High-power direct-current power supply boosting method and device and three-phase rectification voltage doubling device

Abstract

The invention relates to a high-power direct-current power supply boosting method and device and a three-phase rectification voltage doubling device, which are applied to occasions requiring direct-current boosting, and the direct-current boosting device comprises a power supply VIN, an inductor L, a switch K1, a switch K2, a diode D1, a diode D2, a capacitor C1, a capacitor C2 and a load resistor RL. The method comprises the following steps: alternately controlling the on and off actions of the switch K1 and the switch K2, the output voltage VO of the direct current boosting device is smaller than or equal to 2VI, the output voltage VO is the voltage at the two ends of the load resistor RL, and the VI is the input voltage between the positive electrode end S1 and the negative electrode end S2 of the power supply VIN. The three-phase alternating-current power supply can be applied to various application scenes, has no requirement on input current harmonics (during three-phase alternating-current input), and can provide required output voltage with lower cost and higher reliability, so that various compressors popular in the market can be used, convenience is brought to complete machine manufacturers, and the cost is reduced.

Description

Technical Field

[0001] The present invention relates to electronic circuits, and in particular to a high-power DC power supply voltage boosting method and device, and a three-phase rectifier voltage doubling device. Background Art

[0002] In the field of electronic circuits, DC power boost technology is widely used in various scenarios requiring a higher voltage than the input voltage, such as electric vehicle drives, industrial motor control, and commercial or residential heat pump systems. In particular, certain applications have clear requirements for the output DC voltage: the output voltage must not exceed twice the input voltage and must be able to follow variations in input voltage and load without requiring strict voltage regulation. At the same time, the system must have low cost and complexity.

[0003] For example, in the commercial or residential heat pump sector, some regions rely on a 220V three-phase AC power supply. The output voltage, after direct rectification, typically needs to be increased by 50% to 100% compared to the voltage required to power a mainstream compressor. For example, if the input is 220V three-phase AC, the rectified DC voltage is approximately 297V, while a mainstream compressor may require a voltage range of 450V to 540V. To meet this requirement, two main technical solutions have traditionally been used: three-phase active power factor control (APFC) and DC boost (BOOST) technology.

[0004] Three-phase active power factor control (APFC) technology can achieve a voltage boost while suppressing input current harmonics, effectively improving the system's power factor and reducing grid pollution. However, APFC technology is complex to implement, involving multiple sensors and complex control algorithms, resulting in high system costs and potentially reduced reliability due to control complexity. DC boost (BOOST) technology can achieve voltage boost by first rectifying and filtering the circuit and then boosting the voltage. Although its implementation is relatively simple, traditional BOOST circuits still require complex control circuits and expensive electronic components for high-power applications. This is especially true when the output voltage needs to be precisely controlled and strict requirements are placed on input current harmonics, further increasing cost and complexity.

[0005] Therefore, those skilled in the art are in urgent need of developing a new technical solution to solve the above problems. Summary of the Invention

[0006] In order to overcome the problems existing in the related art, the present invention discloses a high-power DC power supply boosting method and device and a three-phase rectifier voltage doubling device.

[0007] According to a first aspect of the disclosed embodiments of the present invention, a high-power DC power supply boosting method is provided, which is applied to a DC boosting device. The DC boosting device includes: a power supply VIN, an inductor L, a switch K1, a switch K2, a diode D1, a diode D2, a capacitor C1, a capacitor C2, and a load resistor RL. A positive terminal S1 of the power supply VIN is connected in series with the inductor L and then connected to the positive terminal of the diode D1 and the first end of the switch K1, respectively. The negative terminal of the diode D1 is connected to the first end of the capacitor C1. The second end of the capacitor C1 is connected in series with the first end of the switch K2 and the second end of the switch K2 in sequence, and is connected to the negative terminal S2 of the power supply VIN. The second end of the switch K1 is connected in series with the first end of the capacitor C2, the second end of the capacitor C2, the positive terminal of the diode D2, and the negative terminal of the diode D2 in sequence, and is connected to the negative terminal S2 of the power supply VIN. The load resistor RL spans the positive terminal S1 and the negative terminal S2 of the power supply VIN and is connected to the negative terminal of the diode D1 and the positive terminal of the diode D2, respectively.

