Power conversion system

Abstract

The application discloses a power conversion system, comprising N power converters, each of which comprises an input end, a first output end and a second output end, each of which receives direct current power through the input end, the first output end of the first power converter in the N power converters is connected in parallel with the second output end of the Nth power converter in the N power converters to form an Nth total output end to output an Nth total output power, and the first output end of the ith power converter in the N power converters is connected in parallel with the second output end of the (i-1)th power converter in the N power converters to form an (i-1)th total output end to output an (i-1)th total output power, wherein N>=i>=2, and i is an integer.

Description

Technical Field

[0001] This invention discloses a power conversion system, and particularly relates to a power conversion system with low cost, high efficiency and low loss. Background Technology

[0002] In current technology, power conversion systems are used to convert power, and traditional power conversion systems include the following two structures. The first type of traditional power conversion system is a single-output-port system, which contains multiple power converters whose outputs are connected in parallel and output power from a single output port. However, the first type of traditional power conversion system cannot meet the needs of applications requiring multiple output ports, and it requires an additional isolation transformer to provide electrical isolation between the multiple power converters, which increases the cost of the power conversion system and reduces charging efficiency.

[0003] The second type of traditional power conversion system is the multi-output port power conversion system. This system contains multiple power converters, and the output port of each power converter is directly connected to the corresponding load, meaning that the multiple power converters have completely independent outputs. However, because the multiple power converters have completely independent outputs, power imbalances among them make it difficult to achieve voltage equalization, or a large reactive current needs to be injected into the power conversion system to achieve voltage equalization. This prevents the power conversion system from meeting power factor requirements and reduces its efficiency.

[0004] Therefore, developing a power conversion system that overcomes the above-mentioned shortcomings is an urgent need at present. Summary of the Invention

[0005] One object of this disclosure is to provide a power conversion system that is low in cost, high in efficiency and low in loss.

[0006] To achieve the above objectives, one embodiment of this disclosure provides a power conversion system comprising N power converters. Each power converter includes an input terminal, a first output terminal, and a second output terminal. Each power converter receives DC power via its input terminal. The first output terminal of the first power converter among the N power converters is connected in parallel with the second output terminal of the Nth power converter among the N power converters to form the Nth total output terminal and output the Nth total output power. The first output terminal of the i-th power converter among the N power converters is connected in parallel with the second output terminal of the (i-1)-th power converter among the N power converters to form the (i-1)-th total output terminal and output the (i-1)-th total output power, where N>=i>=2, and i is an integer. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of the circuit structure of the power conversion system according to the first embodiment of this disclosure.

[0008] Figure 2 for Figure 1 The diagram shows a detailed circuit structure of the power conversion system.

[0009] Figure 3 for Figure 1 The diagram shows the power distribution of the power converter in the power conversion system.

[0010] Figure 4 for Figure 1 The diagram shows the operation and control unit of the power conversion system.

[0011] Figure 5 This is a schematic diagram of the circuit structure of the power conversion system according to the second embodiment of this disclosure.

[0012] Figure 6 for Figure 5 The diagram shows the signal transmission of the port controller in the power conversion system.

[0013] Figure 7 for Figure 5 The diagram shows a detailed structural schematic of the port controller of the power conversion system.

[0014] Figure 8 for Figure 7 The diagram shows a detailed structural diagram of the power coordinator of the port controller.

[0015] Figure 9 for Figure 1 The diagram shows the load loading sequence at the total output of the power conversion system.

[0016] Figure 10A for Figure 1 The power conversion system with Figure 9 The diagram shown illustrates the output power when the load is applied in sequence.

[0017] Figure 10B for Figure 1 The power conversion system with Figure 9 The sequence shown is a schematic diagram of the input power when the load is applied.

[0018] Figure 11A For traditional power conversion systems and Figure 1 The power conversion system with Figure 9 The diagram shows a comparison of the total AC current values ​​when the load is applied in the indicated order.

[0019] Figure 11B For traditional power conversion systems and Figure 1The power conversion system with Figure 9 The diagram shows a comparison of power factor values ​​when the load is applied in the indicated order.

[0020] Figure 11C For traditional power conversion systems and Figure 1 The rectifier unit of the power conversion system is Figure 9 The graph shows a comparison of efficiency when the load is applied in the order shown.

[0021] Figure 12 This is a schematic diagram of the circuit structure of the power conversion system according to the third embodiment of this disclosure.

[0022] Figure 13 for Figure 12 A schematic diagram of signal transmission for the port controller of a power conversion system.

[0023] Figure 14A for Figure 12 A schematic diagram of an embodiment of the input-side controller of the port controller of the power conversion system shown.

[0024] Figure 14B for Figure 12 A schematic diagram of another embodiment of the input-side controller of the port controller of the power conversion system shown.

[0025] Figure 15 for Figure 12 The diagram shows the operation of the output controller of the port controller of the power conversion system.

[0026] Figure 16 for Figure 12 The voltage signal waveforms at the input and total output terminals of the power converter in the power conversion system are shown.

[0027] Figure 17A for Figure 12 The diagram shows the current waveform at the total output of the power conversion system.

[0028] Figure 17B for Figure 12 The waveform diagram shows the phase shift angle of the voltage on the primary winding of the transformer in the power converter of the power conversion system shown.

[0029] Figure 17C for Figure 12 The waveform diagram shows the phase shift angle of the voltage on the second secondary winding of the transformer in the power converter of the power conversion system shown.

[0030] Figure 17D for Figure 12 The voltage waveform at the input terminal of the power converter in the power conversion system shown is a diagram.

[0031] Figure 17E for Figure 12 The voltage waveform at the total output terminal of the power converter in the power conversion system shown is illustrated.

[0032] Figure 17F for Figure 12 The waveform of the input AC current of the power conversion system is shown.

[0033] Figure 18 This is a power distribution diagram of the power converter in the power conversion system of the third embodiment of this disclosure.

[0034] Figure 19 This is a schematic diagram of the power distribution of the power converter in the power conversion system of the fourth embodiment of this disclosure.

[0035] Figure 20 This is a schematic diagram of the circuit structure of a power conversion system group consisting of multiple power conversion systems disclosed herein.

[0036] Figure 21 This is a schematic diagram of the circuit structure of the power conversion system according to the fifth embodiment of this disclosure.

[0037] Figure 22 This is a schematic diagram of the circuit structure of the power conversion system according to the sixth embodiment of this disclosure.

[0038] The reference numerals in the attached figures are explained as follows:

[0039] 1, 1a, 1b, 1c, 1d, 1e, 1f: Power conversion systems

[0040] P: AC power supply

[0041] 2: Rectifier Unit

[0042] 21: Input end

[0043] 22: Output terminal

[0044] 3: Power Converter

[0045] 31: Input end

[0046] 32: First output terminal

[0047] 33: Second output terminal

[0048] 34: First DC / DC conversion circuit

[0049] 341: Input terminal

[0050] 342: Output terminal

[0051] 35: Second DC / DC conversion circuit

[0052] 351: Input terminal

[0053] 352: Output terminal

[0054] 36: Inverter circuit

[0055] 37: Transformer

[0056] 371: Primary winding

[0057] 372: First secondary winding

[0058] 373: Second secondary winding

[0059] 4: Total Output Terminal

[0060] P o1 P o2 P o3 P o4 P o5 P o6 P o7 P o8 ... P oi ...P oN Output power

[0061] P A1 P A2 P A3 P A4 P A5 P A6 P A7 P A8 ... P Ai ... P AN DC power

[0062] P 11ref P 12ref P 21ref P 22ref P 31ref P 32ref P i1ref P i2ref P (i+1)1ref P (i+1)2ref ,

[0063] P N1ref P N2ref Input power reference quantity

[0064] x i Power error value

[0065] Average input power

[0066] V dc1 V dc2 V dciInput voltage

[0067] V o1ref V o2ref V oiref Voltage reference value

[0068] Average input voltage

[0069] V oi V o2 V oN Output voltage

[0070] Average output voltage

[0071] 5: Computation and Control Unit

[0072] 6: Port Controller

[0073] 61: First scale unit

[0074] 62: First Adder

[0075] 63: First Subtractor

[0076] 64: Second Adder

[0077] 65: Third Adder

[0078] 66: Second Subtractor

[0079] 67: Power Coordinator

[0080] 671: Integrating Unit

[0081] 672: Integral Limiting Unit

[0082] 673: Second Scale Unit

[0083] 674: The Fourth Adder

[0084] 675: Low-pass filter unit

[0085] 676: Circulation Limiting Unit

[0086] 68: Input-side controller

[0087] 681: Proportional-Integral Controller

[0088] 69: Output side controller

[0089] Phase shift angle of the voltage on the primary winding of the transformer Phase shift angle of the voltage on the second secondary winding of the transformer

[0090] PI: Proportional Integral

[0091] S A1 S A2 S AN The voltage on the primary winding of the transformer

[0092] S O1 S O2 S ON Voltage on the second secondary winding of the transformer

[0093] 71: Third output terminal

[0094] 72: Third DC / DC conversion circuit

[0095] 721: Input terminal

[0096] 722: Output terminal

[0097] 8: Switch

[0098] 9: Power Conversion System Group

[0099] P1: First power supply

[0100] P2: Second power supply

[0101] L: Load

[0102] Lin1: First input terminal

[0103] Lin2: Second input terminal

[0104] b: Battery Detailed Implementation

[0105] Some typical embodiments embodying the features and advantages of this disclosure will be described in detail in the following description. It should be understood that this disclosure can be varied in different implementations without departing from the scope of this disclosure, and the descriptions and illustrations therein are for illustrative purposes only and are not intended to limit this disclosure.

[0106] Please see Figure 1 and Figure 2 ,in Figure 1 This is a schematic diagram of the circuit structure of the power conversion system according to the first embodiment of this disclosure. Figure 2 for Figure 1 The diagram shows a detailed circuit structure of the power conversion system. As shown, the power conversion system 1 of this disclosure includes N rectifier units 2, N power converters 3, and N total output terminals 4. The power conversion system 1 outputs N output powers through the N total output terminals 4 to provide power to N loads (not shown), where each output power is used to provide power to a corresponding load. The i-th total output terminal 4 of the N total output terminals 4 outputs the i-th output power P.oi For the i-th load, for example, the first total output terminal 4 outputs the first output power P. o1 The first load is supplied, and the Nth total output terminal 4 outputs the Nth output power P. oN The load is supplied with N rectifier units 2. Each of the N rectifier units 2 includes an input terminal 21 and an output terminal 22. The input terminals 21 of the N rectifier units 2 are connected in series to the AC power supply P. Each rectifier unit 2 converts the AC power provided by the AC power supply P into DC power. The i-th rectifier unit 2 among the N rectifier units 2 outputs the i-th DC power P. Ai For example, the first rectifier unit in N rectifier units 2 outputs the first DC power P. A1 The Nth rectifier unit in N rectifier units 2 outputs the Nth DC power P. AN .

