CN102290822A - Method for weakening impacts of PET-CT (position emission computed tomography) startup on power grid - Google Patents

Abstract

The invention relates to a method for weakening impacts of PET-CT startup on a power grid, which is realized by a device for weakening the impacts of PET-CT startup on the power grid. The device comprises a PFC (power factor correction) circuit, wherein an input end of the PFC circuit is connected with an AC (alternating current) power supply and an output end of the AC power supply is connected with an inverter of a PET-CT scanning rack drive motor. The method comprises the following steps: connecting an output end of the PFC circuit with a local energy-storage element in parallel and connecting the local energy-storage element with the inverter in parallel; when the scanning rack drive motor is started, discharging the PFC circuit and the local energy-storage element to supply power for the scanning rack drive motor; and after a scanning rack runs normally, supplying the power for the scanning rack drive motor by the PFC circuit, and charging the local energy-storage element. The method is utilized to meet the required power when the PET-CT scanning rack is started, thus reducing the requirement of the power grid capacity at the time of starting the scanning rack and weakening the impacts on the power grid.

Description

A kind of PET-CT that weakens starts the method that electrical network is impacted

Technical field

The present invention relates to the PET-CT field of electric drive, particularly relate to a kind of PET-CT of weakening and start the method that electrical network is impacted.

Background technology

Positron computer x-ray tomography (PET-CT:Positron Emission Computed Tomography, hereinafter to be referred as PET-CT) be the 3-dimensional image guiding tool, under image-guided, playing the part of important role in the innovation of radiotherapy notion and the application, PET-CT has outstanding information gathering ability, has also caused PET-CT scanning gantry overweight simultaneously; Make PET-CT start, the power difference of demand is bigger during operate as normal, force electrical network to supply with big electric current and cause pressure drop of grid to increase; The impact that when PET-CT starts electrical network is caused is excessive, has increased the requirement of PET-CT to net capacity.

Summary of the invention

Technical problem to be solved by this invention provides a kind of CT of weakening and starts the method that electrical network is impacted, and reduces the impact that electrical network is caused when PET-CT starts.

The technical solution adopted for the present invention to solve the technical problems is: provide a kind of PET-CT of weakening to start the method that electrical network is impacted, this method starts the device realization that electrical network is impacted by weakening PET-CT, this device comprises pfc circuit, the input of described pfc circuit links to each other with AC power, and output links to each other with the inverter that is connected with PET-CT scanning gantry drive motors; May further comprise the steps: at the output of pfc circuit local energy-storage travelling wave tube in parallel, and local energy-storage travelling wave tube is in parallel with inverter; When PET-CT scanning gantry drive motors started, pfc circuit and local energy-storage travelling wave tube discharged and are the power supply of PET-CT scanning gantry drive motors; After the normal operation of PET-CT scanning gantry, be the power supply of PET-CT scanning gantry drive motors by pfc circuit, and be local energy-storage travelling wave tube charging simultaneously.

Described local energy-storage travelling wave tube is super capacitor or storage battery.

Described AC power is the 220V AC power.

Also comprise rectifier bridge and filter capacitor between the input of described pfc circuit and the AC power; The input of described rectifier bridge links to each other with AC power, and output links to each other with filter capacitor; Described filter capacitor is connected in parallel on the input of described pfc circuit.

Beneficial effect

Owing to adopted above-mentioned technical scheme, the present invention compared with prior art, have following advantage and good effect: the present invention is on the basis that does not change original CT performance, structure, by adding a local energy-storage travelling wave tube (for example super capacitor or storage battery), pruning by this part energy-storage travelling wave tube starts the spike of scanning machine posture power demand, improves driving power power output capacity when CT starts.Slackened when CT is interim the impact of electrical network, reduced the demand of CT capacitance.

