltage module 30 outputs a reference voltage to provide overcurrent protection for the circuit. Therefore, the overcurrent protection circuit in this embodiment can implement full-range overcurrent protection for the three-phase motor. Thus, the chip in this embodiment can provide full-range overcurrent protection for the three-phase motor.

[0100] An embodiment of the third aspect of this application provides a three-phase motor, including the overcurrent protection circuit of any embodiment of the first aspect.

[0101] In this embodiment, the three-phase motor may have a U-phase circuit, a V-phase circuit, and a W-phase circuit. Through the overcurrent protection circuit in any embodiment of the first aspect, overcurrent protection can be provided for each phase circuit of the three-phase motor throughout the entire process.

[0102] An embodiment of the fourth aspect of this application provides an electronic device, including a device body and a chip disposed on the device body as described in the third aspect embodiment above.

[0103] In this embodiment, the electronic device may be, but is not limited to, a drone, a car, smart home devices, an electric bicycle, or an electric skateboard. Smart home devices include, but are not limited to, smart rice cookers, smart robot vacuums, smart lights, inverter washing machines, floor fans, and cooling fans. The electronic device according to this embodiment, since it possesses the chip described in the third aspect embodiment, also exhibits the beneficial effects of the third aspect embodiment, which will not be elaborated further here.

[0104] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Although this application has disclosed preferred embodiments as above, it is not intended to limit this application. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the technical solution of this application. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. An overcurrent protection circuit, characterized in that, For connecting a three-phase circuit, the overcurrent protection circuit includes: An amplification module is used to connect to the three-phase circuit and amplify the electrical signals; The amplification module includes: a first-phase amplification circuit, the output of which is connected to a first channel and one of a plurality of second channels; a second-phase amplification circuit, the output of which is connected to the first channel and one of the plurality of second channels; and a third-phase amplification circuit, the output of which is connected to the first channel and one of the plurality of second channels. The comparison module includes multiple input channels, which are respectively connected to the amplification module. The comparison module is used to select different input channels to be turned on according to the direction of the phase current. The comparison module includes a data selector and a comparator. The data selector is a MUX and includes multiple input channels. The input terminal of the data selector is connected to the output terminal of the amplification module, and the output terminal of the data selector is connected to the comparator. The multiple input channels include at least one first channel and multiple second channels. In the ripple zone of the space vector PWM wave, the first channel is turned on. In the freewheeling zone of the space vector PWM wave, the comparator selects one of the multiple second channels to be turned on according to the direction of the phase current. A reference voltage module is connected to the comparison module, and the reference voltage module is used to adjust and output a reference voltage.

2. The overcurrent protection circuit as described in claim 1, characterized in that, The overcurrent protection circuit also includes an adder, the input of which is connected to the first phase amplifier circuit, the second phase amplifier circuit and the third phase amplifier circuit respectively, and the output of which is connected to the first channel.

3. The overcurrent protection circuit as described in claim 2, characterized in that, In the ripple zone of the space vector PWM wave, the reference voltage module outputs a first threshold voltage.

4. The overcurrent protection circuit as described in claim 3, characterized in that, The three-phase circuit includes a first-phase circuit, a second-phase circuit, and a third-phase circuit. In the freewheeling region of the space vector PWM wave, when one of the first-phase circuit, the second-phase circuit, and the third-phase circuit is a first-direction current and the other two are second-direction currents, the reference voltage module outputs a second threshold reference voltage. When two of the first-phase circuit, the second-phase circuit, and the third-phase circuit are first-direction currents and the other is a second-direction current, the reference voltage module outputs a third threshold reference voltage. The direction of the first-direction current is opposite to the direction of the second-direction current.

5. The overcurrent protection circuit as described in claim 2, characterized in that, The second channel includes a first sub-channel, a second sub-channel, and a third sub-channel, wherein the first sub-channel is connected to the first phase circuit, the second sub-channel is connected to the second phase circuit, and the third sub-channel is connected to the third phase circuit.

6. The overcurrent protection circuit as described in claim 5, characterized in that, When the current directions of the second phase circuit and the third phase circuit are the same, the current direction of the second phase circuit is opposite to the current direction of the first phase circuit, and the current direction of the third phase circuit is opposite to the current direction of the first phase circuit, the first sub-channel is turned on.

7. The overcurrent protection circuit as described in claim 5, characterized in that, The second sub-channel is turned on when the current directions of the first phase circuit and the third phase circuit are the same, the current direction of the first phase circuit is opposite to the current direction of the second phase circuit, and the current direction of the third phase circuit is opposite to the current direction of the second phase circuit.

8. The overcurrent protection circuit as described in claim 5, characterized in that, The third sub-channel is turned on when the current directions of the first phase circuit and the second phase circuit are the same, the current direction of the first phase circuit is opposite to the current direction of the third phase circuit, and the current direction of the second phase circuit is opposite to the current direction of the third phase circuit.

9. A chip, characterized in that, The overcurrent protection circuit includes any one of claims 1 to 8.

10. A three-phase motor, characterized in that, The overcurrent protection circuit includes any one of claims 1 to 8.

11. An electronic device, characterized in that, It includes a device body and a chip as described in claim 9 disposed on the device body.

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