[0107] N power converters 3 correspond one-to-one with N rectifier units 2, meaning each power converter 3 is electrically connected to its corresponding rectifier unit 2, and each power converter 3 includes an input terminal 31, a first output terminal 32, and a second output terminal 33. The input terminal 31 of each power converter 3 is electrically connected to the output terminal 22 of its corresponding rectifier unit 2 to receive the DC power P output by the corresponding rectifier unit 2. Ai The first output terminal 32 of the first power converter 3 in the N power converters 3 is connected in parallel with the second output terminal 33 of the Nth power converter 3 in the N power converters 3 to form the Nth total output terminal 4 in the N total output terminals 4 and output the Nth total output power P. ON The first output terminal 32 of the i-th power converter 3 in the N power converters 3 is connected in parallel with the second output terminal 33 of the (i-1)-th power converter 3 in the N power converters 3 to form the (i-1)-th total output terminal 4 in the N total output terminals 4 and output the (i-1)-th total output power P. O(i-1) Where N>=i>=2, and i is an integer. For example, when i is 2, the first output terminal 32 of the second power converter 3 in the N power converters 3 is connected in parallel with the second output terminal 33 of the first power converter 3 in the N power converters 3 to form the first total output terminal 4 in the N total output terminals 4 and output the first total output power P. O1 .

[0108] In this embodiment, each power converter 3 includes a first DC / DC conversion circuit 34 and a second DC / DC conversion circuit 35. The first DC / DC conversion circuit 34 of each power converter 3 has an input terminal 341 and an output terminal 342, and the second DC / DC conversion circuit 35 of each power converter 3 has an input terminal 351 and an output terminal 352. The input terminal 341 of the first DC / DC conversion circuit 34 and the input terminal 351 of the second DC / DC conversion circuit 35 of each power converter 3 are connected in parallel to the input terminal 31 of the corresponding power converter 3. The input power of each power converter 3 (i.e., the DC power P output by the corresponding rectifier unit 2) is... Ai The input power is equal to the sum of the input power of the first DC / DC conversion circuit 34 and the input power of the second DC / DC conversion circuit 35. The output terminal 342 of the first DC / DC conversion circuit 34 of each power converter 3 is electrically connected to the first output terminal 32 of the corresponding power converter 3, and the output terminal 352 of the second DC / DC conversion circuit 35 of each power converter 3 is electrically connected to the second output terminal 33 of the corresponding power converter 3.

[0109] As can be seen from the above, the N power converters 3 of the power conversion system 1 disclosed herein have N total output terminals 4, which can provide electrical energy to N loads. Therefore, compared with the first type of traditional power conversion system which only has a single total output port, the power conversion system 1 disclosed herein can meet the requirements of multiple output ports, and can also make the power conversion system 1 have lower cost and higher charging efficiency. Furthermore, in the power conversion system 1 of this disclosure, the first output terminal 32 of the first power converter 3 among the N power converters 3 is connected in parallel with the second output terminal 33 of the Nth power converter 3, and the first output terminal 32 of the i-th power converter 3 among the N power converters 3 is connected in parallel with the second output terminal 33 of the (i-1)-th power converter 3 among the N power converters 3. Therefore, it can be seen that the power converters 3 of this disclosure are interconnected to form a ring structure. Thus, when the power demand of each total output terminal 4 of the power conversion system 1 is inconsistent, the input power of the input terminal 31 of each power converter 3 can be made consistent through power scheduling among the N power converters 3. Therefore, the power conversion system 1 of this disclosure can more easily meet the power factor requirements, resulting in higher efficiency and lower total loss of the power conversion system 1.

[0110] Please see Figure 3 and cooperate Figure 1 and Figure 2 ,in Figure 3 for Figure 1 The diagram shows the power distribution of the power converter in the power conversion system. As shown, the total output power P output from the i-th total output terminal 4 out of the N total output terminals 4 is...Oi It equals the output power of the second output terminal 33 of the i-th power converter 3 plus the output power of the first output terminal 32 of the (i+1)-th power converter 3, for example, the first total output power P output by the first total output terminal 4. O1 It equals the output power of the second output terminal 33 of the first power converter 3 plus the output power of the first output terminal 32 of the second power converter 3. The Nth total output power P output from the Nth total output terminal 4 is... ON It equals the output power of the second output terminal 33 of the Nth power converter 3 plus the output power of the first output terminal 32 of the first power converter 3. Therefore, the output power of the first output terminal 32 of the i-th power converter 3 out of the N power converters 3 is 1 / 2 of the (i-1)-th total output power P output by the (i-1)-th total output terminal 4. O(i-1) Subtracting the (i-1)th power error value, the output power of the second output terminal 33 of the i-th power converter 3 out of the N power converters 3 is 1 / 2 of the i-th total output power P output by the i-th total output terminal 4. Oi This is obtained by adding the i-th power error value. The output power of the first output terminal 32 of the first power converter 3 in the N power converters 3 is 1 / 2 of the N-th total output power P output by the N-th total output terminal 4. ON Subtracting the Nth power error value, the output power of the second output terminal 33 of the first power converter 3 out of the N power converters 3 is 1 / 2 of the first total output power P output by the first total output terminal 4. O1 The result is obtained by adding the first power error value.

[0111] In the above description, the first power error value to the Nth power error value are the decision variables to be solved. Once the solutions for the first power error value to the Nth power error value are obtained, the output power of the first output terminal 32 and the output power of the second output terminal 33 of each power converter 3 can be determined, so that the input power of the input terminal 31 of each power converter 3 becomes consistent. The following will explain how, under the condition that the input power of the input terminal 31 of each power converter 3 can be consistent, the optimization of the first power error value to the Nth power error value is performed by the following equations to minimize the circulating current power or the loss of the power conversion system 1. That is, the following equations will take minimizing the circulating current power of the power conversion system 1 as the objective function.

[0112] First, in order to minimize the power dispatch among the N power converters 3, i.e., minimize the circulating power, and reduce the loss of the power conversion system 1, the objective function can be expressed by the following equation (1).

[0113]

[0114] Where min is the minimum value, J is the objective function, and x1,…,x N Let be the circulating power to be solved (i.e., the first power error value, ..., the Nth power error value).

[0115] Next, in order to achieve a balance between the input power and the output power of each power converter 3, the input power of the input terminal 31 of each power converter 3 should be equal to the sum of the output power of the first output terminal 32 and the output power of the second output terminal 33, as shown in the following equation (2).

[0116] stP An =0.5P on +x n +0.5P o(n-1) -x n-1 , n = 1, 2, ..., N (2)

[0117] Where st is an abbreviation for subject to, which represents the constraint condition. When n = 1, 2, ..., N, it is substituted into P. An At that time, P A1 ,…,P AN Let P be the input power at input terminal 31 of each power converter 3. When n = 1, 2, ..., N, substitute it into P. on and P o(n-1) At that time, P o1 ,…,P oN This represents the total output power corresponding to each of the 4 output terminals. When n = 1, 2, ..., N, substitute x... n and x n-1 When, x1,…,x N Let be the circulating power to be solved (i.e., the first power error value, ..., the Nth power error value).

[0118] Next, in order to achieve a consistency constraint among the input power of the multiple power converters 3, the input power of each power converter 3 should be equal to the average value of the input power of the multiple power converters 3, as shown in the following equation (3).

[0119]

[0120] Where, when n = 1, 2, ..., N, substitute into P An At that time, P A1 ,…,P AN For the input power of the input terminal 31 of each power converter 3, It is the average value of the input power at the input terminal 31 of multiple power converters 3.

[0121] Furthermore, due to the rated power capacity of the power conversion system 1 itself, its power is limited. In order to make reasonable use of the power capacity of the power conversion system 1, in some embodiments, the power limit value of each power converter 3 is designed to be half of the total power capacity of the power conversion system 1. Therefore, the value of the circulating power to be solved (i.e., the first power error value, ..., the Nth power error value) should not be too large to avoid exceeding the power limit value of the power converter 3, as shown in the following equation (4).

[0122] |x n |≤P Limit -0.5P on n = 1, 2, ..., N (4)

[0123] Where, when n = 1, 2, ..., N, substitute x n When, x1,…,x N Let P be the circulating power to be solved (i.e., the first power error value, ..., the Nth power error value). Limit Let P be the power limit value of power converter 3, when n = 1, 2, ..., N. on At that time, P o1 ,…,P oN This represents the total output power corresponding to each of the 4 total output terminals.

[0124] By performing operations on equations (1) to (4) above, we can obtain the following equations (5) and (6) using analytical methods.

[0125]

[0126] x i =x i-1 -0.5(P oi +P o(i-1) ), i = 2, ..., N (6)

[0127] Where x1 is the first power error value, P oi Let P be the total output power of the i-th power. o(i+1) Let P be the total output power of the (i+1)th generation, where P is the power when i = N. o(i+1) For P o1 . Let x be the average of N total output powers. i Let x be the power error value of the i-th power. i-1 Let P be the power error value of the (i-1)th power. o(i-1) This represents the total output power of the (i-1)th generation.

[0128] From equations (5) and (6) above, the first power error value x1 can be derived first, and then the second power error value x2, ..., up to the Nth power error value x can be obtained sequentially. N .

[0129] Please see Figure 4 and cooperate Figure 1 and Figure 2 ,in Figure 4 for Figure 1 The diagram shows the operation of the operation control unit of the power conversion system. The power conversion system 1 also includes an operation control unit 5, which is electrically connected to the total output terminal 4 of each power converter 3 to receive the N total output power P output from the N power converters 3. o1 ,…,P oN The signal, wherein the operation control unit 5 may be, but is not limited to, a centralized controller. Furthermore, the operation control unit 5 performs further calculations based on the above equations (5) and (6) to obtain the first power error value x1, the second power error value x2, ..., up to the Nth power error value x. N And based on the first power error value x1, the second power error value x2, ..., up to the Nth power error value x1, respectively. N Calculate the input power reference values ​​for the first DC / DC conversion circuit 34 and the second DC / DC conversion circuit 35 of each power converter 3, wherein the input power reference value for the first DC / DC conversion circuit 34 of each power converter 3 is P. n1ref =0.5P o(n-1) -x n Where 1 <= n <= N, and when n = 1, P o(n-1) =P o0 And P o0 Then it represents P oN The input power reference value of the second DC / DC conversion circuit 35 of each power converter 3 is P. n2ref =0.5P on +x n For example, the input power reference of the first DC / DC conversion circuit 34 of the first power converter 3 in a plurality of power converters 3 is P. 11ref =0.5P oN -x1, the input power reference of the second DC / DC conversion circuit 35 of the first power converter 3 in the plurality of power converters 3 is P 12ref =0.5P o1+x1. The output power of the first power converter 3 of each power converter 3 is controlled according to the input power reference of the first power converter 3, and the output power of the second DC / DC conversion circuit 35 of each power converter 3 is controlled according to the input power reference of the second DC / DC conversion circuit 35, so that the input power of the input terminal 31 of each power converter 3 is consistent, and the circulating current power or loss of the power conversion system 1 can be minimized.

[0130] However, in some embodiments, due to the inherent power limit of the power conversion system 1, when the output power imbalance at the total output terminal 4 of multiple power converters 3 is severe, the input power at the input terminals 31 of multiple power converters 3 cannot be completely consistent. Therefore, it is only possible to drive the input power at the input terminals 31 of multiple power converters 3 to tend to be consistent. Thus, the above equation (3) is no longer the constraint condition for optimizing the first power error value to the Nth power error value, and equation (1) needs to be further rewritten as equation (7).

