Single-phase power factor correction inductive current zero-crossing distortion compensation circuit

Abstract

The invention provides a single-phase power factor correction inductive current zero-crossing distortion compensation circuit, which comprises a correction circuit, a compensation circuit and an additional circuit, and is characterized in that the correction circuit is connected with the additional circuit, and the additional circuit is connected with the compensation circuit; the correction circuit is used for outputting direct-current voltage and performing power factor correction; the additional circuit is used for linking the compensation circuit and the correction circuit, the compensation circuit is used for providing negative direct current compensation voltage in a network voltage full-wave period or a neighborhood after network voltage zero crossing, and direct current voltage at the output end of a boost inductor in the correction circuit is compensated through the negative direct current compensation voltage of the compensation circuit. And controlling the actual rising slope of the boost inductive current to be greater than the expected rising slope. According to the invention, the compensation circuit with a simple structure is adopted, the zero-crossing distortion phenomenon of the input current is eliminated, the harmonic wave of the input current is reduced, the harmonic pollution of the power grid is eliminated, and the cost is reduced in the full-wave period of the network voltage or the neighborhood after zero-crossing of the network voltage.

Description

Technical Field

[0001] The present disclosure relates to the technical field of power electronic converters, and more particularly, to a single-phase power factor correction inductor current zero-crossing distortion compensation circuit. Background Art

[0002] For a traditional single-phase active power factor correction circuit (Power Factor Correction, PFC), a typical structure includes an uncontrolled diode rectifier bridge and a Boost DC-DC converter cascaded front and back.

[0003] Its existing practical problems are: (1) Due to the non-ideal problems of power devices, when the power switch is turned on, two ordinary power diodes, one power switch, and one boost inductor are involved in conducting the current, and there are the on-state voltage drops of the ordinary power diodes, the on-state voltage drop of the power switch, and the DC resistance voltage drop of the boost inductor. When the power switch is turned off, two power diodes, one fast-recovery diode, and one boost inductor are involved in conducting the current, and there are diode on-state voltage drops and the DC resistance voltage drop of the boost inductor; (2) After the output of the voltage outer loop in the PFC controller is multiplied by the sine half-wave, the given value of the current inner loop is obtained, which is close to the sine half-wave at steady state and corresponds to the expected actual boost inductor current waveform. When the grid voltage is in [0°, 90°] and [180°, 360°], especially close to 0° or 180°, the actual boost inductor current waveform is completed by charging and discharging under the action of the power switch turning on and off, forming a current waveform with a variable hysteresis width. When the power switch is turned on, the current rises and charges, and the current waveform has a lagging trend. When the power switch is turned off, the current drops and discharges, and the current waveform has a leading trend.

[0004] When ignoring the above various voltage drops, the actually formed slope of the inductor current rise is u i / L1, and the expected slope of the inductor current rise is ω i I im cosω i t. It is required that the actually formed slope of the inductor current rise is greater than the expected slope of the inductor current rise u L1 / L1 > ω i I im cosω i t, u L1 = u i in order to achieve inductor current tracking of the grid voltage. However, when ω i t is close to 0° or 180°, that is, within a certain angle after the grid voltage crosses zero, this condition cannot be established. Wherein, ω i represents the grid voltage angular frequency, I im represents the inductor current amplitude, t represents time, u L1 represents the boost inductor voltage, u irepresents the input voltage. The slope of the actually formed inductor current decline is (u i -u o ) / L1, and the expected slope of the inductor current decline is ω i I im cosω i t. It is required that the slope of the actually formed inductor current decline is less than the expected slope of the inductor current decline (u i -u o ) / L1 < ω i I im cosω i t, where u o represents the output voltage of the PFC, and this condition can hold.

[0005] Taking into account the above voltage drop problem and slope problem, the problem of zero-crossing distortion of the inductor current inevitably occurs, reducing the sinusoidality of the grid-side current and the input power factor being less than 1. For the traditional single-phase power factor correction circuit topology, any improved double-loop control strategy cannot eliminate the zero-crossing distortion problem of the inductor current. With the increase of the output power, the decrease of the grid voltage, and the increase of the grid frequency, the zero-crossing distortion of the inductor current becomes more serious, and this problem needs to be fundamentally solved.

[0006] The solution lies in: (1) requiring the use of power devices without voltage drop; (2) requiring that the slope of the actually formed inductor current rise is always greater than the expected slope of the inductor current rise u L1 / L1 > ω i I im cosω i t. Obviously, the first condition cannot be satisfied, but the second condition can be met or achieved by improving the PFC topology to ensure that within a period of time after the grid voltage crosses zero or throughout the power supply cycle, the slope of the actually formed inductor current rise is greater than the expected slope of the inductor current rise u L1 / L1 > ω i I im cosω i t.

