A multi-load power balancing method based on arbitrary position aligned PWM control

Abstract

This invention provides a multi-load power balancing method based on arbitrary position-aligned PWM control. The duty cycles of multiple loads are sequentially arranged in chronological order, with each load's duty cycle aligned according to its arrangement time. Through three-stage time control, the power supply system achieves balanced power output within a control cycle. By controlling the on-time position of the power switches within the control cycle, balanced power output is achieved across the multi-load system, minimizing load fluctuations in the power supply system.

Description

Technical Field

[0001] The present invention relates to the fields of power electronics and automatic control, and in particular to a multi-load power balancing method based on arbitrary position alignment PWM control. Background Art

[0002] Traditional multi-load PWM power regulation control systems use edge alignment or center alignment for each load PWM control. When controlling multiple loads, they may be turned on or off at the same time. Within a control cycle, the power supply system load may experience drastic jumps, affecting system stability. Summary of the Invention

[0003] In order to address the shortcomings of the existing technology, the present invention provides a multi-load power balancing method based on arbitrary position aligned PWM control, which uses three-segment arbitrary alignment PWM control algorithm with indefinite time to control the position of the conduction time of the power switch within the control cycle, thereby achieving power output balanced control of the multi-load system and minimizing load jumps in the power supply system.

[0004] The technical solution adopted by the present invention to solve the technical problem is: providing a multi-load power balancing method based on arbitrary position alignment PWM control, including the following process:

[0005] Assume that there are n loads in the power supply system, and each load has a switch controlled by a controller. For any k-th load in the power supply system, the timing of the PWM signal sent by the controller follows the following rules:

[0006] Assume ts k =X k-1 *T is the position of the PWM signal in the control period T, that is, the time when the PWM signal used to control the k-th load is issued is ts k ; points D k +X k-1 >100% and D k +X k-1 ≤100% is controlled in two cases, where D k is the duty cycle of the PWM signal sent by the controller to control the k-th load, X k =Dz k %1,

[0007] a. When D k +X k-1 When the value is greater than 100%, the control wave in one control cycle T includes a high level in the t0 period, a low level in the t1 period, and a high level in the t2 period. The high level controls the switch to be turned on, and the low level controls the switch to be turned off.

[0008] t0=(D k +X k-1 -1)*T

[0009] t1=(1-D k )*T

[0010] t2=(1-X k-1 )*T

[0011] PWM signal ts used to control the k-th load k Aligned with the start time of period t2;

[0012] b. When D k +X k-1 When ≤100%: the control wave within one control cycle T includes a low level during the t0 period, a high level during the t1 period, and a low level during the t2 period, where:

[0013] t0=X k-1 *T

[0014] t1=D k *T

[0015] t2=(1-D k -X k-1 )*T

[0016] PWM signal ts used to control the k-th load k Aligned with the start time of period t1.

[0017] The duty cycle D of the PWM signal sent by the controller to control the k-th load k As a percentage.

[0018] Assume T k The controller controls the conduction time of the kth load, T k =D k *T.

[0019] The beneficial effects of the present invention based on its technical solution are:

[0020] This invention provides a multi-load power balancing method based on arbitrary position-aligned PWM control. The duty cycles of multiple loads are sequentially arranged in chronological order, with each load's duty cycle aligned according to its arrangement time. Through three-stage time control, the power supply system achieves balanced power output within a control cycle. By controlling the on-time position of the power switches within the control cycle, balanced power output is achieved across the multi-load system, minimizing load fluctuations in the power supply system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the power supply system.

[0022] Figure 2 This is a schematic diagram of the control situation of a multi-load power balancing method based on arbitrary position alignment PWM control provided by the present invention.

[0023] Figure 3 Schematic diagram of the alignment positions of the two control methods given in the embodiment. DETAILED DESCRIPTION

[0024] The present invention will be further described below with reference to the accompanying drawings and examples.

[0025] The present invention provides a multi-load power balancing method based on arbitrary position alignment PWM control, which includes the following processes:

[0026] Reference Figure 1 , assuming that there are n loads in the power supply system, and each load is equipped with a switch controlled by the controller; for any k-th load in the power supply system, the timing of the PWM signal sent by the controller follows the following rules:

[0027] Assume ts k =X k-1 *T is the position of the PWM signal in the control period T, that is, the time when the PWM signal used to control the k-th load is issued is ts k ;reference Figure 2 , points D k +X k-1 >100% and D k +X k-1 ≤100% is controlled in two cases, where D k is the duty cycle of the PWM signal sent by the controller to control the k-th load, X k =Dz k %1,

[0028] a. Reference Figure 2 (1), when D k +X k-1 When the value is greater than 100%, the control wave in one control cycle T includes a high level in the t0 period, a low level in the t1 period, and a high level in the t2 period. The high level controls the switch to be turned on, and the low level controls the switch to be turned off.

