TW571500B - Distributed power system - Google Patents

Abstract

The present invention relates to a distributed power system in which a backup boost converter is connected between a power factor correction (PFC) converter and a front-end DC converter, and is connected in parallel with a diode. Since the backup converter can operate in the sustaining period, if the output voltage of PFC converter decreases gradually in this period, the backup boost converter will raise the voltage and stabilize it at the preset output voltage, and further supply the voltage to the front-end DC converter for being converted into DC voltage. Thus, the capacity of the energy-storage capacitor of PFC converter can sufficiently be utilized to realize a long sustaining time, and reduce the input voltage variation range of the front-end DC converter, so as to enhance advantages such as efficiency and power density.

Description

571500 V. Description of the invention (1) The present invention is a distributed power system, especially a distributed power system with a hold time requirement. It is used for power converters with a narrow normal input DC range and requiring its output voltage to remain constant during occasional short-term drops in the input voltage. Please refer to the first figure, which is a structural diagram of a general distributed power system, which is composed of a Power Factor Correction (PFC) converter 1 a, a Front End (FE) DC converter 2 a, and a load terminal. Converter 3 a is connected, where power factor correction converter 1 a converts AC input voltage to high-voltage DC voltage (generally 400 V) and implements power factor correction at the input end; front-end DC converter 2 a The aforementioned high-voltage DC voltage is converted into a DC voltage (generally 4 8 or 12 V), and the DC voltage is sent to the load-side converter 3 a to be converted into the voltage required by the corresponding load; the aforementioned front-end DC converter 2 a is designed, under normal circumstances, works at a small duty cycle, leaving sufficient margin to keep it within the hold time, such as 20 milliseconds, when the power factor correction converter 1 a During the discharge of the energy storage capacitor, its output voltage drops from the normal value of 400V to 300V. Since the front-end DC converter 2a is still within the adjustment range, the output voltage can be kept unchanged. However, under normal operating conditions of the power supply system, the duty ratio of the front-end DC converter 2 a is small, and the relative efficiency and power density are low; the energy utilization efficiency of the energy storage capacitor of the power factor correction converter 1 a is low. Or there is a system architecture diagram as above, in which the front-end DC converter 2 a uses an asymmetric half bridge (A Η

571500 V. Description of the invention (2) B) Circuit topology, the transformer uses asymmetric windings, as shown in the second figure, which can increase the duty cycle of the front-end DC converter 2 a under normal operating conditions, and During the period when the output voltage of the power factor correction converter 1 a drops from a normal value of 400 V to 300 V, the output voltage of the front-end DC converter 2 a remains unchanged. For A A B converters, theoretically, the duty cycle The variation range is 0 ~ 0 · 5. The smaller the duty ratio, the more "asymmetric" the symmetrical working conditions of the upper and lower half of the converter, the more unbalanced the component stress and the lower the efficiency. Therefore, under ideal working conditions, The duty cycle should be as close as possible to 0 · 5. In the case where the output voltage of the A Β B converter is stable, the higher the input voltage is, the smaller the duty cycle is. Therefore, if no processing is performed, in order to achieve the hold time, the converter 1 a is corrected at the power factor. During the period when the energy storage capacitor is discharged and the output voltage drops from the normal value of 400V to 300V, it must work within the adjustment range to keep the output voltage constant. That is, the duty cycle of the AHB converter is the largest when the input voltage is 300V. This also results in a small duty cycle during normal operation (input voltage of 400V), and the A Η B converter has poor working efficiency. . However, the output ripple of the A Η B converter of the power supply system is increased, and the power distribution of the complementary legs of the secondary side is more unbalanced; the energy utilization efficiency of the energy storage capacitor of the power factor correction converter 1 a is low. There is another system architecture diagram as above, in which the front-end DC converter 2 a uses an AHB converter, and its transformer uses a variable winding ratio (Range Winding), as shown in the third figure, where the input voltage drops from a normal value of 400 V Change the transformer turns ratio with a switch from 300 V to 300 V