[0007] After retrieval, it is found that the Chinese invention patent "Buck - Boost Circuit with Unity Power Factor" with the patent number CN201210253332.1 provides a buck - boost circuit. The grid - side can approximately achieve unity power factor, overcoming the problem of poor power factor on the grid - side of the original buck - type Buck AC - DC converter. However, it does not address the problem of zero - crossing distortion of the input current or inductor current caused by the above - mentioned voltage drop and slope. Moreover, it uses a relatively large number of power switches or power devices, including an electrolytic capacitor, two diodes, and two power switches IGBTs. Due to the excessive voltage drop of the electrolytic capacitor, the electrical stress on the buck inductor is relatively large, such as an additional increase in voltage level, large current ripple, causing insulation withstand voltage problems, reducing the output voltage quality of the Buck AC - DC converter, and at the same time, the cost is relatively high and the power integration is low.

[0008] In addition, there are also some other solutions. For example, (1) a solution of inserting a DC power supply on the DC negative line of the original PFC. Its disadvantage is the lack of an independent DC power supply, so this solution has no practical value; (2) changing the input AC voltage source so that there is only one zero - crossing moment, and the instantaneous voltage values before and after zero - crossing are much greater than zero, which can eliminate the grid - side current distortion. However, this solution requires modifying the AC input power supply and also has no practical value.

[0009] In view of this, it is very necessary to design a single - phase power factor correction inductor current zero - crossing distortion compensation circuit. Summary of the Invention

[0010] Aiming at the defects in the prior art, the purpose of the present disclosure is to provide a single - phase power factor correction inductor current zero - crossing distortion compensation circuit.

[0011] To achieve the above - mentioned purpose, according to one aspect of the present disclosure, a single - phase power factor correction inductor current zero - crossing distortion compensation circuit is provided, including: a correction circuit, a compensation circuit, and an additional circuit. The correction circuit is connected to the additional circuit, and the additional circuit is connected to the compensation circuit;

[0012] The correction circuit is used to output a DC voltage and perform input power factor correction;

[0013] The additional circuit is used to connect the compensation circuit and the correction circuit;

[0014] The compensation circuit is used to provide a negative DC compensation voltage within the full - wave cycle of the grid voltage or in the neighborhood after the grid voltage zero - crossing. The negative DC compensation voltage of the compensation circuit compensates the DC voltage at the output end of the boost inductor in the correction circuit, and controls the actual rising slope of the boost inductor current to be greater than the expected rising slope.

[0015] Optionally, the correction circuit includes: a filter inductor L1, a boost inductor L2, a filter capacitor C1, an electrolytic capacitor C2, a power diode D1, a power diode D2, a power diode D3, a power diode D4, a power switch S1, a reverse fast recovery diode D5, and a load resistor R2.

[0016] Optionally, it further includes a single-phase AC power supply ui1, and the single-phase AC power supply is connected to the correction circuit.

[0017] Optionally, one end of the filter inductor L1 is connected to the live wire of the single-phase AC power supply ui1, the other end of the filter inductor L1 is respectively connected to one end of the filter capacitor C1, the anode of the power diode D1, and the cathode of the power diode D2, the other end of the filter capacitor C1 is respectively connected to the neutral wire of the single-phase AC power supply ui1, the anode of the power diode D3, and the cathode of the power diode D4, one end of the boost inductor L2 is respectively connected to the cathode of the power diode D1 and the cathode of the power diode D3, the other end of the boost inductor L2 is respectively connected to the anode of the reverse fast recovery diode D5 and the collector of the power switch S1, the cathode of the reverse fast recovery diode D5 is respectively connected to the positive electrode of the electrolytic capacitor C2 and one end of the load resistor R2 to form an output positive electrode, the negative electrode of the electrolytic capacitor C2 is connected to the other end of the load resistor R2 to form an output negative electrode, and the other end of the load resistor R2 is grounded 1.

[0018] Optionally, the compensation circuit includes a Buck - Boost circuit, the Buck - Boost circuit includes a reverse fast recovery diode D7, an electrolytic capacitor C3, a power switch S3, a power inductor L3, and the additional circuit includes a reverse fast recovery diode D6 and a power switch S2.

[0019] Optionally, the anode of the fast recovery diode D6 is respectively connected to the emitter of the power switch S1 and the collector of the power switch S2, the cathode of the fast recovery diode D6 is connected to the output negative electrode, the emitter of the power switch S2 is grounded 2, the collector of the power switch S3 is connected to the output positive electrode, the emitter of the power switch S3 is respectively connected to the cathode of the reverse fast recovery diode D7 and one end of the power inductor L3, the anode of the reverse fast recovery diode D7 is grounded 2, the negative electrode of the electrolytic capacitor C3 is grounded 2, the positive electrode of the electrolytic capacitor C3 is grounded 1, and the power inductor L3 is connected to the output negative electrode.

[0020] Optionally, within the full-wave cycle of the grid voltage or in the neighborhood after the grid voltage crosses zero, the power switch S1 and the power switch S2 are synchronously triggered, and the Buck-Boost circuit provides a negative DC compensation voltage relative to the ground 1 to the correction circuit.

[0021] Optionally, the compensation circuit includes a Boost-Buck circuit, and the Boost-Buck circuit includes a reverse fast-recovery diode D7, electrolytic capacitors C3 and C4, a power switch S3, power inductors L3 and L4. The additional circuit includes a reverse fast-recovery diode D6 and a power switch S2.

