Main power circuit, motor and electrical equipment
By dynamically switching GaN HEMT and Si-IGBT according to motor power in the main power circuit, combining sampling circuits and soft switch switching circuits, the problem of insufficient performance of traditional silicon-based IGBTs at low power is solved, and high under any circumstances is achieved Performance motor drive.
Patent Information
- Application Number
- CN202411311097.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-20
- Publication Date
- 2024-12-13
AI Technical Summary
The performance of traditional silicon-based IGBTs at low power such as switching losses and switching speeds are far inferior to GaN HEMT materials, resulting in insufficient performance in motor driving circuits used in many occasions.
Design a main power circuit, including the first main circuit and the second main circuit, switch different switching tubes according to the power of the motor, use GaN HEMT for low power, use Si-IGBT for high power, and obtain the motor through the sampling circuit. Frequency and DC bus current are used to determine the switching signal, and a soft switch switching circuit is used to reduce losses.
Under any power situation, the advantages of the switch tube can be fully utilized, the circuit performance can be ensured, the loss caused by switching losses and frequent switching can be reduced, and the system efficiency can be improved.
Smart Images
Figure CN119134884A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of power electronics technology, and in particular, to a main power circuit, a motor and an electrical device. Background Art
[0002] Traditional silicon-based IGBTs benefit from their mature applications in various power electronic converters and household appliances. Their simple driving and mature and stable processes make their application reliability much higher than that of GaN HEMTs. Therefore, traditional Si-IGBTs are generally used in the driving circuits of motors that need to be used in multiple occasions. However, the performance of traditional silicon-based IGBTs at low power, such as switching loss and switching speed, is far inferior to that of GaN HEMT materials. Summary of the invention
[0003] In order to overcome the shortcomings of the prior art, the present application provides a main power circuit, a motor and an electrical device to solve the problem that the traditional Si-IGBT is generally used in the driving circuit of the motor that needs to be used in multiple occasions, but the performance of the traditional silicon-based IGBT at low power, such as switching loss and switching speed, is far inferior to that of GaN HEMT materials.
[0004] The technical solution adopted by this application to solve its technical problem is:
[0005] In a first aspect, a main power circuit is provided, comprising:
[0006] A main circuit, wherein the main circuit includes a first main circuit and a second main circuit, and at most only one of the first main circuit and the second main circuit can be connected to the motor at the same time, the first main circuit adopts a first switch tube, and the second main circuit adopts a second switch tube; when the power of the motor is less than a preset power, the performance of the first switch tube is better than that of the second switch tube; when the power of the motor is greater than or equal to the preset power, the performance of the second switch tube is better than that of the first switch tube;
[0007] A sampling circuit, used for acquiring the frequency and / or DC bus current of the motor;
[0008] A switching circuit is used to switch the main circuit connected to the motor after triggering a switching signal, and the switching signal determines whether to be triggered according to the frequency and / or DC bus current of the motor.
[0009] Further, when the frequency of the motor is greater than or equal to a preset switching frequency, and / or when the DC bus current is greater than or equal to a preset switching current, the second main circuit is connected to the motor;
[0010] When the frequency of the motor is lower than the switching frequency and when the DC bus current is lower than the switching current, the first main circuit is connected to the motor.
[0011] Furthermore, the switching circuit is a soft switching circuit.
[0012] Further, the soft switch switching circuit includes a double-throw switch and a second switch with a body diode;
[0013] The first moving contact of the double-throw switch is connected to the first main circuit, the second moving contact of the double-throw switch is connected to the second main circuit, the static contact of the double-throw switch is connected to the DC bus through an inductor, one end of the second switch is connected between the inductor and the static contact, and the other end is connected to the DC bus, and the second switch section is connected in parallel with a first capacitor;
[0014] When the second switch is turned on, the double-throw switch changes from being connected at the first moving contact to being connected at the second moving contact, or the double-throw switch changes from being connected at the second moving contact to being connected at the first moving contact.
