A three-phase power factor correction cascade voltage stabilizing power supply

Abstract

The application discloses a three-phase power factor correction cascade voltage stabilizing power supply, which comprises a power filter, a surge protector, three independent single-phase power factor correction cascade voltage stabilizing power supplies and a current sharing control circuit; the power filter and the surge protector are used for filtering and protecting input three-phase power; the three-phase power is divided into three single-phase powers and supplied to the three independent single-phase power factor correction cascade voltage stabilizing power supplies; the three single-phase power factor correction cascade voltage stabilizing power supplies are connected in parallel after completing single-phase power factor correction circuits and isolation proportional conversion circuits and used as outputs of the three-phase power factor correction cascade voltage stabilizing power supply; and the current sharing control circuit is used for realizing current sharing and phase balance among the three phases. The isolation proportional conversion circuit of the single-phase power factor correction cascade voltage stabilizing power supply is in an open loop working mode. The three-phase power factor correction cascade voltage stabilizing power supply has the characteristics of high reliability, high power density and strong transient response capability.

Description

Technical Field

[0001] This invention belongs to the field of power supply technology, specifically a three-phase power factor correction cascaded regulated power supply. Background Technology

[0002] With the increasing maturity of power electronics technology, more and more power electronic devices are being applied in industrial production, daily life, and military detection. When power electronic devices are powered by the grid, rectification is required on the grid side. Traditional uncontrolled rectification schemes result in periodic pulsations in the input current of the device, leading to severe input current distortion, reduced power factor, and a large amount of harmonic interference entering the grid. To solve these problems, active power factor correction circuits have been rapidly developed, using SPWM modulation to control the input current to achieve high power factor and low THD.

[0003] With the rapid development of high-power power electronics in platforms such as electric vehicles, 5G communication base stations, multi-electric aircraft, and ship electrification, high-power three-phase power factor correction circuits have become a new research hotspot.

[0004] Traditional three-phase six-switch or three-phase three-switch (VIENNA) systems suffer from problems such as unbalanced neutral point voltage, complex control decoupling operations, and complex parameter design. Summary of the Invention

[0005] The purpose of this invention is to provide a three-phase power factor correction cascaded regulated power supply.

[0006] The technical solution to achieve the objective of this invention is: a three-phase power factor correction cascaded regulated power supply, comprising: a power filter, a surge protector, a first single-phase power factor correction cascaded regulated power supply, a second single-phase power factor correction cascaded regulated power supply, a third single-phase power factor correction cascaded regulated power supply, and a current sharing control circuit; the power filter and surge protector complete the filtering and protection of the input three-phase power, and the three-phase power is divided into three single-phase power supplies, which are respectively supplied to the first single-phase power factor correction cascaded regulated power supply, the second single-phase power factor correction cascaded regulated power supply, and the third single-phase power factor correction cascaded regulated power supply; the first single-phase power factor correction cascaded regulated power supply, the second single-phase power factor correction cascaded regulated power supply, and the third single-phase power factor correction cascaded regulated power supply complete the single-phase power factor correction. The corrected and isolated proportional converters are connected in parallel as the output of a three-phase power factor correction cascaded regulated power supply. The current sharing control circuit calculates the difference between the operating current of the first single-phase power factor correction cascaded regulated power supply and the average operating current of the first, second, and third single-phase power factor correction cascaded regulated power supplies, and feeds the difference back to the first, second, and third single-phase power factor correction cascaded regulated power supplies respectively. This completes the adjustment of the duty cycle of the switching control pulse, realizing the current sharing control of the first, second, and third single-phase power factor correction cascaded regulated power supplies.

[0007] Preferably, the first single-phase power factor correction cascaded regulated power supply includes: a single-phase power factor correction circuit, an isolation proportional converter circuit, and a feedback compensation circuit. The single-phase power factor correction circuit and the isolation proportional converter circuit are connected in series. After the single-phase power is corrected by the single-phase power factor correction circuit, a high-voltage DC power is output to the isolation proportional converter circuit. The isolation proportional converter circuit performs isolation proportional conversion on the high-voltage DC power and outputs a low-voltage DC power. The feedback compensation circuit is used to sample the low-voltage DC power, and the output terminal of the feedback compensation circuit is connected to the single-phase power factor correction circuit.

[0008] Preferably, the isolated proportional converter circuit is in open-loop sinusoidal resonant proportional converter operating mode, that is, the transformer waveform of the isolated proportional converter circuit is a sine wave, the isolated proportional converter circuit is an open-loop converter, and the input and output voltages are in a fixed ratio.