[0008] The method comprises:

[0009] By alternately controlling the on and off actions of the switches K1 and K2, the output voltage VO of the DC boost device is made less than or equal to 2VI, where the output voltage VO is the voltage across the load resistor RL, and VI is the input voltage between the positive terminal S1 and the negative terminal S2 of the power supply VIN.

[0010] Optionally, the step of alternately controlling the on and off actions of the switch K1 and the switch K2 so that the output voltage VO of the DC boost device is less than or equal to 2VI includes:

[0011] The switch K1 and the switch K2 are alternately turned on at a frequency of f=1 / T, where each cycle T=T1+T2+T3+T4, T1 is the on-time period of the switch T1, T2 is the dead-time period when the switch K1 and the switch K2 are disconnected, T3 is the on-time period of the switch T2, and T4 is the dead-time period when the switch K1 and the switch K2 are disconnected, T1=T3, T2=T4, and the output voltage VO≤2(T1 / T+T3 / T)VI.

[0012] Optionally, the current fluctuation frequency F of the inductor L is 2f.

[0013] According to a second aspect of the disclosed embodiments of the present invention, a DC boost device is provided, comprising: a power supply VIN, an inductor L, a switch K1, a switch K2, a diode D1, a diode D2, a capacitor C1, a capacitor C2, and a load resistor RL, wherein a positive terminal S1 of the power supply VIN is connected in series with the inductor L and then connected to the positive terminal of the diode D1 and the first end of the switch K1, respectively; a negative terminal of the diode D1 is connected to the first end of the capacitor C1; a second end of the capacitor C1 is connected in series with the first end of the switch K2 and the second end of the switch K2 in sequence, and connected to the negative terminal S2 of the power supply VIN; the second end of the switch K1 is connected in series with the first end of the capacitor C2, the second end of the capacitor C2, the positive terminal of the diode D2, and the negative terminal of the diode D2 in sequence, and connected to the negative terminal S2 of the power supply VIN; the load resistor RL spans the positive terminal S1 and the negative terminal S2 of the power supply VIN and is connected to the negative terminal of the diode D1 and the positive terminal of the diode D2, respectively.

[0014] Optionally, the magnetic core of the inductor L is made of silicon steel sheet, ferrite, or microcrystal.

[0015] Optionally, the switch K1 and the switch K2 are IGBT, MOSFET or SiC MOSFET.

[0016] Optionally, the diode D1 and the diode D2 are FRD, UFRD or SiC SBD.

[0017] Optionally, the capacitor C1 and the capacitor C2 are power capacitors or electrolytic capacitors.

[0018] According to the third aspect of the disclosed embodiment of the present invention, a three-phase rectifier and voltage doubler device is provided, which includes: the DC boost device described in the second aspect of the disclosed embodiment of the present invention, and the power supply VIN is a rectified 220V60Hz three-phase power supply.

[0019] In summary, the present invention relates to a high-power DC power supply boosting method, device, and three-phase rectifier voltage multiplier device, which are applied to a DC boost device, the DC boost device comprising: a power supply VIN, an inductor L, a switch K1, a switch K2, a diode D1, a diode D2, a capacitor C1, a capacitor C2, and a load resistor RL. The method comprises: alternatingly controlling the on and off actions of switches K1 and K2 to make the output voltage VO of the DC boost device less than or equal to 2VI, wherein the output voltage VO is the voltage across the load resistor RL, and the VI is the input voltage between the positive terminal S1 and the negative terminal S2 of the power supply VIN. The method is applicable to a variety of application scenarios, does not require input current harmonics, and can provide the required output voltage at a low cost and high reliability, thereby enabling the use of various popular compressors on the market, which is convenient for complete machine manufacturers and helps reduce costs.