[0015] Further, the soft switch switching circuit includes a double-throw switch and a second switch with a body diode;
[0016] The first moving contact of the double-throw switch is connected to the first main circuit, the second moving contact of the double-throw switch is connected to the second main circuit, the static contact of the double-throw switch is connected to the DC bus through an inductor, one end of a first capacitor is connected between the inductor and the static contact, and the other end is connected to the DC bus, and a clamping branch is connected in parallel at both ends of the inductor; the clamping branch is composed of the second switch and the second capacitor in series;
[0017] When the second switch is turned on, the double-throw switch changes from being connected at the first moving contact to being connected at the second moving contact, or the double-throw switch changes from being connected at the second moving contact to being connected at the first moving contact.
[0018] Further, the switching circuit is a double-throw switch;
[0019] The first moving contact of the double-throw switch is connected to the first main circuit, the second moving contact of the double-throw switch is connected to the second main circuit, and the static contact of the double-throw switch is connected to a DC bus through an inductor.
[0020] Furthermore, the first switch tube is a GaN HEMT.
[0021] Furthermore, the second switch tube is a silicon-based switch tube.
[0022] Furthermore, it also includes: an input adjustment circuit;
[0023] The input adjustment circuit is connected to the power supply and is used to adjust the input characteristics of the power supply.
[0024] Furthermore, the input adjustment circuit includes at least any one of the following circuits:
[0025] Rectification circuit;
[0026] Inverter circuit;
[0027] PFC circuit;
[0028] Filter circuit.
[0029] Furthermore, it also includes: a delay unit, which is used to control the switching circuit to delay the switching of the main circuit connected to the motor for a preset time after triggering the switching signal.
[0030] Furthermore, it also includes:
[0031] The first main circuit and the second main circuit share a heat sink;
[0032] Alternatively, only one heat sink is provided for the second main circuit.
[0033] In a second aspect, a motor is provided, wherein the motor is connected to the main power circuit mentioned above.
[0034] In a third aspect, an electrical device is provided, comprising the above-mentioned motor.
[0035] Beneficial effects:
[0036] The technical solution of the present application provides a main power circuit, a motor and an electrical device. The main power circuit includes a main circuit, a sampling circuit and a switching circuit. The main circuit includes a first main circuit and a second main circuit. Since the first switch tube and the second switch tube are respectively applicable to different situations, the motor frequency and / or DC bus current obtained by the sampling circuit are used to determine whether to trigger the switching signal. After the switching signal is triggered, the switching circuit switches the main circuit connected to the motor. In this way, it is ensured that the first main circuit is used to control the motor at low power, and the second main circuit is used to control the motor at high power, giving full play to the advantages of the first switch tube and the second switch tube, and ensuring that the circuit has good performance in any case. BRIEF DESCRIPTION OF THE DRAWINGS
[0037] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0038] Figure 1 It is a schematic block diagram of a main power circuit structure provided by an embodiment of the present application;
[0039] Figure 2 is a schematic block diagram of a specific main power circuit structure provided in an embodiment of the present application;
[0040] Figure 3 This is a schematic diagram of a main power circuit for soft switching provided by an embodiment of the present application;
[0041] Figure 4 This is another main power circuit schematic diagram of soft switching provided in an embodiment of the present application;
[0042] Figure 5 This is a control flow chart provided by an embodiment of the present application, taking a compressor in a household air conditioner as an example;
[0043] Figure 6 The embodiment of this application provides Figure 5 Schematic diagram of compressor frequency acquisition;
[0044] Figure 7 The embodiment of this application provides Figure 5 The switching principle block diagram of the compressor;
[0045] Figure 8 The embodiment of this application provides Figure 5 Waveform diagram of medium soft switch switching circuit. DETAILED DESCRIPTION
[0046] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme of the present application is described in detail below in conjunction with the accompanying drawings and embodiments. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other implementation methods obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.
[0047] The third generation wide bandgap semiconductors Gallium Nutrude (GaN) and Silicon Carbide (SiC) are now hot research topics and research directions in the field of power electronic devices. GaN High Electron Mobility Transistor (HEMT) is very suitable for high switching frequency applications due to its large bandgap, high electron mobility, and high saturation drift rate. Its manufacturing cost is as competitive as that of silicon-based devices in low voltage applications such as 30-300V. For household appliances, the use of GaN devices can improve the efficiency of the converter so that it can meet the standard requirements in various applications.
