CN216900723U

CN216900723U - Three-phase alternating current power supply detector and gradient power amplifier comprising same

Info

Publication number: CN216900723U
Application number: CN202122530666.6U
Authority: CN
Inventors: 陈良刚; 曾克秋; 赵燕
Original assignee: Koninklijke Philips NV
Current assignee: Koninklijke Philips NV
Priority date: 2021-10-15
Filing date: 2021-10-15
Publication date: 2022-07-05
Anticipated expiration: 2031-10-15

Abstract

The utility model relates to a three-phase alternating current power supply detector, comprising: a phase detection unit comprising first and second phase detection circuits. The first phase detection circuit comprises a first isolating switch, a first phase voltage and a second phase voltage in the three-phase alternating current power supply are respectively applied to a first input control end and a second input control end of the first isolating switch, and the first phase detection circuit generates a first logic level signal according to a signal of a controlled output end of the first isolating switch. The second phase detection circuit comprises a second isolating switch, a first phase voltage and a third phase voltage in the three-phase alternating current power supply are respectively applied to a first input control end and a second input control end of the second isolating switch, and the second phase detection circuit generates a second logic level signal according to a signal of a controlled output end of the second isolating switch. The combination of the high and low levels of the first and second logic level signals is capable of reflecting which phase of the three-phase alternating current power supply is open-phase.

Description

Three-phase alternating current power supply detector and gradient power amplifier comprising same

Technical Field

The utility model relates to the technical field of circuits, in particular to a three-phase alternating current power supply detector used in a gradient power amplifier and the gradient power amplifier comprising the same.

Background

Three-phase alternating current is widely used in various fields. Generally, a three-phase alternating current power grid transmits power through a live wire with the same three-phase frequency, the same potential amplitude and the phase difference of 120 degrees, and an optional neutral wire further comprises a zero wire. The phases of the three live lines may be referred to as U-phase, V-phase and W-phase, respectively. Due to the change of working environment and the existence of factors such as circuit faults, the phase of the three-phase alternating current can be changed, for example, the phase is lost, and therefore, the electric equipment is damaged.

In the field of medical gradient amplifier applications, three-phase power grids typically deliver high-power energy to the gradient amplifier. The three-phase power indicator can realize the visualization of three-phase power information. Furthermore, the indicator may also indicate phase missing information in the three-phase alternating current. However, existing indicators are complex in circuit design, costly, and not easily integrated with other circuits in practical applications.

SUMMERY OF THE UTILITY MODEL

In view of the above, the present invention provides a three-phase ac power detector and a gradient power amplifier including the same, which overcome these and other problems in the prior art.

An aspect of the present invention provides a three-phase ac power detector for use in a gradient power amplifier, comprising: and a phase detection unit including a first phase detection circuit and a second phase detection circuit. The first phase detection circuit comprises a first isolating switch, a first phase voltage and a second phase voltage in a three-phase alternating current power supply are applied to a first input control end and a second input control end of the first isolating switch respectively, and the first phase detection circuit generates a first logic level signal according to a signal of a controlled output end of the first isolating switch. The second phase detection circuit comprises a second isolating switch, a first phase voltage and a third phase voltage in the three-phase alternating current power supply are respectively applied to a first input control end and a second input control end of the second isolating switch, and the second phase detection circuit generates a second logic level signal according to a signal of a controlled output end of the second isolating switch. The combination of the first logic level signal and the second logic level signal indicates which phase voltage of the three-phase alternating current power supply is open-phase. The first isolation switch is opened when any one of the first phase voltage and the second phase voltage is out of phase, and the second isolation switch is opened when any one of the first phase voltage and the third phase voltage is out of phase. As explained in detail below, the phase failure information of the three-phase ac power supply line can be indicated based on only the combination information of the high and low levels of the first and second logic level signals.

In one embodiment, the phase detection unit may further include a first current limiting resistor, a second current limiting resistor, and a third current limiting resistor. The first phase voltage may be applied to the first input control terminal of the first isolator switch and the first input control terminal of the second isolator switch via the first current limiting resistor, the second phase voltage may be applied to the second input control terminal of the first isolator switch via the second current limiting resistor, and the third phase voltage may be applied to the second input control terminal of the second isolator switch via the third current limiting resistor. In this way, the current drawn from the three-phase ac power supply can be limited to a reasonable range, thereby avoiding damage to the phase detection circuit. Preferably, the first phase detection circuit and the second phase detection circuit share the first current limiting resistor, thereby simplifying the overall circuit design.

In other embodiments, the phase detection unit may further include a first current limiting resistor, a second current limiting resistor, a third current limiting resistor, and a fourth current limiting resistor. The first phase voltage may be applied to the first input control terminal of the first isolator switch and the first input control terminal of the second isolator switch via the first current limiting resistor and a fourth current limiting resistor, respectively, the second phase voltage may be applied to the second input control terminal of the first isolator switch via the second current limiting resistor, and the third phase voltage may be applied to the second input control terminal of the second isolator switch via the third current limiting resistor.

In one embodiment, each of the phase detection circuits may include a corresponding one of the isolation switch, the power supply, the pull-down resistor, and the peak detection hold sub-circuit. The first output controlled end of each isolating switch is connected with the power supply, the pull-down resistor is connected with the peak detection holding sub-circuit in parallel at the second output controlled end of each isolating switch, and the other end of the pull-down resistor is grounded.

In this embodiment, each of the peak detection holding sub-circuits may include a detector diode and a capacitor in series. The positive end of the detection diode is connected with the second output controlled end of the corresponding isolating switch, the common joint of the negative end of the detection diode and the capacitor is configured to output a corresponding logic level signal, and the other end of the capacitor is grounded.

Therefore, the phase detection unit realized by a hardware circuit can detect the existence or the lack of the phase of each phase voltage in the three-phase power supply, and the failure, the halt and the program operation error caused by the damage or the interference of the microcontroller such as the MCU, the DSP and the like do not exist, so that the reliability and the safety of the detection are improved, and the detection cost is reduced.