[0131]

[0132] Where min is the minimum value, J is the objective function, and x1,…,x N Let P be the circulating power to be solved (i.e., the first power error value, ..., the Nth power error value), and ρ be the weighting coefficient. The weighting coefficient ρ is set by the operation control unit 5 according to the circuit characteristics of the power conversion system 1. A larger value of the weighting coefficient ρ indicates that it is closer to the target of input power consistency. When n = 1, 2, ..., N, substitute P... AN At that time, P A1 ,…,P AN This refers to the input power at the input terminal 31 of each power converter 3. It is the average value of the input power at the input terminal 31 of multiple power converters 3.

[0133] By performing operations on equations (1), (2), and (7), the following equation (8) can be obtained using analytical methods.

[0134] x = A -1 B

[0135]

[0136] Where x = [x1, x2, ..., x] i , ..., x N ] T x i Let P be the i-th power error value, ρ be the weighting coefficient, and the weighting coefficient is set by the operation control unit 5 according to the circuit characteristics of the power conversion system 1. oiLet A be the total output power of the i-th power. Substituting A and B into x = A -1 From b, x can be calculated.

[0137] The operation control unit 5 can further calculate according to the above equation (8) to obtain the first power error value x1, the second power error value x2, ..., up to the Nth power error value x. N And based on the first power error value x1, the second power error value x2, ..., up to the Nth power error value x1, respectively. N The output power of the first output terminal 32 and the second output terminal 33 of the N power converters 3 are controlled so that the input power of the input terminal 31 of each power converter 3 is as consistent as possible, and the circulating current power or loss of the power conversion system 1 is reduced.

[0138] In some embodiments, the operation and control unit 5 further confirms the first power error value x1, the second power error value x2, ..., up to the Nth power error value x. N Whether the following equation (4) is satisfied, and the operation control unit 5 further controls the first power error value x1, the second power error value x2, ..., up to the Nth power error value x based on the confirmation result of equation (4). N

[0139] |x n |≤P Limit -0.5P on n = 1, 2, ..., N (4)

[0140] That is, confirm the first power error value x1, the second power error value x2, ..., or the Nth power error value x N Whether the error exceeds an upper limit or falls below a lower limit, where the upper limit is P. Limit -0.5P on The lower limit of error is -(P) Limit -0.5P on When the first power error value x1, the second power error value x2, ..., or the Nth power error value x N When the error exceeds the upper limit value, the operation control unit 5 controls the power error value corresponding to the error exceeding the upper limit value to be the upper limit value. When the first power error value x1, the second power error value x2, ..., or the Nth power error value x N When the error is below the lower limit, the operation control unit 5 controls the power error value corresponding to the lower limit to be the lower limit.

[0141] Please see Figure 5 and Figure 6 ,in Figure 5 This is a schematic diagram of the circuit structure of the power conversion system according to the second embodiment of this disclosure. Figure 6 for Figure 5 The diagram shows the signal transmission of the port controller in the power conversion system. As shown, the power conversion system 1a in this embodiment is similar to... Figure 1 The power conversion system 1 shown differs only in that the power conversion system 1a in this embodiment does not have an operation control unit, but has N port controllers 6. Each port controller 6 is electrically connected to the total output terminal 4 of the corresponding power converter 3 to receive the total output power output by the total output terminal 4 of the corresponding power converter 3. The first port controller 6 of the N port controllers 6 is electrically connected to the Nth port controller 6 and the second port controller 6, and the i-th port controller 6 of the N port controllers 6 is electrically connected to the (i-1)-th port controller 6 and the (i+1)-th port controller 6. For example, the second port controller 6 is electrically connected to the first port controller 6 and the third port controller 6, and each port controller 6 receives the input power reference quantity output by the connected port controller 6.

[0142] The first port controller 6 among the N port controllers 6 receives the first total output power P output from the first total output terminal 4 of the first power converter. O1 The input power reference quantity P of the first DC / DC conversion circuit 34 of the first power converter 3 output by the Nth port controller 6. 11ref and the input power reference P of the second DC / DC conversion circuit 35 of the second power converter 3 output by the second port controller 6. 22ref Furthermore, the first port controller 6 of the N port controllers 6 outputs the input power reference value P of the second DC / DC conversion circuit 34 of the first power converter 3. 12ref and the input power reference P of the first DC / DC conversion circuit 34 of the second power converter 3 21ref The i-th port controller 6 of the N port controllers 6 receives the i-th total output power P output from the i-th total output terminal 4 of the i-th power converter. Oi The input power reference P of the first DC / DC conversion circuit 34 of the i-th power converter 3 output by the (i-1)-th port controller 6. i1ref The input power reference P of the second DC / DC conversion circuit 35 of the (i+1)th power converter 3 output by the (i+1)th port controller 6. (i+1)2ref Furthermore, the i-th port controller 6 of the N port controllers 6 outputs the input power reference value P of the second DC / DC conversion circuit 34 of the i-th power converter 3. i2ref The input power reference P of the first DC / DC conversion circuit 34 of the (i+1)th power converter 3 (i+1)1refThe Nth port controller 6 of the Nth port controller 6 receives the Nth total output power P output from the Nth total output terminal 4 of the Nth power converter. ON The input power reference P of the first DC / DC conversion circuit 34 of the Nth power converter 3 output by the (N-1)th port controller 6. N1ref and the input power reference P of the second DC / DC conversion circuit 35 of the first power converter 3 output by the first port controller 6. 12ref Furthermore, the Nth port controller 6 outputs the input power reference P of the second DC / DC conversion circuit 34 of the Nth power converter 3. N2ref and the input power reference P of the first DC / DC conversion circuit 34 of the first power converter 3 11ref It should be noted that i <= (N-1) in the above description. As can be seen from the above description, the N port controllers 6 obtain the input power reference of the corresponding power converter through mutual communication. Each port controller 6 further corrects the output power of the corresponding power converter through an iterative method based on the received input power reference, so that the input power of the input terminal 31 of each power converter 3 is as consistent as possible, and the circulating current power or loss of the power conversion system 1 is reduced.

[0143] Please see Figure 7 and cooperate Figure 5 and Figure 6 ,in Figure 7 for Figure 5 The diagram shows a detailed structural schematic of the port controller of the power conversion system. Figure 7 Taking only one of the N port controllers 6 as an example, it is clear that the circuit structure of the other port controllers 6 is also the same. Figure 7 The port controller 6 shown is as follows. As shown, each port controller 6 includes a first proportional unit 61, a first adder 62, a first subtractor 63, a second adder 64, a third adder 65, a second subtractor 66, and a power coordinator 67.

[0144] The first proportional unit 61 of the first port controller 6 is electrically connected to the first total output terminal 4 to receive the first total output power P output from the first total output terminal 4. O1 and the first total output power P O1 Multiplying by 0.5 yields a first intermediate variable. The first adder 62 of the first port controller 6 is electrically connected to the first proportional unit 61 and the Nth port controller 6 to receive the first intermediate variable and the first power error value X1. The first intermediate variable and the first power error value X1 are added together to obtain the input power reference value P of the second DC / DC conversion circuit 35 of the first power converter 3.12ref The output is sent to the Nth port controller 6. The first subtractor 63 of the first port controller 6 is electrically connected to the first proportional unit 61 and the second port controller 6 to receive the first intermediate variable and the first power error value X1, and subtract the first intermediate variable and the first power error value X1 to obtain the input power reference quantity P of the first DC / DC conversion circuit 34 of the second power converter 3. 21ref The output is sent to the second port controller 6. The second adder 64 of the first port controller 6 is electrically connected to the first adder 62 and the Nth port controller 6 to receive the input power reference quantity P of the second DC / DC conversion circuit 35 of the first power converter 3 output by the first adder 62. 12ref The input power reference quantity P of the first DC / DC conversion circuit 34 of the first power converter 3 output by the Nth port controller 6. 11ref And the input power reference P of the second DC / DC conversion circuit 35 of the first power converter 3 output by the first adder 62 is... 12ref The input power reference quantity P of the first DC / DC conversion circuit 34 of the first power converter 3 output by the Nth port controller 6. 11ref The two components are added together to obtain the input power at the input terminal 31 of the first power converter 3 (i.e., the first DC power P output by the rectifier unit 2). A1 The third adder 65 of the first port controller 6 in the N port controllers 6 is electrically connected to the first subtractor 63 and the second port controller 6 in the N port controllers 6, so as to receive the input power reference quantity P of the first DC / DC conversion circuit 34 of the second power converter 3 output by the first subtractor 63. 21ref and the input power reference P of the second DC / DC conversion circuit 35 of the second power converter 3 output by the second port controller 6. 22ref And the input power reference P of the first DC / DC conversion circuit 34 of the second power converter 3 output by the first subtractor 63 is... 21ref and the input power reference P of the second DC / DC conversion circuit 35 of the second power converter 3 output by the second port controller 6. 22ref The two are added together to obtain the input power at the input terminal 31 of the second power converter 3 (i.e., the second DC power P output by the rectifier unit 2). A2 The second subtractor 66 of the first port controller 6 in the N port controllers 6 is electrically connected to the second adder 64 and the third adder 65 to receive the input power P from the input terminal 31 of the first power converter 3 output by the second adder 64. A1 and the input power P at the input terminal 31 of the second power converter 3 output by the third adder 65 A2And the input power P of the first power converter 31 output by the second adder 64 is... A1 and the input power P at the input terminal 31 of the second power converter 3 output by the third adder 65 A2 Subtracting the two values ​​yields the first power variable. The power coordinator 67 of the first port controller 6 among the N port controllers 6 is electrically connected to the second subtractor 66, the first adder 62, and the first subtractor 63 to receive the first power variable output by the second subtractor 66 and output the first power error value X1 to the first adder 62 and the first subtractor 63.