[0020] Other features and advantages disclosed in the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following detailed description, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0022] Figure 1 is a structural schematic diagram of a DC boost device according to an exemplary embodiment;

[0023] Figure 2 is based on Figure 1 An operating sequence diagram of a high-power DC power supply boosting method is shown;

[0024] Figure 3 is a main circuit principle diagram of a three-phase rectifier and voltage doubler device according to an exemplary embodiment;

[0025] Figure 4 is based on Figure 3 The main circuit operation sequence diagram of a three-phase rectifier voltage doubler power supply is shown. DETAILED DESCRIPTION

[0026] The following is a detailed description of the specific embodiments disclosed in the present invention in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0027] Figure 1 FIG. 1 is a structural diagram of a DC boost device according to an exemplary embodiment. Figure 1As shown, the DC boost device includes: a power supply VIN, an inductor L, a switch K1, a switch K2, a diode D1, a diode D2, a capacitor C1, a capacitor C2, and a load resistor RL. The positive terminal S1 of the power supply VIN is connected in series with the inductor L and then connected to the positive terminal of the diode D1 and the first end of the switch K1, respectively. The negative terminal of the diode D1 is connected to the first end of the capacitor C1. The second end of the capacitor C1 is connected in series with the first end of the switch K2 and the second end of the switch K2 in sequence, and is connected to the negative terminal S2 of the power supply VIN. The second end of the switch K1 is connected in series with the first end of the capacitor C2, the second end of the capacitor C2, the positive terminal of the diode D2, and the negative terminal of the diode D2 in sequence, and is connected to the negative terminal S2 of the power supply VIN. The load resistor RL spans the positive terminal S1 and the negative terminal S2 of the power supply VIN and is connected to the negative terminal of the diode D1 and the positive terminal of the diode D2, respectively.

[0028] For example, the DC boost device in the disclosed embodiment of the present invention is suitable for applications where the output DC voltage does not exceed twice the input DC voltage, allowing the output DC voltage to follow changes in the input voltage and load without requiring voltage regulation. Specifically, inductor L smooths the current. Since a sudden current is generated when switches K1 and K2 switch, it may damage components and generate strong interference. The inclusion of inductor L can suppress these negative effects. Switches K1 and K2 are power switching devices; during operation, the DC boost device alternates between switching at a certain frequency. Diodes D1 and D2 provide reverse isolation and freewheeling during the operation of switches K1 and K2. Capacitors C1 and C2 provide energy storage and voltage superposition during the operation of switches K1 and K2. The positive terminal S1 and negative terminal S2 of power supply VIN are connected to the positive and negative terminals of the input DC power supply, respectively. A load resistor RL is connected across the series-connected capacitors C1 and C2 to serve as the load of the DC boost device.

[0029] Specifically, the magnetic core of the inductor L is made of silicon steel sheet, ferrite, or microcrystal. The switches K1 and K2 are IGBTs, MOSFETs, or SiC MOSFETs. The diodes D1 and D2 are FRDs, UFRDs, or SiC SBDs. The capacitors C1 and C2 are power capacitors or electrolytic capacitors.

[0030] For example, different core materials can be selected according to the switching frequency (i.e., the operating frequency of switch K1 and switch K2), including but not limited to silicon steel sheet, ferrite, microcrystal, etc. Different switching power devices can be selected for switch K1 and switch K2 according to the application, including but not limited to IGBT, MOSFET, SiC MOSFET, etc. It should be noted that Figure 1The figure only shows the connection relationship between switches K1 and K2 in the main circuit; the respective drive control circuits will vary depending on the power switching device selected. Diodes D1 and D2 can also be selected from different diodes, including but not limited to FRDs, UFRDs, and SiC SBDs, depending on the switching frequency. Capacitors C1 and C2 are used for energy storage and output voltage smoothing. Power capacitors or electrolytic capacitors can be selected depending on the switching frequency and load requirements.

[0031] Applied to the above-mentioned DC boost device, the disclosed embodiment of the present invention further provides a high-power DC power boost method, the method comprising: by alternately controlling the on and off actions of switches K1 and K2, so that the output voltage VO of the DC boost device is less than or equal to 2VI, wherein the output voltage VO is the voltage across the load resistor RL, and VI is the input voltage between the positive terminal S1 and the negative terminal S2 of the power supply VIN.