[0022] Optionally, the anode of the fast-recovery diode D6 is respectively connected to the emitter of the power switch S1 and the collector of the power switch S2, the cathode of the fast-recovery diode D6 is connected to the output negative terminal, the emitter of the power switch S2 is grounded to ground 2, one end of the power inductor L3 is connected to the output positive terminal, the other end of the power inductor L3 is respectively connected to the positive electrode of the electrolytic capacitor C3 and the collector of the power switch S3, the emitter of the power switch S3 is grounded to ground 1, the negative electrode of the electrolytic capacitor C3 is respectively connected to one end of the power inductor L4 and the anode of the reverse fast-recovery diode D7, the other end of the power inductor L4 is grounded to ground 2, the cathode of the reverse fast-recovery diode D7 is grounded to ground 1, the negative electrode of the electrolytic capacitor C4 is grounded to ground 2, and the positive electrode of the electrolytic capacitor C4 is grounded to ground 1.

[0023] Optionally, within the full-wave cycle of the grid voltage or in the neighborhood after the grid voltage crosses zero, the power switch S1 and the power switch S2 are synchronously triggered, and the Boost-Buckt circuit provides a negative DC compensation voltage relative to the ground 1 to the correction circuit.

[0024] Compared with the prior art, the embodiments of the present disclosure have at least one of the following beneficial effects:

[0025] Through the above technical solutions, a compensation circuit is cascaded at the output end of the correction circuit. Among them, the correction circuit is linked to the compensation circuit through an additional circuit. Through the step-up and step-down function of the compensation circuit, a negative DC compensation voltage is provided for the correction circuit, so that the actual rising slope of the boost inductor current is greater than the expected rising slope, so as to suppress, compensate or eliminate the inductor current crossover distortion phenomenon caused by the voltage drop and slope problems to the greatest extent within the full-wave cycle of the grid voltage or in the neighborhood after the grid voltage crosses zero, improve the power factor, reduce the harmonics of the input current, eliminate the harmonic pollution of the power grid, and the compensation circuit has a simple structure, good compensation effect and low cost.

[0026] In an embodiment of the present disclosure, the compensation circuit adopts a Buck - Boost circuit, and provides a negative DC compensation voltage for the correction circuit through the Buck - Boost circuit, so as to suppress, compensate or eliminate the inductor current crossover distortion phenomenon caused by voltage drop and slope problems to the greatest extent, improve the power factor, and reduce the harmonics of the input current.

[0027] In an embodiment of the present disclosure, the compensation circuit adopts a Boost - Buck circuit, and provides a negative DC compensation voltage for the correction circuit through the Boost - Buck circuit, so as to suppress, compensate or eliminate the inductor current crossover distortion phenomenon caused by voltage drop and slope problems to the greatest extent, improve the power factor, and reduce the harmonics of the input current. Brief Description of the Drawings

[0028] By reading the detailed description of the non - restrictive embodiments with reference to the following drawings, other features, objectives and advantages of the present disclosure will become more obvious:

[0029] Figure 1 FIG. is a schematic diagram of the topology of a single - phase power factor correction inductor current zero - crossing distortion compensation circuit with a Buck - Boost circuit adopted by the compensation circuit according to an exemplary embodiment.

[0030] Figure 2 FIG. is a schematic diagram of the topology of a single - phase power factor correction inductor current zero - crossing distortion compensation circuit with a Boost - Buck circuit adopted by the compensation circuit according to an exemplary embodiment. Detailed Embodiments

[0031] The present disclosure will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present disclosure, but do not limit the present disclosure in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present disclosure, several modifications and improvements can be made. These all fall within the protection scope of the present disclosure.

[0032] The present disclosure provides a single - phase power factor correction inductor current zero - crossing distortion compensation circuit, including a correction circuit, a compensation circuit and an additional circuit. The correction circuit is connected to the additional circuit, and the additional circuit is connected to the compensation circuit.

[0033] The correction circuit is used to output a DC voltage and perform input power factor correction.

[0034] Among them, the correction circuit adopts a traditional single - phase power factor correction circuit (Power Factor Correction, PFC).

[0035] The additional circuit is used to link the compensation circuit and the correction circuit.

[0036] The compensation circuit is used to provide a negative DC compensation voltage within the full-wave cycle of the grid voltage or in the neighborhood after the grid voltage passes through zero. The negative DC compensation voltage of the compensation circuit compensates and corrects the DC voltage at the output end of the boost inductor in the correction circuit, and controls the actual rising slope of the boost inductor current to be greater than the desired rising slope.

[0037] Through the above technical solution, a compensation circuit is cascaded at the output end of the correction circuit. Among them, the correction circuit is connected to the compensation circuit through an additional circuit. Through the step-up and step-down function of the compensation circuit, a negative DC compensation voltage is provided for the correction circuit, so that the actual rising slope of the boost inductor current is greater than the desired rising slope, so as to suppress, compensate or eliminate the inductor current crossover distortion phenomenon caused by voltage drop and slope problems to the greatest extent within the full-wave cycle of the grid voltage or in the neighborhood after the grid voltage passes through zero, improve the power factor, reduce the harmonics of the input current, eliminate the harmonic pollution of the power grid, and the compensation circuit has a simple structure, good compensation effect and low cost.