[0145] The first proportional unit 61 of the i-th port controller 6 in the N port controllers 6 is electrically connected to the i-th total output terminal 4 to receive the i-th total output power P output from the i-th total output terminal 4. Oi And the total output power P of the i-th generation Oi Multiplying by 0.5 yields the i-th intermediate variable. The first adder 62 of the i-th port controller 6 among the N port controllers 6 is electrically connected to the first proportional unit 61 and the (i-1)-th port controller 6 among the N port controllers 6, to receive the i-th intermediate variable and the i-th power error value X. i And the i-th intermediate variable and the i-th power error value X i After addition, the input power reference value P of the second DC / DC conversion circuit 35 of the i-th power converter 3 is obtained. i2ref The output is sent to the (i-1)th port controller 6. The first subtractor 63 of the i-th port controller 6 among the N port controllers 6 is electrically connected to the first proportional unit 61 and the (i+1)-th port controller 6 among the N port controllers 6 to receive the i-th intermediate variable and the i-th power error value X. i And the i-th intermediate variable and the i-th power error value X i After subtraction, the input power reference value P of the first DC / DC conversion circuit 34 of the (i+1)th power converter 3 is obtained. (i+1)1ref The output is sent to the (i+1)th port controller 6. The second adder 64 of the i-th port controller 6 among the N port controllers 6 is electrically connected to the first adder 62 and the (i-1)-th port controller 6 among the N port controllers 6, so as to receive the input power reference quantity P of the second DC / DC conversion circuit 35 of the i-th power converter 3 output by the first adder 62. i2ref The input power reference quantity P of the first DC / DC conversion circuit 34 of the i-th power converter 3 output by the (i-1)-th port controller 6. i1ref And the input power reference P of the second DC / DC conversion circuit 35 of the i-th power converter 3 output by the first adder 62 is... i2refThe input power reference quantity P of the first DC / DC conversion circuit 34 of the i-th power converter 3 output by the (i-1)-th port controller 6. i1ref The input power P at the input terminal 31 of the i-th power converter 3 is obtained by adding the two components. Ai The third adder 65 of the i-th port controller 6 in the N port controllers 6 is electrically connected to the first subtractor 63 and the (i+1)-th port controller 6 in the N port controllers 6, so as to receive the input power reference P of the first DC / DC conversion circuit 34 of the (i+1)-th power converter 3 output by the first subtractor 63. (i+1)1ref The input power reference P of the second DC / DC conversion circuit 35 of the (i+1)th power converter 3 output by the (i+1)th port controller 6. (i+1)2ref And the input power reference P of the first DC / DC conversion circuit 34 of the (i+1)th power converter 3 output by the first subtractor 63 is... (i+1)1ref The input power reference P of the second DC / DC conversion circuit 35 of the (i+1)th power converter 3 output by the (i+1)th port controller 6. (i+1)2ref The input power P at the input terminal 31 of the (i+1)th power converter 3 is obtained by adding the two values. A(i+1) The second subtractor 66 of the i-th port controller 6 in the N port controllers 6 is electrically connected to the second adder 64 and the third adder 65 to receive the input power P of the i-th power converter 3 at the input terminal 31 of the second adder 64. Ai and the input power P of the (i+1)th power converter 3 output by the third adder 65 at input terminal 31 A(i+1) And the input power P of the i-th power converter 31 output by the second adder 64 is converted into the input power P of the i-th power converter 3. Ai and the input power P of the (i+1)th power converter 3 output by the third adder 65 at input terminal 31 A(i+1) Subtracting the values ​​yields the i-th power variable. The power coordinator 67 of the i-th port controller 6 in the N port controllers 6 is electrically connected to the second subtractor 66, the first adder 62, and the first subtractor 63 to receive the i-th power variable output by the second subtractor 66 and output the i-th power error value X. i To the first adder 62 and the first subtractor 63.

[0146] The first proportional unit 61 of the Nth port controller 6 is electrically connected to the Nth total output terminal 4 to receive the Nth total output power P output from the Nth total output terminal 4. ON And the Nth total output power P ONMultiplying by 0.5 yields the Nth intermediate variable. The first adder 62 of the Nth port controller 6 is electrically connected to the first proportional unit 61 and the (N-1)th port controller 6 of the N port controllers 6 to receive the Nth intermediate variable and the Nth power error value X. N And the Nth intermediate variable and the Nth power error value X N After addition, the input power reference value P of the second DC / DC conversion circuit 35 of the Nth power converter 3 is obtained. N2ref The output is sent to the (N-1)th port controller 6. The first subtractor 63 of the Nth port controller 6 is electrically connected to the first proportional unit 61 and the first port controller 6 of the N port controllers 6 to receive the Nth intermediate variable and the Nth power error value X. N And the Nth intermediate variable and the Nth power error value X N After subtraction, the input power reference value P of the first DC / DC conversion circuit 34 of the first power converter 3 is obtained. 11ref The output is sent to the first port controller 6. The second adder 64 of the Nth port controller 6 is electrically connected to the first adder 62 and the (N-1)th port controller 6 of the N port controllers 6 to receive the input power reference quantity P of the second DC / DC conversion circuit 35 of the Nth power converter 3 output by the first adder 62. N2ref The input power reference quantity P of the first DC / DC conversion circuit 34 of the Nth power converter 3 output by the (N-1)th port controller 6. N1ref And the input power reference P of the second DC / DC conversion circuit 35 of the Nth power converter 3 output by the first adder 62 is... N2ref The input power reference quantity P of the first DC / DC conversion circuit 34 of the Nth power converter 3 output by the (N-1)th port controller 6. N1ref The inputs are added together to obtain the input power P at the input terminal 31 of the Nth power converter 3. AN (i.e., the Nth DC power P output by rectifier unit 2) AN The third adder 65 of the Nth port controller 6 is electrically connected to the first subtractor 63 and the first port controller 6 of the N port controllers 6 to receive the input power reference quantity P of the first DC / DC conversion circuit 34 of the first power converter 3 output by the first subtractor 63. 11ref and the input power reference P of the second DC / DC conversion circuit 35 of the first power converter 3 output by the first port controller 6. 12ref And the input power reference P of the first DC / DC conversion circuit 34 of the first power converter 3 output by the first subtractor 63 is...11ref and the input power reference P of the second DC / DC conversion circuit 35 of the first power converter 3 output by the first port controller 6. 12ref The input power P at the input terminal 31 of the first power converter 3 is obtained by adding them together. A1 The second subtractor 66 of the Nth port controller 6 is electrically connected to the second adder 64 and the third adder 65 to receive the input power P from the input terminal 31 of the Nth power converter 3 output by the second adder 64. AN and the input power P at the input terminal 31 of the first power converter 3 output by the third adder 65 A1 And the input power P of the Nth power converter 31 output from the second adder 64 is converted into the input power P of the second adder 64. AN and the input power P at the input terminal 31 of the first power converter 3 output by the third adder 65 A1 Subtracting the two values ​​yields the Nth power variable. The power coordinator 67 of the Nth port controller 6 is electrically connected to the second subtractor 66, the first adder 62, and the first subtractor 63 to receive the Nth power variable output by the second subtractor 66 and output the Nth power error value X. N To the first adder 62 and the first subtractor 63.

[0147] Please see Figure 8 and cooperate Figures 5 to 7 ,in Figure 8 for Figure 7The diagram shows a detailed structural diagram of the power coordinator of the port controller. As shown, the power coordinator 67 of the port controller 6 further includes an integrator unit 671, an integrator limiting unit 672, a second proportional unit 673, a fourth adder 674, a low-pass filter unit 675, and a circulating current limiting unit 676. The integrator unit 671 of the first port controller 6 out of the N port controllers 6 is connected to the second subtractor 66 to receive the first power variable output by the second subtractor 66. The integrator limiting unit 672 of the first port controller 6 out of the N port controllers 6 is connected to the integrator unit 671, and the first power variable passes through the integrator unit 671 and the integrator limiting unit 672 of the first port controller 6 sequentially to obtain a first transition variable. The second proportional unit 673 of the first port controller 6 out of the N port controllers 6 is connected to the second subtractor 66 to receive the first power variable output by the second subtractor 66, and the first power variable passes through the second proportional unit 673 of the first port controller 6 to obtain a second transition variable. The fourth adder 674 of the first port controller 6 in the N-port controller 6 is connected to the integral limiting unit 672 and the second proportional unit 673 to receive the first transition variable output by the integral limiting unit 672 and the second transition variable output by the second proportional unit 673, and adds the first transition variable output by the integral limiting unit 672 and the second transition variable output by the second proportional unit 673 to obtain the third transition variable. The low-pass filter unit 675 of the first port controller 6 in the N-port controller 6 is connected to the fourth adder 674 to receive the third transition variable output by the fourth adder 674. The circulating current limiting unit 676 of the first port controller 6 in the N-port controller 6 is connected between the low-pass filter unit 675 and the first adder 62, and is also connected between the low-pass filter unit 675 and the first subtractor 63. The third transition variable passes through the low-pass filter unit 675 and the circulating current limiting unit 676 in sequence to obtain the first power error value X1.

[0148] The integrator unit 671 of the i-th port controller 6 in the N-port controller 6 is connected to the second subtractor 66 to receive the i-th power variable output by the second subtractor 66. The integrator-limiting unit 672 of the i-th port controller 6 in the N-port controller 6 is connected to the integrator unit 671, and the i-th power variable passes through the integrator unit 671 and the integrator-limiting unit 672 of the i-th port controller 6 in sequence to obtain the first transition variable. The second proportional unit 673 of the i-th port controller 6 in the N-port controller 6 is connected to the second subtractor 66 to receive the i-th power variable output by the second subtractor 66, and the i-th power variable passes through the second proportional unit 673 of the i-th port controller 6 to obtain the second transition variable. The fourth adder 674 of the i-th port controller 6 in the N-port controller 6 is connected to the integral limiting unit 672 and the second proportional unit 673 to receive the first transition variable output by the integral limiting unit 672 and the second transition variable output by the second proportional unit 673, and adds the first transition variable output by the integral limiting unit 672 and the second transition variable output by the second proportional unit 673 to obtain the third transition variable. The low-pass filter unit 675 of the i-th port controller 6 in the N-port controller 6 is connected to the fourth adder 674 to receive the third transition variable output by the fourth adder 674. The circulating current limiting unit 676 of the i-th port controller 6 in the N-port controller 6 is connected between the low-pass filter unit 675 and the first adder 62, and between the low-pass filter unit 675 and the first subtractor 63. The third transition variable passes sequentially through the low-pass filter unit 675 and the circulating current limiting unit 676 to obtain the i-th power error value X. i .

[0149] The integrator unit 671 of the Nth port controller 6 is connected to the second subtractor 66 to receive the Nth power variable output by the second subtractor 66. The integrator limiting unit 672 of the Nth port controller 6 is connected to the integrator unit 671, and the Nth power variable passes through the integrator unit 671 and the integrator limiting unit 672 of the Nth port controller 6 sequentially to obtain the first transition variable. The second proportional unit 673 of the Nth port controller 6 is connected to the second subtractor 66 to receive the Nth power variable output by the second subtractor 66, and the Nth power variable passes through the second proportional unit 673 of the Nth port controller 6 to obtain the second transition variable. The fourth adder 674 of the Nth port controller 6 in the N-port controller 6 is connected to the integral limiting unit 672 and the second proportional unit 673 to receive the first transition variable output by the integral limiting unit 672 and the second transition variable output by the second proportional unit 673, and adds the first transition variable output by the integral limiting unit 672 and the second transition variable output by the second proportional unit 673 to obtain the third transition variable. The low-pass filter unit 675 of the Nth port controller 6 in the N-port controller 6 is connected to the fourth adder 674 to receive the third transition variable output by the fourth adder 674. The circulating current limiting unit 676 of the Nth port controller 6 in the N-port controller 6 is connected between the low-pass filter unit 675 and the first adder 62, and is also connected between the low-pass filter unit 675 and the first subtractor 63. The third transition variable passes sequentially through the low-pass filter unit 675 and the circulating current limiting unit 676 to obtain the Nth power error value X. N .

