AC-AC converter and power supply system
By designing AC-AC converters with two and three sub-terminals, and utilizing bidirectional power flow and voltage power supply operation, the problems of large size, heavy weight and high cost of existing converters are solved, and efficient power conversion is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-25
- Publication Date
- 2026-03-27
AI Technical Summary
Existing AC-AC converters suffer from problems such as large size, heavy weight, and high cost due to the use of 60 Hz transformers, making it difficult to effectively convert two-wire AC power to three-wire AC power.
The AC-AC converter design employs a first AC terminal with two sub-terminals, a second AC terminal with three sub-terminals, and a first bridge arm with two switching assemblies. It supports balanced and unbalanced loads through bidirectional power flow and voltage power supply operation, and simultaneously supports active and reactive power conversion.
It achieves reduced weight, size, and cost while improving conversion efficiency, and is suitable for power conversion in electric vehicle chargers and home power grids.
Smart Images
Figure CN121749776A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to a converter, in particular, an AC-AC converter and a power supply system. BACKGROUND
[0002] Some power supplies provide two-wire AC. When the power supply needs to be connected to a three-wire AC grid, the two-wire AC usually needs to be converted to three-wire AC by an AC-AC converter. For example, the battery of an electric vehicle is supplied by a bidirectional charger, and the output of the bidirectional charger is two-wire AC. The voltage between the two wires is 240 V. In order to connect to a three-wire domestic AC grid, the AC of the bidirectional charger needs to be converted to the output AC suitable for the domestic AC grid by an AC-AC converter. The conventional AC-AC converter is a 60 Hz transformer. However, the 60 Hz transformer has the disadvantages of large volume, large weight and high cost.
[0003] Therefore, there is a need to provide an AC-AC converter and a power supply system to overcome the aforementioned disadvantages. SUMMARY
[0004] The present application provides an AC-AC converter and a power supply system. The AC-AC converter of the present application includes a first AC terminal having two sub-terminals, a second AC terminal having three sub-terminals, and a first bridge arm having two switching components. The AC-AC converter receives and converts input power between two-wire and three-wire. The two switching components are activated to enable bidirectional power flow. The two switching components operate as voltage sources to simultaneously support balanced and unbalanced loads, and simultaneously support active and reactive power. In addition, the AC-AC converter of the present application has the advantages of reducing weight, volume and cost, and improving conversion efficiency.
[0005] According to the present disclosure, an AC-AC converter is provided. The AC-AC converter includes a first AC terminal, a second AC terminal, a first bridge arm, a second bridge arm, and at least one inductor. The first AC terminal is configured to receive input power and includes a first sub-terminal and a second sub-terminal. The second AC terminal includes a third sub-terminal, a fourth sub-terminal, and a fifth sub-terminal. The third sub-terminal is connected to the first sub-terminal. The fifth sub-terminal is connected to the second sub-terminal. The first bridge arm is connected between the first sub-terminal and the second sub-terminal and includes a first switching component and a second switching component. A connection node is formed between the first switching component and the second switching component. The connection node is connected to the fourth sub-terminal. The second bridge arm includes at least one capacitor. The at least one capacitor is connected to the fourth sub-terminal. One end of the at least one inductor is connected to at least one of the first switching component and the second switching component. The other end of the at least one inductor is connected to at least one of the third sub-terminal, the fourth sub-terminal, and the fifth sub-terminal. A first output power is formed between the third sub-terminal and the fourth sub-terminal. A second output power is formed between the fourth sub-terminal and the fifth sub-terminal.
[0006] According to another aspect of the present disclosure, a power supply system is provided. The power supply system includes an AC power source, a load, and an AC-AC converter. The AC power source provides input power and includes two first conductors. The load receives main output power and includes three second conductors. The AC-AC converter is connected between the AC power source and the load to convert the input power of the AC power source into the main output power of the load. The AC-AC converter includes a first AC terminal, a second AC terminal, a first bridge arm, a second bridge arm, and at least one inductor. The first AC terminal is configured to receive input power and includes a first sub-terminal and a second sub-terminal. The first sub-terminal and the second sub-terminal are connected to the two first conductors of the AC power source, respectively. The second AC terminal includes a third sub-terminal, a fourth sub-terminal, and a fifth sub-terminal. The third sub-terminal is connected to the first sub-terminal. The fifth sub-terminal is connected to the second sub-terminal. The third sub-terminal, the fourth sub-terminal, and the fifth sub-terminal are connected to the three second conductors of the load, respectively. A first output power is formed between the third sub-terminal and the fourth sub-terminal. A second output power is formed between the fourth sub-terminal and the fifth sub-terminal. The first output power and the second output power together form the main output power. The first bridge arm is connected between the first sub-terminal and the second sub-terminal and includes a first switching component and a second switching component. A connection node is formed between the first switching component and the second switching component. The connection node is connected to the fourth sub-terminal. The second bridge arm includes at least one capacitor. The at least one capacitor is connected to the fourth sub-terminal. One end of the at least one inductor is connected to at least one of the first switching component and the second switching component. The other end of the at least one inductor is connected to at least one of the third sub-terminal, the fourth sub-terminal, and the fifth sub-terminal.