According to an aspect of the utility model, each of the phase detection circuits may further include a switching diode. In one embodiment, the first phase voltage may be applied to a positive terminal of the switching diode and a negative terminal of the switching diode is connected to the first input control terminal of the corresponding isolation switch. In other embodiments, the second phase voltage or the third phase voltage may be applied to the negative side terminal of the switching diode and the positive side terminal of the switching diode is connected to the second input control terminal of the corresponding isolation switch.

In one example, the detector may further include a signal processing circuit composed of several logic gate chips. The signal processing circuit is configured to receive the first and second logic level signals from the first and second phase detection circuits and generate a first phase signal indicating presence or absence of information on a phase of the first phase voltage, a second phase signal indicating presence or absence of information on a phase of the second phase voltage, and a third phase signal indicating presence or absence of information on a phase of the third phase voltage, respectively, based on a combination of the first and second logic level signals. As explained in detail below, the signal processing circuit implemented by several logic gate chips, which does not require, for example, a microcontroller to analyze whether a three-phase ac power supply has a phase loss problem, has a high immunity to interference.

According to an aspect of the utility model, the detector may further comprise a signal indicator. In one example, the signal indicator may be connected to the signal processing circuitry to receive the first, second and third phase signals and configured to visually and/or audibly output corresponding phase presence or absence information in response to the first, second and third phase signals, respectively. In another example, the signal indicator may be connected to respective outputs of the first and second phase detection circuits to receive the first and second logic level signals and configured to visually and/or audibly output corresponding phase presence or absence information in response to a combination of the first and second logic level signals. As explained in detail below, the signal indicator may be implemented by a simple hardware circuit, with high immunity to interference. Thus, the detector according to the utility model does not need to be connected to an external display device.

In one example, the detector further includes an ac-dc conversion unit configured to externally connect the first phase voltage, the second phase voltage, and the third phase voltage of the three-phase ac power source, and convert an ac voltage of the three-phase ac power source into a dc voltage. In addition, the ac-dc conversion unit is further configured to supply the dc voltage to at least one of the phase detection unit, the signal processing circuit, and the signal indicator, respectively.

In one example, the ac-dc conversion unit may include a rectifier circuit and a zener diode connected in parallel with the rectifier circuit. For example, the rectifier circuit may include six diodes.

In one example, a dc voltage output from the ac-dc conversion unit is used as the power source in the first and second phase detection circuits. Thus, the detector according to the utility model does not need to be connected to an external power supply.

In one example, each of the phase detection circuits may further include a zener diode. The voltage stabilizing diode is connected between the first input control end and the second input control end of the isolating switch in a crossing mode opposite to the conducting direction of the input control end of the corresponding isolating switch.

Preferably, the three-phase ac power source detector may include the phase detection unit, the signal processing circuit, the signal indicator, and the ac-dc conversion unit, all of which are implemented by hardware circuits and integrated together. Thus, the detector according to the utility model is very convenient to integrate into existing three-phase AC power systems and has strong anti-interference capability under various use conditions.

According to another aspect of the present invention there is provided a gradient power amplifier comprising a three-phase ac power supply detector as described in the preceding paragraph.

Other objects and effects of the present invention will become more apparent and more easily understood by referring to the description taken in conjunction with the accompanying drawings.

Drawings

The utility model will be described and explained in more detail below with reference to embodiments and with reference to the drawings, in which:

FIG. 1 is a schematic diagram of a gradient power amplifier 100 according to one embodiment of the utility model;

FIG. 2 is a schematic diagram of a three-phase AC power source detector 200 according to one embodiment of the utility model;

fig. 3A is a circuit diagram of the phase detection unit 201 according to the first embodiment of the present invention;

fig. 3B is a circuit diagram of the phase detecting unit 201 according to the second embodiment of the present invention;

fig. 3C is a circuit diagram of the phase detecting unit 201 according to the third embodiment of the present invention;

fig. 3D is a circuit diagram of the phase detecting unit 201 according to the fourth embodiment of the present invention;

fig. 3E is a circuit diagram of the phase detection unit 201 according to the fifth embodiment of the present invention;

fig. 4 schematically shows waveform diagrams of respective outputs of the first and second phase detection circuits according to an embodiment of the present invention when the three-phase alternating-current power supply is in a normal phase state;

FIG. 5 schematically illustrates waveforms of respective outputs of first and second phase detection circuits according to an embodiment of the present invention when a U-phase line of a three-phase AC power source is out of phase;

FIG. 6 schematically illustrates waveforms of respective outputs of first and second phase detection circuits according to an embodiment of the present invention when a phase V-phase line of a three-phase AC power source is out of phase;

FIG. 7 schematically illustrates waveforms of respective outputs of first and second phase detection circuits according to an embodiment of the present invention when a W-phase line of a three-phase AC power source is out of phase;

FIG. 8 is a circuit diagram of signal processing circuitry 202 according to one embodiment of the present invention;

FIG. 9 is a circuit diagram of signal indicator 203 according to one embodiment of the present invention;

fig. 10 is a circuit diagram of the ac-dc conversion unit 204 according to an embodiment of the present invention.

In the drawings the same reference numerals indicate similar or corresponding features and/or functions.