[0150] In some embodiments, only a portion of the N total output terminals 4 of the power conversion system 1 of this disclosure are connected to the corresponding loads. For example, only M of the N total output terminals 4 are connected to the corresponding M loads. To reduce the pressure on power distribution among the N power converters 3 of the power conversion system 1, the M loads should be evenly distributed and connected to the M total output terminals 4 respectively, and the power conversion system 1 should load the M loads in a certain order. Please refer to [link to relevant documentation]. Figure 9 and cooperate Figure 1 ,in Figure 9 for Figure 1 The diagram shows the load loading sequence of the total output terminals of the power conversion system. The power conversion system 1 of this disclosure is used to load M loads. When M <= (N / 2), the M non-adjacent total output terminals 4 of the N total output terminals 4 are connected to the M loads respectively. For example, if the power conversion system 1 has eight total output terminals 4, but only four loads need to be connected, then the first load among the four loads can be connected to the first total output terminal 4 of the eight total output terminals 4 to receive the first output power P.o1 The second of the four loads can be connected to the fifth total output terminal 4 out of the eight total output terminals 4 to receive the fifth output power P. o5 The third of the four loads can be connected to the seventh total output terminal 4 out of the eight total output terminals 4 to receive the seventh output power P. o7 The fourth load out of the four loads can be connected to the third total output terminal 4 out of the eight total output terminals 4 to receive the third output power P. o3 Of course, the above connection method is not limited to this. In some embodiments, when M>(N / 2), M of the N total output terminals 4 are connected to M loads respectively. At most one other total output terminal 4 separates two adjacent total output terminals 4 from the M total output terminals 4. That is, at most one unloaded total output terminal 4 separates two consecutively loaded total output terminals 4 from the M total output terminals 4. It is also possible that no unloaded total output terminal 4 separates two consecutively loaded total output terminals 4 from the M total output terminals 4. For example, when the power conversion system 1 has eight total output terminals 4 and needs to be connected to five loads, the first load among the five loads can be connected to the first total output terminal 4 among the eight total output terminals 4 to receive the first output power P. o1 The second of the five loads can be connected to the fifth total output terminal 4 out of the eight total output terminals 4 to receive the fifth output power P. o5 The third of the five loads can be connected to the seventh total output terminal 4 out of the eight total output terminals 4 to receive the seventh output power P. o7 The fourth of the five loads can be connected to the third total output terminal 4 out of the eight total output terminals 4 to receive the third output power P. o3 The fifth of the five loads can be connected to the second total output terminal 4 of the eight total output terminals 4 to receive the second output power P. o2 In some embodiments, when the power conversion system 1 has eight total output terminals 4 and needs to be connected to eight loads, the first load among the eight loads can be connected to the first total output terminal 4 among the eight total output terminals 4 to receive the first output power P. o1 The second of the eight loads can be connected to the fifth total output terminal 4 of the eight total output terminals 4 to receive the fifth output power P. o5 The third of the eight loads can be connected to the seventh total output terminal 4 of the eight total output terminals 4 to receive the seventh output power P. o7 The fourth load among the eight loads can be connected to the third total output terminal 4 among the eight total output terminals 4 to receive the third output power P. o3 The fifth of the eight loads can be connected to the second total output terminal 4 of the eight total output terminals 4 to receive the second output power P.o2 The sixth load out of the eight loads can be connected to the sixth total output terminal 4 out of the eight total output terminals 4 to receive the sixth output power P. o6 The seventh load out of the eight loads can be connected to the fourth total output terminal 4 out of the eight total output terminals 4 to receive the fourth output power P. o4 The eighth load out of the eight loads can be connected to the eighth total output terminal 4 out of the eight total output terminals 4 to receive the eighth output power P. o8 Of course, the loading order mentioned above is not limited to this.

[0151] Please see Figure 10A and Figure 10B ,in Figure 10A for Figure 1 The power conversion system with Figure 9 The diagram shows the output power when the load is applied in the specified order. Figure 10B for Figure 1 The power conversion system with Figure 9 The diagram illustrates the input power when the load is applied in the indicated sequence. Figure 10A It can be seen that when the power conversion system 1 is loaded with the first load, the first total output power P, which is 1, is output from the first total output terminal 4. O1 When the power conversion system 1 is loaded with a second load, the fifth total output power P, which is 1, is output from the fifth total output terminal 4. O5 And so on. Figure 10A In the above, the load value is within the range [0,1]. Only the first load is increased from no load to full load. After being increased to full load, the first load remains at full load. Within this range, the first total output power P O1 Gradually increase, while the total output power remains zero; load numbers are in the range [1, 2], the second load is added from no load to full load; and so on. Figure 10B The input power after processing by the power conversion system 1 of this invention, when the load value is in the interval [0,2], the eight input power values ​​completely overlap, indicating that the input power is consistent; when the load value is in the interval [2,4], only some input power values ​​overlap; when the load value is in the interval [4,8], only some input power values ​​overlap; but compared to Figure 10A The output power and input power shown have good consistency. And from... Figure 10B Therefore, it can be seen that the power conversion system 1 disclosed herein uses a sequential loading order to load M loads, which can make the input power of the N power converters 3 the same or closer.

[0152] Please see Figure 11A , Figure 11B and Figure 11C ,in Figure 11A For traditional power conversion systems and Figure 1 The power conversion system with Figure 9 A comparison chart of total AC current values ​​when the load is applied in the indicated order. Figure 11B For traditional power conversion systems and Figure 1 The power conversion system with Figure 9 The graph shows a comparison of power factor values ​​when the load is applied in the indicated order. Figure 11C For traditional power conversion systems and Figure 1 The rectifier unit of the power conversion system is Figure 9 The efficiency comparison diagram shows the order in which the load is applied. Because the multiple power converters in the second type of conventional power conversion system have completely independent outputs, therefore... Figure 11A , 11B In 11C, the second type of conventional power conversion system is designated as completely independent. Since the power conversion system 1 of this disclosure is a multi-output port system, and the power converters 3 of the power conversion system 1 are arranged in a ring structure, therefore... Figure 11A , 11B In 11C, the power conversion system of this disclosure is a ring multiport. Figure 11A , 11B As can be seen from 11C, the total AC current of the power conversion system 1 disclosed herein is easier to balance and has a higher power factor than the total AC current of a conventional power conversion system. Furthermore, the rectifier unit of the power conversion system 1 disclosed herein has better efficiency, which also means that the reactive current injected to achieve balance in the power conversion system 1 disclosed herein is smaller.

[0153] Please see Figure 12 This is a schematic diagram of the circuit structure of the power conversion system according to the third embodiment of this disclosure. As shown in the figure, the power conversion system 1b of this embodiment is similar to... Figure 5 The power conversion system 1a shown differs only in that each power converter 3 in the power conversion system 1b of this embodiment includes an inverter circuit 36 ​​and a transformer 37. One end of the inverter circuit 36 ​​is connected to the input terminal 31 of the power converter 3. The transformer 37 includes a primary winding 371, a first secondary winding 372, and a second secondary winding 373. The primary winding 371 is coupled to the first secondary winding 372 and the second secondary winding 373. The primary winding 371 is connected to the other end of the inverter circuit 36, the first secondary winding 372 is connected to the first output terminal 32 of the power converter 3, and the second secondary winding 373 is connected to the second output terminal 33 of the power converter 3. In this embodiment, each power converter 3 of the power conversion system 1b may employ an isolated circuit such as a dual active bridge (DAB) or a resonant circuit (LLC).

[0154] Since the transformers 37 of each power converter 3 in the power conversion system 1b of the third embodiment are interconnected—for example, the second secondary winding 373 of the transformer 37 of the i-th power converter 3 is connected to the first secondary winding 372 of the transformer 37 of the (i+1)-th power converter 3, and the second secondary winding 373 of the transformer 37 of the N-th power converter 3 is connected to the first secondary winding 372 of the transformer 37 of the first power converter 3—the transformers 37 of each power converter 3 must operate at the same switching frequency. Please refer to [link to relevant documentation]. Figure 13 and cooperate Figure 12 ,in Figure 13 for Figure 12 The diagram illustrates the signal transmission of the port controllers in the power conversion system. As shown, each total output terminal 4 corresponds to a port controller 6, and each port controller 6 includes an input-side controller 68 and an output-side controller 69. The input-side controller 68 controls the phase shift angle of the primary voltage signal of the transformer 37, ensuring that the input power at the input terminal 31 of each power converter 3 is consistent. The output-side controller 69 controls the phase shift angle of the secondary voltage signal of the transformer 37 to control the output voltage of the total output terminal 4.

[0155] The following will further explain how the power conversion system obtains the phase shift angle of the voltage on the primary winding 371 and the phase shift angle of the voltage on the second secondary winding 373 of the transformer 37 in each power converter 3. In this embodiment, the i-th port controller 6 of the N port controllers 6 of the power conversion system 1b is connected to the i-th total output terminal 4 and the input terminal 31 of the i-th power converter 3, and receives the i-th output voltage V provided by the i-th total output terminal 4. oi The i-th output power P oi and the voltage reference value V at the i-th total output terminal 4 oiref And receives the i-th input voltage V provided by the input terminal 31 of the i-th power converter 3. dci and input power P Ai In this embodiment, the N port controllers 6 are interconnected to obtain the input power P acquired by all port controllers 6 through communication coordination. Ai This allows each port controller 6 to calculate the average input power of the N port controllers 6. Furthermore, the N port controllers 6 can also coordinate through communication to obtain the input voltage V obtained by all port controllers 6. dci This allows each port controller 6 to calculate the average input voltage of the N port controllers 6. Furthermore, the N port controllers 6 can also coordinate through communication to obtain the output voltage V obtained by all port controllers 6. oiThis allows each port controller 6 to calculate the average output voltage of the N port controllers 6.

[0156] Please see Figure 14A and cooperate Figure 12 and Figure 13 ,in Figure 14A for Figure 12 This is a schematic diagram illustrating the operation of an embodiment of the input-side controller of the port controller in the power conversion system shown. As shown, the input-side controller 68 calculates the input power based on the obtained average input power. and the corresponding input power P Ai After subtraction, the proportional-integral controller 681 generates the proportional-integral property, which in turn yields the phase shift angle of the voltage on the primary winding 371 of the transformer 37 in the power converter 3. The phase shift angle of the voltage on the primary winding 371 of transformer 37 in power converter 3. The equation is as follows

[0157] and

[0158]

[0159] in, This is the phase shift angle of the voltage on the primary winding 371 of transformer 37 in the first power converter 3. Let be the phase shift angle of the voltage on the primary winding 371 of the transformer 37 in the i-th power converter 3, and PI be the proportional-integral ratio generated by the power conversion system 1 according to the circuit characteristics. P is the average value of the input power of N power converters 3. A1 For the input power of the first power converter 3 at input terminal 31, P Ai This is the input power of the input terminal 31 of the i-th power converter 3.

[0160] In some embodiments, the input-side controller 68 may also obtain the phase shift angle of the voltage on the primary winding 371 of the transformer 37 based on the input terminal voltage. Please see Figure 14B and cooperate Figure 12 and Figure 13 ,in Figure 14B for Figure 12 This is a schematic diagram of another embodiment of the input-side controller of the port controller of the power conversion system shown. As shown, the input-side controller 68 can also be based on the obtained average input voltage. and the corresponding input voltage V dciAfter subtraction, the proportional-integral controller 681 generates the proportional-integral property, which in turn yields the phase shift angle of the voltage on the primary winding 371 of the transformer 37 in the power converter 3. The phase shift angle of the voltage on the primary winding 371 of transformer 37 in power converter 3. The equation is as follows:

[0161] and

[0162]

[0163] in, This is the phase shift angle of the voltage on the primary winding 371 of transformer 37 in the first power converter 3. Let be the phase shift angle of the voltage on the primary winding 371 of the transformer 37 in the i-th power converter 3, and PI be the proportional-integral ratio generated by the power conversion system 1 according to the circuit characteristics. V is the average value of the voltage at the input terminals 31 of the N power converters 3. dc1 V is the voltage at input terminal 31 of the first power converter 3. dci is the voltage at the input terminal 31 of the i-th power converter 3.