[0032] For example, during the operation of the DC boost device, the switch K1 and the switch K2 are alternately switched between an ON state and an OFF state according to a certain switching frequency and duty cycle.

[0033] Specifically, the output voltage VO of the DC boost device is made less than or equal to 2VI by alternately controlling the on and off actions of the switch K1 and the switch K2, including: alternately turning on the switch K1 and the switch K2 at a frequency of f=1 / T, wherein each cycle T=T1+T2+T3+T4, wherein T1 is the on-time period of the switch K1, T2 is the dead-time period from the off-time of the switch K1 to the on-time of the switch K2, T3 is the on-time period of the switch K2, and T4 is the dead-time period from the off-time of the switch K2 to the on-time of the switch K1. Typically, T1=T3, T2=T4, and the output voltage VO≤2(T1 / T+T3 / T)VI.

[0034] For example, Figure 2 As shown, the switching frequency f=1 / T=1 / (T1+T2+T3+T4), preferably T1=T3 and T2=T4. Switch K1 and switch K2 are alternately turned on once each within one carrier frequency period T, and the two turn-on times (during T1+T2 and T3+T4) are equivalent for the input power supply VIN and the inductor L. The fluctuation frequency of the current in the inductor L is F=2*f, and F≥20KHz is preferably selected to avoid interference from audio noise.

[0035] The duty cycle of switches K1 and K2 when they are on is (T1 + T3) / T. This duty cycle affects the output voltage VO and the dead time protecting switches K1 and K2. The maximum output voltage VO is twice the input voltage VI. Considering that the duty cycle of switches K1 and K2 when they are on is less than 1, the inductor L, capacitors C1, and capacitors C2 are typically large enough to ensure that the output voltage VO is ≤ 2*((T1+T3) / T)*VI. Due to the voltage drops across inductor L, switches K1 and K2, and diodes D1 and D2, the actual output voltage will be lower than 2*((T1+T3) / T)*VI and will gradually decrease as output power increases.

[0036] The dead zone refers to the T2 and T4 periods inserted between periods T1 and T3 when switches K1 and K2 are conducting. If T2=T4=0, the switch duty cycle can be increased to 1. However, in actual applications, common conduction (K1 and K2 conducting at the same time) may occur due to differences in component characteristics. Therefore, the switch duty cycle must be reduced and T2 and T4 must be inserted to completely eliminate this dangerous state.

[0037] During the conduction period of the electronic switch K1 (T1, at this time: K2 is closed and D1 is cut off due to the reverse voltage), the input power supply charges the energy storage capacitor C2. At this time, the charging current flows as follows: VIN+→L→K1→C2→D2→VIN-; the voltage across capacitor C2 can reach up to the input voltage (ignoring the voltage drop of L, K1, and D2).

[0038] At the moment when the switch K1 turns from on to off, the current flowing through the inductor L is I, and the energy stored in the inductor L is L*I 2 / 2; thus, during the time period T2 when both switches K1 and K2 are closed, the stored energy of the inductor L is gradually released by charging the series-connected capacitors C1 and C2 through the diodes D1 and D2 via the self-inductance potential superimposed on the input voltage.

[0039] During the T3 period when switch K2 is turned on and switch K1 is turned off, diode D2 is cut off due to the reverse voltage, and the input power supply charges the energy storage capacitor C1. At this time, the charging current flows as follows: VIN+→L→D1→C1→K2→VIN-; the voltage across capacitor C1 can reach up to the input voltage (ignoring the voltage drops of L, K2, and D1).

[0040] When the switch K2 turns from on to off, the current flowing through the inductor L is I, and the energy stored in the inductor L is L*I 2 Thus, during the time period T4 when both switches K1 and K2 are closed, the energy stored in the inductor L is gradually released by charging the series-connected capacitors C1 and C2 through the diodes D1 and D2 via the self-inductance potential and the input voltage.

[0041] The voltage of capacitor C1 and capacitor C2 is connected in series in a forward direction as an output voltage and provided to the load resistor RL. When selecting capacitor C1 and capacitor C2, a sufficiently large capacity is selected to achieve smooth discharge to the load resistor RL.