[0007] The above disclosed features and advantages of the present application will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the application. BRIEF DESCRIPTION OF DRAWINGS
[0008] Figure 1 A circuit schematic diagram of an AC-AC converter of a first embodiment of the present application.
[0009] Figure 2 A circuit schematic diagram of an AC-AC converter of a first embodiment of the present application. Figure 1 A waveform diagram of input power and switching operation of an embodiment of the AC-AC converter of the present application.
[0010] Figure 3 A waveform diagram of input power and switching operation of another embodiment of the AC-AC converter of the present application. Figure 1 A waveform diagram of input power and switching operation of another embodiment of the AC-AC converter of the present application.
[0011] Figure 4 A circuit schematic diagram of an AC-AC converter of a second embodiment of the present application.
[0012] Figure 5 A circuit schematic diagram of an AC-AC converter of a third embodiment of the present application.
[0013] Figure 6 A circuit schematic diagram of an AC-AC converter of a fourth embodiment of the present application.
[0014] Figure 7 A circuit schematic diagram of an AC-AC converter of a fifth embodiment of the present application.
[0015] Figure 8 A circuit schematic diagram of an AC-AC converter of a sixth embodiment of the present application.
[0016] Figure 9 A circuit schematic diagram of an AC-AC converter of a seventh embodiment of the present application.
[0017] Figure 10 A circuit schematic diagram of an AC-AC converter of an eighth embodiment of the present application.
[0018] Figure 11 A circuit schematic diagram of an AC-AC converter of a ninth embodiment of the present application.
[0019] Figure 12 A circuit schematic diagram of an AC-AC converter of a tenth embodiment of the present application.
[0020] Figure 13 A circuit schematic diagram of an AC-AC converter of an eleventh embodiment of the present application.
[0021] Figures 14A to 14I A circuit schematic diagram of a switch of the AC-AC converter of the present application.
[0022] Figure 15 Circuit schematic diagram of an AC-AC converter according to a twelfth embodiment.
[0023] Figures 16A to 16G Circuit schematic diagram of a first filter of an AC-AC converter according to the present application.
[0024] Figures 17A to 17D Circuit schematic diagram of a second filter of an AC-AC converter according to the present application.
[0025] Figure 18 Circuit schematic diagram of an AC-AC converter according to a thirteenth embodiment.
[0026] Figure 19 Circuit schematic diagram of an AC-AC converter according to a fourteenth embodiment.
[0027] Figure 20 Circuit schematic diagram of a power supply system according to the present application.
[0028] Figure 21 Circuit schematic diagram of a signal generating device of a power supply system according to an embodiment of the present application.
[0029] Figure 22 Circuit schematic diagram of a signal generating device of a power supply system according to another embodiment of the present application.
[0030] List of reference signs
[0031] 1, 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j, 1k, 1m, 1n: AC-AC converter
[0032] 11: first AC-AC converter
[0033] 12: second AC-AC converter
[0034] 2: first AC terminal
[0035] 21: first sub-terminal
[0036] 22: second sub-terminal
[0037] 3: second AC terminal
[0038] 31: third sub-terminal
[0039] 32: fourth sub-terminal
[0040] 33: fifth sub-terminal
[0041] 4: first bridge arm
[0042] 41: first switching component
[0043] 42: second switch assembly
[0044] 5: second bridge leg
[0045] 61: first filter
[0046] 62: second filter
[0047] 63: first protection device
[0048] 64: second protection device
[0049] 71: first relay
[0050] 72: first current sensor
[0051] 73: second relay
[0052] 74: second current sensor
[0053] 8: signal generating device
[0054] 81: detection circuit
[0055] 82: signal generator
[0056] 83: microcontroller unit
[0057] 9: power supply system
[0058] 91: first alternating current power supply
[0059] 92: second alternating current power supply
[0060] 93: load
[0061] C1: first capacitor
[0062] C2: second capacitor
[0063] Cin: input capacitor
[0064] L1: first inductor
[0065] L2: second inductor
[0066] L3: third inductor
[0067] R1: first resistor
[0068] R2: second resistor
[0069] R12: third resistor
[0070] S1: first switch
[0071] S2: second switch
[0072] S3: third switch
[0073] S4: fourth switch
[0074] A: connection node
[0075] ZC: zero-crossing signal DETAILED DESCRIPTION
[0076] The present application will be described in more detail by referring to the following examples. It should be noted that the following description of examples of the present application is only illustrative and not restrictive while not being exhaustive nor limited to the particular forms disclosed.