[0164] Please see Figure 15 and cooperate Figure 12 and Figure 13 ,in Figure 15 for Figure 12 The diagram shows the operation of the output controller of the power conversion system. As shown, the output controller 69 operates based on the obtained voltage reference value V at the corresponding total output terminal 4. oiref and average output voltage The phase shift angle of the voltage on the second secondary winding 373 of the transformer 37 in the power converter 3 is obtained by subtracting the proportional-integral controller 681 and generating the proportional-integral controller 681. The phase shift angle of the voltage on the second secondary winding 373 of transformer 37 in power converter 3. The equation is as follows:

[0165] and

[0166]

[0167] in, The phase shift angle is the voltage on the second secondary winding 373 of transformer 37 in the first power converter 3. Let PI be the phase shift angle of the voltage on the second secondary winding 373 of the transformer 37 in the i-th power converter 3, and let PI be the proportional-integral ratio generated by the power conversion system 1 according to the circuit characteristics. o1ref The voltage reference value at the total output terminal 4 of the first power converter 3, V oiref V is the voltage reference value at the total output terminal 4 of the i-th power converter 3. o1 V is the voltage at the total output terminal 4 of the first power converter 3. oi This is the voltage at the total output terminal 4 of the i-th power converter 3.

[0168] When the input controller 68 and output controller 69 of the port controller 6 calculate the phase shift angle of the voltage on the primary winding 371 of the transformer 37 in the corresponding power converter 3, and the phase shift angle of the voltage on the second secondary winding 373 of transformer 37 Then, the voltages at input terminal 31 and total output terminal 4 of power converter 3 are controlled respectively. Please refer to [link / reference]. Figure 16 and cooperate Figures 12 to 15 ,in Figure 16 for Figure 12 The voltage signal waveforms at the input and total output terminals of the power converter in the power conversion system are shown. Figure 16 The three waveforms at the top represent the voltage S on the primary winding 371 of transformer 37 in the first power converter 3. A1 The voltage S on the primary winding 371 of transformer 37 in the second power converter 3 A2 And the voltage S on the primary winding 371 of transformer 37 in the Nth power converter 3 AN It is understandable that the voltage signal waveform diagram only shows the input voltage signals of three of the N power converters 3, while the input voltage signals of the remaining power converters 3 can be similarly represented. Figure 16 The input voltage signal of the power converter 3 shown. Figure 16 As can be seen from the three waveforms above, the voltage S on the primary winding 371 of transformer 37 in the first power converter 3 is... A1 With phase shift angle The voltage S on the primary winding 371 of transformer 37 in the second power converter 3 A2 With phase shift angle The voltage on the primary winding 371 of transformer 37 in the Nth power converter 3 has a phase shift angle. The input power of the input terminal 31 of each power converter 3 is controlled according to the corresponding phase shift angle, so that the input power of the input terminal 31 of each power converter 3 is consistent.

[0169] Figure 16The three waveforms at the bottom of the diagram represent the voltage S on the second secondary winding 373 of the transformer 37 in the first power converter 3. O1 The voltage S on the second secondary winding 373 of transformer 37 in the second power converter 3 O2 And the voltage signal S on the second secondary winding 373 of transformer 37 in the Nth power converter 3 ON Understandably, the voltage signal waveform diagram only shows the voltage on the second secondary winding 373 of the transformer 37 in three of the N power converters 3, while the voltage on the second secondary winding 373 of the transformer 37 in the remaining power converters 3 can be similarly represented. Figure 16 The voltage on the second secondary winding 373 of the transformer 37 in the power converter 3 shown. Figure 16 The three waveforms below show that the voltage S on the second secondary winding 373 of transformer 37 in the first power converter 3 is... O1 With phase shift angle The voltage S on the second secondary winding 373 of transformer 37 in the second power converter 3 O2 With phase shift angle The voltage S on the second secondary winding 373 of transformer 37 in the first power converter 3 ON With phase shift angle The output power of the total output terminal 4 of each power converter 3 is determined according to the corresponding phase shift angle. control.

[0170] In one embodiment, it is assumed that the transformers 37 of the N power converters 3 in the power conversion system 1b all have the same turns ratio, for example, a turns ratio of 1:1:…:1, and the output capacitance of the total output terminal 4 of each power converter 3 is 1mF. Please refer to [link to relevant documentation]. Figure 17A , it is Figure 12 The figure shows the current waveform at the total output terminal of the power conversion system. As shown in the figure, where... Figure 17A The first waveform in the diagram is the current waveform of the first total output terminal 4 out of the N total output terminals 4. Figure 17A The second waveform in the diagram is the current waveform of the second total output terminal 4 out of the N total output terminals 4. Figure 17A The third waveform in the diagram shows the current waveform of the Nth total output terminal 4 out of the N total output terminals 4. When the currents at the N total output terminals 4 of the power conversion system 1 may be inconsistent, for example... Figure 17A As shown, the power conversion system 1 can be controlled using the aforementioned control method for controlling the phase shift angle. The phase shift angle of the voltage on the primary winding 371 of the transformer 37 in the power converter 3, output by the port controller 6 of the power conversion system 1b, is... and the phase shift angle of the voltage on the second secondary winding 373 of transformer 37 Can Figure 17B and 17C As shown. The power conversion system 1b can utilize the phase shift angle of the voltage on the primary winding 371 of the transformer 37 in the power converter 3. and the phase shift angle of the voltage on the second secondary winding 373 of transformer 37 This further ensures that the input voltage at the input terminal 31 of each power converter 3 is consistent, and stabilizes the output voltage at the total output terminal 4. Please refer to [link / reference]. Figure 17D and Figure 17E ,in Figure 17D for Figure 12 The voltage waveform at the input terminal of the power converter in the power conversion system shown is as follows. Figure 17E for Figure 12 The voltage waveform at the total output terminal of the power converter in the power conversion system shown is illustrated. Figure 17D The first waveform in the diagram represents the input voltage V at the input terminal 31 of the first power converter 3 out of N power converters 3. A1 Waveform relative to time, Figure 17D The second waveform in the diagram shows the input voltage V at the input terminal 31 of the second power converter 3 out of the N power converters 3. A2 Compared to a time waveform, Figure 17D The third waveform in the diagram shows the input voltage V at the input terminal 31 of the Nth power converter 3 out of the N power converters 3. AN Relative to the time waveform. From Figure 17D It is understood that the power conversion system 1 disclosed herein can keep the input voltage of the input terminal 31 of each power converter 3 consistent, for example, equal to 1580V. Figure 17E The first waveform in the diagram represents the output voltage V at the total output terminal 4 of the first power converter 3 out of N power converters 3. O1 Waveform relative to time, Figure 17E The second waveform in the diagram represents the output voltage V at the total output terminal 4 of the second power converter 3 out of N power converters 3. O2 Waveform relative to time, Figure 17E The Nth waveform in the diagram represents the output voltage V at the total output terminal 4 of the Nth power converter 3 out of the N power converters 3. ON A waveform diagram relative to time. (From...) Figure 17E It is understood that the power conversion system 1 of this disclosure can maintain a stable output voltage at the total output terminal 4 of each power converter 3, for example, equal to 2000V. Furthermore, the power conversion system 1b can also ensure that the input voltage at the input terminal 31 of each power converter 3 is consistent, and that the waveform of the input AC current at the input terminal 31 is good, such as… Figure 17F As shown.

[0171] In some embodiments, the power converter of the power conversion system may include not only two DC / DC conversion circuits, but also three or more DC / DC conversion circuits. The following example illustrates a power conversion system comprising eight power converters, each containing three DC / DC conversion circuits. Please refer to [link to relevant documentation]. Figure 18 This is a power distribution diagram of the power converter in the power conversion system of the third embodiment of the present disclosure. As shown in the figure, each power converter 3 of the power conversion system 1c of this embodiment includes an input terminal 31, a first output terminal 32 and a second output terminal 33, as well as a third output terminal 71.

[0172] The first output terminal 32 of the first power converter 3, the second output terminal 33 of the Nth power converter 3, and the third output terminal 71 of the second power converter 3 are connected in parallel to form the Nth total output terminal 4 of the N total output terminals 4, thereby outputting the Nth total output power P. ON For example, in this embodiment, the eighth total output terminal 4 outputs the eighth total output power P. O8 The first output terminal 32 of the i-th power converter 3, the second output terminal 33 of the (i-1)-th power converter 3, and the third output terminal 71 of the (i+1)-th power converter 3 are connected in parallel to form the (i-1)-th total output terminal 4 of the N total output terminals 4, thereby outputting the (i-1)-th total output power P. O(i-1) Where N>=i>=2, and i is an integer. For example, when i is 2, the first output terminal 32 of the second power converter 3 in the N power converters 3, the second output terminal 33 of the first power converter 3 in the N power converters 3, and the third output terminal 71 of the third power converter 3 in the N power converters 3 are connected in parallel to form the first total output terminal 4 in the N total output terminals 4 and output the first total output power P. O1In this embodiment, each power converter 3 of the power conversion system 1c includes a first DC / DC conversion circuit 34 and a second DC / DC conversion circuit 35, as well as a third DC / DC conversion circuit 72. The third DC / DC conversion circuit 72 of each power converter 3 has an input terminal 721 and an output terminal 722. The input terminal 721 of the third DC / DC conversion circuit 72 of each power converter 3 is connected in parallel with the input terminals 341 of the first DC / DC conversion circuit 34 and 351 of the second DC / DC conversion circuit 35, and is connected to the input terminal 31 of the corresponding power converter 3. The output terminal 722 of the third DC / DC conversion circuit 72 of each power converter 3 is electrically connected to the third output terminal 71 of the corresponding power converter 3. This connection method can increase the output power of the total output terminal 4, further improving the reliability of the power conversion system. In this embodiment, the power conversion system 1c can load a load as in the power conversion system 1 of the first embodiment, and the loading method in this embodiment is also similar. Figure 9 The loading method shown is not described in detail here. Of course, in some embodiments, each power converter of the power conversion system may include more output terminals, and is not limited to the two output terminals described in the first embodiment or the three output terminals described in the third embodiment.

[0173] Please see Figure 19 This is a power distribution diagram of the power converter in the power conversion system of the fourth embodiment of this disclosure. As shown in the figure, the power conversion system 1d of this embodiment is similar to the power conversion system 1 of the first embodiment, except that the power conversion system 1d of this embodiment also includes at least one switch 8, for example, multiple switches 8. Each switch 8 is located between two of the N total output terminals 4, such that two of the N total output terminals 4 are connected in parallel, and the total output power corresponding to the two parallel total output terminals 4 increases. In this embodiment, each switch 8 is located between two adjacent total output terminals 4. For example, one of the multiple switches 8 is located between the first total output terminal 4 and the second total output terminal 4, and the other switch 8 is located between the (N-1)th total output terminal 4 and the Nth total output terminal 4.