List of reference numerals：

100 gradient power amplifier

U-phase circuit of U-phase three-phase alternating current power supply

V-phase circuit of V three-phase alternating current power supply

W-phase line of W three-phase alternating current power supply

200 three-phase AC power supply detector

201 phase detection unit

202 signal processing circuit

203 signal indicator

204 ac-dc conversion unit

L₁First voltage leading-in terminal

L₂Second voltage leading-in terminal

L₃Third voltage leading-in terminal

O100 DC power supply

O101 first logic level signal

O102 second logic level signal

O103 first phase signal

O104 second phase signal

O105 third phase signal

R₁First/third current limiting resistor

R₂Second current limiting resistor

R₃Third current limiting resistor

R₄First pull-down resistor

R₅Second pull-down resistor

D₁First switch diode

D₂Second switch diode

D₃First voltage regulator diode

D₄Second voltage regulator diode

D₅First detection diode

D₆Second detection diode

IC1 first isolating switch

IC1-1 first input control terminal of first isolating switch IC1

Second input control terminal of IC1-2 first isolating switch IC1

IC1-3 first output controlled terminal of first isolating switch IC1

Second output controlled terminal of IC1-4 first isolating switch IC1

IC2 second isolating switch

First input control terminal of IC2-1 second isolating switch IC2

Second input control terminal of IC2-2 second isolating switch IC2

First output controlled terminal of IC2-3 second isolating switch IC2

Second output controlled terminal of IC2-4 second isolating switch IC2

C₁First capacitor

C₂Second capacitor

PKD₁First peak detection holding sub-circuit

PKD₂Second peak detection holding sub-circuit

IC4 exclusive-OR gate

IC5, IC6, IC8, IC9 NAND gate

IC7 inverter

Current limiting resistor of R13, R14 and R15 signal indicator 203

Light emitting diodes of the D14, D15 and D16 signal indicators 203

R₆、R₇、R₈Current-limiting resistor of AC-DC conversion unit 204

C₃Third capacitance

C₄Fourth capacitor

C₅Fifth capacitor

D₇、D₈、D₉、D₁₀、D₁₁、D₁₂Six diodes constituting a rectifier circuit

Z1 zener diode

R₉、R₁₀Power resistor with current limiting function

Q1 NPN type triode

R₁₁、R₁₂Signal resistor

C₆Decoupling capacitor

IC3 three-terminal output voltage adjustable voltage stabilizing chip

Detailed Description

Preferred embodiments of the present invention will be described below in more detail with reference to the accompanying drawings. It is to be understood that the following embodiments are exemplary, but not restrictive, in that they are used only for the purpose of illustrating the principles of the present invention, and are not intended to limit the scope of the utility model.

At present, a conventional three-phase power supply detection scheme utilizes a plurality of optocouplers and corresponding operational amplifier circuits, and combines a microcontroller to detect a phase failure. For example, a microcontroller such as a dedicated single chip Microcomputer (MCU) or a Digital Signal Processor (DSP) is used to analyze waveform phase information of an output signal to determine whether a phase loss or a phase inversion occurs in a three-phase power supply. However, such a microcontroller is complicated in structure, and there is a program running error, abnormality, or crash (crash) due to damage or malfunction of the device. Moreover, since such a microcontroller is expensive and needs to be programmed, the development cycle of the whole three-phase power supply detection scheme is long and the cost is high. Furthermore, since the operating power supply of the microcontroller comes from an external device, it is not easy to integrate with other circuits in the gradient power amplifier.

The inventor of the utility model notices that in the application scene of the medical gradient amplifier, the three-phase alternating current power supply connected to the gradient amplifier usually only has phase loss of any phase of U phase, V phase and W phase, or does not have phase loss; without the occurrence of phase loss or phase inversion of more than two phases. Therefore, in order to make the circuit simpler, reduce the cost, and at the same time improve the reliability of detection, the inventors of the present invention have proposed a three-phase ac power supply detector implemented by a hardware circuit not including a microcontroller, to allow an engineer to detect the presence or absence of a phase of each phase voltage in a three-phase power supply.

Fig. 1 is a schematic diagram of a gradient power amplifier 100 according to one embodiment of the utility model. The input of the gradient power amplifier 100 includes a three-phase ac power supply detector 200 (described in detail below) to receive the U-phase, V-phase and W-phase input voltages of the three-phase ac power supply. Fig. 2 specifically illustrates a three-phase ac power detector 200 according to an embodiment of the present invention. In the context of the present invention, a three-phase ac power supply detector 200 may be used for the medical gradient power amplifier 100. However, those skilled in the art will appreciate that the detector 200 of the present invention may be used in other applications requiring three-phase AC power. For example, such detectors are easily integrated into other three-phase converter applications (e.g., amplifiers, UPS, converters, power supplies, etc.).

Referring to fig. 2, the three-phase ac power source detector 200 includes a phase detection unit 201 configured to generate a first logic level signal O101 and a second logic level signal O102 based on a first phase voltage U, a second phase voltage V, and a third phase voltage W in the three-phase ac power source to detect the presence or absence of a phase of each phase voltage in the three-phase power source.

Next, the phase detection unit 201 proposed by the present invention is specifically described and explained with continuing reference to fig. 2 and with reference to fig. 3A to 3E.

According to one example of the present invention, the phase detection unit 201 includes a first phase detection circuit and a second phase detection circuit. In this example, the first phase detection circuit includes a first isolation switch IC 1. As shown in fig. 3A to 3E, a first phase voltage U (i.e., the voltage of the U-phase line) and a second phase voltage V (i.e., the voltage of the V-phase line) in the three-phase ac power supply are respectively passed through a first voltage introduction terminal L₁And a second voltage lead-in terminal L₂Is applied to the first input control terminal IC1-1 and the second input control terminal IC1-2 of the first isolating switch IC 1. The second phase detection circuit second isolation switch IC 2. As shown in fig. 3A to 3E, the first-phase voltage U and the third-phase voltage W (i.e., the voltage of the W-phase line) in the three-phase ac power supply are respectively passed through the first voltage introduction terminal L₁And a third voltage lead-in terminal L₃Is applied to the first input control terminal IC2-1 and the second input control terminal IC2-2 of the second isolation switch IC 2. In the example of fig. 3A-3E, the first and second phase detection circuits share a first voltage lead-in L₁To receive the first phase voltage U. According to the utility model, the first voltage lead-in terminal L of the first and second phase detection circuit₁A second voltage lead-in terminal L₂And a third voltage lead-in terminal L₃May be connected directly to the respective conductors of the first phase voltage U, the second phase voltage V and the third phase voltage W. In other examples, the first and second phase detection circuits may each have a respective voltage input (not shown) for receiving the first phase voltage U externallyShown in the figure). In the context of the present invention, the term "disconnector" includes optical couplers (as shown in fig. 3B to 3D), solid-state relays (e.g., electromagnetic relays, as shown in fig. 3E), high-frequency relays, and other components having a disconnector function, wherein the optical couplers are driven by optical triggering, and the solid-state relays are driven by electromagnetic triggering. For example, if the "isolator switch" is an optocoupler, the first input control terminal IC1-1 or IC2-1 may be a positive input terminal of the optocoupler, and the second input control terminal IC1-2 or IC2-2 may be a negative input terminal of the optocoupler. According to the present invention, the first phase detection circuit is configured to generate a first logic level signal O101 according to a signal of the controlled output terminal of the first isolator IC1, and the second phase detection circuit is configured to generate a second logic level signal O102 according to a signal of the controlled output terminal of the second isolator IC2, wherein a combination of the first logic level signal O101 and the second logic level signal O102 indicates which phase voltage of the three-phase alternating current power source is out of phase.