[0029] t0=(D k +X k-1 -1)*T

[0030] t1=(1-D k )*T

[0031] t2=(1-X k-1 )*T

[0032] PWM signal ts used to control the k-th load k Aligned with the start time of period t2;

[0033] b. Reference Figure 2 (2) When D k +X k-1 When ≤100%: the control wave within one control cycle T includes a low level during the t0 period, a high level during the t1 period, and a low level during the t2 period, where:

[0034] t0=X k-1 *T

[0035] t1=D k *T

[0036] t2=(1-D k -X k-1 )*T

[0037] PWM signal ts used to control the k-th load k Aligned with the start time of period t1.

[0038] The duty cycle D of the PWM signal sent by the controller to control the k-th load k As a percentage.

[0039] Assume T k The controller controls the conduction time of the kth load, T k =D k *T.

[0040] Reference Figure 3 , take a power control system with 5 loads: the rated power of a single load is Pd, the total output power of the power supply system is Pz, the duty cycles are D1, D2, D3, D4, and D5 respectively, and the corresponding duty cycle times are T1, T2, T3, T4, and T5 respectively; the control period is T. Figure 3 (2) According to the multi-load power balancing method based on arbitrary position alignment PWM control, the alignment positions ts1, ts2, ts3, ts4, and ts5 of each load system in period T are calculated respectively:

[0041] (1) Load 1:

[0042] ts1=X0*T=0

[0043] t0=X0*T=0

[0044] t1=D1*T=T1

[0045] t2=(1-D1-X0)*T=(1-D1)*T=T-T1

[0046] (2) Second load:

[0047] ts2=X1*T=D1*T=T1

[0048] t0=X1*T=D1*T=T1

[0049] t1=D2*T=T2

[0050] t2=(1-D2-X1)*T=(1-D2-D1)*T=T-T2-T1

[0051] (3) The third load:

[0052] ts3=X2*T=(D1+D2)*T=T1+T2

[0053] t0=(D3+X2-1)*T=T1+T2+T3-T

[0054] t1=(1-D3)*T=T-T3

[0055] t2=(1–X2)*T=T-T1-T2

[0056] (4) Load 4:

[0057] ts4=X3*T=T1+T2+T3-T

[0058] t0=X3*T=T1+T2+T3-T

[0059] t1=D4*T=T4

[0060] t2=(1-D4-X3)*T=2*T-T4-T3-T2-T1

[0061] (5) Load 5:

[0062] ts5=X4*T=T1+T2+T3+T4-T

[0063] t0=X4*T=T1+T2+T3+T4-T

[0064] t1=D5*T=T5

[0065] t2=0

[0066] After calculation, using the multi-load power balancing method based on arbitrary position alignment PWM control provided by the present invention, at any time within the control period T, the total output power of the power supply system Pz = 2Pd. Figure 3(1) The alignment point of each load is the same: in the 0-ta phase, Pz = 5Pd; in the ta-tb phase, Pz = 4Pd; in the tb-tc phase, Pz = 3Pd; in the tc-td phase, Pz = 2Pd; in the td-te phase, Pz = Pd; and in the te-tf phase, Pz = 0. This shows that the total load of the power supply system varies greatly from large to small within each control cycle using the traditional control method. However, the total load of the power supply system using the control method of the present invention is relatively stable.

[0067] The present invention provides a multi-load power balancing method based on arbitrary position aligned PWM control, which uses three sections of arbitrary aligned PWM control algorithm with indefinite time to control the position of the conduction time of the power switch within the control cycle, thereby achieving power output balanced control of the multi-load system and minimizing load jumps in the power supply system.

Claims

1. A multi-load power balancing method based on arbitrary position alignment PWM control, characterized in that The following processes are included: Assume that there are n loads in an AC power supply system. Each load has a control period of T, and each load has a switch that is controlled on and off by a controller. For any k-th load in the AC power supply system, the timing of the PWM signal sent by the controller follows the following rule: Assume ts k =Y k-1 T is the position of the PWM signal in the control period T, that is, the time when the PWM signal used to control the k-th load is issued is ts k ; points D k +Y k-1 >100% and D k +Y k-1 ≤100% for two conditions, where D k is the duty cycle of the PWM signal sent by the controller to control the k-th load, T k The controller controls the on-time of the k-th load, Y k =DZ k %1, DZ k k ;Balance control is performed according to the following two situations: a. When D k +Y k-1 When >100%, the control wave within a control cycle T includes a high level during the t0 period, a low level during the t1 period, and a high level during the t2 period. The high level controls the on-state of the switch, and the low level controls the off-state of the switch. t0=(D k +Y k-1 -1)T t1=(1-D k )T t2=(1-Y k-1 )T PWM signal ts used to control the k-th load k Aligned with the start time of period t2; b. When D k +Y k-1 When ≤100%: the control wave within a control cycle T includes a low level during the t0 period, a high level during the t1 period, and a low level during the t2 period, where: t0=Y k-1 T t1=D k T t2=(1-D k -Y k-1 )T PWM signal ts used to control the k-th load k Aligned with the start time of period t1.

2. The multi-load power balancing method based on arbitrary position alignment PWM control according to claim 1, characterized in that: The duty cycle D of the PWM signal sent by the controller to control the k-th load k As a percentage.

3. The multi-load power balancing method based on arbitrary position alignment PWM control according to claim 1, characterized in that: T k =D k T。

Images