[0038] A single-phase power factor correction inductor current zero-crossing distortion compensation circuit further includes a single-phase AC power supply ui1. The single-phase AC power supply is connected to the correction circuit, and the single-phase AC power supply ui1 is used to provide an AC voltage.

[0039] In a possible embodiment, the correction circuit includes: a filter inductor L1, a boost inductor L2, a filter capacitor C1, an electrolytic capacitor C2, a power diode D1, a power diode D2, a power diode D3, a power diode D4, a power switch S1, a reverse fast recovery diode D5, and a load resistor R2.

[0040] Specifically, one end of the filter inductor L1 is connected to the live wire of the single-phase AC power supply ui1, and the other end of the filter inductor L1 is respectively connected to one end of the filter capacitor C1, the anode of the power diode D1, and the cathode of the power diode D2. The other end of the filter capacitor C1 is respectively connected to the neutral wire of the single-phase AC power supply ui1, the anode of the power diode D3, and the cathode of the power diode D4. One end of the boost inductor L2 is respectively connected to the cathode of the power diode D1 and the cathode of the power diode D3. The other end of the boost inductor L2 is respectively connected to the anode of the reverse fast recovery diode D5 and the collector of the power switch S1. The cathode of the reverse fast recovery diode D5 is respectively connected to the positive electrode of the electrolytic capacitor C2 and one end of the load resistor R2 to form an output positive electrode. The negative electrode of the electrolytic capacitor C2 is connected to the other end of the load resistor R2 to form an output negative electrode, and the other end of the load resistor R2 is grounded1.

[0041] Figure 1 It is a schematic diagram of the topology of a single-phase power factor correction inductor current zero-crossing distortion compensation circuit using a Buck-Boost circuit shown according to an exemplary embodiment.

[0042] AsFigure 1 As shown, in a possible embodiment, the compensation circuit includes a Buck-Boost circuit, and the Buck-Boost circuit includes a reverse fast recovery diode D7, an electrolytic capacitor C3, a power switch S3, and a power inductor L3. The additional circuit includes a reverse fast recovery diode D6 and a power switch S2.

[0043] Specifically, the anode of the fast recovery diode D6 is respectively connected to the emitter of the power switch S1 and the collector of the power switch S2. The cathode of the fast recovery diode D6 is connected to the output negative terminal. The emitter of the power switch S2 is grounded 2. The collector of the power switch S3 is connected to the output positive terminal. The emitter of the power switch S3 is respectively connected to the cathode of the reverse fast recovery diode D7 and one end of the power inductor L3. The anode of the reverse fast recovery diode D7 is grounded 2. The negative terminal of the electrolytic capacitor C3 is grounded 2. The positive terminal of the electrolytic capacitor C3 is grounded 1. The power inductor L3 is connected to the output negative terminal.

[0044] In this embodiment, within the full-wave cycle of the line voltage or in the neighborhood after the line voltage passes through zero, the power switches S1 and S2 are synchronously triggered, and the Buck-Boost circuit provides a negative DC compensation voltage relative to ground 1 to the correction circuit.

[0045] A single-phase power factor correction inductor current zero-crossing distortion compensation circuit provided by the present disclosure includes: a correction circuit, a Buck-Boost circuit, and an additional circuit. Its working principle is as follows:

[0046] The correction circuit is adjusted by adopting the double closed-loop control strategy of a traditional single-phase active power factor correction circuit, and the on and off of the power switch S1 is controlled in real time to obtain a stable DC output voltage of the electrolytic capacitor C2.

[0047] Among them, when the AC input voltage of the single-phase AC power supply ui1 changes, the power switch S1 is operated for high-frequency conduction and off according to the known double closed-loop control strategy. During the conduction period of the power switch S1, the single-phase AC power supply ui1, the filter inductor L1, the boost inductor L2, and the conducting power switch S1 form a loop, and the boost inductor L2 stores energy. During the off period of the power switch S1, the energy stored in the boost inductor L2 is released to the electrolytic capacitor C2 and the load resistor R2 through the power diode D1 and the power diode D4 (in the positive half-cycle of the line voltage) or the power diode D2 and the power diode D3 (in the negative half-cycle of the line voltage), and the reverse fast recovery diode D5. The boost inductor L2 and the single-phase AC power supply ui1 supply power to the electrolytic capacitor C2 and the load resistor R2 together, so as to obtain an input power factor close to unity on the grid side, that is, the filter inductor L1 and the filter capacitor C1 play a filtering role, and an approximate sine-wave current flows through the filter inductor L1.

[0048] Due to the problems of the conduction voltage drop of the diode, the DC resistance voltage drop of the boost inductor L2, and the actual rising slope of the current of the boost inductor L2 being less than the expected rising slope, the input current waveform flowing through the filter inductor L1 or the DC current waveform flowing through the boost inductor L2 exhibits crossover distortion near the zero-crossing of the grid voltage. The average value of the output voltage decreases, and the grid-side power factor is lower than 1.

[0049] The Buck-Boost circuit adopts a Buck-Boost DC-DC converter. By controlling the duty cycle of the Buck-Boost circuit to be no greater than 50%, it ensures that the Buck-Boost circuit operates in the buck mode, completing the conversion from the DC output voltage of the electrolytic capacitor C2 to a negative voltage, for example, from +385V to -50V.