According to the operation principle of the present invention, as shown in the embodiment of fig. 3A to 3E, for the UV phase, if any one of the U-phase and the V-phase is out of phase, the control terminal of the first isolator IC1 is floating, so that the first isolator IC1 does not work (i.e., is turned off). For the UW phase, if any one of the U-phase and the W-phase is out of phase, the control terminal of the second isolator IC2 is floating, and the second isolator IC2 does not operate (i.e., is turned off). If none of the three phase power supplies are open phase, both the first isolation switch IC1 and the second isolation switch IC2 are operating normally (i.e., closed).

Alternatively, in other examples, the first phase voltage may also be a voltage of a U-phase line or a voltage of a W-phase line; correspondingly, the second and third phase voltages can also be converted accordingly. In this case, the working principle of the present invention can be realized.

Table 1 shows the respective levels of the first and second logic level signals O101, O102 when none or only one of the three phases U, V, W is open-phase, in accordance with an example of the present invention.

TABLE 1

Phase state	O101	O102
			U-phase open-phase of three-phase power supply	0	0
V-phase open-phase of three-phase power supply	0	1
			W-phase open-phase of three-phase power supply	1	0
Three-phase power supply without phase loss	1	1

Where the logic level high is set to 1 and the logic level low is set to 0.

As shown in table 1, since the first logic level signal O101 is generated based on the voltages of the first phase U and the second phase V, the first isolation switch IC1 is closed and the first logic level signal O101 maintains the high level "1" as long as neither the U-phase nor the V-phase is open-phase. Otherwise, as long as either one of the U-phase and the V-phase is out of phase, the first isolation switch IC1 is turned off, and the first logic level signal O101 is at a low level "0". Also, since the second logic level signal O102 is generated based on the voltages of the first phase U and the third phase W, the second isolation switch IC2 is closed and the second logic level signal O102 maintains the high level "1" as long as neither the U-phase nor the W-phase is open-phase. Otherwise, as long as either one of the U-phase and the W-phase is open, the second isolation switch IC2 is turned off, and the second logic level signal O102 is low level "0". Therefore, according to the present invention, it is possible to determine which phase line of the three-phase ac power supply is out of phase based on only the combination of the levels of the first logic level signal O101 and the second logic level signal O102 without referring to the waveform shape and the phase of the output signal. In other examples, the first logic level signal O101 may also be a low level "0" when the first isolation switch IC1 is closed. Vice versa, the first logic level signal O101 may also be high level "1" when the first isolation switch IC1 is open. Accordingly, when the second isolation switch IC2 is closed, the second logic level signal O102 may also be a low level "0". Vice versa, the second logic level signal O102 may also be high level "1" when the second isolation switch IC2 is open.

The first logic level signal O101 and the second logic level signal O102 may be detected by any suitable means. For example, the first and second logic level signals may be detected and analyzed using a logic level detector, a logic level analyzer, the signal processing circuit 202 of the present invention as described in detail below, and the like. Thus, it is possible to directly determine whether the three-phase power supply is open-phase and which one of the three-phase power supply is open-phase based on the detected combination of the first and second logic level signals. Therefore, by adopting the detection scheme of the utility model, microcontrollers such as MCU, DSP and the like are not needed to analyze the waveform phase of the output signal, the cost is reduced, and the safety and the reliability of detection are improved.

Preferably, the phase detecting unit 201 may include a first current limiting resistor R₁(see FIGS. 3A, 3B, 3D and 3E)/R_1’(see FIG. 3C), a second current limiting resistor R₂(see FIGS. 3A-3E), a third current limiting resistor R₃(see FIGS. 3A-3E), and even a fourth current limiting circuitResistance R_1”(see FIG. 3C). Preferably, the first phase detection circuit and the second phase detection circuit share a first current limiting resistor R₁(see FIGS. 3A, 3B, 3D, and 3E) and are commonly passed through a first current limiting resistor R₁Is connected to the first voltage lead-in terminal L₁Thereby simplifying the overall circuit design. In this embodiment, the first phase voltage U is passed via a first current limiting resistor R₁Applied to the first input control terminal IC1-1 of the first isolating switch IC1 and the first input control terminal IC2-1 of the second isolating switch IC2, the second phase voltage V is passed through the second current limiting resistor R₂Is applied to a second input control terminal IC1-2 of the first isolating switch IC1, and a third phase voltage W is passed through a third current limiting resistor R₃Is applied to the second input control terminal IC2-2 of the second isolation switch IC 2.

In other embodiments, the first phase detection circuit may have a first current limiting resistor R_1’And a second current limiting resistor R₂And the second phase detection circuit may have a fourth current limiting resistor R_1”And a third current limiting resistor R₃(see FIG. 3C). In this embodiment, the first phase voltage U is passed via a first current limiting resistor R_1’And a fourth current limiting resistor R_1”Applied to the first input control terminal IC1-1 of the first isolating switch IC1 and the first input control terminal IC2-1 of the second isolating switch IC2, respectively, and the second phase voltage V is passed through the second current limiting resistor R₂Is applied to a second input control terminal IC1-2 of the first isolating switch IC1, and a third phase voltage W is passed through a third current limiting resistor R₃Is applied to a second input control terminal IC2-2 of the second isolation switch IC 2.