[0077] Figure 1 A circuit schematic diagram of an AC-AC converter according to a first embodiment of the present application. Figure 2 A circuit schematic diagram of an AC-AC converter according to a first embodiment of the present application. Figure 1 Waveform diagrams of input power and switching operation of an embodiment of the AC-AC converter 1. In this embodiment, the AC-AC converter 1 is connected between an AC power source and a load to convert input power of the AC power source into main output power of the load. The connection relationship and conversion method of the AC-AC converter 1 will be described in detail below. As shown in FIG. 1, the AC-AC converter 1 includes a first AC terminal 2, a second AC terminal 3, a first bridge arm 4, a second bridge arm 5, and a first inductor L1. Figure 1
[0078] The first AC terminal 2 is connected to the AC power source to receive input power. The first AC terminal 2 includes a first sub-terminal 21 and a second sub-terminal 22. The first AC terminal 2 is connected to the AC power source through the first sub-terminal 21 and the second sub-terminal 22. In this embodiment, the voltage of the input power is 240 V.
[0079] The second AC terminal 3 connects a load to provide a main output power. The second AC terminal 3 includes a third sub-terminal 31, a fourth sub-terminal 32, and a fifth sub-terminal 33. The third sub-terminal 31 of the second AC terminal 3 connects the first sub-terminal 21 of the first AC terminal 2. The fourth sub-terminal 32 of the second AC terminal 3 is a neutral terminal and can be grounded. The fifth sub-terminal 33 of the second AC terminal 3 connects the second sub-terminal 22 of the first AC terminal 2. A first output power of the main output power is formed between the third sub-terminal 31 and the fourth sub-terminal 32 of the second AC terminal 3. A second output power of the main output power is formed between the fourth sub-terminal 32 and the fifth sub-terminal 33 of the second AC terminal 3. A third output power of the main output power is formed between the third sub-terminal 31 and the fifth sub-terminal 33 of the second AC terminal 3. In the embodiment, the first output power and the second output power are each half of the input power, for example, 120 V, and the third output power is the same as the input power. In the embodiment, the first output power and the second output power can be any value, and the sum of the first output power and the second output power is 240 V.
[0080] The first bridge arm 4 is connected between the first sub-terminal 21 and the second sub-terminal 22 of the first AC terminal 2. The first bridge arm 4 includes a first switch assembly 41 and a second switch assembly 42. The first switch assembly 41 and the second switch assembly 42 form a connection node A therebetween. In the embodiment, the first switch assembly 41 includes a first switch S1 and a second switch S2. The first switch S1 and the second switch S2 are connected in series to form a bidirectional AC switch. The first switch S1 connects the first sub-terminal 21 of the first AC terminal 2. The second switch S2 connects the connection node A. The second switch assembly 42 includes a third switch S3 and a fourth switch S4. The third switch S3 and the fourth switch S4 are connected in series to form a bidirectional AC switch. The third switch S3 connects the connection node A. The fourth switch S4 connects the second sub-terminal 22 of the first AC terminal 2.
[0081] The second bridge arm 5 is connected in parallel with the first bridge arm 4. In the embodiment, the second bridge arm 5 includes a first capacitor C1 and a second capacitor C2. The first capacitor C1 and the second capacitor C2 are connected in series. The first capacitor C1 is connected between the third sub-terminal 31 and the fourth sub-terminal 32 of the second AC terminal 3. The second capacitor C2 is connected between the fourth sub-terminal 32 and the fifth sub-terminal 33 of the second AC terminal 3.
[0082] One end of the first inductor L1 connects the connection node A between the first switch assembly 41 and the second switch assembly 42. The other end of the first inductor L1 connects the fourth sub-terminal 32 of the second AC terminal 3.
[0083] An embodiment of the AC-AC converter 1 of this invention includes a controller, the controller being configured to provide a first signal for controlling a first switch S1 of a first switching assembly 41, a second signal for controlling a second switch S2 of the first switching assembly 41, a third signal for controlling a third switch S3 of the second switching assembly 42, and a fourth signal for controlling a fourth switch S4 of the second switching assembly 42.
[0084] In one embodiment of this case, the first signal controlling the first switch S1, the second signal controlling the second switch S2, the third signal controlling the third switch S3, and the fourth signal controlling the fourth switch S4 respectively include, but are not limited to, driving signals for driving the first switch S1, the second switch S2, the third switch S3, and the fourth switch S4.
[0085] like Figure 2 As shown, in this embodiment, the operation of the input electrical energy, the operation of the first switch S1 of the first switching assembly 41, the operation of the second switch S2 of the first switching assembly 41, the operation of the third switch S3 of the second switching assembly 42, the operation of the fourth switch S4 of the second switching assembly 42, and the zero-crossing signal ZC are displayed sequentially. The first signal controls the first switch S1. The second signal controls the second switch S2. The third signal controls the third switch S3. The fourth signal controls the fourth switch S4. During the positive half-cycle, the first and third signals are complementary, and the second and fourth signals are positive. During the negative half-cycle, the second and fourth signals are complementary, and the first and third signals are positive. In other words, during the positive half-cycle of the input electrical energy, the interleaved high-frequency switching signals control the first switch S1 and the third switch S3. There is a non-overlapping dead time between the two switches S1 and S3. In this embodiment, during the positive half-cycle, the second switch S2 and the fourth switch S4 remain in the on state. Conversely, during the negative half-cycle of the input power, interleaved high-frequency switching signals control the second switch S2 and the fourth switch S4. There is a non-overlapping dead time between the two switches S2 and S4. During the positive half-cycle, the zero-crossing signal ZC is positive. During the negative half-cycle, the zero-crossing signal ZC is negative. In this embodiment, during the negative half-cycle, the first switch S1 and the third switch S3 remain in the on state. In some embodiments, since the second switch S2 and the fourth switch S4 are in the on state, the first switch S1 can be turned off before the third switch S3 is turned on. Therefore, current will flow through the diode of the first switch S1 or the diode of the third switch S3 according to the current direction, thereby reducing the overvoltage stress of the AC-AC converter 1.