[0048] However, under higher rated voltage conditions, GaN devices are not as stable as traditional silicon-based devices due to their limited rated current capacity. For higher voltage and higher power applications, SiC devices are significantly better than traditional silicon devices. Therefore, GaN is more suitable for medium and low voltage and low power applications, while SiC is more suitable for high power and high voltage applications. GaN switching tubes are an excellent choice for low voltage applications. Since they can run at a switching frequency of up to 10MHz, they can effectively improve the power density of the converter and have unparalleled advantages over Si and SiC. Therefore, they are widely used in low voltage converters such as consumer electronics, enterprise, industry, and transportation.
[0049] However, in actual use, the driven motor may need to operate at low voltage and low power for a period of time, and at high voltage and high power for another period of time, such as the compressor used in variable frequency air conditioners. Since Si-based devices have been widely used in various power electronic converters and household appliances, their drive is simple, the process is mature and stable, and their ability to conduct large currents is better than GaN HEMT, so the existing technology uses traditional silicon-based IGBTs. However, the performance of traditional silicon-based IGBTs at low power, such as switching loss and switching speed, is far inferior to that of GaN HEMT devices.
[0050] To solve this problem, refer to Figure 1 and Figure 2 , an embodiment of the present application provides a main power circuit, including:
[0051] A main circuit, the main circuit includes a first main circuit and a second main circuit, and at the same time, at most only one of the first main circuit and the second main circuit can be connected to the motor, the first main circuit adopts a first switch tube, and the second main circuit adopts a second switch tube; when the power of the motor is less than a preset power, the performance of the first switch tube is better than that of the second switch tube; when the power of the motor is greater than or equal to the preset power, the performance of the second switch tube is better than that of the first switch tube; exemplarily, the first switch tube is a GaN HEMT, that is, the first main circuit is a GaN HEMT type main circuit. The second switch tube is a silicon-based switch tube, preferably a Si-IGBT. The second main circuit is an IPM type main circuit or a Si-IPM type main circuit integrated by Si-IGBT.
[0052] A sampling circuit, used for acquiring the frequency and / or DC bus current of the motor;
[0053] As a preferred implementation scheme of the embodiment of the present application, the sampling circuit includes a current sampling circuit and a frequency sampling circuit, wherein the current sampling circuit is used to obtain the DC bus current and the frequency sampling circuit is used to obtain the frequency of the motor.
[0054] The specific structure of the current sampling circuit can be set according to the implementation needs, and this application does not make specific restrictions. The frequency sampling circuit is determined by obtaining the motor line voltage. Because the motor frequency is proportional to the line voltage, the frequency can be directly determined by the line voltage, or the motor frequency can be obtained by converting the motor line voltage.
[0055] It should be noted that in order to save costs, the frequency sampling circuit will only perform sampling under any of the following conditions:
[0056] The time interval from the last sampling is the preset time length;
[0057] The outdoor ambient temperature changes by a preset value.
[0058] The preset value is determined according to the workload; the greater the workload, the smaller the preset value.
[0059] Exemplarily, when the workload is less than or equal to a threshold value, the preset value is a first value, and when the workload is greater than the threshold value, the preset value is a second value, wherein the second value is smaller than the first value.
[0060] A switching circuit is used to switch the main circuit connected to the motor after triggering a switching signal, and the switching signal determines whether to be triggered according to the frequency and / or DC bus current of the motor.
[0061] As a preferred implementation scheme of the embodiment of the present application, when the frequency of the motor is greater than or equal to the preset switching frequency, and / or when the DC bus current is greater than or equal to the preset switching current, the second main circuit is connected to the motor; when the frequency of the motor is greater than or equal to the preset switching frequency, and / or when the DC bus current is greater than or equal to the preset switching current, it means that the power of the motor at this time is higher than the preset power, and therefore the second main circuit is switched to be connected to the motor.
[0062] When the frequency of the motor is less than the switching frequency, and when the DC bus current is less than the switching current, the first main circuit is connected to the motor. When the frequency of the motor is less than the switching frequency, and when the DC bus current is less than the switching current, it means that the power of the motor is lower than the preset power, so the first main circuit is switched to be connected to the motor.
[0063] As an optional implementation of the present application, the switching circuit is a double-throw switch, the first moving contact of the double-throw switch is connected to the first main circuit, the second moving contact of the double-throw switch is connected to the second main circuit, and the static contact of the double-throw switch is connected to the DC bus via an inductor.