571500 V. Description of the invention (3) Duty cycle of the front-end DC converter 2 a under normal operating conditions; However, the power system has a sudden change in the working state of the A Η B converter during the hold time and period, and the output voltage is easy. There is fluctuation; the energy utilization efficiency of the energy storage capacitor of the power factor correction converter 1 a is low. The reason is that the inventor's intensive research and scientific application have been used to design a capacity that can fully utilize the energy storage capacitor of the power factor correction converter to achieve a long hold time and reduce the front-end DC converter. A distributed power supply system with an input voltage range that improves its efficiency and power density. To achieve this, a specific method of the present invention is to connect a backup boost (B ο 〇ts) converter between the power factor correction converter and the front-end DC converter, and in parallel with a diode, the The backup boost converter is composed of a boost transformer topology, a controller, and a hysteresis comparator connection. Since the backup boost converter works only during the hold time, during this time, the power factor correction converter If the output voltage gradually decreases, the backup boost converter will boost this voltage and stabilize it at the set output voltage value, and then supply it to the front-end DC converter to convert it into a DC voltage. Small, and the energy storage capacitor energy of the power factor correction converter can be fully utilized. Another object of the present invention is to provide a distributed power supply system capable of improving efficiency and power density. Since the backup boost converter operates only in the holding time period, the working time is relatively short, so it can be designed at high frequency and high power density. , The volume is small, and the AC input voltage does not work under normal conditions (when the energy of the front-end DC converter is transmitted by the diode not by the backup boost converter)

Page 6 571500 V. Description of the invention (4)), so it does not consume power. In order to allow your reviewers to further understand the features and technical contents of the present invention, please refer to the following detailed description and drawings of the present invention. However, the accompanying drawings are for reference and explanation only, and are not intended to limit the present invention. . Please refer to the fourth figure. The present invention is one that can make full use of the capacity of the energy storage capacitor of the power factor correction converter to achieve a long holding time and reduce the input voltage range of the front-end DC converter, thereby improving its efficiency and A distributed power system of power density, which is a backup boost converter 4 connected between a power factor correction converter 1 and a front-end DC converter 2 and connected in parallel with a diode 5, the front end The DC converter 2 can be A Η B or other circuit topology; the backup boost converter 4 sets the output voltage V 2set slightly lower than the normal output voltage Vlset of the power factor correction converter 1. The backup boost converter 4 includes a boost converter topology 4 1, a hysteresis comparator 4 2 and a controller 4 3, wherein: the boost converter topology 4 1 is composed of a switching element Q 2 and an inductor L 2. Diode D 1 and capacitor C 2 are connected. The switching element is a metal-oxide semiconductor in this creative embodiment. The source terminal is grounded, the drain terminal is connected to the inductor L 2 -terminal, and the diode D 1 -terminal. When connected, the other end of the inductor L 2 is connected to the output end of the power factor correction converter 1, the other end of the diode D 1 is connected to one end of the capacitor C 2 and the input end of the front-end DC converter 2, and the other end of the capacitor C 2 is grounded. Hysteresis comparator 4 2 is connected to the output of power factor correction converter 1

Page 7 571500 V. Description of the invention (5) The terminal is composed of a comparator, a resistor connection, and a reference voltage V ref. Please refer to the sixth diagram, which has two functions, and refer to the fifth diagram. In the power factor correction converter During the start of 1, when the output voltage V 1 of the power factor correction converter 1 has not risen to V high (V high is set to any value between V 2set and V 1 set), the backup boost is prohibited The converter 4 works; after the output voltage V 1 of the power factor correction converter 1 is reduced to V 100 watts, the backup boost converter 4 is prohibited from operating to prevent the components in the backup boost converter 4 from operating. Overcurrent. The controller 4 3 is connected to the output terminal of the hysteresis comparator 42 and the gate terminal of the switching element Q 2. The controller 4 3 is used to control the duty cycle of the switching Q 2 element. When VV 2 set, the backup is increased. The output of the voltage transformer 4 is stabilized at the value of V 2set, and when V 1 > V 2set, the backup boost converter 4 does not work, and the diode 5 is turned on and transfers power. When the AC voltage is normally input, that is, the output of the power factor correction converter 1 is normal, the duty cycle of the backup boost converter 4 is naturally zero, does not work, and the diode 5 is turned on. At this time, the front-end DC converter The input voltage of 2 is V 1 set. When the AC voltage is powered off or dropped sharply, the storage capacitor of the power factor correction converter 1 discharges and the output voltage drops. When it drops to V 2set, the duty cycle of the backup boost converter 4 naturally rises from zero. The output voltage is stabilized at V 2 set, the diode 5 is turned off, and the output voltage of the front-end DC converter 2 remains unchanged. When the output voltage of the power factor correction converter 1 continues to decrease to a certain value V low (for example, half of V lse t), the backup boost converter 4

