PowerBI-JavaScript setAccessToken doesn't work

I'm using PowerBI-JavaScript library to embed the dashboard on my website :

var config = {
        type: 'dashboard',
        tokenType: models.TokenType.Embed,
        accessToken: accessToken,
        embedUrl: embedUrl,
        id: embedDashboardId
    };

    // Get a reference to the embedded dashboard HTML element
    var dashboardContainer = $('#dashboardContainer')[0];

    // Embed the dashboard and display it within the div container.
    var dashboard = powerbi.embed(dashboardContainer, config);

I wanna use setAccessToken to update my AccessToken keeping dashboard not expired, so I make function below :

function setToken() {
        dashboard.setAccessToken("newtoken")
            .then(function (r) {
                console.log(r);
                console.log("Update success!!")
            })
            .catch(function (e) {
                console.error('Error setting access token', e);
            });

    }

I can see "Update success!!" on console eventually. But when I use getAccessToken(), AccessToken is same as before. It didn't update my AccessToken!!

Please give me a advisement or solution to fix this problem! I would appreciate.