[0064] However, in actual control, since the double-throw switch is a hard switch, the switch current is not zero at this moment, and there is a high bus voltage on the switch, so the power loss is large at the switching moment. Especially when switching frequently, the loss is too large.
[0065] Therefore, as another optional implementation of the present application, the switching circuit is a soft switching circuit.
[0066] like Figure 3 As shown, in one embodiment, the soft switch switching circuit includes a double-throw switch S1 and a second switch S2 with a body diode;
[0067] The first moving contact of the double-throw switch S1 is connected to the first main circuit, the second moving contact of the double-throw switch S1 is connected to the second main circuit, and the static contact of the double-throw switch S1 is connected to the second main circuit through the inductor L r Connected to the DC bus, one end of the second switch S2 is connected to the inductor L r The other end is connected to the DC bus, and the second switch S2 is connected in parallel with the first capacitor C r ;
[0068] When the second switch S2 is turned on, the double-throw switch S1 changes from the first moving contact connection to the second moving contact connection, or the double-throw switch S1 changes from the second moving contact connection to the first moving contact connection.
[0069] That is, the embodiment of the present application realizes the switching of the double-throw switch S1 by turning on the second switch S2. r And capacitors can form a resonant circuit to reduce the spike noise generated when the double-throw switch S1 is actuated.
[0070] like Figure 4 As shown, in another embodiment, the soft switch switching circuit includes a double-throw switch S1 and a second switch S2 with a body diode;
[0071] The first moving contact of the double-throw switch S1 is connected to the first main circuit, the second moving contact of the double-throw switch S1 is connected to the second main circuit, and the static contact of the double-throw switch S1 is connected to the second main circuit through the inductor L r Connect the DC bus, the first capacitor C r One end is connected to the inductor L r The other end is connected to the DC bus, and the inductor L rA clamping branch is connected in parallel at both ends; the clamping branch is composed of the second switch S2 and the second capacitor C c Series composition;
[0072] When the second switch S2 is turned on, the double-throw switch S1 changes from the first moving contact connection to the second moving contact connection, or the double-throw switch S1 changes from the second moving contact connection to the first moving contact connection.
[0073] That is, the embodiment of the present application realizes the switching of the double-throw switch S1 by turning on the second switch S2. r And capacitors can form a resonant circuit to reduce the spike noise generated when the double-throw switch S1 is actuated.
[0074] like Figure 2 As shown, it also includes: an input adjustment circuit;
[0075] The input adjustment circuit is connected to the power supply and is used to adjust the input characteristics of the power supply.
[0076] As a preferred implementation of the embodiment of the present application, the input adjustment circuit includes at least any one of the following circuits:
[0077] Rectification circuit;
[0078] Inverter circuit;
[0079] PFC circuit;
[0080] Filter circuit.
[0081] In addition, a delay unit is also included, and the delay unit is used to control the switching circuit to delay the switching of the main circuit connected to the motor for a preset time after the switching signal is triggered. In one embodiment, the delay unit is a hardware circuit. In another embodiment, the delay unit is software controlled and is set in the control chip. The delay unit is set to avoid frequent switching.
[0082] The main power circuit provided in the embodiment of the present application includes a main circuit, a sampling circuit and a switching circuit. The main circuit includes a first main circuit and a second main circuit. Since the first switch tube and the second switch tube are respectively applicable to different situations, it is determined whether to trigger the switching signal according to the motor frequency and / or DC bus current obtained by the sampling circuit. After the switching signal is triggered, the switching circuit switches the main circuit connected to the motor. In this way, it is ensured that the first main circuit is used to control the motor at low power, and the second main circuit is used to control the motor at high power, giving full play to the advantages of the first switch tube and the second switch tube, and ensuring that the circuit has good performance in any case.
[0083] Based on the same inventive concept, the present application also provides a motor, which is connected to the main power circuit provided in the above embodiment.
[0084] Based on the same inventive concept, the present application also provides an electrical device, including the motor provided in the above embodiment.
[0085] like Figure 5 As shown, the present application is explained by taking the compressor in a household air conditioner as an example. Since the compressor is a device that uses a motor to drive a piston to achieve compression, the frequency of the compressor is directly used instead of the motor frequency for the following explanation.