571500 V. Description of the invention (6) The switching element Q 2 is turned off by the hysteresis comparator 4 2, and the input and output voltages of the front-end DC converter 2 rapidly drop to zero. If the AC voltage power-off time is not long enough for the designed holding time, the output voltage of the power factor correction converter 1 will rise as the AC voltage recovers, and the duty cycle of the backup boost converter 4 will decrease accordingly. The output voltage of the factor correction converter 1 is higher than V 2set, the duty cycle of the backup boost converter 4 is naturally reduced to zero, the diode 5 is turned on, and the normal working state is restored. The output voltage is stable. Referring again to the sixth figure, it is a diagram of an embodiment of the present invention, wherein the energy storage capacitor in the power factor correction converter 1 is 4 40 microfarads, and the normal output voltage V 1 set is 4 0 V; the front-end DC converter 2 Using A Η B converter, backup boost converter 4 with a switching frequency of 3 0 0 κ Η ζ, inductor L 2 magnetic core is RM6, capacitor C 2 is 10 microfarads; controller is UCC 3 8 1 3, The measured waveform is shown in Figure 7. From this waveform, it can be seen that its hold time is 2 8 · 8 ms. During the hold time, the output voltage V 1 of the power factor correction converter 1 is reduced from 40 0V to 2 2 0V ( V low), and the change value of the input voltage V 2 of the A 变化 B converter 2 is reduced from only 4 0 to 37 0 (again, 2361 :). According to this, the design of the holding time through the present invention can achieve the following effects: 1. The energy of the energy storage capacitor of the power factor correction converter can be fully utilized to achieve a long holding time or reduce the capacity of the energy storage capacitor. 2 · Improve the efficiency of the converter under normal operating conditions, thereby increasing power density.

571500 V. Description of the invention (7) 3 There is no adverse effect on the performance of the front-end DC converter. 4 · Commonly used in front-end DC converters of various circuit topologies. In summary, the circuit design of the present invention has the following characteristics: A. The energy of the energy storage capacitor of the power factor correction converter can be fully utilized to achieve a long holding time or reduce the capacity of the energy storage capacitor. B · Make the front-end DC converter work at a larger duty cycle, which can reduce the voltage rating of the secondary rectifier and improve efficiency and power density. C · The backup boost converter has a short working time, so it can be designed at high frequency and high power density, with a small volume, and the converter is naturally put in and out of work. In the process, there is no voltage or current overshoot . Therefore, the present invention fully complies with the requirements for patent applications and has industrial applicability. Therefore, if you apply for the application in accordance with the Patent Law, please check and approve the case in detail to protect the rights of the inventor. If there is any suspicion, please follow the instructions. According to the above, it is only the best specific embodiment of the present invention, but the features of the present invention are not limited to this. Any person skilled in the art can easily think of changes or modifications in the field of the present invention. Both can be covered by the patent scope of this case.

571500 Brief description of the diagram The first diagram is the architecture diagram of a traditional distributed power system. The second diagram is a circuit diagram of an asymmetric half-bridge circuit topology in the front-end DC converter of the first diagram. The third diagram is a circuit diagram of an asymmetric half-bridge converter in the front-end DC converter of the first diagram. The fourth figure is a structural diagram of the present invention. The fifth diagram is a relationship diagram of the input and output voltages of the hysteresis comparator of the present invention. The sixth diagram is an embodiment diagram of the present invention. The seventh diagram is a waveform diagram measured at various points in the embodiment of the present invention. Drawing number name description

1 Power factor correction converter 2 Front-end DC converter 3 Load-side converter 4 Backup boost converter 4 1 Boost converter topology 4 2 Hysteresis comparator 4 3 Controller 5 Diode la Power factor correction converter 2 a Front-end DC converter