The resistance value of the current-limiting resistor can be set or selected according to specific application, and aims to limit the magnitude of the current of the branch circuit where the current is located so as to prevent the series-connected components from being burnt due to overlarge current. However, those skilled in the art will appreciate that in appropriate application scenarios, the current limiting resistor R₁、R₂、R₃And may be omitted to simplify the overall design of the phase detection circuit. In this case, the input control terminals of the first and second

disconnection switch ICs

1 and 2 may be directly connected to the first voltage introduction terminalL₁A second voltage lead-in terminal L₂And a third voltage lead-in terminal L₃Wherein the first input control terminal IC1-1 of the first isolation switch IC1 and the first input control terminal IC2-1 of the second isolation switch IC2 are commonly connected to the first voltage leading-in terminal L₁。

In one example, with continued reference to fig. 3A-3E, the first phase detection circuit may include at least a first isolation switch IC1, a first power supply O100, a first pull-down resistor R₄And a first peak detect hold sub-circuit PKD₁. In the example of fig. 3B-3D, a first output controlled terminal IC1-3 of a first isolator IC1 (e.g., a first optocoupler) is connected to a first power supply O100, and a first pull-down resistor R is connected at a second output controlled terminal IC1-4 of the first optocoupler IC1₄And the first peak detection holding sub-circuit PKD₁Connected in parallel and a first pull-down resistor R₄And the other end of the same is grounded. In the present embodiment, the first power source O100 is preferably provided by an ac/dc conversion unit 204 (described in detail below) of the three-phase ac power source detector 200, and the operating voltage thereof is +5V, for example. However, it will be appreciated by those skilled in the art that the first power supply O100 may also be implemented as a separate +5V voltage source.

In this example, the first peak detect hold sub-circuit PKD₁May comprise a first detector diode D in series₅And a first capacitor C₁. First detector diode D₅Is connected with the second output controlled terminal IC1-4 of the first optical coupler IC 1. First detector diode D₅And the negative terminal of the first capacitor C₁Is configured to output a first logic level signal O101. A first capacitor C₁And the other end of the same is grounded.

According to the utility model, the peak detection holding sub-circuit is used for collecting and holding the peak value of the output signal of the controlled end of the isolating switch. Thus, the holding sub-circuit PKD for the first peak detection₁For example, if the isolation switch is normally operated, the output of the first logic level signal O101 is 1; otherwise, the first logic level signal O101 is output as 0.

Preferably, for example, if the input voltage of a three-phase AC power supplyThe first phase detection circuit may further include a first switching diode D₁. In the illustrated exemplary embodiment, the first phase voltage U is fed via a first voltage feed L₁Is applied to a first switching diode D₁A forward terminal of the first switching diode D₁Is connected to a first input control terminal IC1-1 of the first isolator IC1 (e.g., a positive input terminal IC1-1 of the optocoupler IC 1). Alternatively, the second phase voltage V is fed via a second voltage feed L₂Is applied to a first switching diode D₁And the positive terminal of the first switching diode D1 is connected to the second input control terminal IC1-2 of the first isolator switch IC1 (e.g., the negative input terminal IC1-2 of the optocoupler IC1), as shown in fig. 3D. In the case that the first isolation switch IC1 is a first optocoupler (see fig. 3B to 3D), if the input voltage is not high (e.g., the input voltage does not exceed the voltage endurance limit of the input control terminal of the optocoupler), the first switching diode D may be omitted₁(not shown).

With continued reference to fig. 3A-3E, the second phase detection circuit may include a second isolation switch IC2, a second power supply O100, and a second pull-down resistor R₅And a second peak detect hold sub-circuit PKD₂. In the examples of fig. 3B-3D, a first output controlled terminal IC2-3 of a second isolator IC2 (e.g., a second optocoupler) is connected to a second power supply O100, and a second pull-down resistor R is connected at a second output controlled terminal IC2-4 of the second optocoupler IC2₅And a second peak detect hold sub-circuit PKD₂Connected in parallel, and a second pull-down resistor R₅And the other end of the same is grounded. In the present embodiment, since both the first and second power sources are preferably provided by the ac-dc conversion unit 204 of the three-phase ac power source detector 200, both the first and second power sources are denoted by the same reference numeral O100. It will be appreciated by those skilled in the art that the first and second power supplies may also be indicated with different reference numerals if they are implemented as separate voltage sources of, for example, + 5V.

In this example, the second peak detect hold sub-circuit PKD₂May comprise a second detector diode D in series₆And a second capacitor C₂. Second examinationWave diode D₆And the positive end of the second optical coupler IC2 is connected with a second output controlled end IC2-4 of the second optical coupler IC 2. Second detector diode D₆Negative terminal of and the second capacitor C₂Is configured to output a second logic level signal O102. Second capacitor C₂And the other end of the same is grounded. Holding sub-circuit PKD for second peak detection₂On the other hand, if the circuit works normally, the output of the first logic level signal O102 is 1; otherwise, the first logic level signal O102 is output as 0.

Preferably, the second phase detection circuit may further include a second switching diode D, for example, if the input voltage of the three-phase ac power supply is high₂. In the illustrated exemplary embodiment, the first phase voltage U is fed via a first voltage feed L₁Is applied to the second switching diode D₂And a second switching diode D₂Is connected to a first input control terminal IC2-1 (e.g., a positive input terminal IC2-1 of an optocoupler IC2) of the second isolator IC 2. Alternatively, the third phase voltage W is fed via a third voltage supply L₃Is applied to the second switching diode D₂And a second switching diode D₂Is connected to the second input control terminal IC2-2 of the second isolator switch IC2 (e.g., the negative input terminal IC2-2 of the optocoupler IC2), as shown in fig. 3D. In the case that the second isolation switch IC2 is a second optical coupler (see fig. 3B to 3D), if the input voltage is not high (for example, the input voltage does not exceed the withstand voltage limit of the input control terminal of the optical coupler), the second switching diode D may be omitted₂(not shown).