[0086] The switching time control conditions are as follows:
[0087] When the compressor is on, if any of the following conditions are met, it switches to Si-IPM control:
[0088] ①When it is detected that the DC bus current of the inverter circuit I≥
switching current
[0089] ②When compressor frequency f≥
Switching frequency
[0090] If the above conditions are not met, the control is switched to GaN HEMT type main circuit control.
[0091] according to Figure 7 It can be seen that Figure 7 It is mainly divided into three parts. The first is the internal logic unit of the microcontroller, such as Figure 7 The second is the main power circuit part, as shown in the solid line box; Figure 7 The third part is the peripheral connection and control part, remote control and power supply part, etc. This application mainly switches different main circuits according to the detected motor operating frequency and DC bus working current to achieve more efficient and high-performance air conditioning. Figure 3 or Figure 4 As shown, the normal working state of the double-throw switch S1 is to connect to the GaN HEMT type main circuit. Only when the switching signal is generated, the action signal is issued, and a certain delay is set, and the double-throw switch S1 is output through the I / O port, and then the double-throw switch S1 is actuated through the driving module. The double-throw switch S1 switches to the Si-IGBT integrated IPM module to drive the motor to work.
[0092] After powering on, the I / O module unit b port of the single-chip microcomputer outputs a low level. When this low level passes through the drive module, the double-throw switch S1 does not operate, and the three-phase main circuit is still the GaN HEMT type main circuit. By transmitting the collected DC bus current or motor frequency to the logic algorithm processing unit (see the relevant logic Figure 5 ) for processing. There are two cases after processing: one is that the frequency and current meet Figure 5The switching condition in the logic switches to the requirements of the Si-IPM main circuit. At this time, the I / O module unit outputs a high-level switching signal and starts the soft switching circuit. The driver module drives the double-throw switch S1 to operate, and the double-throw switch S1 switches to the Si-IPM module. Second, the frequency does not meet Figure 5 The switching requirements in the logic, at this time, the I / O module unit still outputs a low-level signal, the double-throw switch S1 does not operate, and the main circuit is still a GaN HEMT type main circuit.
[0093] Figure 7 In the switching principle diagram, after the switching action is made, a signal a is usually output to the I / O port of the microcontroller. The microcontroller starts a certain delay based on the signal a and then determines whether the switching is completed. If the switching is completed, the existing state is maintained; if the switching action is not completed smoothly, it will be triggered again. Figure 5 The logic shown in the figure makes a judgment and outputs the corresponding switching action. The purpose of this part is to detect that the switching condition is met and then perform the switching action after the condition is stable to avoid frequent switching. That is, after completing a switching action, the next switching can be triggered by the delay unit, so that the time between the two switches is at least the preset delay time, where the specific length of the delay time is set according to actual needs.
[0094] After completing a switching action, wait for the next detection to see if the switching condition is met. If the condition is met, continue to execute Figure 5 The logic in the circuit is switched to a GaN HEMT type main circuit.
[0095] The specific frequency collection method is as follows Figure 6 As shown, the motor frequency is collected by the Hall sensor module built into the motor.
[0096] Since the double-throw switch S1 will inevitably generate spike noise when it is in action, a resonant soft switching circuit is set up here to achieve zero voltage switching by introducing LC resonance in the DC link, such as Figure 3 or Figure 4 As shown in the main circuit diagram, a second switch S2 is used to make the switch switching time u Cr =0, which means that soft switching of the circuit topology is realized.
[0097] Since the motor inductance current changes very little during the entire resonance process and can be almost ignored, the motor inductance current during the resonance process can be equivalent to a constant. The specific working waveform of zero voltage soft switching is as follows: Figure 8 As shown, its specific working principle is as follows:
[0098] In the t0-t1 time period: before the t0 time period, the resonant inductance L r The current i Lr >IL Motor load inductor current, switch S2 divides part of the resonant inductor L r The current of S2 is in the on state. When it is in the t0-t1 period, S2 is turned off and the circuit resonates. At this moment, i Lr >I L ,i Lr For capacitor C r Charging, Cr Increases until it reaches the input bus voltage U DC .