[0042] The disclosed embodiment of the present invention further provides a three-phase rectifying and voltage doubling device, which includes: a DC boost device, and the power supply VIN is a rectified 220V60Hz three-phase power supply.

[0043] For example, in some application scenarios, the input voltage is a 220V 60Hz three-phase power supply, and needs to be converted into a 450-540V DC voltage as the output voltage. Under normal circumstances, the output DC voltage Uout of the three-phase rectifier circuit does not exceed the effective value of the input line voltage Uin. times, that is, Uout≤ *Uin. When Uin=220V, Uout≤ *220=297V, which cannot meet the output voltage requirement. At this time, APFC or BOOST technology can be used, but it will incur higher costs and reduce reliability. In a large number of application scenarios, there are no requirements for input current harmonics, and the output voltage can be tolerated to vary within a certain range with the input voltage and load. The method in the disclosed embodiment of the present invention can be used to achieve an increase in output voltage at a relatively low cost and high reliability. The input power supply of the three-phase rectifier and voltage doubler device is a 220V / 60Hz three-phase AC power supply. The output voltage after rectification is approximately 297V, which is used as the input voltage of the voltage doubler circuit, that is: VI=297V; the output is DC 480~540V, and the power is 15KW.

[0044] The main circuit of the three-phase rectifier and voltage doubler device is as follows: Figure 3 As shown in the figure, the inductor L is a silicon steel core reactor, which not only suppresses the sudden current generated by the electronic switch switching, but also improves the input power factor of the entire device and reduces output voltage fluctuations. The electronic switch is an insulated gate bipolar transistor (IGBT), which is turned on and off by the drive signal voltages VG1 and VG2 respectively. (Other types of power devices can also be used, including but not limited to MOSFETs and SiC MOSFETs.)

[0045] The main circuit operation sequence of the three-phase rectifier and voltage doubler device is as follows: Figure 4 As shown in Figure 1, the drive signal voltages VG1 and VG2 can have different forms and value ranges depending on the electronic switch used; T is the switching period, and the switching frequency f=1 / T.

[0046] Preferably, the switching frequency is 10 kHz. Since the two electronic switches are alternately turned on once each within a carrier frequency cycle, and the two turns on are equivalent to the inductor L, the fluctuation frequency of the inductor current is 10 kHz × 2 = 20 kHz, which is higher than the human hearing range.

[0047] Preferably, T=100uS (f=1 / T=10KHz). Considering the performance and consistency of components, T2=T4=5uS is selected, then T1=T3=(T-T2-T4) / 2=(100-5-5) / 2=45uS. The duty cycle k1=T1 / T=45 / 100=0.45, k2=T3 / T=45 / 100=0.45, so the total duty cycle k=k1+k2=0.9. Therefore, the output DC voltage VO≤2*k*VIN=2*0.9*( *220)=535V.

[0048] Preferably, the inductance of the reactor is 2 mH, and the capacitance of the energy storage capacitors C1 and C2 is 300 uF.

[0049] When the output power of this three-phase rectifier and voltage doubler reaches 15KW, the input power factor is about 0.95 and the output voltage is about 530V (fluctuation range ±11V), which can fully meet the needs of application scenarios.

[0050] In summary, the present invention relates to a high-power DC power supply boosting method, device, and three-phase rectifier voltage multiplier device, which are applied to a DC boost device, the DC boost device comprising: a power supply VIN, an inductor L, a switch K1, a switch K2, a diode D1, a diode D2, a capacitor C1, a capacitor C2, and a load resistor RL. The method comprises: alternatingly controlling the on and off actions of switches K1 and K2 so that the output voltage VO of the DC boost device is less than or equal to 2VI, wherein the output voltage VO is the voltage across the load resistor RL, and the VI is the input voltage between the positive terminal S1 and the negative terminal S2 of the power supply VIN. The method is applicable to a variety of application scenarios, does not require input current harmonics, and can provide the required output voltage at a low cost and high reliability, thereby enabling the use of various popular compressors on the market, which is convenient for complete machine manufacturers and helps reduce costs.