[0050] The power switch S2 and the power switch S1 maintain the same drive pulse. Within the full-wave cycle of the grid voltage or in the neighborhood after the zero-crossing of the grid voltage, the actual rising slope of the current of the boost inductor L2 is greater than the expected rising slope. It realizes the maximum suppression, compensation, or elimination of the zero-crossing distortion of the inductor current caused by the voltage drop and slope problems, improves the grid-side power factor, reduces the pollution caused by harmonic currents to the power grid. At the same time, due to the increase in the rising slope of the current of the boost inductor L2, the energy storage of the boost inductor L2 is enhanced. Under the same other conditions, the average value of the output DC voltage is increased.

[0051] Among them, represents the actual rising slope of the boost inductor L2, ω i I in cosω i t represents the expected rising slope of the boost inductor L2, ω i represents the grid voltage angular frequency, I in represents the amplitude of the inductor current of the boost inductor L2, t represents time, represents the voltage of the boost inductor L2, u i represents the input voltage before the diode rectifier bridge (D1~D4), and L2 represents the inductance value of the boost inductor L2.

[0052] As an example, the Buck-Boost circuit in the compensation circuit provides a stable negative voltage of -1 relative to the ground, such as -50V, indicating that the voltage between ground 2 and ground 1 is -50V. Within the full-wave cycle of the grid voltage or in the neighborhood after the zero-crossing of the grid voltage, the power switch S1 and the power switch S2 are simultaneously triggered to conduct, and the -50V voltage provided by the Buck-Boost circuit is synchronously introduced into the correction circuit and applied between the anode and cathode of the fast-recovery diode D6. The traditional single-phase active power factor correction circuit does not include the fast-recovery diode D6. In the present disclosure, an additional circuit is added to the correction circuit, then the actual rising slope of the current of the boost inductor L2 is greater than the expected rising slope. Thus, it is possible to maximally suppress, compensate for, or eliminate the zero-crossing crossover distortion of the inductor current caused by the voltage drop and slope problems, improve the grid-side power factor to 1, enable the correction circuit to obtain a unity input power factor, and also reduce the harmonic current pollution. ω i t corresponds to the angle of the instantaneous grid-side voltage of 50V. Between 0 and this angle, ω i t changes with time.

[0053] In a possible embodiment, the compensation circuit has a simple structure, and the power switch S2 in the additional circuit of the present disclosure can be omitted.

[0054] Using a single-phase power factor correction inductor current zero-crossing distortion compensation circuit with a Buck-Boost circuit provided by the present disclosure, without modifying the double-loop control structure, control strategy, and parameter selection of the voltage outer loop and current inner loop of the original single-phase power factor correction circuit, triggering the power switch S1 and the power switch S2 simultaneously, and determining the appropriate output DC voltage of the Buck-Boost circuit at the same time. The output DC voltage is negative and satisfies

[0055] In a possible embodiment, when using a single-phase power factor correction inductor current zero-crossing distortion compensation circuit provided by the present disclosure, including: a correction circuit, a Buck-Boost circuit, and an additional circuit for test work, the parameter settings of its various functional modules and electronic components are as follows:

[0056] Single-phase AC power supply input voltage ui1: 220Vac, power frequency 50Hz; or 110Vac, power frequency 60Hz; or 115Vac, intermediate frequency 400 voltage.

[0057] Output voltage: greater than 20% of the maximum peak value of the grid voltage. For example, 400V (for 220Vac), 200V (for 110Vac), 200V (for 115Vac);

[0058] Switching frequency of power switches S1 and S2: 40kHz, or 60kHz, or others;

[0059] Switching frequency of power switch S3: 40kHz;

[0060] Output power level: 3.5kW, or not limited;

[0061] Filter inductor L1: 50μH;

[0062] Boost inductor L2: 250μH;

[0063] Power inductor L3: 100μH;

[0064] Filter capacitor C1: 0.47 μF, AC 275V;

[0065] Electrolytic capacitor C2: 6 x 680 μF, DC 400V;

[0066] Electrolytic capacitor C3: 220 μF, DC 100V;

[0067] Power diodes D1 - D4: 35A, 600V at 25°C, forming a diode rectifier bridge stack;

[0068] Power diodes D5 - D6: 35A, 600V at 25°C, reverse fast recovery type, single tubes;

[0069] Load resistor R2: 40 Ω, 3.5 kW, power dissipation capacity 4.5 kW.

[0070] The single - phase power factor correction inductor current zero - crossing distortion compensation circuit using a Buck - Boost circuit provided by the present disclosure can suppress, compensate or eliminate the inductor current zero - crossing crossover distortion to the greatest extent, achieve the total current distortion approaching zero, obtain a near - unity power factor on the grid side, prevent harmonic current from polluting the grid, and has a strong boosting ability. Therefore, it can increase the output voltage range of the subsequent voltage - source inverter, expand the constant - torque range of the motor, and can drive larger - power loads; moreover, the power switch S2 of the present disclosure can be omitted, with a simple structure, strong operability, and a wide range of application scenarios, and can be widely applied in the fields of commerce, home appliances, communication, charging piles, and wireless power transmission for vehicles.