Description of drawings

Fig. 1 is the used PET-CT scanning gantry driven by power structural representation of the present invention;

Fig. 2 is the working cycle diagram of scanning gantry drive motors;

Fig. 3 is the used power-actuated structural representation of PET-CT scanning gantry of embodiment 1;

Fig. 4 is the used power-actuated structural representation of PET-CT scanning gantry of embodiment 2.

Embodiment

Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiment only to be used to the present invention is described and be not used in and limit the scope of the invention.Should be understood that in addition those skilled in the art can make various changes or modifications the present invention after the content of having read the present invention's instruction, these equivalent form of values fall within the application's appended claims institute restricted portion equally.

Embodiments of the present invention relate to a kind of PET-CT of weakening and start the method that electrical network is impacted, and this method realizes the device that electrical network impacts by weakening the PET-CT startup, as shown in Figure 1, comprises rectifier bridge 1, inverter 2 and PET-CT scanning gantry drive motors 3; Described rectifier bridge 1 input is connected with AC power 4, output is connected with filter capacitor 5, and described inverter 2 links to each other with PET-CT scanning gantry drive motors 3, and described device also comprises pfc circuit 6, the input of described pfc circuit 6 links to each other with filter capacitor 5, and output links to each other with inverter 2.This method may further comprise the steps: at the output of pfc circuit 6 local energy-storage travelling wave tube 7 in parallel, and local energy-storage travelling wave tube 7 is in parallel with inverter 2; When PET-CT scanning gantry drive motors started, pfc circuit and local energy-storage travelling wave tube discharged and are the power supply of PET-CT scanning gantry drive motors; After the normal operation of PET-CT scanning gantry, be the power supply of PET-CT scanning gantry drive motors by pfc circuit, and be local energy-storage travelling wave tube charging simultaneously.

Be not difficult to find, the present invention is not changing original PET-CT scanning gantry performance, on the basis of structure, by adding a local energy-storage travelling wave tube, prune by this part energy-storage travelling wave tube and to start the spike of scanning machine posture power demand, improve driving power power output capacity when PET-CT starts, promptly in the scanning gantry start-up course, by pfc circuit and local energy-storage travelling wave tube discharge while drive motors, required electric energy when starting to satisfy the PET-CT scanning gantry, to the demand of net capacity, weakened impact when having reduced the startup of PET-CT scanning gantry to electrical network.

With two embodiment the present invention is further described below.

Embodiment 1: a kind of weakening PET-CT based on super capacitor starts the method that electrical network is impacted, and this method realizes the device that electrical network impacts by weakening the PET-CT startup, as shown in Figure 3, comprises rectifier bridge 1, inverter 2 and PET-CT scanning gantry drive motors 3; Described rectifier bridge 1 input is connected with 220V AC power 4, output is connected with filter capacitor 5, and described inverter 2 links to each other with PET-CT scanning gantry drive motors 3, and described device also comprises pfc circuit 6, the input of described pfc circuit 6 links to each other with filter capacitor 5, and output links to each other with inverter 2.Super capacitor 7-1 is connected between pfc circuit 6 and the inverter 2, it is the output that described super capacitor 7-1 is connected in parallel on pfc circuit 6, and it is simultaneously in parallel with inverter 2, discharge by super capacitor 7-1, assist pfc circuit 6 to start the PET-CT scanning gantry, to remedy the drawback of pfc circuit outputting power deficiency, make the PET-CT scanning gantry start more steadily, rapidly.

Fig. 2 adopts the working cycle diagram of the scanning gantry drive motors behind the present invention, the Discovery ST CT that produces with U.S. GE company is an objective for implementation, learn that Discovery ST PET-CT scanning gantry drive motors is in one-period, among the figure, heavy line is the power output of inverter, fine line is a motor working current, and dotted line is the electrical network input current, and the square frame line is the magnitude of voltage of super capacitor.Be t start-up time ₁, starting power is p ₁, promptly the PET-CT scanning gantry startup stage; Parallel-adder settle-out time is t ₂, stable operation power is p ₂, i.e. PET-CT scanning gantry stable operation stage; The regenerative braking time is t ₃, regenerative brake power is p ₃, i.e. PET-CT scanning gantry regenerative braking stage; Downtime that powers on is t ₄, powering on and shutting down power is p ₄(supposing to be close to 0), i.e. PET-CT scanning gantry idle stop stage.The startup stage of the PET-CT scanning gantry, PET-CT scanning gantry drive motors operating current is greater than the electrical network input current as can be seen from Figure.