3 a load-side converter

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Claims (1)

571500 Case No. 91113102 VI. Scope of patent application 1 The system includes: The system converts the AC input voltage into a high-voltage DC voltage and loads the required output terminals. Among them, if the backup voltage is boosted, the supply is 2 and the front lift is 3, and the control terminal is connected to the output terminal. The output power of the correction and variable wheel is due to the voltage; the front end directly lifts the direct electric backup, and the front end directly backs up the power converter. The front end of the power converter is straightforward. The voltage and digital correction converter with ring-ratio power factor converter converts the current and voltage of the converter; the converter converts the voltage and converts the voltage and conversion factor. The current converter will be converted to a patented converter. The patented converter is required to carry the DC converter. The digital correction output electric power factor is sent to the negative AND device, and the output of the connector is only in the JE conversion voltage booster. The range can be a range-inclusive device, which is connected to the converter at the power converter and converts the high-voltage DC voltage into a DC load-side converter to convert it to a corresponding converter connected to the power factor correction converter. Enter the input voltage and work with a diode for two periods of time. During this period, the output voltage gradually decreases, and then the voltage rises and is set to a distributed output voltage as described in item 1. Power supply system, symmetric half-bridge (Α) Β) or other distributed power supply system described in item 1, having an input end, an output end, and an output end of a factor correction converter, and an input end; a power factor correction converter During the start-up process of the output terminal, when the power factor does not rise to any value between the normal output voltage of the backup boost converter and the converter Page 12 571500 _ Case No. 91113102 VI. Patent application scope 92.1 ¾ Date: 丨, amended. /:;,, · 1: When the value is the same, the backup boost converter is prohibited to work; the power factor correction converter The output voltage of the backup boost converter is reduced to a value that makes the backup boost converter inoperative, and the backup boost converter is prohibited from operating; and a controller connected between the output of the hysteresis comparator and the control end of the boost converter topology , Used to control the duty cycle of the boost converter topology. 4 · The distributed power supply system described in item 3 of the scope of patent application, wherein the boost converter topology is composed of metal oxide semiconductor, inductor, diode and capacitor connection, and the source of the metal oxide semiconductor is extremely grounded; It is connected to one end of the inductor and one end of the diode, the other end of the inductor is connected to the output of the power factor correction converter, the other end of the diode is connected to the end of the capacitor and the input of the front-end DC converter, and the other end of the capacitor is grounded; Connected to the output of the controller. 5. The distributed power system according to item 3 of the scope of patent application, wherein the hysteresis comparator is composed of a comparison circuit and a reference voltage. 6 · A distributed power system is a backup boost converter connected between a power factor correction converter and a front-end DC converter and connected in parallel with a diode. The backup boost converter includes: A boost converter topology, which has an input terminal, an output terminal, and a control terminal. The input terminal is connected to the output terminal of the power factor correction converter, and the output terminal is connected to the input terminal of the front-end DC converter. The converter is connected to the output terminal of the power factor correction converter. When the power factor correction converter is started, when the output voltage of the power factor correction converter has not risen to between the set output voltage of the backup boost converter and Anything between the normal output voltage of the power factor correction converter 571500 _ Case No. 91113102 VI. When the scope of the patent application is at the intended value, the backup boost converter is prohibited to work; the output voltage of the power factor calibrator is reduced to a value that makes the backup boost converter inoperative and the backup boost converter is prohibited Work; and a controller connected to the output of the hysteresis comparator and the control of the boost topology to control the duty cycle of the boost converter topology 7 · Distributed as described in item 6 of the scope of patent application The boost converter topology of the power supply is composed of metal oxide semiconductor, inductor, and two-pole capacitor connection. The source of the metal oxide semiconductor is extremely grounded. One end of the drain electrode is connected to one end of the diode. The other end of the inductor is connected to the power factor correction output. The other end of the diode is connected to one end of the capacitor and the front-end DC input end, and the other end of the capacitor is grounded; the gate terminal is connected to the controller. 8 · The distributed power supply as described in item 6 of the scope of the patent application, wherein the hysteresis comparator is a voltage converter with a positive conversion consisting of a comparison circuit and a reference voltage. system,