[0009] Preferably, the single-phase power factor correction circuit is a regulated output of a boost power factor correction topology, and the internal feedback regulation of the single-phase power factor correction circuit has two modes: adaptive fast response mode and high-precision response mode;

[0010] The adaptive fast response mode and high-precision response mode are automatically switched through online intelligent judgment. When the transient rate of change of current over time in the current sampling circuit on the output side of the single-phase power factor correction circuit exceeds a set threshold, the feedback compensation circuit in the single-phase power factor correction cascaded regulated power supply is turned off, and the system automatically switches to adaptive fast response mode. In other states, the default operating mode is high-precision response mode.

[0011] Preferably, in the adaptive fast response mode, the single-phase power factor correction circuit linearly compensates the output voltage based on the output current of the single-phase power factor correction circuit. The larger the output current, the higher the output voltage compensation; the smaller the output current, the lower the output voltage compensation. The voltage is regulated according to the primary equivalent internal resistance of the isolation proportional converter circuit. The single-phase power factor correction circuit adaptively adjusts the output voltage by sampling its output current to compensate for the voltage fluctuations caused by the equivalent internal resistance of the isolation proportional converter circuit when the load current changes. In the adaptive fast response mode, the feedback voltage regulator circuit completes adaptive fast closed-loop feedback based on the voltage and current sampling loop of the single-phase power factor correction circuit.

[0012] Preferably, in the high-precision response mode, the feedback compensation circuit completes loop feedback compensation based on the output voltage sampled at the load end and sends it to the single-phase power factor correction circuit. When the output voltage sample value is lower than the set voltage output of the feedback compensation circuit, the output level of the feedback compensation circuit becomes higher, the duty cycle of the switching control pulse of the single-phase power factor correction circuit becomes larger, the output voltage of the single-phase power factor correction circuit becomes higher, and the output of the isolation proportional converter circuit becomes higher accordingly, thus completing the closed-loop negative feedback of the output voltage of the single-phase power factor correction cascaded regulated power supply.

[0013] Preferably, the isolation proportional converter circuit is equivalent to an isolated proportional controlled source with a fixed series internal resistance, Rout. Let the conversion ratio be K, then the primary current is K times that of the secondary current, which is K × Iout. The secondary voltage is K times that of the primary voltage, which is K × Vin. The output voltage of the isolation proportional converter circuit is...

[0014] Vout = K × Vin - Iout × Rout.

[0015] Compared with the prior art, the significant advantages of this invention are:

[0016] 1. High reliability: This invention achieves three-phase power factor correction by combining three independent single-phase power factor correction circuits, which simplifies the control algorithm for power factor correction and avoids problems such as unbalanced neutral voltage, complex control decoupling calculations, and complex parameter design.

[0017] 2. High Power Density: This invention achieves three-phase power factor correction by combining three independent single-phase power factor correction circuits, simplifying the power factor correction control algorithm and significantly reducing the computational resources required for closed-loop control of power factor correction. This allows for a significant increase in the switching frequency of the power factor correction circuit, enabling high power density power factor correction. The cascaded isolation proportional converter circuit is an open-loop proportional sine converter. Open-loop converters do not have problems such as closed-loop feedback oscillation, making it easy to increase the switching frequency and achieve high power density isolation conversion. At the same time, closed-loop feedback is achieved through the combination of cascaded voltage regulators, improving power density without affecting the accuracy of closed-loop feedback.

[0018] 3. Strong transient response capability: The three-phase power factor correction cascaded regulated power supply has two working modes: adaptive fast response mode and high-precision response mode. When the load current transformation rate is high, it automatically switches to the adaptive response mode to achieve strong transient response capability. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the composition of the three-phase power factor correction cascaded regulated power supply of the present invention.

[0020] Figure 2 This is a circuit diagram of the single-phase power factor correction cascaded regulated power supply of the present invention.

[0021] Figure 3 This is the equivalent circuit diagram of the isolated proportional converter in the single-phase power factor correction cascaded regulated power supply of the present invention.

[0022] Figure 4 This is the compensation curve of the isolated proportional converter output voltage of the three-phase power factor correction cascaded regulated power supply of the present invention in adaptive fast response mode. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings.