[0099] Time period t1-t2: At this moment, S is turned off, i Lr Continue to C r Charging, Cr Continue to rise until i Lr Less than the load inductor current I L , the charging process ends, at time t2, the capacitor C r Voltage across the two ends u Cr Reach peak value;
[0100] Time period t2-t3: This period C r In discharge mode, at t2-u Cr Down to U in During the time period, the capacitor C r At the same time, to L r and L discharges, when i Lr When it drops to 0, C r Still discharging, i Lr Reverse rise; until u Cr =U in , the capacitor discharge process ends at time t3, at which time L r Reach the reverse resonant current peak;
[0101] Time period t3-t4: At time t3, i Lr Reaching the reverse resonance peak, the current i Lr Start to descend in the opposite direction, u Cr It also continues to decrease until t4, at which time the diode connected in parallel with S2 is turned on, and C r Voltage u Cr is clamped to 0;
[0102] t4-t0: S2 is turned on. At this moment, i Lr It rises linearly until it reaches time t0 again, and S2 is turned off.
[0103] As shown in the above analysis, the turn-on moment of S2 is exactly the switching moment of the S1 switch, thereby achieving zero voltage switching between the two topologies.
[0104] Figure 4The circuit and Figure 3 Compared with the previous example, a second capacitor C is added c , that is, the switch tube clamping capacitor, can significantly reduce the maximum input voltage of the DC bus during soft switching, thereby reducing the voltage stress on the high-frequency switch tube on the AC side, but the soft switching switch tube is connected in series on the DC bus.
[0105] Figure 4 The advantage of the soft switching circuit is that the voltage stress of the switch tube is not Figure 3 The circuit is large; however Figure 3 The soft switching process of the switch can be simulated by switch S2 to achieve the same effect, and a capacitor device is saved.
[0106] According to the switching requirements, in cooling mode, when the outdoor ambient temperature reaches below -20℃ or above 60℃, the compressor will stop, the compressor will not run, and the double-throw switch S1 contact will hit the GaN HEMT main circuit side; in heating mode, when the outdoor ambient temperature reaches below -25℃ or above 30℃, the compressor will stop, the compressor will not run, and the double-throw switch S1 contact will hit the GaN HEMT main circuit side. In addition, the frequency detection of the compressor meets the following conditions:
[0107] ①Update every 40 seconds;
[0108] ②Update every time the outdoor ambient temperature changes by 2°C; update every time the outdoor ambient temperature rises by 1°C during high load;
[0109] It should be noted that the frequency needs to be within the upper and lower limits. The lower limit of the compressor operating frequency is 15Hz and the upper limit is 120Hz.
[0110] The solution provided in the embodiment of the present application adopts a processing chip with an intelligent switching function. According to the characteristics that Si tubes are suitable for high-power use and GaN is more suitable for low-power use, an intelligent switching module is set to use Si-IPM to drive the motor at high power and use GaN HEMT to drive the motor at low power, so as to minimize power consumption and improve the efficiency of the air conditioner.
[0111] According to the different characteristics of Si-IGBT and GaN HEMT, by setting certain detection conditions, when the detection conditions are met, the topology of different materials can be switched to drive the motor, and a certain soft switching circuit can be set to achieve zero voltage switching between different converters to improve the working efficiency of the entire system and reduce the loss of the entire system. In addition, GaN HEMT and Si-IGBT can share the same heat sink, and even only the heat sink of Si-IGBT is needed, without adding a heat sink for GaN HEMT.
[0112] Advantages of this application plan:
[0113] 1. GaN is an emerging switching device. It has no reverse recovery loss, can greatly reduce the size of the heat sink, and can operate at a higher switching frequency than the traditional Si-IGBT. It is much smaller in weight and size than the previous Si-tube IGBT. Another advantage is that it does not have a large PN junction forward conduction voltage drop like Si tubes.
[0114] 2. For applications in household appliances, since GaN has higher power density and smaller size, it can better reduce the size of the converter and have higher efficiency.
[0115] 3. When the frequency is high enough, the conduction and switching losses of GaN HEMT are significantly improved, especially in electrical appliances such as household air conditioners.
[0116] 4. Hybrid switching control of Si-IGBT and GaN HEMT can achieve high-performance control of air-conditioning motors in the full frequency range, with lower switching loss and conduction loss.
[0117] 5. Users can change the motor frequency according to their own habits and select the topology of switch tubes of different materials to achieve motor control.