In a preferred example, the first and second phase detection circuits may further include first zener diodes D, respectively₃And a second zener diode D₄To protect the isolation switches, such as the first and second

isolation switch ICs

1 and 2, from being damaged by the reverse voltage. First voltage regulator diode D₃The first input control terminal IC1-1 and the second input control terminal IC1-2 of the first isolating switch IC1 are connected in opposite conducting directions to the input control terminal of the first isolating switch IC 1. Likewise, a second zener diode D₄Conduction with input control terminal of second isolation switch IC2The direction of the first input control terminal IC2-1 and the second input control terminal IC2-2 of the second isolating switch IC2 are opposite. It will be appreciated by those skilled in the art that the first zener diode D may be omitted to simplify the circuit₃And a second zener diode D₄(not shown).

In fig. 4, (a) schematically shows a waveform diagram of a three-phase alternating current power supply in a normal phase state; (b) a waveform diagram of the second output controlled terminal IC1-4 of the first isolation switch IC1 under normal phase conditions is schematically shown; (c) a waveform diagram of the second output controlled terminal IC2-4 of the second isolation switch IC2 in a normal phase state is schematically shown; (d) a waveform diagram schematically showing the first logic level signal O101 in the normal phase state; and (e) schematically shows a waveform diagram of the second logic level signal O102 in the normal phase state.

In fig. 5, (a) schematically shows a waveform diagram of a three-phase alternating-current power supply when the U-phase line is out of phase; (b) the waveform diagram of the second output controlled terminal IC1-4 of the first isolating switch IC1 when the U-phase line is out of phase is schematically shown; (c) a waveform diagram of a second output controlled terminal IC2-4 of the second isolation switch IC2 when the U-phase line is out of phase is schematically shown; (d) a waveform diagram schematically showing the first logic level signal O101 when the U-phase line is out of phase; and (e) schematically shows a waveform diagram of the second logic level signal O102 when the U-phase line is out of phase.

In fig. 6, (a) schematically shows a waveform diagram of a three-phase alternating-current power supply when the V-phase line is out of phase; (b) the waveform diagram of the second output controlled terminal IC1-4 of the first isolating switch IC1 when the phase V line is out of phase is schematically shown; (c) a waveform diagram of the second output controlled terminal IC2-4 of the second isolation switch IC2 when the phase V-phase line is out of phase is schematically shown; (d) a waveform diagram schematically showing the first logic level signal O101 when the phase V-phase line is out of phase; and (e) schematically shows a waveform diagram of the second logic level signal O102 when the V-phase line is out of phase.

In fig. 7, (a) schematically shows a waveform diagram of a three-phase alternating-current power supply when the W-phase line is out of phase; (b) the waveform diagram of the second output controlled terminal IC1-4 of the first isolating switch IC1 when the W-phase line is out of phase is schematically shown; (c) a waveform diagram of a second output controlled terminal IC2-4 of the second isolation switch IC2 when the W-phase line is out of phase is schematically shown; (d) a waveform diagram schematically showing the first logic level signal O101 when the W-phase line is out of phase; and (e) schematically shows a waveform diagram of the second logic level signal O102 when the W phase line is out of phase.

As can be seen from fig. 4 to 7, the waveform diagrams of the first logic level signal O101 and the second logic level signal O102 are consistent with the results reflected in table 1.

Preferably, with continued reference to fig. 2, the detector 200 may further comprise a signal processing circuit 202 configured to receive the first and second logic level signals O101 and O102 from the first and second phase detection circuits and to generate a first phase signal O103 indicating phase presence or absence information of the first phase voltage U, a second phase signal O104 indicating phase presence or absence information of the second phase voltage V, and a third phase signal O105 indicating phase presence or absence information of the third phase voltage W, respectively, based on a combination of the first and second logic level signals.

Table 2 shows the respective level outputs of the first phase signal O103, the second phase signal O104 and the third phase signal O105 in response to different level output combinations of the first logic level signal O101 and the second logic level signal O102 according to an example of the present invention.

TABLE 2

O101/O102	O103/U phase	O104/V phase	O105/W phase
				0/0	0	1	1
0/1	1	0	1
				1/0	1	1	0
1/1	1	1	1

Where the logic level high is set to 1 and the logic level low is set to 0.

As shown in table 2, which of the first phase signal O103, the second phase signal O104, and the third phase signal O105 is at the low level "0" means that the wire of the corresponding phase in the three-phase power supply is out of phase. Conversely, if all three phase signals are at a high level "1", it means that none of the three phase power supplies is out of phase. Therefore, according to the present invention, when the detector 200 includes the signal processing circuit 202, a microcontroller such as an MCU, a DSP, or the like is not required to detect and analyze the first and second logic level signals, thereby reducing costs and improving safety and reliability of detection. Those skilled in the art will appreciate that the signal processing circuit 202 may be implemented as a hardware circuit comprising diodes, amplifiers, resistors, etc., as long as it implements the functions of table 2.

Likewise, the first phase signal O103, the second phase signal O104, and the third phase signal O105 may be detected by any suitable means. For example, the first, second, and third phase signals may be detected and analyzed using a logic level detector, a logic level analyzer, or the like.

In one example of fig. 8, the signal processing circuit 202 may include logic gate chip ICs 4-IC 9, where IC4 is an exclusive or gate; IC5, IC6, IC8, IC9 are nand gates, and IC7 is an inverter. The combination of these logic gate chips can convert and decode the state combination of the first logic level signal O101 and the second logic level signal O102, so as to obtain the phase missing information of the three-phase alternating current from the first phase signal O103, the second phase signal O104 and the third phase signal O105, wherein 0 represents that the phase is missing, and 1 represents that the phase is not missing.