[0024] like Figure 1The three-phase power factor correction cascaded regulated power supply shown includes: a power filter 1, a surge protector 2, a first single-phase power factor correction cascaded regulated power supply 3, a second single-phase power factor correction cascaded regulated power supply 4, a third single-phase power factor correction cascaded regulated power supply 5, and a current sharing control circuit 6. The power filter 1 and surge protector 2 filter and protect the input three-phase power. The three-phase power is divided into three single-phase power supplies, which are then fed to the first single-phase power factor correction cascaded regulated power supply 3, the second single-phase power factor correction cascaded regulated power supply 4, and the third single-phase power factor correction cascaded regulated power supply 5. The first single-phase power factor correction cascaded regulated power supply 3, the second single-phase power factor correction cascaded regulated power supply 4, and the third single-phase power factor correction cascaded regulated power supply 5 perform single-phase power factor correction and isolation proportional conversion, and are then connected in parallel as the output of the three-phase power factor correction cascaded regulated power supply. The current sharing control circuit 6 achieves current sharing and phase balance among the three phases. The current sharing control circuit 6 calculates the difference between the operating current of the single-phase power factor correction cascaded voltage regulator 3 and the average operating current of the three power factor correction cascaded voltage regulators 3, 4, and 5. This difference is then fed back to the single-phase power factor correction circuit to adjust the duty cycle of its switching control pulse, thereby achieving current sharing control for the single-phase power factor correction cascaded voltage regulator 3. Similarly, current sharing control is achieved for the single-phase power factor correction cascaded voltage regulators 4 and 5.

[0025] like Figure 2 As shown, the first single-phase power factor correction cascaded regulated power supply 3, the second single-phase power factor correction cascaded regulated power supply 4, and the third single-phase power factor correction cascaded regulated power supply 5 of the present invention internally include: a single-phase power factor correction circuit 301, an isolation proportional conversion circuit 302, and a feedback compensation circuit 303.

[0026] The isolation proportional converter circuit 302 is in open-loop sinusoidal resonant proportional converter mode. The switching frequency of the isolation proportional converter circuit 302 is matched with the series resonant frequency, and the working waveform is a sine wave. The isolation proportional converter circuit 302 is an open-loop converter with a fixed ratio between the input and output voltages.

[0027] The single-phase power factor correction circuit 301 is a regulated output of a boost power factor correction topology, and its internal feedback regulation has two modes: adaptive fast response mode and high-precision response mode.

[0028] The adaptive fast response mode and high-precision response mode automatically switch via online intelligent judgment. When the transient rate of change of current over time in the current sampling circuit on the output side of the single-phase power factor correction circuit exceeds a set threshold, it indicates that the load is in a fast-switching pulse operating mode, requiring improved load response capability. The feedback compensation circuit 303 within the single-phase power factor correction cascaded regulated power supply is then automatically switched to adaptive fast response mode. In other states, the default operating mode is high-precision response mode.

[0029] In the adaptive fast response mode, the single-phase power factor correction circuit 301 does not adjust the voltage with the feedback compensation circuit 303. Instead, it linearly compensates the output voltage based on the output current of the single-phase power factor correction circuit 301. The larger the output current, the higher the output voltage compensation; the smaller the output current, the lower the output voltage compensation. Voltage adjustment is performed according to the primary equivalent internal resistance of the isolation proportional converter circuit 302. The single-phase power factor correction circuit 301 adaptively adjusts the output voltage by sampling its output current to compensate for voltage fluctuations caused by the equivalent internal resistance of the isolation proportional converter circuit 302 when the load current changes. This mode offers fast response and high loop stability, but the voltage compensation accuracy is not as accurate as the precise voltage feedback in the high-precision response mode. In the adaptive fast response mode, the feedback voltage regulator circuit completes adaptive fast closed-loop feedback based on the voltage and current sampling loop of the single-phase power factor correction circuit 301.

[0030] In the high-precision response mode, the output voltage of the isolation proportional converter circuit 302 is sampled and then sent to the single-phase power factor correction circuit 301 via the feedback compensation circuit 303 to complete voltage regulation, achieving precise feedback regulation of the output voltage. In this high-precision response mode, the feedback compensation circuit 303 completes loop feedback compensation based on the output voltage sampled at the load end and sends it to the single-phase power factor correction circuit 301. When the sampled output voltage value is lower than the set output voltage of the feedback compensation circuit 303, the output level of the feedback compensation circuit 303 increases, the duty cycle of the switching control pulse of the single-phase power factor correction circuit 301 increases, the output voltage of the single-phase power factor correction circuit 301 increases, and the output of the isolation proportional converter circuit 302 increases accordingly, completing the closed-loop negative feedback of the output voltage of the single-phase power factor correction cascaded regulated power supply.