[0174] In some embodiments, the power conversion system of this disclosure may not only be a system with the aforementioned single-phase circuit architecture, but also three power conversion systems interconnected to form a power conversion system group with a three-phase circuit architecture. Please refer to [link to relevant documentation]. Figure 20 This is a schematic diagram of the circuit structure of a power conversion system group consisting of multiple power conversion systems disclosed herein. As shown in the figure, the power conversion system group 9 includes three... Figure 1The power conversion systems 1 in the diagram are interconnected to form a system group with a three-phase circuit architecture. In other embodiments, the power conversion system group may be composed of multiple power conversion systems from other embodiments of this disclosure, which will not be described further here.

[0175] The input terminals 21 of the rectifier units 2 of the three power conversion systems 1 in the power conversion system group 9 are connected in series to the AC power supply P. The i-th total output terminal 4 of the N total output terminals 4 of each of the three power conversion systems 1 is connected in parallel with the i-th total output terminals 4 of the N total output terminals 4 of the other two power conversion systems 1 to output the i-th output power P. oi For example, the first total output terminal 4 of the three power conversion systems 1 are connected in parallel to output the first output power P. o1 The Nth total output terminal 4 of the three power conversion systems 1 are connected in parallel to output the Nth output power P. oN In other embodiments, the i-th total output terminal 4 of the N total output terminals 4 of each of the three power conversion systems 1 is connected in series with the i-th total output terminals 4 of the N total output terminals 4 of the other two power conversion systems 1 to output the i-th output power P. oi In this embodiment, the power conversion system group 9 interconnects the three power conversion systems 1 to form a three-phase circuit architecture, which can eliminate the imbalance between the electrical energy generated by each power conversion system 1.

[0176] Figure 21Schematic diagram of the circuit structure of the power conversion system according to the fifth embodiment of the present disclosure. As shown in the figure, the power conversion system 1e of this embodiment includes N rectifier units 2, N power converters 3, and N total output terminals 4. The power conversion system 1e receives two power supplies (i.e., the first power supply P1 and the second power supply P2) through the N rectifier units 2 and the N power converters 3, where the first power supply P1 and the second power supply P2 can be, but are not limited to, two 10 kV power supplies with different power sources. The (2k - 1)-th power converter 3 among the N power converters 3 is electrically connected to the first power supply P1 through the corresponding rectifier unit 2, and the 2k-th power converter 3 among the N power converters 3 is electrically connected to the second power supply P2 through the corresponding rectifier unit 2, where 1 ≤ k and k is an integer. In other words, the odd-numbered power converters 3 among the N power converters 3 are electrically connected to the first power supply P1, and the even-numbered power converters 3 among the N power converters 3 are electrically connected to the second power supply P2. That is, the power conversion system 1e converts the electrical energy of the first power supply P1 through the odd-numbered rectifier units 2 and the odd-numbered power converters 3, and converts the electrical energy of the second power supply P2 through the even-numbered rectifier units 2 and the even-numbered power converters 3. And since the first output terminal 32 of the first power converter 3 among the N power converters 3 is connected in parallel with the second output terminal 33 of the N-th power converter 3 among the N power converters 3 to form the N-th total output terminal 4 among the N total output terminals 4, it can be seen that the output power output by the N-th total output terminal 4 includes the converted electrical energy of the first power supply P1 and the converted electrical energy of the second power supply P2. Similarly, each of the remaining total output terminals 4 includes the converted electrical energy of the first power supply P1 and the converted electrical energy of the second power supply P2.

[0177] In addition, the power conversion system 1e includes N rectifier units 2, N power converters 3, and N total output terminals 4, and outputs N output powers via the N total output terminals 4 to provide to (N / 2) loads L, where 1 <= k <= (N / 2), N is an even number, and k is an integer. For example, the power conversion system 1e of this embodiment includes four rectifier units 2, four power converters 3, and four total output terminals 4, and the power conversion system 1e outputs four output powers via the four total output terminals 4 to provide to two loads L, which are hereinafter referred to as the first load L and the second load L for convenience of reference. In this embodiment, each of the first load L and the second load L has two input terminals, which are hereinafter referred to as the first input terminal Lin1 and the second input terminal Lin2 for convenience of reference. Therefore, the first load L and the second load L have a total of four input terminals (i.e., two first input terminals Lin1 and two second input terminals Lin2), and the four input terminals are respectively connected to the four total output terminals 4 in one-to-one correspondence. For example, the first input terminal Lin1 of the first load L is connected to the first total output terminal 4, the second input terminal Lin2 of the first load L is connected to the second total output terminal 4, the first input terminal Lin1 of the second load L is connected to the third total output terminal 4, and the second input terminal Lin2 of the second load L is connected to the fourth total output terminal 4. As can be seen from the above, the first load L receives the electric energy output from the first total output terminal 4 and the second total output terminal 4 respectively, and the second load L also receives the electric energy output from the third total output terminal 4 and the fourth total output terminal 4 respectively. Since each total output terminal 4 includes the electric energy of the converted first power supply P1 and the electric energy of the converted second power supply P2, it can be known that the first load L receives the electric energy of the converted first power supply P1 and the electric energy of the converted second power supply P2, and the second load L also receives the electric energy of the converted first power supply P1 and the electric energy of the converted second power supply P2. Therefore, when the first power supply P1 fails, the first load L and the second load L can still receive the power supply provided by the second power supply P2. On the contrary, when the second power supply P2 fails, the first load L and the second load L can still receive the power supply provided by the first power supply P1, so as to avoid the situation that the power conversion system 1e cannot supply power, thereby realizing the function of redundant power supply. And since the first total output terminal 4 is supplied with power by the first power converter 3 and the second power converter 3 respectively, when one of the first power converter 3 or the second power converter 3 fails, the other can also supply power to realize the function of redundant power supply. In some embodiments, each total output terminal 4 of the power conversion system 1e is further connected to a corresponding battery b to charge the battery b.

[0178] In some embodiments, the output power output by the total output terminal of the power conversion system is not only provided to (N / 2) loads, but also provided to N loads. Please refer to Figure 22, which is a schematic circuit diagram of the power conversion system according to the sixth embodiment of the present disclosure. As shown in the figure, the power conversion system 1f of this embodiment is similar to the power conversion system 1e of the fifth embodiment. However, compared with the power conversion system 1e of the fifth embodiment that only provides output power to (N / 2) loads L, the power conversion system 1f of this embodiment outputs N output powers via N total output terminals 4 to provide to N loads L, where 1 <= k <= (N / 2), and k is an integer. For example, the power conversion system 1f of this embodiment includes four rectifier units 2, four power converters 3, and four total output terminals 4. The power conversion system 1f outputs four output powers via the four total output terminals 4 to provide to four loads L, which are hereinafter referred to as the first load L, the second load L, the third load L, and the fourth load L for convenience. The first load L, the second load L, the third load L, and the fourth load L each have two input terminals, which are hereinafter referred to as the first input terminal Lin1 and the second input terminal Lin2 for convenience. Therefore, the first load L, the second load L, the third load L, and the fourth load L together have eight input terminals (i.e., four first input terminals Lin1 and four second input terminals Lin2). Each of the two input terminals of each load L is respectively connected to two different output terminals among the first total output terminal 4 to the Nth total output terminal 4, and each of the first total output terminal 4 to the Nth total output terminal 4 is connected to two different loads L among the N loads L. For example, the first input terminal Lin1 of the first load L is connected to the first total output terminal 4, the second input terminal Lin2 of the first load L is connected to the second total output terminal 4, the first input terminal Lin1 of the second load L is connected to the second total output terminal 4, the second input terminal Lin2 of the second load L is connected to the third total output terminal 4, the first input terminal Lin1 of the third load L is connected to the third total output terminal 4, the second input terminal Lin2 of the third load L is connected to the fourth total output terminal 4, the first input terminal Lin1 of the fourth load L is connected to the fourth total output terminal 4, and the second input terminal Lin2 of the fourth load L is connected to the first total output terminal 4. As can be seen from the above, similar to the power conversion system 1e of the fifth embodiment, the power conversion system 1f of this embodiment can also achieve the function of redundant power supply.

[0179] In summary, the power conversion system of this disclosure has N power converters with N total output terminals, which can provide electrical energy to N loads. Therefore, the power conversion system of this disclosure can meet the requirements of multiple output ports, and also makes the power conversion system lower in cost and higher in charging efficiency. In addition, the first output terminal of the first power converter in the power conversion system of this disclosure is connected in parallel with the second output terminal of the Nth power converter in the power conversion system of this disclosure, and the first output terminal of the i-th power converter in the power conversion system of this disclosure is connected in parallel with the second output terminal of the (i-1)-th power converter in the power conversion system of this disclosure. Therefore, it can be seen that the power converters of this disclosure are interconnected to form a ring structure. Therefore, when the power demand of each total output terminal of the power conversion system is inconsistent, the input power of each power converter can be made consistent through power scheduling among the N power converters. Therefore, the power conversion system of this disclosure can more easily meet the power factor requirements, resulting in higher efficiency and lower total loss of the power conversion system. Furthermore, the power conversion system disclosed herein can achieve redundant power supply by utilizing the arrangement of the rectifier unit, power converter, and total output terminal with the load.

Claims

1. A power conversion system comprising: N power converters, each of the power converters comprising an input terminal, a first output terminal and a second output terminal, each of the power converters receiving a direct current power via the input terminal, the first output terminal of a first power converter of the N power converters being connected in parallel with the second output terminal of an Nth power converter of the N power converters to form an Nth total output terminal to output an Nth total output power, the first output terminal of an ith power converter of the N power converters being connected in parallel with the second output terminal of an (i-l)th power converter of the N power converters to form an (i-l)th total output terminal to output an (i-l)th total output power, where N>=i>=2 and i is an integer.

2. The power conversion system of claim 1, wherein, each of the power converters comprising a first direct current / direct current conversion circuit and a second direct current / direct current conversion circuit, an input terminal of the first direct current / direct current conversion circuit and an input terminal of the second direct current / direct current conversion circuit of each of the power converters being connected in parallel to the input terminal of the corresponding power converter, input power of each of the power converters being equal to a sum of input power of the first direct current / direct current conversion circuit and input power of the second direct current / direct current conversion circuit.

3. The power conversion system of claim 2, wherein, output power of the first output terminal of the ith power converter being the (i-l)th total output power divided by 2 minus an (i-l)th power error value, output power of the second output terminal of the ith power converter being an ith total output power divided by 2 plus an ith power error value, output power of the first output terminal of the first power converter being the Nth total output power divided by 2 minus an Nth power error value, output power of the second output terminal of the first power converter being a first total output power divided by 2 plus a first power error value, where the ith total output power is equal to output power of the first output terminal of the (i+l)th power converter plus output power of the second output terminal of the ith power converter.