[0086] In some embodiments, one of the switches between the first switch S1 and the third switch S3 has a duty cycle less than 50% and the other switch has a duty cycle greater than 50%, and the first switch S1 and the third switch S3 are complementary. The sum of the duty cycle of the first switch S1 and the duty cycle of the third switch S3 is 100%. In some embodiments, one of the switches between the second switch S2 and the fourth switch S4 has a duty cycle less than 50% and the other switch has a duty cycle greater than 50%, and the second switch S2 and the fourth switch S4 are complementary. The sum of the duty cycle of the second switch S2 and the duty cycle of the fourth switch S4 is 100%.
[0087] As shown above, the AC-AC converter 1 of the present application comprises a first AC terminal 2 having two sub-terminals 21, 22, a second AC terminal 3 having three sub-terminals 31, 32, 33, and a first bridge arm 4 having two switching assemblies 41, 42. The AC-AC converter 1 receives and converts input power between two-wire and three-wire. The two switching assemblies 41, 42 are activated to achieve bidirectional power flow. The two switching assemblies 41, 42 operate as voltage sources to simultaneously support balanced and unbalanced loads, and simultaneously support active power and reactive power. In addition, the AC-AC converter 1 of the present application has the advantages of reducing weight, volume and cost, and improving conversion efficiency.
[0088] In some embodiments, the operation mode of the switches can be adjusted according to the actual application requirements. Figure 3 Figure 1 The input power and switching operation waveform diagram of another embodiment of the AC-AC converter. As shown in FIG. 4, the first signal controls and / or drives the first switch S1 and the second switch S2. The second signal controls and / or drives the third switch S3 and the fourth switch S4. The first signal and the second signal are complementary. Figure 3
[0089] The circuit schematic diagram of the AC-AC converter of the second embodiment of the present application. Compared with the AC-AC converter 1 of FIG. 1, as shown in FIG. 5, in the first switching assembly 41 of the AC-AC converter 1a of the present embodiment, the gate of the first switch S1 and the gate of the second switch S2 are connected to each other to form a first bidirectional switch. In the second switching assembly 42 of the AC-AC converter 1a of the present embodiment, the gate of the third switch S3 and the gate of the fourth switch S4 are connected to each other to form a second bidirectional switch. In the present embodiment, the first switch S1 and the second switch S2 of the first switching assembly 41 and the third switch S3 and the fourth switch S4 of the second switching assembly 42 are controlled according to the operation waveform shown in FIG. 3. Figure 4 Figure 1 Figure 4 Figure 3
[0090] Figure 5 This is a circuit diagram of the AC-AC converter according to the third embodiment of this case. Compared to Figure 1 AC-AC converter 1, such as Figure 5 As shown, the second bridge arm 5 of the AC-AC converter 1b in this embodiment includes a first capacitor C1. The first capacitor C1 is connected between the third sub-terminal 31 and the fourth sub-terminal 32 of the second AC terminal 3. It should be emphasized that this embodiment is not limited to this one.
[0091] Figure 6 This is a circuit diagram of the AC-AC converter according to the fourth embodiment of this case. Compared to Figure 1 AC-AC converter 1, such as Figure 6 As shown, the second bridge arm 5 of the AC-AC converter 1c in this embodiment includes a second capacitor C2. The second capacitor C2 is connected between the fourth sub-terminal 32 and the fifth sub-terminal 33 of the second AC terminal 3. It should be emphasized that this embodiment is not limited to this one.
[0092] Figure 7 This is a circuit diagram of the AC-AC converter according to the fifth embodiment of this case. Compared to Figure 1 AC-AC converter 1, such as Figure 7 As shown, the AC-AC converter 1d in this embodiment includes an input capacitor Cin. The input capacitor Cin is connected in parallel with the first bridge arm 4. The input capacitor Cin is designed to filter high-frequency switching noise.
[0093] Figure 8 This is a circuit diagram of the AC-AC converter according to the sixth embodiment of this case. Compared to Figure 6 AC-AC converter 1c, such as Figure 8 As shown, the AC-AC converter 1e in this embodiment further includes an input capacitor Cin. The input capacitor Cin is connected in parallel with the first bridge arm 4. The input capacitor Cin is designed to filter high-frequency switching noise.