Preferably, with continued reference to fig. 2, the detector 200 may further comprise a signal indicator 203 connected to the signal processing circuit 202 to receive the first, second and third phase signals O103, O104 and O105 and configured to visually and/or audibly output respective phase presence or absence information in response to the first, second and third phase signals O103, O104 and O105. In the simplest implementation, the signal indicator 203 may comprise three branches, each branch comprising a current limiting resistor and a light emitting diode. One end of the current limiting resistor of each branch is connected to the output of the signal processing circuit 202 to receive the corresponding phase present or absent signal. The other end of the current-limiting resistor is connected to the positive end of the light-emitting diode, and the negative end of the light-emitting diode is grounded. In one example of fig. 9, the first branch of the signal indicator 203 includes a current limiting resistor R13 and a light emitting diode D14 connected in series, wherein the current limiting resistor R13 is connected to the signal processing circuit 202 to receive the first phase signal O103, and a positive terminal of the light emitting diode D14 is connected to the current limiting resistor R13 and a negative terminal thereof is connected to ground; the second branch of the signal indicator 203 comprises a current limiting resistor R14 and a light emitting diode D15 connected in series, wherein the current limiting resistor R14 is connected to the signal processing circuit 202 to receive the second phase signal O104, and the positive terminal of the light emitting diode D15 is connected to the current limiting resistor R14 and the negative terminal thereof is connected to ground; the third branch of the signal indicator 203 comprises a current limiting resistor R15 and a light emitting diode D16 connected in series, wherein the current limiting resistor R14 is connected to the signal processing circuit 202 to receive the third phase signal O105, and the positive terminal of the light emitting diode D16 is connected to the current limiting resistor R15 and the negative terminal thereof is connected to the ground. Thus, according to table two, when the phase signal is at high level "1", the corresponding led is lit. Conversely, when the phase signal is at a low level "0", the corresponding led is extinguished, thereby indicating that the corresponding phase line is open.

In another example (not shown), instead of the signal processing circuit 202, the phase detection unit may be followed by a further signal indicator directly. The further signal indicator may comprise two branches, each branch comprising a current limiting resistor and a light emitting diode. One end of the current limiting resistor of each branch circuit is connected to one output end of the phase detection unit so as to receive the corresponding logic level signal. The other end of the current-limiting resistor is connected to the positive end of the light-emitting diode, and the negative end of the light-emitting diode is grounded. According to table one, when the logic level signal is high level "1", the corresponding led is turned on. In contrast, when the logic level signal is a low level "0", the corresponding light emitting diode is turned off. Accordingly, by combining the on/off information of the two light emitting diodes, it is possible to determine which phase line has the phase failure.

Preferably, with continued reference to fig. 2, the detector 200 may further include an ac-dc conversion unit 204 configured to externally connect the first phase voltage U, the second phase voltage V, and the third phase voltage W of the three-phase ac power source and convert the ac voltage of the three-phase ac power source into a dc voltage. More preferably, the ac/dc conversion unit 204 may be further configured to supply the dc voltage to at least one of the phase detection unit 201, the signal processing circuit 202, and the signal indicator 203, respectively.

In one example, the ac-dc conversion unit 204 may preferably include at least a rectifier circuit and a zener diode connected in parallel with the rectifier circuit. More preferably, the rectifier circuit may include six diodes. Those skilled in the art will appreciate that the rectifier circuit may be implemented using other known circuits, as long as it converts ac power to dc power.

In one example of fig. 10, the first phase voltage U is via a current limiting resistor R connected in series₆And a third capacitance C₃The first branch of the rectifier circuit connected to the ac-dc conversion unit 204, the second phase voltage V via the series current limiting resistor R₇And a fourth capacitance C₄A second branch of the rectifier circuit of the ac-dc converter unit 204 is connected in, and the third phase voltage W is passed via a series-connected current-limiting resistor R₈And a fifth capacitance C₅And a third branch of the rectifier circuit of the ac-dc conversion unit 204 is connected. The rectifier circuit of the ac-dc conversion unit 204 comprises six diodes D₇、D₈、D₉、D₁₀、D₁₁And D₁₂. The rectifier circuit is connected in parallel with a zener diode Z1. As shown in FIG. 10, R₉、R₁₀、IC3、Q1、R₁₁、R₁₂、 C₆Forming an adjustable linear voltage-stabilizing direct-current power supply sub-circuit. R is₉And R₁₀Is a power resistor that functions as a current limiting. Q1 is an NPN transistor that enhances the current capacity of the circuit. R₁₁And R₁₂The combination of the signal resistors can realize the voltage value adjustment of the output voltage O100. C₆Is a decoupling capacitor. IC3 is a three-terminal output voltage adjustable voltage regulator chip, such as TL 431. Collector of Q1 via R₉In parallel with the rectifier circuit and zener diode Z1. R₁₀Connected across the collector and base of Q1. R in series₁₁And R₁₂And C₆Parallel to the emitter of Q1, where voltage O100 is output. The output of IC3 is connected to the base of Q1, and the regulation terminal of IC3 is connected to R₁₁And R₁₂In the meantime. Input terminal of IC3 and R₁₂And C₆And the other ends of the same are commonly grounded as shown in fig. 10.

In addition, those skilled in the art will appreciate that the ac/dc conversion unit 204 may be implemented in other ways as long as it can convert the ac voltage of the three-phase ac power source into a dc voltage suitable for the chip to operate. When the detector 200 includes the ac/dc converting unit 204, the dc voltage of the ac/dc converting unit 204 may be used as the power source O100 in the first and second phase detecting circuits. In this way, the detector 200 does not require a separate voltage source, thereby facilitating integration of the detector into existing three-phase electrical systems.

In the preferred embodiment shown in fig. 2, the three-phase ac power supply detector 200 includes a phase detection unit 201, a signal processing circuit 202, a signal indicator 203, and an ac/dc conversion unit 204. Thus, it is possible to safely and reliably detect whether or not the three-phase ac power supply is open-phase and which phase of the three-phase ac power supply is open-phase, without requiring a separate detection means or a dedicated microcontroller.

It should be noted that the above-mentioned embodiments illustrate rather than limit the utility model, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in a claim or in the description. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. In the system claims enumerating several units, several of these elements can be embodied by one and the same item of software and/or hardware. The use of the words "first", "second" and "third", etc. do not denote any order. These words are to be understood as names.