[0031] like Figure 3 As shown, the isolation proportional converter circuit 302 of the present invention can be equivalent to an isolation proportional controlled source with a fixed series internal resistance, the equivalent series internal resistance being Rout. If the conversion ratio is K, then the primary current is K times that of the secondary current, the primary current is K×Iout, the secondary voltage is K times that of the primary voltage, and the secondary voltage is K×Vin.

[0032] The output voltage of the isolation proportional converter circuit 302 is

[0033] Vout = K × Vin - Iout × Rout

[0034] like Figure 4 The diagram illustrates linear compensation of the output voltage in adaptive fast response mode. The red line represents the waveform of the open-loop voltage drop of the output power supply as a function of the load current without compensation. The blue line represents the calculated design value for adaptive voltage compensation, and the green line represents the expected voltage after adaptive compensation. In the adaptive fast response mode, the voltage regulation of the single-phase power factor correction circuit is based on closed-loop feedback from the input voltage feedback loop and the input current feedback loop of the power factor correction circuit. Linear compensation of the output voltage is performed based on the output current of the single-phase power factor correction circuit. The compensation voltage amplitude is adjusted according to the equivalent series resistance of the isolation proportional converter circuit as a function of the linear drop in output voltage caused by the load current.

[0035] This invention splits three-phase power into three single-phase power supplies, which are then fed into three independent single-phase power factor correction (PFC) cascaded regulated power supplies. These three PFC cascaded regulated power supplies, after completing the single-phase PFC circuit and the isolation proportional converter circuit, are connected in parallel as the output of the three-phase PFC cascaded regulated power supply. The isolation proportional converter circuit of the single-phase PFC cascaded regulated power supply operates in open-loop mode. By combining three independent single-phase PFC circuits to achieve three-phase PFC correction, the control algorithm for PFC is simplified, avoiding problems such as midpoint voltage imbalance, complex control decoupling calculations, and complex parameter design. This significantly reduces the computational resources required for closed-loop control of PFC, and can greatly increase the switching frequency of the PFC circuit to achieve high power density PFC correction. The cascaded isolation proportional converter circuit is an open-loop proportional sine converter. Open-loop converters do not have problems such as closed-loop feedback oscillation, making it easy to increase the switching frequency and achieve high power density isolation conversion. Simultaneously, the combination of cascaded regulators achieves closed-loop feedback, increasing power density without affecting the accuracy of closed-loop feedback. The single-phase power factor correction (PFC) cascaded regulated power supply described herein features a boost PFC topology with a regulated output. Its internal feedback regulation has two modes: in adaptive fast response mode, the feedback regulator completes adaptive fast closed-loop feedback based on the voltage and current sampling loop of the single-phase PFC circuit; in high-precision response mode, the feedback regulator samples the output voltage of the isolated proportional converter circuit to achieve precise feedback regulation of the output voltage. The three-phase PFC cascaded regulated power supply also has two operating modes: adaptive fast response mode and high-precision response mode. It automatically switches to adaptive response mode when the load current conversion rate is high to achieve strong transient response capability. The three-phase PFC cascaded regulated power supply of this invention features high reliability, high power density, and strong transient response capability.