[0051] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the scope of protection of the present disclosure.

[0052] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0053] In addition, the various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A high-power DC power supply boosting method, characterized in that: The device is applied to a DC boost device, the DC boost device comprising: a power supply VIN, an inductor L, a switch K1, a switch K2, a diode D1, a diode D2, a capacitor C1, a capacitor C2, and a load resistor RL. The positive terminal S1 of the power supply VIN is connected in series with the inductor L, and then connected to the positive terminal of the diode D1 and the first end of the switch K1, respectively. The negative terminal of the diode D1 is connected to the first end of the capacitor C1. The second end of the capacitor C1 is connected in series with the first end of the switch K2 and the second end of the switch K2, and connected to the negative terminal S2 of the power supply VIN. The second end of the switch K1 is connected in series with the first end of the capacitor C2, the second end of the capacitor C2, the positive terminal of the diode D2, and the negative terminal of the diode D2, and connected to the negative terminal S2 of the power supply VIN. The load resistor RL spans the positive terminal S1 and the negative terminal S2 of the power supply VIN, and is connected to the negative terminal of the diode D1 and the positive terminal of the diode D2, respectively. The method comprises: By alternately controlling the on and off actions of the switches K1 and K2, the output voltage VO of the DC boost device is made less than or equal to 2VI, where the output voltage VO is the voltage across the load resistor RL, and VI is the input voltage between the positive terminal S1 and the negative terminal S2 of the power supply VIN.

2. The high-power DC power supply boosting method according to claim 1, characterized in that: The method of alternately controlling the on and off actions of the switch K1 and the switch K2 so that the output voltage VO of the DC boost device is less than or equal to 2VI includes: The switch K1 and the switch K2 are alternately turned on at a frequency of f=1 / T, where each cycle T=T1+T2+T3+T4, T1 is the on-time period of the switch T1, T2 is the dead-time period when the switch K1 and the switch K2 are disconnected, T3 is the on-time period of the switch T2, and T4 is the dead-time period when the switch K1 and the switch K2 are disconnected, T1=T3, T2=T4, and the output voltage VO≤2(T1 / T+T3 / T)VI.

3. The high-power DC power supply boosting method according to claim 2, characterized in that: The current fluctuation frequency of the inductor L is F=2f.

4. A DC boost device, characterized in that: The DC boost device includes: a power supply VIN, an inductor L, a switch K1, a switch K2, a diode D1, a diode D2, a capacitor C1, a capacitor C2, and a load resistor RL. A positive terminal S1 of the power supply VIN is connected in series with the inductor L and then connected to the positive terminal of the diode D1 and the first end of the switch K1, respectively. The negative terminal of the diode D1 is connected to the first end of the capacitor C1. The second end of the capacitor C1 is connected in series with the first end of the switch K2 and the second end of the switch K2 in sequence, and is connected to the negative terminal S2 of the power supply VIN. The second end of the switch K1 is connected in series with the first end of the capacitor C2, the second end of the capacitor C2, the positive terminal of the diode D2, and the negative terminal of the diode D2 in sequence, and is connected to the negative terminal S2 of the power supply VIN. The load resistor RL spans the positive terminal S1 and the negative terminal S2 of the power supply VIN and is connected to the negative terminal of the diode D1 and the positive terminal of the diode D2, respectively.

5. The DC boost device according to claim 4, characterized in that: The magnetic core of the inductor L is made of silicon steel sheet, ferrite, or microcrystal.

6. The DC boost device according to claim 4, characterized in that: The switch K1 and the switch K2 are IGBT, MOSFET or SiC MOSFET.

7. The DC boost device according to claim 4, characterized in that: The diode D1 and the diode D2 are FRD, UFRD or SiC SBD.

8. The DC boost device according to claim 4, characterized in that: The capacitor C1 and the capacitor C2 are power capacitors or electrolytic capacitors.

9. A three-phase rectifier and voltage multiplier device, characterized in that: The three-phase rectifying and voltage doubling device comprises: a DC boost device according to any one of claims 4 to 8, and the power supply VIN is a rectified three-phase AC power supply, including but not limited to 220V 60Hz.

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