[0071] Figure 2 It is a schematic diagram of the topology of a single - phase power factor correction inductor current zero - crossing distortion compensation circuit using a Boost - Buck circuit shown according to an exemplary embodiment.

[0072] As Figure 2 shown, in a possible embodiment, the compensation circuit includes a Boost - Buck circuit. The Boost - Buck circuit includes a reverse fast - recovery diode D7, an electrolytic capacitor C3, an electrolytic capacitor C4, a power switch S3, a power inductor L3, a power inductor L4, and the additional circuit includes a reverse fast - recovery diode D6 and a power switch S2.

[0073] Specifically, the anode of the fast-recovery diode D6 is respectively connected to the emitter of the power switch S1 and the collector of the power switch S2. The cathode of the fast-recovery diode D6 is connected to the output negative terminal. The emitter of the power switch S2 is grounded at GND2. One end of the power inductor L3 is connected to the output positive terminal, and the other end of the power inductor L3 is respectively connected to the positive electrode of the electrolytic capacitor C3 and the collector of the power switch S3. The emitter of the power switch S3 is grounded at GND1. The negative electrode of the electrolytic capacitor C3 is respectively connected to one end of the power inductor L4 and the anode of the reverse fast-recovery diode D7. The other end of the power inductor L4 is grounded at GND2. The cathode of the reverse fast-recovery diode D7 is grounded at GND1. The negative electrode of the electrolytic capacitor C4 is grounded at GND2, and the positive electrode of the electrolytic capacitor C4 is grounded at GND1.

[0074] In this embodiment, within the full-wave cycle of the grid voltage or in the neighborhood after the grid voltage passes through zero, the power switches S1 and S2 are synchronously triggered, and the Boost-Buck circuit provides a negative DC compensation voltage relative to GND1 to the correction circuit.

[0075] A single-phase power factor correction inductor current zero-crossing distortion compensation circuit provided by the present disclosure includes: a correction circuit, a Boost-Buck circuit, and an additional circuit. Its working principle is as follows:

[0076] The correction circuit is adjusted by adopting the double-loop control strategy of the traditional single-phase active power factor correction circuit, and the on and off of the power switch S1 are controlled in real time to obtain a stable DC output voltage of the electrolytic capacitor C2.

[0077] Among them, when the AC input voltage of the single-phase AC power supply ui1 changes, the power switch S1 is operated for high-frequency conduction and cutoff according to the known double-loop control strategy. During the conduction period of the power switch S1, the single-phase AC power supply ui1, the filter inductor L1, the boost inductor L2, and the conducting power switch S1 form a loop, and the boost inductor L2 stores energy. During the cutoff period of the power switch S1, the energy stored in the boost inductor L2 is released to the electrolytic capacitor C2 and the load resistor R2 through the power diode D1 and the power diode D4 (in the positive half-cycle of the grid voltage) or the power diode D2 and the power diode D3 (in the negative half-cycle of the grid voltage), and the reverse fast-recovery diode D5. The boost inductor L2 and the single-phase AC power supply ui1 supply power to the electrolytic capacitor C2 and the load resistor R2 together, so as to obtain an input power factor close to unity on the grid side, that is, the filter inductor L1 and the filter capacitor C1 play a filtering role, and an approximate sine-wave current flows through the filter inductor L1.

[0078] Due to the problems of the conduction voltage drop of the diode, the DC resistance voltage drop of the boost inductor L2, and the actual rising slope of the current in the boost inductor L2 being less than the expected rising slope, the input current waveform flowing through the filter inductor L1 or the DC current waveform flowing through the boost inductor L2 shows crossover distortion near the zero-crossing of the grid voltage, the average value of the output voltage decreases, and the grid-side power factor is lower than 1.

[0079] The Boost-Buck circuit uses a Boost-Buck DC-DC converter. By controlling the duty cycle of the Boost-Buck circuit to be no greater than 15%, it ensures that the Boost-Buck circuit operates in the buck mode and completes the conversion from the DC output voltage of the electrolytic capacitor C2 to a negative voltage, such as converting from +385V to -50V.

[0080] The power switch S2 and the power switch S1 maintain the same drive pulse. During the full-wave cycle of the grid voltage or in the neighborhood after the zero-crossing of the grid voltage, the actual rising slope of the current in the boost inductor L2 is greater than the expected rising slope. It realizes the maximum suppression, compensation, or elimination of the zero-crossing distortion of the inductor current caused by the voltage drop and slope problems, improves the grid-side power factor, reduces the pollution of the power grid caused by harmonic currents. At the same time, due to the increase in the rising slope of the current in the boost inductor L2, the energy storage of the boost inductor L2 is enhanced. Under the same other conditions, the average value of the output DC voltage is increased.

[0081] Among them, represents the actual rising slope of the boost inductor L2, ω i I in cosω i t represents the expected rising slope of the boost inductor L2, ω i represents the angular frequency of the grid voltage, I in represents the amplitude of the inductor current of the boost inductor L2, and t represents time. represents the voltage of the boost inductor L2, u i represents the input voltage before the diode rectifier bridge (D1~D4), and L2 represents the inductance value of the boost inductor L2.