Super capacitor stored voltage value and electrical network input current stack back operating current lucky and motor coincide mutually as can be seen from Figure 2.Wherein, the major parameter of super capacitor and pfc circuit can be obtained according to following equation.

$p_1{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HDA0000082916340000011.png,HDA0000082916340000021.png"\; state="\{\{state\}\}">t</figure-callout>}}_1=(0.5*C*{\mathrm{<figure-callout\; id="2"\; label="U"\; filenames="HDA0000082916340000011.png,HDA0000082916340000022.png"\; state="\{\{state\}\}">U</figure-callout>}}_2^2-0.5*{\mathrm{<figure-callout\; id="1"\; label="U"\; filenames="HDA0000082916340000011.png,HDA0000082916340000021.png"\; state="\{\{state\}\}">U</figure-callout>}}_1^2)*{\mathrm{\&eta;}}_1+P_{\mathrm{PFC}}*{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HDA0000082916340000011.png,HDA0000082916340000021.png"\; state="\{\{state\}\}">t</figure-callout>}}_1$

E _all＝p ₁t ₁+p ₂t ₂-p ₃t ₃

$P_{\mathrm{PFC}}=\frac{E_{\mathrm{all}}}{{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HDA0000082916340000011.png,HDA0000082916340000021.png"\; state="\{\{state\}\}">t</figure-callout>}}_1+{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HDA0000082916340000011.png,HDA0000082916340000022.png"\; state="\{\{state\}\}">t</figure-callout>}}_2+{\mathrm{<figure-callout\; id="3"\; label="t"\; filenames="HDA0000082916340000021.png,HDA0000082916340000022.png"\; state="\{\{state\}\}">t</figure-callout>}}_3{+\mathrm{<figure-callout\; id="4"\; label="t"\; filenames="HDA0000082916340000022.png"\; state="\{\{state\}\}">t</figure-callout>}}_4}$

In the following formula, C is the rated capacity of super capacitor; η ₁Efficiency for charge-discharge for super capacitor; E _AllBe scanning gantry required gross energy in a complete work period; P _PFCFor scanning gantry in a complete work period, the average output power of pfc circuit; U ₁, U ₂Voltage when being followed successively by the beginning voltage of electric capacity in a work period and starting end.In actual applications, for shortening the start preheating stand-by period or satisfying power demand under the idle machine state, the average output power P of pfc circuit _PFCCan elect bigger numerical value as.

Embodiment 2: a kind of weakening PET-CT based on storage battery starts the method that electrical network is impacted, as shown in Figure 4, this method starts the device realization that electrical network is impacted by weakening PET-CT, as shown in Figure 3, comprises rectifier bridge 1, inverter 2 and PET-CT scanning gantry drive motors 3; Described rectifier bridge 1 input is connected with 220V AC power 4, output is connected with filter capacitor 5, and described inverter 2 links to each other with PET-CT scanning gantry drive motors 3, and described device also comprises pfc circuit 6, the input of described pfc circuit 6 links to each other with filter capacitor 5, and output links to each other with inverter 2.Storage battery 7-2 is connected between pfc circuit 6 and the inverter 2, it is the output that described storage battery 7-2 is connected in parallel on pfc circuit 6, and it is simultaneously in parallel with inverter 2, discharge by storage battery 7-2, assist pfc circuit 6 to start the PET-CT scanning gantry, to remedy the drawback of pfc circuit outputting power deficiency, make the PET-CT scanning gantry start more steadily, rapidly.