[0118] It should be noted that, in the description of this application, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of this application, unless otherwise specified, the meaning of "plurality" refers to at least two.
[0119] It can be understood that the same or similar parts of the above embodiments can be referenced to each other, and the contents not described in detail in some embodiments can refer to the same or similar contents in other embodiments.
Claims
1. A main power circuit, characterized in that: include: A main circuit, wherein the main circuit includes a first main circuit and a second main circuit, and at most only one of the first main circuit and the second main circuit can be connected to the motor at the same time, the first main circuit adopts a first switch tube, and the second main circuit adopts a second switch tube; When the power of the motor is less than the preset power, the performance of the first switch tube is better than that of the second switch tube; When the power of the motor is greater than or equal to the preset power, the performance of the second switch tube is better than that of the first switch tube; A sampling circuit, used for acquiring the frequency and / or DC bus current of the motor; A switching circuit is used to switch the main circuit connected to the motor after triggering a switching signal, and the switching signal determines whether to be triggered according to the frequency and / or DC bus current of the motor.
2. The main power circuit according to claim 1, characterized in that: When the frequency of the motor is greater than or equal to a preset switching frequency, and / or when the DC bus current is greater than or equal to a preset switching current, the second main circuit is connected to the motor; When the frequency of the motor is lower than the switching frequency and when the DC bus current is lower than the switching current, the first main circuit is connected to the motor.
3. The main power circuit according to claim 1, characterized in that: The switching circuit is a soft switching circuit.
4. The main power circuit according to claim 3, characterized in that: The soft switch switching circuit includes a double-throw switch and a second switch with a body diode; The first moving contact of the double-throw switch is connected to the first main circuit, the second moving contact of the double-throw switch is connected to the second main circuit, the static contact of the double-throw switch is connected to the DC bus through an inductor, one end of the second switch is connected between the inductor and the static contact, and the other end is connected to the DC bus, and the second switch section is connected in parallel with a first capacitor; When the second switch is turned on, the double-throw switch changes from being connected at the first moving contact to being connected at the second moving contact, or the double-throw switch changes from being connected at the second moving contact to being connected at the first moving contact.
5. The main power circuit according to claim 3, characterized in that: The soft switch switching circuit includes a double-throw switch and a second switch with a body diode; The first moving contact of the double-throw switch is connected to the first main circuit, the second moving contact of the double-throw switch is connected to the second main circuit, the static contact of the double-throw switch is connected to the DC bus through an inductor, one end of a first capacitor is connected between the inductor and the static contact, and the other end is connected to the DC bus, and a clamping branch is connected in parallel at both ends of the inductor; the clamping branch is composed of the second switch and the second capacitor in series; When the second switch is turned on, the double-throw switch changes from being connected at the first moving contact to being connected at the second moving contact, or the double-throw switch changes from being connected at the second moving contact to being connected at the first moving contact.
6. The main power circuit according to claim 1, characterized in that: The switching circuit is a double-throw switch; The first moving contact of the double-throw switch is connected to the first main circuit, the second moving contact of the double-throw switch is connected to the second main circuit, and the static contact of the double-throw switch is connected to a DC bus through an inductor.
7. The main power circuit according to claim 1, characterized in that: The first switch tube is a GaN HEMT.
8. The main power circuit according to claim 1, characterized in that: The second switch tube is a silicon-based switch tube.
9. The main power circuit according to claim 1, characterized in that: Also includes: Input adjustment circuit; The input adjustment circuit is connected to the power supply and is used to adjust the input characteristics of the power supply.
10. The main power circuit according to claim 9, characterized in that: The input adjustment circuit includes at least any one of the following circuits: Rectification circuit; Inverter circuit; PFC circuit; Filter circuit.
11. The main power circuit according to claim 1, characterized in that: Also includes: The delay unit is used to control the switching circuit to delay the switching of the main circuit connected to the motor for a preset time after triggering the switching signal.
12. The main power circuit according to claim 1, characterized in that: Also includes: The first main circuit and the second main circuit share a heat sink; Alternatively, only one heat sink is provided for the second main circuit.
13. A motor, characterized in that: The motor is connected to the main power circuit according to any one of claims 1-12.
14. An electrical device, characterized in that: Including the motor as claimed in claim 13.