[0082] As an example, the Boost-Buck circuit in the compensation circuit provides a stable negative voltage of -1 relative to the ground, such as -50V, indicating that the voltage between ground 2 and ground 1 is -50V. During the full-wave cycle of the grid voltage or in the neighborhood after the zero-crossing of the grid voltage, the power switch S1 and the power switch S2 are simultaneously triggered to conduct, and the -50V voltage provided by the Boost-Buck circuit is synchronously introduced into the correction circuit and applied between the anode and cathode of the fast-recovery diode D6. The traditional single-phase active power factor correction circuit does not include the fast-recovery diode D6. In the present disclosure, an additional circuit is added to the correction circuit, and then the actual rising slope of the current in the boost inductor L2 is greater than the expected rising slope. Thus, it is possible to suppress, compensate or eliminate the zero-crossing crossover distortion of the inductor current caused by the voltage drop and slope problems to the greatest extent, improve the grid-side power factor to 1, the correction circuit obtains a unity input power factor, and it is also possible to reduce the harmonic current pollution. ω i t corresponds to the angle of the instantaneous value of the grid-side voltage of 50V. Between 0 and this angle, ω i t changes with time.

[0083] In a possible embodiment, the compensation circuit has a simple structure, and the power switch S2 in the additional circuit of the present disclosure can be omitted.

[0084] Using a single-phase power factor correction inductor current zero-crossing distortion compensation circuit with a Boost-Buck circuit provided by the present disclosure, there is no need to modify the double-loop control structure, control strategy and parameter selection of the voltage outer loop and current inner loop of the original single-phase power factor correction circuit. At the same time, the power switch S1 and the power switch S2 are triggered, and the appropriate output DC voltage of the Buck-Boost circuit is determined. The output DC voltage is negative and satisfies

[0085] In a possible embodiment, when using a single-phase power factor correction inductor current zero-crossing distortion compensation circuit provided by the present disclosure, including a correction circuit, a Boost-Buck circuit and an additional circuit for test work, the parameter settings of its various functional modules and electronic components are as follows:

[0086] Single-phase AC power supply input voltage ui1: 220Vac, industrial frequency 50Hz, or 110Vac, industrial frequency 60Hz;

[0087] Output voltage: greater than 20% of the maximum peak value of the grid voltage, such as 385V or 400V;

[0088] Switching frequency of power switches S1 and S2: 40kHz, or 60kHz, or others;

[0089] Switching frequency of power switch S3: 40kHz;

[0090] Output power level: 3.5kW, or not limited;

[0091] Filter inductor L1: 50μH;

[0092] Boost inductor L2: 250μH;

[0093] Power inductors L3, L4: 100μH;

[0094] Filter capacitor C1: 0.47μF, AC withstand voltage 275V;

[0095] Electrolytic capacitor C2: 6x680 μF, DC withstand voltage 400V;

[0096] Electrolytic capacitors C3 and C4: 220 μF, DC withstand voltage 100V;

[0097] Power diodes D1 - D4: At 25°C, 35A, 600V, forming a diode rectifier bridge stack;

[0098] Reverse fast recovery power diodes D5 - D7: At 25°C, 35A, 600V, reverse fast recovery type, single - tube package;

[0099] Load resistor R1: Equivalent 40Ω, 3.5kW, power dissipation capacity greater than 4.5kW.

[0100] Adopting a single - phase power factor correction inductor current zero - crossing distortion compensation circuit with a Boost - Buck circuit provided by the present disclosure can suppress, compensate, or eliminate the inductor current zero - crossing crossover distortion to the greatest extent, achieve a total current distortion approaching zero, obtain a near - unity power factor on the grid side, prevent harmonic current from polluting the grid, and has a strong boosting ability. Therefore, it can increase the output voltage range of the subsequent voltage - source inverter, expand the constant - torque range of the motor, and be able to drive a larger - power load; moreover, the power switch S2 of the present disclosure can be omitted, with a simple structure, strong operability, and a wide range of application scenarios, and can be widely applied in the fields of commerce, home appliances, communication, charging piles, and wireless power transmission for vehicles.

[0101] The specific embodiments of the present disclosure have been described above. It should be understood that the present disclosure is not limited to the above - mentioned specific implementation manners, and those skilled in the art can make various deformations or modifications within the scope of the claims, which do not affect the essence of the present disclosure. The above - mentioned preferred features can be combined arbitrarily without conflict.

Claims

1. A single-phase power factor correction inductor current zero-crossing distortion compensation circuit, characterized in that: include: A correction circuit, a compensation circuit and an additional circuit, wherein the correction circuit is connected to the additional circuit, and the additional circuit is connected to the compensation circuit; The correction circuit is used to output a DC voltage and perform input power factor correction; The additional circuit is used to link the compensation circuit and the correction circuit; The compensation circuit is used to provide a negative DC compensation voltage within a full-wave cycle of the grid voltage or in the vicinity of the grid voltage passing through zero. The negative DC compensation voltage of the compensation circuit is used to compensate the DC voltage at the output end of the boost inductor in the correction circuit, and the actual rising slope of the boost inductor current is controlled to be greater than the expected rising slope.