[0094] Figure 9 This is a circuit diagram of the AC-AC converter according to the seventh embodiment of this case. Compared to Figure 1 The first inductor L1 of the AC-AC converter 1, such as Figure 9 As shown, in this embodiment, the first inductor L1 of the AC-AC converter 1f is connected between one end of the second switching assembly 42 and the fifth sub-terminal 33 of the second AC terminal 3, and is also connected between the second sub-terminal 22 of the first AC terminal 2 and the fifth sub-terminal 33 of the second AC terminal 3.
[0095] Figure 10 This is a circuit diagram of the AC-AC converter according to the eighth embodiment of this case. Compared to Figure 1 The first inductor L1 of the AC-AC converter 1, such asFigure 10 As shown, in this embodiment, the first inductor L1 of the AC-AC converter 1g is connected between one end of the first switching assembly 41 and the third sub-terminal 31 of the second AC terminal 3, and is also connected between the first sub-terminal 21 of the first AC terminal 2 and the third sub-terminal 31 of the second AC terminal 3.
[0096] Figure 11 This is a circuit diagram of the AC-AC converter according to the ninth embodiment of this case. Compared to Figure 1 AC-AC converter 1, such as Figure 11 As shown, the AC-AC converter 1h of this embodiment further includes a second inductor L2. The second inductor L2 is connected between one end of the second switching assembly 42 and the fifth sub-terminal 33 of the second AC terminal 3, and is also connected between the second sub-terminal 22 of the first AC terminal 2 and the fifth sub-terminal 33 of the second AC terminal 3.
[0097] Figure 12 This is a circuit diagram of the AC-AC converter according to the tenth embodiment of this case. Compared to Figure 1 AC-AC converter 1, such as Figure 12 As shown, in this embodiment, the first inductor L1 of the AC-AC converter 1i is connected between one end of the first switching assembly 41 and the third sub-terminal 31 of the second AC terminal 3, and is also connected between the first sub-terminal 21 of the first AC terminal 2 and the third sub-terminal 31 of the second AC terminal 3. The AC-AC converter 1i in this embodiment further includes a second inductor L2. The second inductor L2 is connected between one end of the second switching assembly 42 and the fifth sub-terminal 33 of the second AC terminal 3, and is also connected between the second sub-terminal 22 of the first AC terminal 2 and the fifth sub-terminal 33 of the second AC terminal 3.
[0098] Figure 13 This is a circuit diagram of the AC-AC converter according to the eleventh embodiment of this case. Compared to Figure 1 AC-AC converter 1, such as Figure 13 As shown, the AC-AC converter 1j of this embodiment further includes a second inductor L2 and a third inductor L3. The second inductor L2 is connected between one end of the second switching assembly 42 and the fifth sub-terminal 33 of the second AC terminal 3, and is also connected between the second sub-terminal 22 of the first AC terminal 2 and the fifth sub-terminal 33 of the second AC terminal 3. The third inductor L3 is connected between one end of the first switching assembly 41 and the third sub-terminal 31 of the second AC terminal 3, and is also connected between the first sub-terminal 21 of the first AC terminal 2 and the third sub-terminal 31 of the second AC terminal 3.
[0099] In some embodiments, the first switch S1, the second switch S2, the third switch S3, and the fourth switch S4 can be formed by switches of any form. For example... Figures 14A to 14I As shown, the two switches in the same switching assembly can be bidirectional switches, two unidirectional switches, parallel switches, series switches, double-sided switches, AC switches, or four-quadrant switches.
[0100] Figure 15 This is a circuit diagram of the AC-AC converter according to the twelfth embodiment of this case. Compared to Figure 1 AC-AC converter 1, such as Figure 15 As shown, the AC-AC converter 1k of this embodiment further includes a first filter 61, a second filter 62, a first protection device 63, and a second protection device 64. The first filter 61 and the second filter 62 are designed to suppress conducted and radiated electromagnetic interference to comply with EMC standards. The first filter 61 is connected to the first sub-terminal 21 and the second sub-terminal 22 of the first AC terminal 2. Figures 16A to 16G As shown, the first filter 61 is a combination of inductors and capacitors. The second filter 62 is connected to the third sub-terminal 31, the fourth sub-terminal 32, and the fifth sub-terminal 33 of the second AC terminal 3. Figures 17A to 17D As shown, the second filter 62 is a combination of inductors and capacitors. A first protection device 63 is connected between the first AC terminal 2 and the first filter 61. A second protection device 64 is connected between the second AC terminal 3 and the second filter 62. In some embodiments, the first protection device 63 and the second protection device 64 can be any surge and overvoltage protection device, such as a fuse, switch, precharger, or surge protector (SPD).