Fig. 2 adopts the working cycle diagram of the scanning gantry drive motors behind the present invention, the Discovery ST CT that produces with U.S. GE company is an objective for implementation, learn that Discovery ST PET-CT scanning gantry drive motors is in one-period, among the figure, heavy line is the power output of inverter, fine line is a motor working current, and dotted line is the electrical network input current, and the square frame line is the dump energy of storage battery.Be t start-up time ₁, starting power is p ₁, promptly the PET-CT scanning gantry startup stage; Parallel-adder settle-out time is t ₂, stable operation power is p ₂, i.e. PET-CT scanning gantry stable operation stage; The regenerative braking time is t ₃, regenerative brake power is p ₃, i.e. PET-CT scanning gantry regenerative braking stage; Downtime that powers on is t ₄, powering on and shutting down power is p ₄(supposing to be close to 0), i.e. PET-CT scanning gantry idle stop stage.The startup stage of the PET-CT scanning gantry, PET-CT scanning gantry drive motors operating current is greater than the electrical network input current as can be seen from Figure.

The dump energy of storage battery and electrical network input current stack back operating current lucky and motor coincide mutually as can be seen from Figure 2.The major parameter of storage battery and pfc circuit can be obtained according to following equation.

p ₁*t ₁＝U*C _n*η ₁+P _PFC*t ₁

E _all＝p ₁t ₁+p ₂t ₂-p ₃t ₃

$P_{\mathrm{PFC}}=\frac{E_{\mathrm{all}}}{{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HDA0000082916340000011.png,HDA0000082916340000021.png"\; state="\{\{state\}\}">t</figure-callout>}}_1+{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HDA0000082916340000011.png,HDA0000082916340000022.png"\; state="\{\{state\}\}">t</figure-callout>}}_2+{\mathrm{<figure-callout\; id="3"\; label="t"\; filenames="HDA0000082916340000021.png,HDA0000082916340000022.png"\; state="\{\{state\}\}">t</figure-callout>}}_3{+\mathrm{<figure-callout\; id="4"\; label="t"\; filenames="HDA0000082916340000022.png"\; state="\{\{state\}\}">t</figure-callout>}}_4}$

In the following formula, U is the output voltage of storage battery; C _nBe battery rating; η ₁Be charging and discharging of accumulator efficient; E _AllBe scanning gantry required gross energy in a complete work period; P _PFCFor scanning gantry in a complete work period, the average output power of pfc circuit.

Claims (4)

1. one kind weakens the method that the PET-CT startup is impacted electrical network, it is characterized in that, this method starts the device realization that electrical network is impacted by weakening PET-CT, this device comprises pfc circuit, the input of described pfc circuit links to each other with AC power, and output links to each other with the inverter that is connected with PET-CT scanning gantry drive motors; May further comprise the steps: at the output of pfc circuit local energy-storage travelling wave tube in parallel, and local energy-storage travelling wave tube is in parallel with inverter; When PET-CT scanning gantry drive motors started, pfc circuit and local energy-storage travelling wave tube discharged and are the power supply of PET-CT scanning gantry drive motors; After the normal operation of PET-CT scanning gantry, be the power supply of PET-CT scanning gantry drive motors by pfc circuit, and be local energy-storage travelling wave tube charging simultaneously.

2. weakening PET-CT according to claim 1 starts the method that electrical network is impacted, and it is characterized in that described local energy-storage travelling wave tube is super capacitor or storage battery.

3. weakening PET-CT according to claim 1 starts the method that electrical network is impacted, and it is characterized in that described AC power is the 220V AC power.

4. weakening PET-CT according to claim 1 starts the method that electrical network is impacted, and it is characterized in that, also comprises rectifier bridge and filter capacitor between the input of described pfc circuit and the AC power; The input of described rectifier bridge links to each other with AC power, and output links to each other with filter capacitor; Described filter capacitor is connected in parallel on the input of described pfc circuit.

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