2. The single-phase power factor correction inductor current zero-crossing distortion compensation circuit according to claim 1, characterized in that: The correction circuit includes: a filter inductor L1, a boost inductor L2, a filter capacitor C1, an electrolytic capacitor C2, a power diode D1, a power diode D2, a power diode D3, a power diode D4, a power switch S1, a reverse fast recovery diode D5 and a load resistor R2.

3. The single-phase power factor correction inductor current zero-crossing distortion compensation circuit according to claim 2, characterized in that: It also includes a single-phase AC power supply ui1, which is connected to the correction circuit.

4. The single-phase power factor correction inductor current zero-crossing distortion compensation circuit according to claim 3, characterized in that: One end of the filter inductor L1 is connected to the live wire of the single-phase AC power supply ui1, the other end of the filter inductor L1 is respectively connected to one end of the filter capacitor C1, the anode of the power diode D1, and the cathode of the power diode D2, the other end of the filter capacitor C1 is respectively connected to the neutral line of the single-phase AC power supply ui1, the anode of the power diode D3, and the cathode of the power diode D4, one end of the boost inductor L2 is respectively connected to the cathode of the power diode D1 and the cathode of the power diode D3, the other end of the boost inductor L2 is respectively connected to the anode of the reverse fast recovery diode D5 and the collector of the power switch S1, the cathode of the reverse fast recovery diode D5 is respectively connected to the positive electrode of the electrolytic capacitor C2 and one end of the load resistor R2 to form an output positive electrode, the negative electrode of the electrolytic capacitor C2 is connected to the other end of the load resistor R2 to form an output negative electrode, and the other end of the load resistor R2 is grounded 1.

5. The single-phase power factor correction inductor current zero-crossing distortion compensation circuit according to claim 4, characterized in that: The compensation circuit includes a Buck-Boost circuit, and the Buck-Boost circuit includes a reverse fast recovery diode D7, an electrolytic capacitor C3, a power switch S3, and a power inductor L3. The additional circuit includes a reverse fast recovery diode D6 and a power switch S2.

6. The single-phase power factor correction inductor current zero-crossing distortion compensation circuit according to claim 5, characterized in that: The anode of the fast recovery diode D6 is respectively connected to the emitter of the power switch S1 and the collector of the power switch S2, the cathode of the fast recovery diode D6 is connected to the output negative electrode, the emitter of the power switch S2 is connected to ground 2, the collector of the power switch S3 is connected to the output positive electrode, the emitter of the power switch S3 is respectively connected to the cathode of the reverse fast recovery diode D7 and one end of the power inductor L3, the anode of the reverse fast recovery diode D7 is connected to the ground 2, the negative electrode of the electrolytic capacitor C3 is connected to the ground 2, the positive electrode of the electrolytic capacitor C3 is connected to the ground 1, and the power inductor L3 is connected to the output negative electrode.

7. The single-phase power factor correction inductor current zero-crossing distortion compensation circuit according to claim 6, characterized in that: In a full-wave period of the grid voltage or in the vicinity of the grid voltage passing through zero, the power switch S1 and the power switch S2 are synchronously triggered, and the Buck-Boost circuit provides a negative DC compensation voltage relative to the ground 1 to the correction circuit.

8. The single-phase power factor correction inductor current zero-crossing distortion compensation circuit according to claim 4, characterized in that: The compensation circuit includes a Boost-Buck circuit, and the Boost-Buck circuit includes a reverse fast recovery diode D7, an electrolytic capacitor C3, an electrolytic capacitor C4, a power switch S3, a power inductor L3, and a power inductor L4. The additional circuit includes a reverse fast recovery diode D6 and a power switch S2.

9. The single-phase power factor correction inductor current zero-crossing distortion compensation circuit according to claim 8, characterized in that: The anode of the fast recovery diode D6 is respectively connected to the emitter of the power switch S1 and the collector of the power switch S2, the cathode of the fast recovery diode D6 is connected to the output negative electrode, the emitter of the power switch S2 is connected to ground 2, one end of the power inductor L3 is connected to the output positive electrode, the other end of the power inductor L3 is respectively connected to the positive electrode of the electrolytic capacitor C3 and the collector of the power switch S3, the emitter of the power switch S3 is connected to the ground 1, the negative electrode of the electrolytic capacitor C3 is respectively connected to one end of the power inductor L4 and the anode of the reverse fast recovery diode D7, the other end of the power inductor L4 is connected to ground 2, the cathode of the reverse fast recovery diode D7 is connected to the ground 1, the negative electrode of the electrolytic capacitor C4 is connected to the ground 2, and the positive electrode of the electrolytic capacitor C4 is connected to the ground 1.

10. The single-phase power factor correction inductor current zero-crossing distortion compensation circuit according to claim 9, characterized in that: In a full-wave period of the grid voltage or in the vicinity of the grid voltage passing through zero, the power switch S1 and the power switch S2 are synchronously triggered, and the Boost-Buckt circuit provides a negative DC compensation voltage relative to the ground 1 to the correction circuit.

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