[0036] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A three-phase power factor correction cascaded regulated power supply, characterized in that, include: The system includes a power filter (1), a surge protector (2), a first single-phase power factor correction cascaded regulated power supply (3), a second single-phase power factor correction cascaded regulated power supply (4), a third single-phase power factor correction cascaded regulated power supply (5), and a current sharing control circuit (6). The power filter (1) and surge protector (2) provide filtering and protection for the input three-phase power. The three-phase power is divided into three single-phase power supplies, which are respectively supplied to the first single-phase power factor correction cascaded regulated power supply (3), the second single-phase power factor correction cascaded regulated power supply (4), and the third single-phase power factor correction cascaded regulated power supply (5). The first single-phase power factor correction cascaded regulated power supply (3)... The second single-phase power factor correction cascaded regulated power supply (4) and the third single-phase power factor correction cascaded regulated power supply (5) are connected in parallel after completing single-phase power factor correction and isolation proportional conversion as the output of the three-phase power factor correction cascaded regulated power supply. The current sharing control circuit (6) calculates the difference between the operating current of the first single-phase power factor correction cascaded regulated power supply (3) and the average operating current of the first single-phase power factor correction cascaded regulated power supply (3), the second single-phase power factor correction cascaded regulated power supply (4), and the third single-phase power factor correction cascaded regulated power supply (5), and feeds the difference back to the first single-phase power factor correction cascaded regulated power supply (3), the second single-phase power factor correction cascaded regulated power supply (4), and the third single-phase power factor correction cascaded regulated power supply (5), respectively. The power factor correction cascaded regulated power supply (4) and the third single-phase power factor correction cascaded regulated power supply (5) adjust the duty cycle of the switching control pulse to achieve current sharing control of the first single-phase power factor correction cascaded regulated power supply (3), the second single-phase power factor correction cascaded regulated power supply (4), and the third single-phase power factor correction cascaded regulated power supply (5). The first single-phase power factor correction cascaded regulated power supply (3) includes a single-phase power factor correction circuit (301), an isolation proportional converter circuit (302), and a feedback compensation circuit (303). The single-phase power factor correction circuit (301) and the isolation proportional converter circuit (302) are connected in series. The single-phase power is corrected by the single-phase power factor correction circuit (301) and then output as high-voltage DC to the isolation proportional converter circuit. The isolation proportional converter circuit performs isolation proportional conversion on the high-voltage DC and outputs as low-voltage DC. The feedback compensation circuit (303) is used to sample the low-voltage DC. The output terminal of the feedback compensation circuit (303) is connected to the single-phase power factor correction circuit (301). The single-phase power factor correction circuit (301) is a regulated output of the boost power factor correction topology. The internal feedback regulation of the single-phase power factor correction circuit (301) has two modes: adaptive fast response mode and high-precision response mode. The adaptive fast response mode and the high-precision response mode are automatically switched by online intelligent judgment. When the transient rate of change of current in the current sampling circuit on the output side of the single-phase power factor correction circuit exceeds the set threshold, the feedback compensation circuit (303) in the single-phase power factor correction cascaded regulated power supply is turned off and automatically switched to the adaptive fast response mode; in other states, the default working mode is the high-precision response mode. In the adaptive fast response mode, the single-phase power factor correction circuit (301) performs linear compensation of the output voltage based on the output current of the single-phase power factor correction circuit (301). The larger the output current, the higher the output voltage compensation; the smaller the output current, the lower the output voltage compensation. The voltage is regulated according to the primary equivalent internal resistance of the isolation proportional converter circuit (302). The single-phase power factor correction circuit (301) adaptively adjusts the output voltage by taking its output current to compensate for the voltage fluctuation caused by the equivalent internal resistance of the isolation proportional converter circuit (302) when the load current changes. In the adaptive fast response mode, the feedback voltage regulator circuit completes adaptive fast closed-loop feedback based on the voltage and current sampling loop of the single-phase power factor correction circuit (301).

2. The three-phase power factor correction cascaded regulated power supply according to claim 1, characterized in that, The isolation proportional converter circuit (302) is in open-loop sinusoidal resonant proportional converter mode and the switching frequency matches the series resonant frequency. That is, the transformer waveform of the isolation proportional converter circuit (302) is a sine wave, the isolation proportional converter circuit (302) is an open-loop converter, and the input and output voltages are in a fixed ratio.

3. The three-phase power factor correction cascaded regulated power supply according to claim 1, characterized in that, In high-precision response mode, the feedback compensation circuit (303) completes loop feedback compensation based on the output voltage sampled at the load end and sends it to the single-phase power factor correction circuit (301). When the output voltage sampled value is lower than the set voltage output of the feedback compensation circuit (303), the output level of the feedback compensation circuit (303) becomes higher, the duty cycle of the switching control pulse of the single-phase power factor correction circuit (301) becomes larger, the output voltage of the single-phase power factor correction circuit (301) becomes higher, and the output of the isolation proportional converter circuit (302) becomes higher accordingly, thus completing the closed-loop negative feedback of the output voltage of the single-phase power factor correction cascaded regulated power supply.

4. The three-phase power factor correction cascaded regulated power supply according to claim 1, characterized in that, The isolation proportional converter circuit (302) is equivalent to an isolated proportional controlled source with a fixed series internal resistance, Rout. Let the conversion ratio be K, then the primary current is K times that of the secondary current, which is K × Iout. The secondary voltage is K times that of the primary voltage, which is K × Vin. The output voltage of the isolation proportional converter circuit (302) is: Vout = K × Vin - Iout × Rout.

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