[0101] Figure 18 This is a circuit diagram of the AC-AC converter according to the thirteenth embodiment of this case. In this embodiment, the AC-AC converter 1m is a unidirectional converter from the first AC terminal 2 to the second AC terminal 3. Compared to Figure 1 AC-AC converter 1, such as Figure 18As shown, the AC-AC converter 1m of this embodiment further includes an input capacitor Cin, a second filter 62, a first relay 71, a first current sensor 72, a second relay 73, a second current sensor 74, a first resistor R1, a second resistor R2, and a third resistor R12. The input capacitor Cin is connected in parallel with the first bridge arm 4 and is connected between the first sub-terminal 21 and the second sub-terminal 22 of the first AC terminal 2. The second filter 62 is connected to the third sub-terminal 31, the fourth sub-terminal 32, and the fifth sub-terminal 33 of the second AC terminal 3. The second filter 62 is a combination of inductors and capacitors. For example, the second filter 62 can be a common-mode inductor. The first relay 71 and the first current sensor 72 are connected in series between the first sub-terminal 21 of the first AC terminal 2 and one end of the second filter 62 to provide overload protection control. The second relay 73 and the second current sensor 74 are connected in series between the second sub-terminal 22 of the first AC terminal 2 and the other end of the second filter 62 to provide overload protection control. The first resistor R1 is connected between the third sub-terminal 31 and the fourth sub-terminal 32 of the second AC terminal 3. The second resistor R2 is connected between the fourth sub-terminal 32 and the fifth sub-terminal 33 of the second AC terminal 3. The third resistor R12 is connected between the third sub-terminal 31 and the fifth sub-terminal 33 of the second AC terminal 3. The voltage of the third sub-terminal 31 minus the voltage of the fourth sub-terminal 32 equals the voltage of the first resistor R1. The voltage of the fifth sub-terminal 33 minus the voltage of the fourth sub-terminal 32 equals the voltage of the second resistor R2. In this embodiment, the current of the AC-AC converter 1m satisfies the following equation: This represents the current at the first AC terminal 2. This represents the current flowing through the first resistor, R1. This represents the current flowing through the second resistor R2. This represents the current flowing through the third resistor, R12.
[0102] In this embodiment, components with strong current tolerance are selected. Furthermore, since the AC-AC converter 1m in this embodiment is a unidirectional converter from the first AC terminal 2 to the second AC terminal 3, after applying 240V input power, the first relay 71 and the second relay 73 form a circuit to supply phase voltage to the first resistor R1, the second resistor R2, and the third resistor R12. Therefore, the AC-AC converter 1m in this embodiment cannot completely replace the autotransformer in general wiring applications, and its usage conditions are correspondingly limited.
[0103] Figure 19This is a circuit diagram of the AC-AC converter according to the fourteenth embodiment of this case. In this embodiment, the AC-AC converter 1n is a unidirectional converter from the second AC terminal 3 to the first AC terminal 2. Compared to Figure 1 AC-AC converter 1, such as Figure 19 As shown, the AC-AC converter 1n of this embodiment further includes an input capacitor Cin, a second filter 62, a first relay 71, a first current sensor 72, a second relay 73, a first resistor R1, a second resistor R2, and a third resistor R12. The input capacitor Cin is connected in parallel with the first bridge arm 4 and is connected between the first sub-terminal 21 and the second sub-terminal 22 of the first AC terminal 2. The second filter 62 is connected to the third sub-terminal 31, the fourth sub-terminal 32, and the fifth sub-terminal 33 of the second AC terminal 3. The second filter 62 can be a combination of inductors and capacitors. For example, the second filter 62 can be a transformer. The first relay 71 is connected between one end of the second filter 62 and the third sub-terminal 31 of the second AC terminal 3. The second relay 73 is connected between the other end of the second filter 62 and the fifth sub-terminal 33 of the second AC terminal 3. The first current sensor 72 is connected between the central node of the second bridge arm 5 and the central node of the second filter 62. The first resistor R1 is connected between the third sub-terminal 31 and the fourth sub-terminal 32 of the second AC terminal 3. The second resistor R2 is connected between the fourth sub-terminal 32 and the fifth sub-terminal 33 of the second AC terminal 3. The third resistor R12 is connected between the third sub-terminal 31 and the fifth sub-terminal 33 of the second AC terminal 3. In this embodiment, the current of the AC-AC converter 1n satisfies the following equation: This represents the current at the second AC terminal 3. This represents the current flowing through the first resistor, R1. This represents the current flowing through the second resistor R2.
[0104] Before the first relay 71 and the second relay 73 form an open circuit, the first switch S1, the second switch S2, the third switch S3, and the fourth switch S4 will be activated through detection and control. When the first relay 71 and the second relay 73 receive 240V input power, the 120V phase voltage of the first resistor R1 and the second resistor R2 will be immediately adjusted and simultaneously supplied to the household phase load. The AC-AC converter 1n of this embodiment completely replaces the autotransformer in general wiring applications. In addition, the circuit elements of this embodiment can carry the current of the first resistor R1 and the second resistor R2, that is... Furthermore, the current from the third resistor R12 will not flow into the component. Therefore, the current withstand requirement of the component can be significantly reduced.