Claims

1. A three-phase alternating current power supply detector (200) for use in a gradient power amplifier, the detector comprising:

a phase detection unit (201) comprising a first phase detection circuit and a second phase detection circuit,

wherein the first phase detection circuit comprises a first isolating switch (IC1), a first phase voltage (U) and a second phase voltage (V) in a three-phase alternating current power supply are respectively applied to a first input control terminal (IC1-1) and a second input control terminal (IC1-2) of the first isolating switch (IC1), the first phase detection circuit generates a first logic level signal (O101) according to a signal of a controlled output terminal of the first isolating switch (IC1),

wherein the second phase detection circuit comprises a second isolating switch (IC2), a first phase voltage (U) and a third phase voltage (W) in the three-phase alternating current power supply are respectively applied to a first input control end (IC2-1) and a second input control end (IC2-2) of the second isolating switch (IC2), the second phase detection circuit generates a second logic level signal (O102) according to a signal of a controlled output end of the second isolating switch (IC2),

wherein a combination of the first logic level signal (O101) and the second logic level signal (O102) indicates which phase of the three-phase AC power supply is open-phase, and

wherein the first isolation switch (IC1) is open when either of the first phase voltage (U) and the second phase voltage (V) is out of phase, and the second isolation switch (IC2) is open when either of the first phase voltage (U) and the third phase voltage (W) is out of phase.

2. The detector of claim 1, wherein the phase detection unit (201) further comprises a first current limiting resistor (R)₁) A second current limiting resistor (R)₂) And a third current limiting resistor (R)₃)，

Wherein the first phase voltage is applied to the first input control terminal (IC1-1) of the first isolator switch (IC1) and the first input control terminal (IC2-1) of the second isolator switch (IC2) via the first current limiting resistor, the second phase voltage is applied to the second input control terminal (IC1-2) of the first isolator switch (IC1) via the second current limiting resistor, and the third phase voltage is applied to the second input control terminal (IC2-2) of the second isolator switch (IC2) via the third current limiting resistor.

3. The detector of claim 1, wherein the phase detection unit (201) further comprises a first current limiting resistor (R)₁'), a second current limiting resistor (R)₂) A third current limiting resistor (R)₃) And a fourth current limiting circuitResistor (R)₁”)，

Wherein the first phase voltage is applied to the first input control terminal (IC1-1) of the first isolating switch (IC1) and the first input control terminal (IC2-1) of the second isolating switch (IC2) via the first current limiting resistor and a fourth current limiting resistor, respectively, the second phase voltage is applied to the second input control terminal (IC1-2) of the first isolating switch (IC1) via the second current limiting resistor, and the third phase voltage is applied to the second input control terminal (IC2-2) of the second isolating switch (IC2) via the third current limiting resistor.

4. The detector of claim 1, wherein each of the phase detection circuits further comprises a switching diode (D)₁，D₂)，

Wherein the first phase voltage (U) is applied to the switching diode (D)₁，D₂) And a negative terminal of the switching diode is connected to the first input control terminal (IC1-1, IC2-1) of the respective isolation switch (IC1, IC 2).

5. The detector of claim 1, wherein each of the phase detection circuits further comprises a switching diode (D)₁，D₂)，

Wherein the second phase voltage (V) or the third phase voltage (W) is applied to the negative-going terminal (D) of the switching diode₁，D₂) And the forward terminals of the switching diodes are connected to the second input control terminals (IC1-2, IC2-1) of the respective isolation switches (IC1, IC 2).

6. The detector of claim 1, wherein each of said phase detection circuits further comprises a zener diode (D)₃，D₄) The voltage stabilizing diode is bridged between the first input control end and the second input control end of the isolating switch in a reverse conducting direction of the input control end of the corresponding isolating switch.

7. The detector of any of claims 1-6, wherein each of the phase detection circuits comprises a respective said isolation switch (IC1, IC2), a power supply (O100), a pull-down resistor (R)₄，R₅) And a peak detection hold sub-circuit (PKD)₁，PKD₂)，

Wherein a first output controlled terminal (IC1-3, IC2-3) of each of the isolation switches is connected with the power supply, the pull-down resistor is connected in parallel with the peak detection holding sub-circuit at a second output controlled terminal (IC1-4, IC2-4) of each of the isolation switches, and the other end of the pull-down resistor is grounded.

8. The detector of claim 7, wherein each of the peak detect hold sub-circuits (PKDs)₁，PKD₂) Comprising a detector diode (D) in series₅，D₆) And a capacitor (C)₁，C₂) The positive end of the detector diode is connected with the second output controlled end of the corresponding isolating switch, the common joint of the negative end of the detector diode and the capacitor is configured to output a corresponding logic level signal (O101, O102), and the other end of the capacitor is grounded.

9. The detector of any of claims 1-6, further comprising a signal processing circuit (202) comprised of a number of logic gate chips, the signal processing circuit configured to receive the first and second logic level signals (O101, O102) from the first and second phase detection circuits and to generate a first phase signal (O103) indicating phase presence or absence information of the first phase voltage, a second phase signal (O104) indicating phase presence or absence information of the second phase voltage, and a third phase signal (O105) indicating phase presence or absence information of the third phase voltage, respectively, based on a combination of the first and second logic level signals.

10. The detector of claim 9, wherein the detector further comprises a signal indicator (203),

wherein the signal indicator is connected to the signal processing circuit to receive the first, second and third phase signals and is configured to visually and/or audibly output corresponding phase presence or absence information in response to the first, second and third phase signals, respectively, or

Wherein the signal indicator is connected to the respective outputs of the first and second phase detection circuits to receive the first and second logic level signals and is configured to visually and/or audibly output corresponding phase presence or absence information in response to a combination of the first and second logic level signals.

11. The detector of claim 10, further comprising a ac-to-dc conversion unit (204) configured to externally connect the first phase voltage (U), the second phase voltage (V), and the third phase voltage (W) of the three-phase ac power source and convert the ac voltage of the three-phase ac power source into a dc voltage, wherein the ac-to-dc conversion unit is further configured to supply the dc voltage to at least one of the phase detection unit, the signal processing circuit, and the signal indicator, respectively.

12. The detector of claim 11, wherein the ac-to-dc conversion unit includes a rectifier circuit and a zener diode connected in parallel with the rectifier circuit.

13. The detector of claim 11, wherein a dc voltage output by said ac to dc conversion unit is used as said power supply in each of said phase detection circuits.

14. A gradient power amplifier (100) comprising a three-phase alternating current power supply detector (200) according to any one of claims 1-13.