4. The power conversion system of claim 3, wherein, the power conversion system further comprising an arithmetic control unit connected to the total output terminals of each of the power converters to receive signals reflecting N total output powers outputted by the N power converters, where the arithmetic control unit is configured to obtain the first power error value via equation (1) below and to obtain second power error value to the Nth power error value via equation (2) below, and to control output powers of the first output terminals and the second output terminals of the N power converters according to results of the arithmetic operations of the power error values, x i = x i-1 - 0.5(P oi + P o(i-1) ), i = 2,..., N... (2) where x1 is the first power error value, P oi is the i-th total output power, P o(i+1) is the (i+1)-th total output power, where when i=N, P o(i+1) is P o1 , is the average of the N total output powers, x i is the i-th power error value, x i-1 is the (i-1)-th power error value, P o(i-1) is the (i-1)-th total output power.

5. The power conversion system of claim 3, wherein, the power conversion system further comprising an arithmetic control unit connected to the total output terminals of each of the power converters to receive the N total output powers outputted by the N power converters, where the arithmetic control unit is configured to obtain all of the power error values via equations below, and to control output powers of the first output terminals and the second output terminals of the N power converters according to results of the arithmetic operations of the power error values, x = A -1 B where x = [x1, x2,..., x i ] N ] T , x i is the i-th power error value, p is a weighting coefficient set by the operation control unit according to the circuit characteristics of the power conversion system, and P oi is the i-th total output power.

6. The power conversion system of claim 5, wherein, When the operation control unit confirms that the i-th power error value exceeds an error upper limit value, the operation control unit controls the i-th power error value to be the error upper limit value, and when the operation control unit confirms that the i-th power error value is lower than an error lower limit value, the operation control unit controls the i-th power error value to be the error lower limit value.

7. The power conversion system of claim 3, wherein, The power conversion system further comprises N port controllers, each of the port controllers is connected to the total output terminal of the corresponding power converter, wherein the first port controller of the N port controllers receives the first total output power, the input power reference quantity of the first DC / DC conversion circuit of the first power converter and the input power reference quantity of the second DC / DC conversion circuit of the second power converter of the N power converters, outputs the input power reference quantity of the second DC / DC conversion circuit of the first power converter and the input power reference quantity of the first DC / DC conversion circuit of the second power converter; the i-th port controller of the N port controllers receives the i-th total output power, the input power reference quantity of the first DC / DC conversion circuit of the i-th power converter and the input power reference quantity of the second DC / DC conversion circuit of the (i+1)-th power converter, outputs the input power reference quantity of the second DC / DC conversion circuit of the i-th power converter and the input power reference quantity of the first DC / DC conversion circuit of the (i+1)-th power converter; the N-th port controller of the N port controllers receives the N-th total output power, the input power reference quantity of the first DC / DC conversion circuit of the N-th power converter and the input power reference quantity of the second DC / DC conversion circuit of the first power converter, outputs the input power reference quantity of the second DC / DC conversion circuit of the N-th power converter and the input power reference quantity of the first DC / DC conversion circuit of the first power converter, wherein i<= (N-1).

8. The power conversion system of claim 7, wherein, Each of the port controllers includes a first scaling unit, a first adder, a first subtractor, a second adder, a third adder, a second subtractor and a power coordinator, the first scaling unit of the first port controller is used to multiply the first total output power by 0.5 to obtain a first intermediate variable, the first adder of the first port controller is used to add the first intermediate variable and the first power error value to obtain the input power reference of the second DC / DC converter of the first power converter, the first subtractor of the first port controller is used to subtract the first intermediate variable and the first power error value to obtain the input power reference of the first DC / DC converter of the second power converter, the second adder of the first port controller is used to add the input power reference of the second DC / DC converter of the first power converter and the input power reference of the first DC / DC converter of the first power converter to obtain the input power of the first power converter, the third adder of the first port controller is used to add the input power reference of the first DC / DC converter of the second power converter and the input power reference of the second DC / DC converter of the second power converter to obtain the input power of the second power converter, the second subtractor of the first port controller is used to subtract the input power of the first power converter from the input power of the second power converter to obtain a first power variable, the power coordinator in the first power converter is used to receive the first power variable and output the first power error value; the first scaling unit of the i-th port controller is used to multiply the i-th total output power by 0.5 The first adder of the i-th port controller is configured to add the i-th intermediate variable and the i-th power error value to obtain the input power reference of the second DC / DC converter of the i-th power converter, the first subtractor of the i-th port controller is configured to subtract the i-th intermediate variable and the i-th power error value to obtain the input power reference of the first DC / DC converter of the (i+1)-th power converter, the second adder of the i-th port controller is configured to add the input power reference of the second DC / DC converter of the i-th power converter and the input power reference of the first DC / DC converter of the i-th power converter to obtain the input power of the i-th power converter, the third adder of the i-th port controller is configured to add the input power reference of the first DC / DC converter of the (i+1)-th power converter and the input power reference of the second DC / DC converter of the (i+1)-th power converter to obtain the input power of the (i+1)-th power converter, the second subtractor of the i-th port controller is configured to subtract the input power of the i-th power converter from the input power of the (i+1)-th power converter to obtain an i-th power variable, and the power coordinator of the i-th power converter is configured to receive the i-th power variable and output the i-th power error value. The first scaling unit of the N-th port controller is configured to multiply the N-th total output power by 0.5 to obtain an N-th intermediate variable, the first adder of the N-th port controller is configured to add the N-th intermediate variable and the N-th power error value to obtain the input power reference of the second DC / DC converter of the N-th power converter, the first subtractor of the N-th port controller is configured to subtract the N-th intermediate variable and the N-th power error value to obtain the input power reference of the first DC / DC converter of the first power converter, the second adder of the N-th port controller is configured to add the input power reference of the second DC / DC converter of the N-th power converter and the input power reference of the first DC / DC converter of the N-th power converter to obtain the input power of the N-th power converter, the third adder of the N-th port controller is configured to add the input power reference of the first DC / DC converter of the first power converter and the input power reference of the second DC / DC converter of the first power converter to obtain the input power of the first power converter, the second subtractor of the N-th port controller is configured to subtract the input power of the N-th power converter from the input power of the first power converter to obtain an N-th power variable, and the power coordinator of the N-th power converter is configured to receive the N-th power variable and output the N-th power error value.

9. The power conversion system of claim 8, wherein, Each of the power coordinators comprises a second proportional unit, an integral unit, an integral limiting unit, a fourth adder, a low-pass filter unit and a circulating current limiting unit, the first power variable is sequentially subjected to the integral unit and the integral limiting unit of the first port controller to obtain a first transition variable, the first power variable is subjected to the second proportional unit of the first port controller to obtain a second transition variable, the fourth adder of the first port controller is used to add the first transition variable and the second transition variable to obtain a third transition variable, the third transition variable is sequentially subjected to the low-pass filter unit and the circulating current limiting unit of the first port controller to obtain the first power error value; the i-th power variable is sequentially subjected to the integral unit and the integral limiting unit of the i-th port controller to obtain the first transition variable, the i-th power variable is subjected to the second proportional unit of the i-th port controller to obtain the second transition variable, the fourth adder of the i-th port controller is used to add the first transition variable and the second transition variable to obtain the third transition variable, the third transition variable is sequentially subjected to the low-pass filter unit and the circulating current limiting unit of the i-th port controller to obtain the i-th power error value; the N-th power variable is sequentially subjected to the integral unit and the integral limiting unit of the N-th port controller to obtain the first transition variable, the N-th power variable is subjected to the second proportional unit of the N-th port controller to obtain the second transition variable, the fourth adder of the N-th port controller is used to add the first transition variable and the second transition variable to obtain the third transition variable, the third transition variable is sequentially subjected to the low-pass filter unit and the circulating current limiting unit of the N-th port controller to obtain the N-th power error value.

10. The power conversion system of claim 1, wherein, The power conversion system is connected to M loads, when M<= (N / 2), non-adjacent M total output terminals in the N total output terminals are respectively connected to the M loads.

11. The power conversion system of claim 1, wherein, The power conversion system is connected to M loads, when M>(N / 2), M total output terminals in the N total output terminals are respectively connected to the M loads, and the maximum interval between two adjacent total output terminals in the M total output terminals is one total output terminal outside the M total output terminals.

12. The power conversion system of claim 1, wherein, Each of the power converters comprises an inverter circuit and a transformer, the transformer comprises a primary winding, a first secondary winding and a second secondary winding, one end of the inverter circuit is connected to the input terminal of the power converter, the other end of the inverter circuit is connected to the primary winding, the first secondary winding is connected to the first output terminal of the power converter, and the second secondary winding is connected to the second output terminal of the power converter.

13. The power conversion system of claim 12, wherein, The equation of the phase shift angle of the voltage on the primary winding of each of the power converters is as follows, or or wherein, is the phase-shift angle of the voltage on the primary winding of the i-th power converter, and is the phase-shift angle of the voltage on the primary winding of the i-th power converter, and PI is the proportional integral generated by the power conversion system according to the circuit characteristics, is the average of the input power of the N power converters, and A1 is the input power of the input terminal of the first power converter, and Ai is the input power of the input terminal of the i-th power converter, and is the average of the voltage of the input terminal of the N power converters, and dc1 is the voltage of the input terminal of the first power converter, and dci is the voltage of the input terminal of the i-th power converter.

14. The power conversion system of claim 12, wherein, The equation of the phase shift angle of the voltage on the second secondary winding of each of the power converters is as follows, wherein, is the phase-shift angle of the voltage on the second secondary winding of the i-th power converter, and is the phase-shift angle of the voltage on the second secondary winding of the i-th power converter, and PI is a proportional-integral generated by the power conversion system according to circuit characteristics, V o1ref is the voltage reference value of the total output end of the first power converter, V oiref is the voltage reference value of the total output end of the i-th power converter, V o1 is the voltage of the total output end of the first power converter, V oi is the voltage of the total output end of the i-th power converter.

15. The power conversion system of claim 1, further comprising N rectifier units corresponding to the N power converters, the input terminals of the N rectifier units being connected in series to an AC power source, and the output terminals of the N rectifier units being connected to the input terminals of the corresponding power converters, respectively.

16. The power conversion system of claim 1, wherein, The first output terminal of the first one of the N power converters, the second output terminal of the Nth one of the N power converters, and the third output terminal of the second one of the N power converters are connected, the first output terminal of the ith one of the N power converters, the second output terminal of the (i-l)th one of the N power converters, and the third output terminal of the (i+l)th one of the N power converters are connected.

17. The power conversion system of claim 1, further comprising a switch for connecting two of the N total output terminals in parallel.

18. The power conversion system of claim 1, wherein the power conversion system is connected to (N / 2) loads, each of the loads having two input terminals, the (N / 2) loads having N input terminals in total, the N input terminals of the (N / 2) loads being connected to the first total output terminal to the Nth total output terminal one-to-one, the (2k-l)th one of the N power converters being electrically connected to a first power source, and the 2kth one of the N power converters being electrically connected to a second power source, where 1=<k<= (N / 2), and N is even, and k is an integer.

19. The power conversion system of claim 1, wherein the power conversion system is connected to N loads, each of the loads having two input terminals, the two input terminals of each of the loads being connected to two different ones of the first total output terminal to the Nth total output terminal, respectively, each of the first total output terminal to the Nth total output terminal being connected to two different ones of the N loads, the (2k-l)th one of the N power converters being electrically connected to a first power source, and the 2kth one of the N power converters being electrically connected to a second power source, where 1=<k<= (N / 2), and k is an integer.

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