[0105] Figure 20 This is a circuit diagram of the power supply system for this case. Figure 20 As shown, the power supply system 9 of this embodiment includes a first AC power source 91, multiple second AC power sources 92, a load 93, a first AC-AC converter 11, and a second AC-AC converter 12. The first AC power source 91 is the power grid and includes two wires providing input power. The multiple second AC power sources 92 are combinations of bidirectional on-board chargers and electric vehicle power supply equipment for electric vehicles, combinations of solar panels and photovoltaic inverters, or other renewable energy sources. The load 93 is a household appliance and includes three wires receiving the main output power. The first AC-AC converter 11 is connected between the first AC power source 91 and the load 93. One end of the second AC-AC converter 12 is connected to the multiple second AC power sources 92, and the other end of the second AC-AC converter 12 is connected to the load 93. In one embodiment, when the first AC power source 91 is operating, the first AC-AC converter 11 converts the input power of the first AC power source 91 into the main output power. When the first AC power source 91 fails, at least one of the plurality of second AC power sources 92 provides input power to the second AC-AC converter 12, which converts the input power from at least one of the plurality of second AC power sources 92 into main output power. Power switching is controlled by a microgrid interconnection device, an automatic transfer switch, or an arbitrary switching control circuit.
[0106] In some embodiments, the signal generating device generates signals that drive the first switch S1, the second switch S2, the third switch S3, and the fourth switch S4. Figure 21 This is a circuit diagram of a signal generation device for a power supply system according to an embodiment of this case. Figure 21 As shown, a signal generating device 8 is disposed in the AC-AC converter 1. The signal generating device 8 includes a detection circuit 81 and a signal generator 82. The detection circuit 81 receives input electrical energy of 240 V AC voltage from either the first AC power supply 91 or the second AC power supply 92 and converts it into a zero-crossing signal in phase with the AC voltage. The detection circuit 81 includes at least a comparator, multiple resistors, and multiple capacitors. The signal generator 82 generates multiple control signals for the first switch S1, the second switch S2, the third switch S3, and the fourth switch S4 based on the zero-crossing signal. In this embodiment, the AC-AC converter 1 is connected to the first AC power supply 91 (or the second AC power supply 92) via wires to transmit input electrical energy of 240 V AC voltage.
[0107] Figure 22 This is a circuit diagram of the signal generation device for a power supply system according to another embodiment of this case. Figure 22As shown, the signal generating device 8 is disposed in the first AC power supply 91 (or the second AC power supply 92) and the AC-AC converter 1. The signal generating device 8 includes a detection circuit 81, a signal generator 82, and a microcontroller unit (MCU) 83. The detection circuit 81 and the microcontroller unit 83 are disposed in the first AC power supply 91 (or the second AC power supply 92). The detection circuit 81 receives input electrical energy with an AC voltage of 240 V and converts it into a zero-crossing signal in phase with the AC voltage. The detection circuit 81 includes at least a comparator, multiple resistors, and multiple capacitors. The microcontroller unit 83 receives the zero-crossing signal and converts it into a digital signal. The signal generator 82 is disposed in the AC-AC converter 1. The signal generator 82 generates multiple control signals for the first switch S1, the second switch S2, the third switch S3, and the fourth switch S4 based on the digital signal. In this embodiment, the AC-AC converter 1 and the first AC power supply 91 (or the second AC power supply 92) are connected by wires to transmit the digital signal. The conductors must have a low voltage amplitude (e.g., 5V or 3.3V) to meet insulation withstand voltage requirements.
[0108] As described above, this invention provides an AC-AC converter and a power supply system. The AC-AC converter includes a first AC terminal with two sub-terminals, a second AC terminal with three sub-terminals, and a first bridge arm with two switching assemblies. The AC-AC converter receives and converts input electrical energy between two and three wires. The two switching assemblies activate to achieve bidirectional power flow. The two switching assemblies operate as a voltage power supply to simultaneously support balanced and unbalanced loads, as well as active and reactive power. Furthermore, the AC-AC converter of this invention has the advantages of reduced weight, size, and cost, and improved conversion efficiency.
[0109] Although this application has been described with reference to embodiments that are currently considered practical and feasible, it is not limited to the disclosed embodiments. Rather, all variations, modifications, or similar structures falling within the scope and spirit of the appended claims are covered by this application and should be interpreted in the broadest possible sense.
Claims
1. An AC-AC converter, comprising: A first AC terminal is configured to receive an input electrical energy and includes a first sub-terminal and a second sub-terminal; A second AC terminal includes a third sub-terminal, a fourth sub-terminal, and a fifth sub-terminal, wherein the third sub-terminal is connected to the first sub-terminal, and the fifth sub-terminal is connected to the second terminal; A first bridge arm is connected between the first sub-terminal and the second sub-terminal, and includes a first switch assembly and a second switch assembly, wherein a connection node is formed between the first switch assembly and the second switch assembly, and the connection node is connected to the fourth sub-terminal. A second bridge arm, including at least one capacitor connected to the fourth sub-terminal; and At least one inductor, wherein one end of the at least one inductor is connected to at least one of the first switching assembly and the second switching assembly, and the other end of the at least one inductor is connected to at least one of the third sub-terminal, the fourth sub-terminal, and the fifth sub-terminal. A first output power is formed between the third sub-terminal and the fourth sub-terminal, and a second output power is formed between the fourth sub-terminal and the fifth sub-terminal.
2. The AC-AC converter of claim 1, wherein the at least one capacitor includes a single capacitor connected between the third sub-terminal and the fourth sub-terminal, or connected between the fourth sub-terminal and the fifth sub-terminal.
3. The AC-AC converter of claim 2, wherein the at least one capacitor is connected between the connection node and the fourth sub-terminal.
4. The AC-AC converter of claim 1, wherein the at least one capacitor comprises two capacitors, one of which is connected between the third sub-terminal and the fourth sub-terminal, and the other of which is connected between the fourth sub-terminal and the fifth sub-terminal.
5. The AC-AC converter of claim 4, wherein the at least one inductor is connected between the connection node and the fourth sub-terminal, between one end of the first switching assembly and the third sub-terminal, and / or between one end of the second switching assembly and the fifth sub-terminal.
6. The AC-AC converter of claim 1, wherein the first switching assembly includes a first switch and a second switch connected in series, and the second switching assembly includes a third switch and a fourth switch connected in series.
7. The AC-AC converter of claim 6, further comprising a controller configured to provide a first signal for controlling the first switch, a second signal for controlling the second switch, a third signal for controlling the third switch, and a fourth signal for controlling the fourth switch, wherein during a positive half-cycle, the first signal and the third signal are complementary, and the second signal and the fourth signal are positive; and during a negative half-cycle, the second signal and the fourth signal are complementary, and the first signal and the third signal are positive.
8. The AC-AC converter of claim 6, further comprising a controller configured to provide a first signal to control the first switch and the second switch and a second signal to control the third switch and the fourth switch, wherein the first signal and the second signal are complementary.
9. The AC-AC converter of claim 6, wherein a gate of the first switch and a gate of the second switch are connected to each other to form a first bidirectional switch, and a gate of the third switch and a gate of the fourth switch are connected to each other to form a second bidirectional switch.
10. The AC-AC converter of claim 9, further comprising a controller configured to provide a first signal to control the first switch, a second signal to control the second switch, a third signal to control the third switch, and a fourth signal to control the fourth switch, wherein during a positive half-cycle, the first signal and the third signal are complementary, and the second signal and the fourth signal are positive; and during a negative half-cycle, the second signal and the fourth signal are complementary, and the first signal and the third signal are positive.
11. The AC-AC converter of claim 1, wherein the first output power and the second output power are each half of the input power.
12. The AC-AC converter of claim 1, wherein the AC-AC converter includes a first filter and a second filter, the first filter being connected to the first sub-terminal and the second sub-terminal of the first AC terminal, and the second filter being connected to the third sub-terminal, the fourth sub-terminal and the fifth sub-terminal of the second AC terminal.
13. The AC-AC converter of claim 12, wherein the AC-AC converter includes a first protection device and a second protection device, the first protection device being connected between the first AC terminal and the first filter, and the second protection device being connected between the second AC terminal and the second filter.
14. The AC-AC converter of claim 1, wherein a third output power is formed between the third sub-terminal and the fifth sub-terminal.
15. A power supply system, comprising: An AC power source provides an input electrical energy and includes two first wires; A load that receives a main output power and includes three second wires; as well as An AC-AC converter, connected between the AC power source and the load, converts the input electrical energy of the AC power source into the main output electrical energy of the load, and includes: A first AC terminal is configured to receive the input electrical energy and includes a first sub-terminal and a second sub-terminal, wherein the first sub-terminal and the second sub-terminal are respectively connected to the two first wires of the AC power supply; A second AC terminal includes a third sub-terminal, a fourth sub-terminal, and a fifth sub-terminal, wherein the third sub-terminal is connected to the first sub-terminal, the fifth sub-terminal is connected to the second sub-terminal, the third sub-terminal, the fourth sub-terminal, and the fifth sub-terminal are respectively connected to the three second wires of the load, a first output power is formed between the third sub-terminal and the fourth sub-terminal, a second output power is formed between the fourth sub-terminal and the fifth sub-terminal, and the first output power and the second output power together form the main output power; A first bridge arm is connected between the first sub-terminal and the second sub-terminal, and includes a first switch assembly and a second switch assembly, wherein a connection node is formed between the first switch assembly and the second switch assembly, and the connection node is connected to the fourth sub-terminal. A second bridge arm, including at least one capacitor connected to the fourth sub-terminal; and At least one inductor, wherein one end of the at least one inductor is connected to at least one of the first switching assembly and the second switching assembly, and the other end of the at least one inductor is connected to at least one of the third sub-terminal, the fourth sub-terminal and the fifth sub-terminal.
16. The power supply system of claim 15, wherein the power supply system includes a signal generating device disposed on the AC power supply or the AC-AC converter, and includes a detection circuit and a signal generator, the detection circuit receiving the input electrical energy and converting it into a zero-crossing signal, and the signal generator generating a plurality of control signals for the first switching assembly and the second switching assembly based on the zero-crossing signal.